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Dry versus liquid feeding in two contrasting finishing systems(fully slatted versus straw based housing)
Finishing Pigs: Systems ResearchProduction Trial 1
CONTENTS
EXECUTIVE SUMMARY
INTRODUCTION
OBJECTIVES
OUTLINE OF RESEARCH METHODOLOGY
Trial design
Diets and feeding
Animals and their management
Animals
Pig identification and weighing
Management
Research measurements
KEY RESULTS
Production
Feeding and housing
Variability
Feeds
Pig health and welfare
Losses and health conditions
Health monitoring
Behaviour
Slaughter assessments
Microbial status
Feed, water and straw
Faeces, effluent and dust
Pigs
Environmental impact
Ammonia and dust
Waste
Meat quality
Fresh meat, chemical composition and sensory quality
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TABLES Page
Table 1 Pig performance and carcase quality by housing and feeding system 11
Table 2 Pig performance and carcase quality by feeding within housing system 12
Table 3 Formulation against actual use of raw feed ingredients in the production of grower and finisher
liquid diets 13
Table 4 Nutrient analysis (%) of complete liquid and dry diets 13
Table 5 Major end products of natural fermentation in liquid diets 13
Table 6 Pig losses by housing and feeding system 14
Table 7 Pig losses by feeding within housing system 14
Table 8 Veterinary treatment (pig days) by housing and feeding system 15
Table 9 Veterinary treatment (pig days) by feeding within housing system 15
Table 10 Hygiene and skin lesion scores by feeding within housing system 15
Table 11 Acute Phase Proteins in blood by feeding within housing system 16
Table 12 Percentage time spent performing general activities by feeding within housing system 16
Table 13 Percentage time spent performing manipulative behaviours by feeding within housing system 16
Table 14 Slaughter assessments by feeding within housing system 17
Table 15 Microbial status of the feed, drinking water and fresh straw 17
Table 16 Microbial status of pen faeces, slurry and dust by housing and feeding system 18
Table 17 Detection of Salmonella in faecal, effluent and dust samples by housing, week and room 18
Table 18 Microbial status of pigs at slaughter by housing and feeding system 19
Table 19 Ammonia and dust emission and dust concentration 20
Table 20 Production and composition of waste 20
Table 21 Meat quality by housing and feeding system 21
APPENDICES 22
I OTHER RESULTS 24
II DETAILED RESEARCH METHODOLOGY 31
III SYSTEMS TECHNICAL SPECIFICATIONS 48
GLOSSARY 54
REFERENCES 57
ACKNOWLEDGEMENTS 59
EXECUTIVE SUMMARY
This report is based on the results from the first of four major production trials under the Finishing Systems Research Programme.
The research is evaluating two contrasting systems of housing (fully slatted v straw based) and liquid feeding technologies for pig
performance, carcase quality, cost of production, pig health and welfare, microbial status, environmental impact and meat quality.
PRODUCTION TRIAL 1
Dry and liquid (ad libitum) feeding were evaluated within a fully slatted and a straw based housing system using a total of 1024 pigs
housed in pen groups of 32 with a mean weight of 34kg (SD 4.0kg) at entry. Numbers per pen were reduced at week 6 to 25 in the
fully slatted and 20 in the straw based system and pigs were finished to slaughter at around 104kg.
The key findings according to the main effects of feeding, housing and systems interaction between feeding and housing are presented
below.
Feeding
Production
Liquid feeding significantly improved daily gain (796 v 754 g/day). Feed intake was significantly reduced in liquid fed pigs (1.75 v 1.85
kg/day).With liquid feeding, the combined effects of an improved daily gain and reduced intake resulted in a significant improvement
in feed conversion ratio (2.27 v 2.53).
Backfat thickness (P2) was similar in liquid and dry fed pigs (11.45 v 11.39 mm) at an average dead weight of 77kg.
There were no significant differences in the variability of gain and carcases quality (P2) between liquid and dry fed pigs.
Liquid feeding reduced cost of production by 4.6p/kg dead weight.
Pig health and welfare
Overall mortality was low (1.2% in liquid and 0.6% in dry fed pigs).The number of pigs failing to complete the study for health reasons
did not differ significantly between feeding systems (4.8% in liquid and 6.2% in dry fed pigs), but significantly more pigs were removed
from the dry fed groups for respiratory conditions.Veterinary treatment for health was higher in liquid fed pigs (352 v 223 pig days),
with respiratory conditions and lameness being the major reasons for treatment. This included a greater level of management
intervention to curtail biting requiring increased use of BITEX for tail spraying and antibiotic treatment for tail injury in liquid fed
pigs.
Liquid fed pigs had a significantly lower hygiene score (i.e. were dirtier) than dry fed pigs (71% v 82% clean skin). Liquid feeding gave
rise to significant behavioural differences: liquid fed pigs were less active (59% v 52% of time spent ‘sleeping’) and spent less time
performing investigatory behaviours, particularly towards other pigs (7.5% v 9.4%) and pen parts (6.3% v 9.1%).
Post-slaughter assessment of foot damage showed no overall difference between liquid and dry fed pigs. Liquid fed pigs had
significantly less gastric ulceration than dry fed pigs (1.3 v 3.0 on a 0-5 severity scale).There were no significant differences in the
lung scores of liquid and dry fed pigs (1.5 v 1.2 on a 0-55 severity scale).
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Microbial status
Fermentation became established in the liquid feed by the presence of naturally occurring microbes as indicated by the significant
increase in viable aerobic and anaerobic, lactic acid bacteria and yeast counts. End product analysis indicated a lactic acid bacteria
dominated fermentation (1.3% lactic acid, 0.2% acetic acid and 0.3% ethanol).
Conversely, liquid feeding significantly decreased the microbial loading of the gut as shown by reductions in viable aerobic and
anaerobic, lactic acid bacteria, coliform and yeast counts at slaughter.
The lactic acid bacteria to coliform ratio in the gut and faeces was favourably and significantly increased by liquid feeding (1.48 v
1.31).
Salmonella could not be detected in samples of compounded dry diets, individual ingredients used in the production of liquid diets,
the final liquid feed mixtures or fresh straw. Pigs were the mostly likely route for Salmonella entry as around 8% tested positive
(ELISA) and one pig tested positive for caecal presence at entry.
Liquid feeding significantly reduced the percentage of pigs which tested positive for Salmonella at slaughter (ELISA 16 v 35%;
Caecal presence 23 v 39%).
Environmental impact
There were no significant effects of dry or liquid feeding on dust and ammonia emissions or waste composition.
Liquid feeding significantly increased effluent production (7.31 v 5.20 litres per pig/day).
Meat quality
There were no differences of commercial importance in fresh and sensory meat quality of liquid and dry fed pigs.
Housing
Conclusive differences between the effects of housing systems will be established following the completion of the four production
studies. Interim key results from the first study are summarised below, but these should be treated with caution.
Production
There were no consistent effects of housing on growth performance and carcase quality.
The cost of production was 4.3p/kg dead weight higher in the straw based system.
Pig health and welfare
Number of pigs removed for health conditions was higher from the fully slatted system (34 v 13), with lameness and tail injury
being the major reasons for removal.
Tail biting was also found in the straw based system with one pig removed for tail injury compared with 14 from the fully slatted
system.
Veterinary treatment for health was higher in the straw based system (359 v 216 pig days), with respiratory conditions being the
major reasons for treatment. Pigs housed in the fully slatted system required a greater level of management intervention to curtail
biting, with increased use of BITEX for tail spraying. Antibiotic treatment for tail injury was also higher in the fully slatted system.
Pigs in the fully slatted system had a significantly better hygiene score (85% v 68% clean skin).
Pigs in the straw based system were significantly more active than those in the fully slatted system, spending less time lying down
(67% v 74%) and less time ‘sleeping’ (51% v 61%).
Pigs in the straw based system spent a significant amount of their time investigating and manipulating straw (14.2%), whereas pigs
in the slatted system spent only 1.3% of their time investigating and manipulating the hanging ‘toy’ that was provided for them. Pigs
in the straw based system spent less time investigating pen components (6.7% v 8.8%), although a similar amount of time was
spent investigating other pigs in both systems (8.4% v 8.3%).
Post-slaughter assessment of the feet found no overall difference in the amount of damage; however there were significant
differences in the type of damage (on a 0-3 scale of severity). Pigs in the straw based system had significantly higher scores for
white line lesions (1.2 v 0.9) and toe erosions (1.2 v 0.5). Pigs in fully slatted system had more severe heel erosions (1.2 v 0.3).
Gastric ulceration (on a 0-5 scale of severity) was higher in pigs from the fully slatted system (2.5 v 1.9). There were no
significant effects of housing system on rind-side damage or lung score.
Microbial status
No major differences were found between the housing systems, with the exception of a significant increase in the microbial
loading (total aerobic viable and coliform counts) of dust sampled from the straw based system.
A higher percentage of pigs from the straw based system tested positive for Salmonella at slaughter (ELISA and caecal presence)
but the difference was not statistically significant.
Environmental impact
No major differences were found between the housing systems.
Meat quality
No significant differences were found between the housing systems.
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Feeding and housing interactions
Production
Growth and feed conversion benefits from liquid feeding were significantly higher in the straw based system during the finishing
stage.
Liquid feeding reduced cost of production by 1.6p/kg dead weight in the fully slatted system and 7.6p/kg dead weight in the straw
based system.
Pig health and welfare
The number of pigs removed for health conditions was higher with liquid feeding in the fully slatted system and with dry feeding in
the straw based system.
Whilst liquid feeding increased veterinary treatment for health conditions in both housing systems, the pattern of health
conditions requiring treatment differed according to feeding and housing system. Liquid feeding with fully slatted housing
increased veterinary treatment for lameness and tail biting/injury, whereas liquid feeding with straw based housing increased
treatment for respiratory and enteric conditions.
Liquid feeding reduced the hygiene score of the pigs in straw based housing to a much greater extent than in slatted housing.
However, there were no significant interactions between feeding and housing systems in respect of behavioural measures or post
mortem health assessments.
Microbial status
There were no consistent or major interactions between feeding and housing systems.
Environmental impact
There were no significant feeding and housing interactions.
Meat quality
Sensory evaluations showed that cooked lean samples from liquid fed pigs housed in the straw based system had significantly
increased boar flavour scores, though this increase is unlikely to be of importance at the consumer level.There were no other
consistent or significant feeding and housing interactions.
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INTRODUCTION
The Finishing Systems Research Programme addresses Industry strategic and Government policy requirements covering several
priorities through a multidisciplinary approach.
Research activity is centred at MLC’s Stotfold Pig Development Unit using the purpose built Finishing Systems Research Unit.This
consists of a Feed Centre, which manufactures, processes and delivers liquid feed to growing/finishing pigs in two contrasting
systems of production, fully slatted v straw based housing.
The two housing systems will be evaluated over four production trials, with each trial designed to investigate liquid feeding
technology.
This report is based on the results of the first production trial, which compared dry and liquid feeding and provides the detailed
background information to the reporting of the subsequent trials.
OBJECTIVES
The objective of the research programme is to investigate the effect of housing and feeding and the interaction between housing
and feeding on:
Pig performance and cost of production
Pig health and welfare
Microbial status
Environmental impact
Meat quality
OUTLINE OF RESEARCH METHODOLOGY
Trial design
Dry and liquid feeding were evaluated in two contrasting systems of housing (straw- based v fully slatted) using growing and
finishing pigs from 34kg to slaughter at 104kg live weight.
Each house consisted of four rooms, with four pens within each room. Dry and liquid feeding treatments were replicated within
housing system and between rooms according to the following pattern.
Figure 1 Allocation of feeding treatments (dry v liquid) according to housing system and rooma
a Allocation of feeding treatment by room was necessary for the determination of the effects of feeding treatment (liquid v dry) on environmental
impact (see pages 20, 40, 41 and 47 for detail).
Room 1 2 3 4
Straw based Liquid Dry Liquid Dry
Room 1 2 3 4
Fully slatted Dry Liquid Dry Liquid
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Diets and feeding
The dry and liquid diets were formulated to the same nutrient specification using similar ingredients (see page 32 for
formulations). In Trial 1, no liquid co-products were used in the production of liquid diets.
There were two diets for both dry and liquid fed pigs, a grower diet fed from entry to about 60 kg (14.7 MJ DE/kg, 1.2% total
lysine) and a finisher diet from 60 kg to slaughter (14.2 MJ DE/kg, 0.9% total lysine).
The dry diets were manufactured commercially in 3mm pellets.The liquid diets were produced on site by milling cereals and
mixing individual ingredients using the liquid feeding system.
The dry diets were offered in ad libitum hoppers. Liquid feeding was computer controlled by feed demand at the troughs using
sensors, which signalled for refill on empty.Troughs were refilled with 15kg drops. Liquid feed was available ad libitum except
during the period between 24:00 and 01:00 hours when the system was automatically paused, allowing pigs to clear troughs of any
accumulated residues.
Animals and their management
Animals
A total of 1024 (Large White x Landrace) x Large White pigs weighing between 30 to 40kg were received in 8 equal batches of
132 over 11 weeks and transferred to the housing according to the following pattern.
Figure 2 Batch entry order during stocking according to housing system and room
Pig identification and weighing
Two pigs were randomly identified for slaughter for the baseline assessment of health and gut microbial status and two surplus
pigs were randomly selected and removed to alternative accommodation.The remaining 128 pigs were ear tagged for individual
identification and sorted by weight from lightest to heaviest.The batch was divided into 4 equal groups of 32 pigs in order of
weight: Light Light (LL), Light Medium (LM), Medium Heavy (MH) and Heavy Heavy (HH). Each group was randomly allocated to
one of four pens in the room.
On week 6 pigs were weighed and numbers were reduced from 32 to 25 and 20 pigs per pen in the fully slatted and straw based
systems respectively. Pigs removed were pre-selected to represent the range (minimum and maximum) and average weight in the
pen so that the overall distribution of individual weights was not skewed by random selection.
Pigs were weighed 9 days prior to slaughter and those weighing more than 95 kg were selected for slaughter so that the target
weight at slaughter could be close to 105kg. Pigs were re-weighed the day before slaughter.
Room 1 2 3 4
Straw based Batch 7 Batch 5 Batch 3 Batch 1
Room 1 2 3 4
Fully slatted Batch 8 Batch 6 Batch 4 Batch 2
Management
The management and care of the pigs is detailed in Appendix II and in brief covered the following elements:
Biosecurity to minimise the cross transfer of micro-organisms potentially associated with a particular feeding and housing system.
Management of the environmental control system to achieve target temperature and ventilation rates. Provision of toys for the
environmental enrichment of pigs in the fully slatted housing. Daily inspection to safeguard health and welfare, and under
Veterinary supervision to take appropriate action in the care and treatment of pigs with health conditions. Daily removal of soiled
bedding and provision of fresh straw in the straw based building. Daily inspection of drinkers and feeders to ensure correct
operation and absence of faecal contamination. Maintaining a high level of hygiene and tidiness in the feed centre and service areas.
Research measurements
To establish the potential effects of feeding (dry v liquid) and housing (straw based v fully slatted) on pig performance, pig health
and welfare, microbial ecology, environmental impact and meat quality the following measurements and records were taken.
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Pig production Pig weights, feed intake (automatically for liquid, manually for dry), nutrient analysis of feed
ingredients and complete diets, mortality and other losses, slaughter weight, commercial carcase
classification measurements (weight and P2), labour use (pig husbandry and cleaning), medicine
use, power consumption (liquid feed production and delivery, housing heating, lighting and
ventilation and cleaning), water use (liquid feed, drinking and cleaning), straw use, effluent and
manure production and cost of production.
Pig health and
behaviour
All pigs: any individual health or welfare condition, pen faecal consistency, veterinary treatments,
reasons for death (post mortem) or pigs removed from study.
Focal pigs (6 per pen): skin lesions and cleanliness, hock bursitis, behavioural time budgets, feeding
behaviour.At slaughter: skin damage, foot lesions, osteochondrosis, heart and lung scores, gastric
ulceration. Blood samples at entry, mid-point and slaughter evaluated for acute phase proteins,
generalised immunity and PRRS virus.
Microbial status Salmonella:All pigs at entry and slaughter blood sampled for ELISA test, plus all pigs at slaughter
tested for the presence of Salmonella in caecal samples. Individual feed ingredients, complete
diets, straw, dust, pen faeces and effluent routinely tested for the presence of Salmonella.Where
appropriate, microbial evaluations of systems samples also included total aerobic and anaerobic
viable counts, lactic acid bacteria, enterobacteraciae, coliform and yeast counts and Lawsonia and
Brachyspira.
Environmental impact In the straw and fully slatted housing by room: ammonia and dust concentrations and emissions.
Effluent and farm yard manure production and composition.
Meat quality Fat firmness, subcutaneous fat skatole and indole contents, and fatty acid profile, drip loss, muscle
colour, simulated retail display, oxidative rancidity (TBARS) and sensory evaluation of cooked
loins.
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KEY RESULTS
Production
Feeding and housing
Pig performance and carcase quality according to housing and feeding system are given in Table 1. Pig performance and carcase
quality according to feeding system (dry v liquid) within housing system are given in Table 2.
Table 1 Pig performance and carcase quality by housing and feeding system
Housing System Feeding System s.e.d.b Pa
Fully Straw Liquid Dry H F I
slatted based
Live weight (kg)
Entry 35.62 32.75 34.14 34.23 1.286 *
Mid 67.00 61.78 65.50 63.28 1.982 **
Final 102.60 103.20 103.00 102.90 0.753 **
Feed intake (kg/pig day)
Grower 1.51 1.39 1.44 1.47 0.040 ** **
Finisher 2.21 2.39 2.22 2.39 0.053 ** **
Overall 1.82 1.78 1.75 1.85 0.021 * *** *
Growth (g/day)
Grower 707 666 717 656 17.2 * ***
Finisher 832 852 853 831 16.0 **
Overall 781 768 796 754 9.6 *** **
Feed conversion ratio
Grower 2.15 2.10 2.00 2.24 0.062 *** *
Finisher 2.67 2.83 2.60 2.89 0.075 0.06 *** **
Overall 2.39 2.41 2.27 2.53 0.027 ***
Carcase quality
Slaughter weight (kg) 103.6 103.7 103.6 103.7 0.54 *
Carcase weight (kg) 77.09 76.89 76.60 77.38 0.415 0.07 *
Killing out % 74.40 74.18 73.96 74.62 0.207 **
Backfat P2 (mm) 11.75 11.08 11.45 11.39 0.304 *
Number (n) of observations per mean = 16.a In this and subsequent tables, significant probability (P) values for housing system (H), feeding system (F) and interaction (I) between housing
and feeding system are given as *, ** or *** for P values <0.05, <0.01 and <0.001 respectively. P values >0.05 and <0.1 are presented
numerically and P>0.1 are left blank.A P value of <0.05 (5% level) is taken as a statistically significant effect.b s.e.d. is the standard error of difference.
Table 2 Pig performance and carcase quality by feeding within housing system
Fully slatted Straw based s.e.d. P
Liquid Dry Liquid Dry H F I
Live weight (kg)
Entry 36.26 34.98 32.02 33.48 1.819 *
Mid 69.38 64.63 61.62 61.93 2.803 **
Final 101.60 103.60 104.30 102.20 1.065 **
Feed intake (kg/pig day)
Grower 1.44 1.59 1.44 1.35 0.057 ** **
Finisher 2.16 2.26 2.27 2.52 0.075 ** **
Overall 1.75 1.90 1.75 1.80 0.029 * *** *
Growth (g/day)
Grower 733 682 702 629 24.4 * ***
Finisher 815 849 891 813 22.6 **
Overall 785 777 807 730 13.6 *** **
Feed conversion ratio
Grower 1.96 2.33 2.05 2.15 0.088 *** *
Finisher 2.66 2.68 2.54 3.10 0.106 0.06 *** **
Overall 2.27 2.50 2.26 2.57 0.038 ***
Carcase quality
Slaughter weight (kg) 102.9 104.3 104.3 103.1 0.76 *
Carcase weight (kg) 76.18 78.00 77.01 76.76 0.587 0.07 *
Killing out % 74.04 74.77 73.89 74.48 0.293 **
Backfat P2 (mm) 11.70 11.81 11.19 10.97 0.430 *
Number of observations per mean = 8
Variability
There were no significant differences in the variability for intake, growth and carcase fatness according to feeding and housing
system.
Feeding and housing could influence the variability in the growth rate and carcase fatness of individual pigs. For example ad libitum
liquid feeding may generate greater competition for feed during automatic delivery and in turn this may result in a greater spread
of growth rate and subsequent fatness of pigs at slaughter.This was investigated by subjecting the within pen standard deviation (a
measure of variability) for daily gain and carcase P2 to statistical analysis. No significant effects of feeding or housing system were
found (see Appendix I Table 7).
Feeds
The target formulation against actual use of raw feed ingredients in the production of grower and finisher liquid diets are given in
Table 3.The results from the laboratory analysis of samples of complete liquid and dry diets are given in Table 4.
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Table 3 Formulation against actual use of raw feed ingredients in the production of grower and finisher
liquid diets
Grower diet Finisher diet
Formulation Actual Formulation Actual
Ingredient (%)
Wheat 41.30 40.78 38.62 36.93
Barley 13.77 12.09 12.87 11.01
Wheatfeed 10.00 10.02 20.00 20.36
Soya bean meal (HP) 18.37 19.50 10.05 13.52
Rapeseed meal 5.00 5.19 10.00 9.84
Fish meal 2.50 3.79 --- ---
Soya oil 5.96 5.65 5.36 5.29
Minerals and vitamins 3.10 3.00 3.10 3.05
Formulations adjusted according to sample analysis of newly delivered batches of major individual feed ingredients
(see Appendix II Table 1).
Table 4 Nutrient analysis (%) of complete liquid and dry diets
Liquid dietsa Dry diets
Grower (n=11) Finisher (n=16) Grower (n=8) Finisher (n=9)
Mean SDd Mean SD Mean SD Mean SD
Dry matterb 14.7 3.25 16.2 2.93 88.6 0.33 88.7 0.31
Crude protein 19.0 3.25 19.6 4.21 17.3 0.46 15.0 0.77
Oil (B) 10.0 1.50 8.8 1.19 7.0 0.38 6.2 0.56
NDAF 14.1 4.68 17.5 4.34 11.6 0.45 14.2 0.59
Ash 6.5 0.72 5.8 0.87 5.3 0.42 5.1 0.44
Total lysine 1.05 0.23 0.88 0.16 0.98 0.15 0.75 0.12
Calcium 0.70 0.106 0.61 0.077 - - - -
Phosphorus 0.69 0.058 0.65 0.079 - - - -
Copper (mg/kg) 180 26.2 112 27.5 - - - -
DE (MJ/kg)c 14.1 0.55 13.8 0.53 14.6 0.23 14.0 0.29a In liquid diets the nutrients were adjusted to a meal equivalent of 87% dry matter.b The target dry matter content of liquid diets was 20%, which was achieved according to the weight of ingredients and water used and recorded
automatically by the liquid feeding system. However, a representative sample of the final diet was difficult to obtain due to the rapid settling of
the particulate fraction when the stirrers were switched off for sampling.c Estimated by regression MAFF (1993).d Standard deviation.
Additional samples of liquid diets were taken on site and tested for dry matter content and pH.The dry matter content (see
note b under Table 4) and pH of the grower and finisher diets were very similar and averaged 17.7% (SD 1.87) and 4.9 (SD 0.21)
respectively.
Major end products of natural fermentation found in the liquid diets are given in Table 5.
Table 5 Major end products of natural fermentation in liquid diets
Mean (n = 6) SD
mg/kg mmol/litre % mg/kg mmol/litre %
Ethanol 3175 64 0.3 822 16 0.08
Lactic acid 13272 147 1.3 1485 17 0.15
Acetic acid 2328 38 0.2 660 11 0.07
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Pig health and welfare
Losses and health conditions
Pig losses through deaths and health conditions by housing and feeding system are given in Table 6. The results are presented by
feeding system within each housing system in Table 7.Veterinary treatment for health conditions by housing and feeding system are
given in Table 8. The results are presented by feeding system within each housing system in Table 9.
Table 6 Pig losses by housing and feeding system
Housing system Feeding system
Fully slatted Straw based Liquid Dry
Losses (number)
Deaths
Grower 3 (0.59)a 6 (1.17) 6 (1.17) 3 (0.59)
Finisher 0 0 0 0
Removed
Grower 21 11 11 21
Finisher 13 2 9 6
Total 37 19 26 30
Health condition (number)
Respiratory 4 5 1 8
Enteric 1 2 1 2
Lameness/physical damage 11 3 10 4
Tail injury 14 1 6 9
Multipleb 1 3 2 2
Otherc 6 5 6 5
Total 37 19 26 30a Value in parenthesis is % mortality.b Individual pigs with multiple conditions (e.g. respiratory, enteric, post-weaning multi-systemic wasting syndrome or PMWS).c Includes prolapsed, abscess, sudden death, poor body condition and meningitis.
Table 7 Pig losses by feeding within housing system
Fully Slatted Straw Based
Liquid Dry Liquid Dry
Losses (number)
Deaths
Grower 2 (0.78) 1 (0.39) 4 (1.56) 2 (0.78)
Finisher 0 0 0 0
Removed
Grower 10 11 1 10
Finisher 9 4 0 2
Total 21 16 5 14
Health condition (number)
Respiratory 1 3 0 5
Enteric 1 0 0 2
Lameness/physical damage 9 2 1 2
Tail injury 6 8 0 1
Multiple 0 1 2 1
Other 4 2 2 3
Total 21 16 5 14
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Table 8 Veterinary treatment (pig days)a by housing and feeding system
Housing system Feeding system
Fully slatted Straw based Liquid Dry
Health condition
Respiratory 26 250 150 126
Enteric 0 49 40 9
Lameness/physical damage 71 45 78 38
Tail bitingb 83 1 50 34
Tail injuryc 28 0 23 5
Multiple 0 0 0 0
Other 8 14 11 11
Total 216 359 352 223a Each day a pig was treated for a given health condition, including consecutive and repeated treatments on the same pig.b In pens where an outbreak of tail biting was observed tails were sprayed with BITEX (topical application containing a bitter compound, 1%
bitrex) as a management intervention to curtail biting.c Pigs with tail injury due to biting and at risk of infection or with signs of infection were treated with veterinary prescribed antibiotics.
Table 9 Veterinary treatment (pig days) by feeding within housing system
Fully Slatted Straw Based
Liquid Dry Liquid Dry
Health condition
Respiratory 5 21 145 105
Enteric 0 0 40 9
Lameness/physical damage 59 12 19 26
Tail biting 50 33 0 1
Tail injury 23 5 0 0
Multiple 0 0 0 0
Other 3 5 8 6
Total 140 76 212 147
Health monitoring
Weekly skin lesion and hygiene scores according to feeding within housing system are given in Table 10. Results from analysis of
blood samples for Acute Phase Proteins at different stages in the trial are shown in Table 11.
Table 10 Hygiene and skin lesion scores by feeding within housing system
Fully slatted Straw based P
Liquid Dry Liquid Dry H F I
Lesions/pig 14 11 13 16
Hygiene score (% clean) 82 87 60 76 *** *** **
Bursitis (0-5) 1.1 1.0 1.0 1.1
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Table 11 Acute Phase Proteins in blood by feeding within housing system
Fully slatted Straw based P
Liquid Dry Liquid Dry H F I
At entry
C-Reactive protein 129 148 137 129
Haptoglobin 0.73 0.75 0.62 0.56
At mid-point
C-Reactive protein 174 147 74 170
Haptoglobin 1.64 1.23 0.81 1.09 ** *
At slaughter
C-Reactive protein 80 113 91 93
Haptoglobin 0.67 0.71 0.39 0.48 **
Behaviour
Percentage time spent performing general activities by feeding within housing system is given in Table 12. Percentage time spent
performing manipulative behaviours by feeding within housing system is given in Table 13.
Table 12 Percentage time spent performing general activities by feeding within housing system
Fully slatted Straw based P
Liquid Dry Liquid Dry H F I
% Time
Lying 78 69 69 65 ** **
‘Sleeping’ 65 56 52 49 *** **
Eating 3.9 4.4 4.6 5.0
Drinking 0.4 1.2 0.7 1.2 ***
Table 13 Percentage time spent performing manipulative behaviours by feeding within housing system
Fully slatted Straw based P
Liquid Dry Liquid Dry H F I
% Time
Straw - - 14.0 14.3 ***
Toy 1.1 1.5 - - *** **
Other pig 7.0 10.0 7.9 8.8 **
Pen parts 6.9 10.6 5.7 7.6 * ***
Slaughter assessments
A summary of all slaughter assessments by feeding within housing system is given in Table 14.
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Table 14 Slaughter assessments by feeding within housing system
Fully slatted Straw based P
Liquid Dry Liquid Dry H F I
Foot lesions ( 0-3 scale)
White line lesion 0.8 1.0 1.1 1.2 *
Toe erosion 0.5 0.4 1.2 1.1 ***
Sole erosion 0.7 0.9 0.7 0.8
Heel erosion 1.0 1.3 0.3 0.2 ***
Osteochondrosis (04 scale)
Front score 2.5 2.4 2.5 2.7
Rear score 2.0 2.0 2.0 1.9
Gastric ulceration (0-5 scale) 1.7 3.2 0.9 2.8 ** ***
Rind-side damage (0-5 scale) 2.2 2.3 2.3 2.2
Lung score (0-55 scale) 1.5 1.0 1.5 1.3
Microbial status
Feed, water and straw
All microbial analysis results, unless otherwise indicated, are presented as Log10 colony forming units (cfu) per gram or per ml as
appropriate.The microbial status of the compounded complete dry diets and individual feed ingredients used in the production of
the resulting liquid diets, and water and straw samples is given in Table 15.
Table 15 Microbial status of the feed, drinking water and fresh straw
n
Liquid feed ingredients
Wheat 1 ND 5.06 4.39 2.61 3.80 4.13
Barley 1 ND 6.64 6.34 4.53 6.27 2.74
Wheatfeed 2 ND 5.78 5.12 4.02 3.09 2.76
Soya bean meal (HP) 1 ND 4.38 3.31 3.70 2.47 3.16
Rapeseed meal 2 ND 6.23 5.91 5.13 3.33 4.76
Fish meal 1 ND 3.48 4.76 ND ND ND
Minerals and vitamins (Grower) 1 ND 1.48 2.60 ND ND ND
Minerals and vitamins (Finisher) 2 ND 3.36 2.95 1.18 ND ND
Complete liquid diets
Grower 12 ND 8.72b 8.63b 9.15b 2.19 6.80b
Finisher 12 ND 8.95b 8.83b 9.25b 2.41 7.17b
Complete dry diets
Grower 14 ND 5.13a 4.47a 3.17a 1.98 2.66a
Finisher 14 ND 4.78a 4.04a 3.12a 2.16 3.52a
Drinking water ND
Fresh straw ND
ND = not detecteda, b Mean bearing the same superscript letter within the same column are not statistically significant (P>0.05).
Faeces, effluent and dust
The microbial status of faecal, effluent and dust samples according to housing and feeding system is given in Table 16.The detection
of Salmonella in faecal, effluent and dust samples is presented by housing system, room, batch, pen and date in Table 17.
Sal
mo
nella
Tota
l Aer
obi
cV
iabl
e C
oun
t
Tota
l Ana
ero
bic
Via
ble
Co
unt
Lac
tic
acid
bact
eria
Co
unt
Ent
ero
bact
erac
iae
Co
unt
Co
lifo
rm C
oun
t
Yeas
t C
oun
t
18
Table 16 Microbial status of pen faeces, slurry and dust by housing and feeding system
Housing system Feeding system s.e.d. P
n Fully Straw Liquid Dry H F I
slatted based
Total Aerobic Viable Count
Faeces 12 8.73 8.66 8.65 8.74 0.139
Dust 38 6.91 7.92 7.41 7.44 0.137 ***
Total Anaerobic Viable Count
Faeces 12 8.95 8.98 8.87 9.06 0.118
Lactic Acid Bacteria (LAB) Count
Faeces 12 8.35 8.46 8.25 8.56 0.111 **
Coliform Count
Faeces 12 6.73 6.59 6.31 7.01 0.197 **
Dust 38 2.11 3.30 2.72 2.71 0.187 *** *
LAB : Coliform Ratio
Faeces 12 1.25 1.29 1.32 1.22 0.037 *
Enterobacteraciae Count
Effluent 12 5.48 5.47 5.51 0.292 - -
Table 17 Detection of Salmonella in faecal, effluent and dust samples by housing, week and room
Faeces Effluent Dust
Housing system Week of Room Pen number Room Log10 Room Log10
study tested positive cfu/ml cfu/g
Fully slatted 6 3 21, 23 3 35 3 2
9 3 4
11 3 23 3 14
12 3 5
13 3,1 5, 160 2 2
15 3 23 3,2,1 160,22,35
16 2 4
18 1 4 1 4
Straw based 10 1 3,4 3 <2
12 2 5,7
14 1,3 1,3,9,10,11,12 1,2 2,<2
16 2 8
Pigs
The microbial status of the pigs at entry, according to housing and feeding systems allocation, is given in Appendix I Table 8.With
the exception of Salmonella ELISA showing a significantly higher percentage positive for pigs entering the fully slatted compared
with the straw based system (10% v 5%, P<0.01), overall the microbial status was broadly similar according to systems allocation.
This shows that there was no initial treatment bias for the microbial status of pigs at the start of the trial.The presence of
Brachyspira and Lawsonia in the caecal contents of pigs slaughtered at entry are given in Appendix I,Table 9.The microbial status
of pigs at slaughter is given in Table 18.
19
Table 18 Microbial status of pigs at slaughter by housing and feeding system
Housing system Feeding system s.e.d. P
n Fully Straw Liquid Dry H F I
slatted based
Salmonella 16
Caecal %positive 28 34 23 39 7.5 *
ELISA %positive 22 29 16 35 7.3 *
Total Aerobic Viable Count
96
Ileal 8.29 8.32 8.04 8.58 0.283 **
Caecal 8.12 8.21 7.78 8.56 0.217 **
Colon 8.52 8.51 8.09 8.94 0.230 **
Total Anaerobic Viable Count
96
Ileal 8.57 8.65 8.38 8.84 0.266 ***
Caecal 8.97 9.14 8.81 9.30 0.250 **
Colon 9.12 9.24 8.89 9.48 0.213 **
Lactic Acid Bacteria (LAB) Count
96
Ileal 8.07 8.20 7.94 8.33 0.284 **
Caecal 8.19 8.30 7.85 8.65 0.243 ** *
Colon 8.74 8.81 8.39 9.16 0.224 **
Coliform Count 96
Ileal 8.07 7.80 7.55 8.33 0.409 **
Caecal 6.31 6.54 5.84 7.02 0.304 **
Colon 6.44 6.44 5.79 7.10 0.275 **
LAB : Coliform Ratio 96
Ileal 1.01 1.06 1.07 1.01 0.027 0.064 *
Caecal 1.32 1.31 1.37 1.26 0.029 **
Colon 1.38 1.41 1.48 1.31 0.033 **
Yeast Count 96
Ileal 5.06 4.85 4.56 5.36 0.318 **
Caecal 4.32 4.03 4.03 4.32 0.314 0.074 0.07 ***
Colon 4.04 3.83 3.91 3.97 0.252 0.094 0.09
20
Environmental impact
Ammonia and dust
Ammonia and dust emission and dust concentration according to housing and feeding system are presented in Table 19.
Table 19 Ammonia and dust emission and dust concentration
Fully slatted Straw based
Liquid Dry Liquid Dry
Ammonia
Emission (g NH3-N per lu hour) 1.90 1.64 2.02 1.94
Dust
Concentration (mg per m3) 1.83 3.17 1.81 2.02
Emission (g per lu hour) 0.85 1.80 1.09 1.21
There were no significant differences between different housing and feeding systems (n=4).
Waste
The volume of effluent and weight of farm yard manure generated and composition is presented in Table 20. Liquid compared with
dry feeding significantly (P<0.001; s.e.d. 0.367) increased the volume of effluent produced in the fully slatted system.
Table 20 Production and compositiona of waste
Fully slatted Straw based
Liquid Dry Liquid Dry
Production (pig/day)
Effluent (litres) 7.31 5.20 - -
Farm Yard Manure (kg) - - 3.40
Compositiona (n=7)
Dry matter (%) 6.90 6.45 17.2
Ammoniacal nitrogen
(mg NH4-N/kg) 3105 3033 2385
Kjeldahl nitrogen (mg N/kg) 4355 4076 5561
Total phosphorous (mg/kg) 837 1238 1551a Composition results highly influenced by sampling error and not statistically significant.
Meat quality
Fresh meat, chemical composition and sensory quality
The results from the evaluation of fresh meat samples for quality and chemical composition and sensory panel scoring of cooked
samples are presented in Table 21.There were no consistent significant interactions between feeding and housing system.
The subcutaneous fat characteristics and sample fatty acid profiles by housing and feed system are presented in Appendix I Table 10.
21
Table 21 Meat quality by housing and feeding system
Housing system Feeding system s.e.d. P
n Fully Straw Liquid Dry H F I
slatted based
Fresh 64
Drip loss (%) 6.75 5.36 5.79 6.31 0.932
Colour Saturation
Day 3 7.43 7.16 7.65 6.94 0.179 ***
Retail cutting 7.28 7.05 7.50 6.83 0.219 **
Display day 1 9.00 8.37 8.90 8.46 0.217 ** *
Display day 2 8.69 8.30 8.69 8.29 0.192 * *
Display day 3 8.56 7.96 8.46 8.07 0.213 **
TBARS 20
Display day 1 0.024 0.030 0.030 0.024 0.003
Display day 3 0.069 0.083 0.085 0.067 0.008 *
Taints (ppm) 20
Indole 0.030 0.032 0.034 0.028 0.006
Skatole 0.044 0.062 0.056 0.049 0.015
Cooking loss (%) 23.17 22.66 22.93 22.89 0.664
Eating 64
Lean
Juiciness 14.58 14.94 15.01 14.51 0.446
Tenderness 15.50 16.03 15.76 15.77 0.449
Pork flavour 13.12 13.36 13.34 13.14 0.378
Abnormal flavour 3.03 2.89 2.73 3.19 0.321
Boar flavoura 1.88 1.98 2.10 1.76 0.173 0.051 **
Overall Acceptability 13.43 13.77 13.63 13.57 0.442
Fat
Pork flavour 11.63 11.74 11.98 11.39 0.397
Abnormal flavour 1.88 2.04 1.93 2.00 0.206
Boar flavour 1.41 1.45 1.46 1.40 0.105
Pork odour 10.12 10.21 10.22 10.11 0.401
Abnormal odour 2.95 2.93 2.81 3.07 0.309
Androstenone odour 1.60 1.72 1.64 1.68 0.173
Skatole odour 1.45 1.35 1.42 1.38 0.124a The H x F significant interaction (P<0.01) for boar flavour in the lean was due to a higher mean score (2.40) given to samples from pigs housed
in the straw based system fed liquid feed.
22
APPENDICES Page
APPENDIX I OTHER RESULTS 24
Tables
Table 1 Inputs and waste production 24
Table 2 Input costs 25
Table 3 Cost of production (p/kg dead weight) by housing and feeding system 26
Table 4 Cost of production (p/kg dead weight) by feeding within housing system 26
Table 5 Sensitivity analysis for cost of production (p/kg dead weight) by feeding within housing system 27
Table 6 Nutrient analysis of liquid feed ingredients 28
Table 7 Variability (SD) in gain and carcase quality by housing and feeding system 28
Table 8 Microbial status of pigs at entry by housing and feeding system 29
Table 9 Brachyspira and Lawsonia presence in caecal contents at entry 30
Table 10 Subcutaneous fat characteristics and fatty acid profile of the lean 30
APPENDIX II DETAILED RESEARCH METHODOLOGY 31
Pig production 31
Housing 31
Feed centre 31
Feeding 32
Feed sampling and laboratory analysis 33
Animals 34
Pig identification and weighing 35
Management 35
Straw and water use and power consumption 36
Waste production 36
Pig health and welfare 36
Blood sampling 37
Health monitoring 37
Skin lesions and cleanliness 37
Behavioural recording 37
Slaughter assessments 38
Microbial status 38
Sampling 38
Microbial evaluations 39
Environmental impact 40
Ventilation rate 41
Ammonia 41
Dust 41
Waste 41
Meat quality 42
Carcase measurements and sampling 42
Chemical analysis 44
Simulated retail display 44
Sensory evaluation 44
23
Page
Data processing 46
Production 46
Pig health and welfare 46
Microbial status 46
Meat quality 46
Statistical analysis 47
Production 47
Pig health and welfare 47
Microbial status 47
Environmental impact 47
Meat quality 47
Tables
Table 1 Meal equivalent formulations and nutrient specifications of diets 32
Table 2 Feed and feed ingredients sampled and their laboratory analysis 34
Table 3 Blood sampling and analysis for health and Salmonella status 37
Table 4 Summary of microbial evaluations of samples 39
Table 5 Media and conditions for microbial counts performed on samples 40
Table 6 Summary of environmental monitoring 40
Table 7 Selection of focal pigs for carcase and meat quality evaluations 43
Table 8 Sensory evaluation of cooked loin chops 45
APPENDIX III SYSTEMS TECHNICAL SPECIFICATIONS 48
Finishing system 48
Buildings 48
Ventilation system 48
Liquid feeding trough 51
Feed centre 52
Tables
Table 1 Settings for the environmental control system in the finishing buildings 48
24
APPENDIX I OTHER RESULTSTable 1 Inputs and waste production
Fully slatted Straw basedLiquid Dry Liquid Dry
Feed (kg)Grower (Per pig) 64.9 69.1 60.7 61.2Finisher (Per pig) 85.7 104.4 108.4 124.8
Labour (minutes)Husbandry
Per pig day 0.14 0.14 0.40 0.40Per pig 11.8 12.6 36.0 37.8
CleaningPer pig day 0.06 0.06 0.05 0.05
Per pig 5.3 5.3 4.6 4.7Medicines
Per pig day (p) 0.34 0.12 0.89 0.63Per pig (p) 28.60 10.44 80.05 59.60
Power consumption (kWh)Buildings
Per pig day 0.49 0.49 0.37 0.37Per pig 40.79 43.28 33.01 34.70
Liquid feed production and deliveryPer pig day 1.15 - 1.15 -
Per pig 95.89 - 103.19 -Power washing
Per pig day 0.09 0.09 0.04 0.04Per pig 7.60 7.64 4.02 4.09
Water used (litres)a
Drinking and liquid feedPer pig day 7.69 5.91 6.72 4.46
Per pig 640.46 522.20 602.20 419.85Cleaning
Per pig day 1.28 1.21 0.63 0.61Per pig 106.13 106.63 56.32 57.34
Straw used (kg)Per pig day - - 0.49 0.49
Per pig - - 44.23 46.49MortalityGrowing stage (34 to 64kg)
(%) 0.78 0.39 1.56 0.78Mean weight (kg) 32.00 58.5 38.63 38
Finishing stage (64 to 103kg)(%) 0 0 0 0
Pigs removedGrowing stage (34 to 64kg)
(%) 3.91 4.30 0.39 3.91Mean weight (kg) 47.65 45 35.00 39.05
Finishing stage (64 to 103kg)(%) 4.50 2.00 0.00 1.25
Mean weight (kg) 79.22 80.88 0.00 87.75Waste production (kg)Farm Yard Manure
Per pig day - - 3.40 3.40Per pig - - 304.26 319.78
EffluentPer pig day 7.31 5.20 - -
Per pig 608.06 460.57 - -a Meters used to monitor drinking and cleaning water overestimated actual use by around 25%.Values given in Table 1 above are based
on previous research (Gill, 1988).
25
Table 2 Input costs
Unit Cost per unit (£) Notes
Variable Inputs
Weaner pig 32.50 Weaner costs were loaded for systems mortality. Pigs
removed during the growing stage for health conditions
were added to mortality losses.
Feed Based on September 2003 costs.
Barley t 85
Wheatfeed t 75
Wheat t 92
Rapeseed Meal t 108
Soya bean meal t 160
Fish meal t 480
Soya oil t 380
Grower mins/vits supplement t 345
Finisher mins/vits supplement t 280
Grower compound t 167 Includes £25/t margin plus £7/t delivery over baseline
raw feed costs
Finisher compound t 149 As above
Labour hr 7.15 Average of basic rate plus 10hrs o/t per week, including
National Insurance etc.
Power kWh 0.04 Assuming 50/50 normal and cheap rate tariff.
Water m3 0.70
Straw t 30 Wheat straw
Waste management
Farm Yard Manure t Contractor disposal cost of £2.40 per m3
Effluent t Contractor disposal cost of £1.72 per m3
Capital Investment Total Capital cost of feeding equipment (dry and liquid)
depreciated over 20 years at 6% interest. Capital cost of
straw and fully slatted housing depreciated over 30 and
25 years at 6% interest. Repair/maintenance costs at 2%
for housing and 4% for feeding equipment.
Liquid feeding
Mill 8,500 1t/hr 3-phase hammer mill + elevator - including
installation
Central processing unit 42,300 Bins and augers for 3 cereals, 2 proteins and oil, with
processing tank and controls, installed in new building.
Pig house tank/pipeline 13,620 Tank, pipeline and 16 feeders.
Dry feeding
Bin/Auger/feeders 5,300 Feed bin, centreless auger and 16 feeders.
Housing
Fully slatted m3 227 Average of trade quotes based on building plan.
Straw based m3 193 As above.
26
Table 3 Cost of productiona (p/kg dead weight) by housing and feeding system
Housing system Feeding system
Fully Straw Liquid Dry
slatted based
Variable costs
Feed 33.7 34.6 28.9 39.5
Vet and Med 0.3 1.0 0.8 0.5
Bedding 0 2.1 1.0 1.0
Total 34.0 37.6 30.7 41.0
Fixed costs
Housing 5.6 4.9 5.1 5.4
Feed system 1.4 1.5 2.3 0.6
Labour 3.0 6.9 4.7 5.1
Energy 4.8 4.2 6.9 2.0
Water 0.7 0.4 0.6 0.5
Slurry storage and disposal 2.0 1.1 1.6 1.4
Total 17.5 18.8 21.2 14.9
Total Finishing Cost 51.5 56.4 51.9 55.9
Weaner cost 43.3 42.7 42.7 43.3
TOTAL COST 94.8 99.1 94.6 99.2a Totals are correct individual costs subject to rounding to one decimal place.
Table 4 Cost of production (p/kg dead weight) by feeding within housing system
Fully slatted Straw based
Liquid Dry Liquid Dry
Variable costs
Feed 29.0 38.4 28.7 40.5
Vet and Med 0.4 0.2 1.1 0.8
Bedding 0.0 0.0 2.1 2.0
Total 29.4 38.6 31.8 43.4
Fixed costs
Housing 5.5 5.6 4.6 5.1
Feed system 2.2 0.5 2.4 0.6
Labour 3.0 3.0 6.5 7.2
Energy 7.4 2.2 6.5 1.8
Water 0.8 0.6 0.4 0.4
Slurry storage and disposal 2.3 1.7 1.0 1.1
Total 21.2 13.6 21.4 16.2
Total Finishing Costs 50.6 52.2 53.2 59.6
Weaner cost 43.3 43.3 42.1 43.3
TOTAL COST 93.9 95.5 95.3 102.9
27
Table 5 Sensitivity analysis for cost of production (p/kg dead weight) by feeding within housing system
Fully slatted Straw based
Liquid Dry Liquid Dry
Base line cost of productiona 93.9 95.5 95.3 102.9
Cost of liquid feeding system (+/- of baseline)
+10% 94.1 - 95.5 -
-10% 93.7 - 95.0 -
Feed costs (+/- of base line)
+10% 96.8 98.6 98.1 106.1
-10% 91.0 92.4 92.4 99.7
No difference in growth rate and FCR between dry and liquid fed pigs (see data)
97.3 95.5 102.0 102.9
Installation sizeb
Below IPPC threshold
1000 pig places 94.5 - 95.9 -
At IPPC threshold
2000 pig places 93.9 95.5 95.3 102.9
Above IPPC threshold
4000 pig places 93.5 - 94.7 -a From Table 4.b Estimated to determine the effects of unit size on the spread of overhead costs associated with capital investment in a liquid feeding system.
28
Table 6 Nutrient analysis of liquid feed ingredients
Nutrients (% dry matter) n DM CP Oil (B) NDAF Ash DE (MJ/kg)a Total lysine Ca P Na
Feed ingredient
Whole grain wheat 2 86.80 12.45 2.30 11.30 1.50 14.53
Wheatfeed pellets 2 85.30 15.55 4.45 31.15 4.00 11.70
Whole grain barley 1 86.80 10.30 2.90 15.90 5.60 12.73
Rapeseed meal 2 88.55 33.00 4.85 28.80 6.75 12.90
Soya bean meal (HP) 1 88.30 49.10 1.90 8.30 6.10 16.31
Fish meal 1 90.80 60.30 10.60 8.50 22.10 13.99
Grower mineral and
vitamins premix 2 2.93 22.25 4.78 9.97
Finisher mineral and
vitamins premix 3 2.47 23.49 2.50 11.04a Estimated by regression MAFF (1993).
Table 7 Variability (SD) in gain and carcase quality by housing and feeding system
Housing system Feeding system s.e.d. P
n Fully Straw Liquid Dry H F I
slatted based
Growth (g/day)
Grower 16 165 178 184 159 17.5
Finisher 16 152 137 153 136 16.0
Overall 16 91 85 97 80 8.7 0.06
Carcase quality
Slaughter weight (kg) 16 4.40 5.01 5.06 4.34 0.492
Carcase weight (kg) 16 3.73 3.97 3.91 3.79 0.375
Killing out % 16 2.42 2.13 2.23 2.32 0.179
Backfat P2 (mm) 16 2.24 1.97 2.19 2.02 0.151 0.08
29
Table 8 Microbial status of pigs at entry by housing and feeding system
Housing system Feeding system s.e.d. P
n Fully Straw Liquid Dry H F I
slatted based
Salmonella
Caecal %positive 16 See note (a) below - - - -
ELISA %positive 16 10 5 6 9 1.60 ** *
Total Aerobic Viable Count 8
Ileal 8.06 8.44 8.58 7.93 0.310 0.059 *
Caecal 8.45 8.44 8.65 8.23 0.200 0.058
Colon 8.69 8.68 8.72 8.65 0.220
Total Anaerobic Viable Count 8
Ileal 8.39 9.04 9.04 8.40 0.628 0.061 0.064
Caecal 8.95 9.30 9.13 9.13 0.263
Colon 9.19 9.20 9.23 9.15 0.173
Lactic Acid Bacteria (LAB) 8
Ileal 7.77 8.48 8.32 7.93 0.442
Caecal 8.38 8.61 8.59 8.40 0.293
Colon 8.80 8.76 8.83 8.72 0.223
Coliform count 8
Ileal 6.82 6.81 7.12 6.51 0.571
Caecal 7.54 7.15 7.42 7.27 0.376
Colon 7.48 7.12 7.40 7.16 0.488
LAB : Coliform Ratio 8
Ileal 1.15 1.30 1.18 1.26 0.132
Caecal 1.12 1.21 1.16 1.17 0.063
Colon 1.20 1.24 1.20 1.24 0.069
Yeast count 8
Ileal 4.59 4.78 4.70 4.67 0.652
Caecal 4.87 4.36 4.70 4.53 0.500
Colon 4.46 4.06 4.34 4.14 0.578
Note: (a) One pig was found positive for Salmonella presence.
Table 9 Brachyspira and Lawsonia presence in caecal contents at entry
Date Animal no. B. hyodysenteriae B. innocens B. pilosicoli Lawsonia
22 Apr 02
7 May 02
13 May 02
27 May 02
5 Jun 02
17 Jun 02
24 Jun 02
1 Jul 02
Table 10 Subcutaneous fat characteristics and fatty acid profile of the lean
Housing system Feeding system s.e.d. P
n Fully Straw Liquid Dry H F I
slatted based
Fat characteristics
Backfat P2 (mm) 16 11.75 11.08 11.45 11.39 *
Fat Firmness (subjective) 64 4.50 4.52 4.14 4.87 0.169 ***
Mean penetrometer score 64 706.4 698.3 677.3 727.4 18.6 **
g fatty acids/100g lean 20 1.28 1.04 1.22 1.10 0.096 *
g/100g fatty acids 20
Saturated 32.91 31.49 31.41 33.00 0.613 * *
Monounsaturated 30.22 28.32 29.78 28.76 1.276
Polyunsaturated 32.46 35.34 34.31 33.49 1.497
Aldehydes 1.47 1.70 1.36 1.80 0.131 **
Total 97.06 96.85 96.87 97.04 0.124
30
19
39
64
73
178
196
229
231
283
316
269
296
443
391
401
485
-
-
+
+
-
-
-
-
+
-
+
+
+
-
-
-
+
+
+
+
-
-
-
-
+
-
+
+
+
+
+
-
+
-
-
-
+
-
-
-
+
-
-
+
-
-
-
-
+
-
-
-
-
-
-
-
-
-
-
-
+
-
-
-
31
APPENDIX II DETAILED RESEARCH METHODOLOGY
Pig production
Housing
The Finishing Systems Research Unit (FSRU) located at MLC’s Stotfold Pig Development Unit consists of a Feed Centre, which
manufactures and delivers liquid feed to growing/finishing pigs in two contrasting systems of production, fully slatted v straw based
housing.
Each house consists of four rooms and each room contains four pens. Both houses have a reception area with pig weighing
facilities, ventilation controllers and storage for clothing and other equipment.The drawings for the two housing systems and pen
layouts are further details can be found in Appendix III.
Feed centre
The feed centre houses a dry feed storage and milling unit and a state-of-the-art liquid processing and feeding system (see
Appendix III for further detail).
The dry feed storage holds six ingredients in cloth silos, whole grain wheat and barley, pelleted wheatfeed, soyabean meal and
rapeseed meal.Wheat, barley and wheatfeed are hammer milled into small cloth bins (fitted with load cells) before transfer by
auger to the central processing tank of the liquid feeding system.The dry feed storage houses 3 small rip and tip bins for mineral
and vitamin supplements and fishmeal.These bins also deliver material to the central processing tank by independent augers.
Feed centre
Fully-slatted house
Straw-based house
Liquid co-product storage tanks
32
The liquid feeding system was supplied by Meyer Lohne (Germany), and designed in association with MLC to meet the
requirements of the research programme. It consists of 6 tanks fitted with load cells, with a central processing tank as the focal
point for the intake, proportioning and blending of all individual ingredients (dry and up to 4 liquid co-products, plus soya oil) to
any formulation specified in the computer controlled Winfeed programme.The central processing tank can heat materials to 95°C
and then chill before transfer to one of 5 different tanks. Depending on protocol, the blend can be transferred into one of two
fermentation tanks, as in the case of a cereal mix, or into a protein tank as in the case of a protein rich blend.These can then be
transferred independently to one of two feeding tanks linked to the dual pipeline system delivering feed to the two pig finishing
buildings.All tanks have the facility for micro additions of dry and liquid products, such as enzymes and organic acids and the
processing and fermentation tanks are equipped with pH control systems.
The dual pipeline arrangement can phase-feed to deliver different proportions of the two mixes held in the feeding tanks
according to the nutritional requirements of each pen group of pigs.
Feeding
Pigs were fed a growing and a finishing diet either in dry pelleted or in liquid form.The liquid and dry diets were formulated to
similar nutrient specification and using similar feed ingredients (see Table 1).
Table 1 Meal equivalent formulations and nutrient specifications of diets
Grower diets Finisher diets
Liquid Dry Liquid Dry
Ingredient (%)
Wheat 41.30 38.25 38.62 35.15
Barley 13.77 12.65 12.87 11.75
Wheatfeed 10.00 10.00 20.00 20.00
Soya bean meal (HP) 18.37 2.00 10.05 ---
Fullfat soya --- 21.50 --- 12.50
Rapeseed meal 5.00 5.00 10.00 10.00
Fish meal 2.50 2.50 --- ---
Fat blend --- --- --- 2.50
Soya oil 5.96 2.00 5.36 2.00
Molasses --- 3.00 --- 3.00
Minerals and vitaminsa 3.10 3.10 3.10 3.10
Nutrient Specificationb
DE (MJ/kg) 14.75 14.72 14.13 14.22
Lysine (%) 1.22 1.17 0.94 0.89
Ca (%) 0.79 0.90 0.73 0.83
P (%) 0.68 0.67 0.59 0.56
Na (%) 0.40 0.42 0.40 0.40a Mineral and vitamin supplement provided per kg of grower diet:Vitamins A, D and E 9000, 1500 and 75 iu respectively,Vitamin K 1000 ug,
Riboflavin 5 mg, Pyridoxine 6 mg, Cyanocobalamin 45 mg, Biotin 100 ug, Pantothenic acid 24 mg, Niacin 23 mg, Copper 175 mg, Zinc 85 mg,
Manganese 35 mg, Iron 40 mg, Iodine 1.75 mg and Selenium 0.4 mg. Mineral and vitamin supplement provided per kg of finisher diet:Vitamins A,
D and E 6000, 1500 and 70 iu respectively,Vitamin K 1000 ug, Riboflavin 2 mg, Pyridoxine 4 mg, Cyanocobalamin 30 mg, Biotin 66 ug, Pantothenic
acid 16 mg, Niacin 15 mg,Thiamine 0.5 mg, Copper 100 mg, Zinc 80 mg, Manganese 25 mg, Iron 100 mg, Iodine 0.5 mg, Cobalt 0.5 mg and
Selenium 0.45 mg.The supplements also provided per kg of grower diet: 1.74 g lysine as lysine hydrochloride, 9.10 g salt, 6.04 g Calcium and
1.53 g Phosphorous; and per kg of finisher diet 1.27 g lysine as lysine hydrochloride, 9.75 g salt, 6.67 g Calcium and 0.69 g Phosphorous.b Differences in expected nutrient specifications between dry and liquid formulations are due to differences in MLC and Farm Nutrition matrix
values for individual ingredients.
33
Dry feed was manufactured (Farm Nutrition, Provimi Ltd) in 3mm pellets and delivered in 25kg bags.The feed was manually
weighed and tipped into ad libitum hoppers. Feed was offered ad libitum.To estimate intake and feed conversion ratios (feed
intake/body weight gain), residual feed was weighed when pigs were weighed and deducted from feed inputs.
The liquid feed was manufactured on site in the Feed Centre (see Appendix III) according to formulations given in Table 1. The
formulations were adjusted according to sample analysis of newly delivered batches of major individual feed ingredients.Water was
pre-weighed into the Central Processing Tank (Tank 3) to produce liquid feed (grower or finisher) in batches of around 370kg with
a 20% target dry matter content.
Whole grain wheat and barley and wheatfeed pellets were hammer milled (4.5 mm screen) and transferred with other feed
ingredients to the Central Processing Tank.
The components were mixed and transferred to Tanks 5 and 6 (grower) and 4 (finisher) for temporary storage at ambient
temperature before delivery in complete batches to feeding Tanks 1 (A) and 2 (B) respectively.This process was led by feed
demand at the troughs using sensors, which signalled for refill on empty.Troughs were refilled with 15kg drops of either grower or
finisher feed according to growth stage of each pen group (when mean weight of pigs in pen exceeded 60kg, they were
transferred from the grower to the finisher diet). Liquid feed was available ad libitum except during 24:00 and 01:00 when the
system was automatically paused, allowing pigs to clear troughs of any accumulated residues.
Feed sampling and laboratory analysis
Each newly delivered batch of individual feed ingredient and compounded dry pelleted feed was sampled and dispatched (Sciantec
Analytical Services Ltd., North Yorkshire, England) for nutrient analysis.The results from the analysis of feed ingredients were used
to adjust formulations in the production of liquid diets to meet target DE and total lysine content.
Grower and finisher liquid diets were sampled during the course of the trial from Feed Tanks A and B for on site determination of
oven dry matter content (24hrs at 100oC), and pH (Hanna Instruments HI 991000).Weekly liquid diet samples were stored for
subsequent dispatch and laboratory analysis for nutrient content (Sciantec Analytical Services Ltd., North Yorkshire, England).
A summary of samples taken and associated laboratory analysis are given in Table 2.
34
Cru
de p
rote
in (
CP
)
Oil
(B)
Neu
tral
det
erge
nt
plus
amyl
ase
fibre
(N
DA
F)
Ash
Tota
l lys
ine
Cal
cium
(C
a) a
nd
pho
spho
rous
(P
)
So
dium
(N
a)
Co
pper
(C
u)
Fatt
y an
d vo
lati
le a
cid
pro
files
,eth
ano
l and
pH
Room 1 2 3 4
Batch 7 Batch 5 Batch 3 Batch 1
Straw basedPen 2 Pen 4 Pen 6 Pen 8 Pen 10 Pen 12 Pen 14 Pen 16
Pen 1 Pen 3 Pen 5 Pen 7 Pen 9 Pen 11 Pen 13 Pen 15
Room 1 2 3 4
Batch 8 Batch 6 Batch 4 Batch 2
Fully SlattedPen 31 Pen 29 Pen 27 Pen 25 Pen 23 Pen 21 Pen 19 Pen 17
Pen 32 Pen 30 Pen 28 Pen 26 Pen 24 Pen 22 Pen 20 Pen 18
Table 2 Feed and feed ingredients sampled and their laboratory analysis
Feed ingredient
Whole grain wheat � � � � �
Wheatfeed pellets � � � � �
Whole grain barley � � � � �
Rapeseed meal � � � � �
Soya bean meal (HP) � � � � �
Fish meal � � � � �
Grower mineral and vitamins premix � � �
Finisher mineral and vitamins premix � � �
Complete liquid diet � � � � � � � � �
Complete dry pelleted diet � � � � � �
DM, Oil (B),Ash, Ca, P, Na and Cu were determined according to the methods described by MAFF (1982). CP was determined by
nitrogen gas analyzer (Leco FP – 528) using induction furnace and thermal conductivity. NDAF was determined according to the
method described by MAFF (1993).Total lysine content in feed samples was analysed according to Liu et al. (1995).The
component fatty acid content of the lipid fraction were determined according to ISO (1995) and ISO (2001).Volatile fatty acid
content, lactic acid and ethanol in liquid feed samples were analysed according to Fussel and McCalley (1987). pH was measured
using a pH probe (Hanna Instruments HI 991000).
Animals
A total of 1056 (Large White x Landrace) x Large White pigs weighing between 30 to 40kg were received in 8 equal batches of
132 over 11 weeks commencing 12th April 2002. Pigs were delivered on a Friday and transferred to a room in the finishing
systems housing according to the pattern given below.
Dry
mat
ter
(DM
)
35
Pig identification and weighing
On the following Monday, two pigs were randomly identified for slaughter for the baseline assessment of gut microbial status and
two surplus pigs were randomly selected and removed to alternative accommodation.The remaining 128 pigs were ear tagged for
individual identification, weighed and then sorted by weight, from lightest to heaviest.The batch was divided into 4 equal groups of
32 pigs in order of weight: Light Light (LL), Light Medium (LM), Medium Heavy (MH) and Heavy Heavy (HH). Each group was
randomly allocated to one of four pens in the room.
Pigs were weighed at two weekly intervals for growth performance monitoring and to establish the timing (week 6) at which pen
weight within room averaged 60kg for stocking density reduction and the switch from grower to finisher diet. On week 6 pigs
were weighed and stocking density in the fully slatted and straw based systems was reduced from 32 to 25 and 20 pigs per pen
respectively. Pigs removed were pre-selected to represent the range (minimum and maximum) and average weight in the pen so
that the overall distribution of individual weights was not potentially skewed by random selection.
Pigs were weighed 9 days prior to slaughter and those weighing more than 95 kg were selected for slaughter so that weight at
slaughter could be as close as possible to a target of 105kg. Pigs were weighed again the day before slaughter for determination of
end point liveweight.
Pigs selected for slaughter were slap marked for individual identification and this was recorded on the slaughter sheets with
corresponding information for pen number, pig ear tag number, sex, dispatch weight and pre-selection code for focal pigs (see
Health and Welfare Monitoring). Slap marking clearly distinguished focal pigs from other trial pigs.
Management
Pigs were managed according to standard protocol covering the following key responsibilities:
The day before entry the environmental control system was set up to achieve target temperature and ventilation rates (see
Appendix III:Ventilation system).
Staff changed overalls and wellington boots before entering each building. Foot dips (Virudine,Antec International Ltd., Suffolk)
were used on entry and exit. Separate foot dips were used for each building and these were cleaned and replenished twice per
week.
Pigs in the slatted building were provided with chains and plastic mats were used in the first two weeks in the fully slatted house
to reduce draughts in the lying area.
Pigs were inspected twice daily for signs of ill health and welfare.Appropriate action was taken to manage pigs with health
conditions. Health conditions were recorded and appropriate action was taken to safe guard the welfare of each pig.Treatments
were carried out according to veterinary recommendations and all veterinary treatments were documented. Pigs that did not
respond to veterinary treatment and where welfare was at risk, were weighed and removed from the study and recorded with
date.
All deaths and culls for health conditions were recorded and a post-mortem was conducted by a Veterinary Surgeon to assess the
cause of death.
36
In each room, the ventilation system was checked and temperature readings were taken and recorded using a hand held probe
during the morning inspection of animals every Monday,Wednesday and Friday. Readings were taken at pig level in the middle of
each of 4 pens in each room.
Soiled bedding was removed daily from each pen.The straw based system was scraped out daily (farm scraper was cleaned and
disinfected (Virkon S,Antec International Ltd., Suffolk) before use to limit microbial cross contamination) and fresh straw was
made available at the rate of about a third of a bale per pen per day.
All nipple drinkers were inspected daily to ensure satisfactory water flow. Feed troughs and probe sensors were inspected twice
daily, any contaminated feed, faeces and straw were removed. Central passages were cleaned daily.
Straw and water use and power consumption
Straw use was monitored by recording the number of bales used daily and a sub-sample of bales were weighed during the trial as
an estimate of total weight used.
Drinking water used within each room and water used for cleaning each finishing building was measured using 12.5 mm water
meters (Minomess,Apartment Water Meters, Minol Messtechnik, Germany).
Power consumption in the Feed Centre for the milling, material transfer, mixing, circulation and delivery of liquid feeds to troughs
was measured using electric meters (RDL Power Rail 303). Power consumption for heating and ventilation of each finishing
building was measured using electric meters (RDL 3P100ANL Power Meters).
Waste production
In the fully slatted house, the volume of effluent produced by each pen group of pigs was measured by dipstick at four locations
within the pen area. Measurements were taken before and after emptying to estimate difference in surface fall (h). Slurry pit width
(w), length (l) and h were used to calculate the volume of effluent produced by each pen group as w x l x h.
Manure production from the straw based system was weighed daily by scraping waste onto a trailer fitted with weight cells.The
weight of manure produced was estimated by taking load cell readings before and after loading with waste. It was not practical to
estimate waste production at the pen level due to the use of common scraping passages either side of the central passage (see
Appendix III, buildings).
Pig health and welfare
Standard management procedures for monitoring and safeguarding the health and welfare of pigs on trial were complemented by
more detailed observations on sub-samples of pigs (focal pigs).
Following entry and allocation of pigs within batch to pens, 3 pairs (balanced by weight and sex) were selected as focal pigs; one
pair at approximately median weight of the group, one pair within the upper quartile weight band and another pair in the lower
quartile weight band. Focal pigs remained in the pen after stocking density reduction at around 60kg for subsequent monitoring to
finishing and at slaughter.Any focal pig removed or lost from the trial (health, welfare or death) was replaced with a pig of the
same sex and approximate start weight.
37
Blood sampling
Pigs were blood sampled under veterinary supervision (Home office Licence number PPL 70/5367) for the determination of health
and Salmonella exposure status at entry, at mid-point in the trial (at stocking density reduction) and during exsanguination at
slaughter.The number of pigs sampled and analysis is summarised in Table 3 below.
Table 3 Blood sampling and analysis for health and Salmonella status
Analysis Pigs
Salmonella ELISA test All pigs at entry (8 batches x 128 pigs per batch, n = 1024)
Focal pigs at mid-point, batches 1 to 4 (4 batches x 24 pigs per batch, n = 96)
All pigs at slaughter (n = 720)
Acute Phase Proteins All focal pigs at start (8 batches x 24 pigs per batch, n = 192)
Focal pigs at mid-point, batches 1 to 4 (4 batches x 24 pigs per batch, n = 96)
All focal pigs at slaughter ( 8 batches x 24 pigs per batch, n= 192)
Generalised immunity Focal pigs at start, mid-point and slaughter, batches 1 to 4 (n = 288)
PRRS virus Focal pigs (15 from 24 per batch), batches 1 and 8 only, start, mid-point and slaughter (n = 90)
Health monitoring
All pigs, including focals were subjected to weekly detailed health monitoring.This included records of any incidence of external
clinical signs of respiratory, locomotory and enteric disorders, behavioural vices such as tail, flank or ear lesions and any other
problems (e.g. hernias, abscesses and rectal prolapse).
The average faecal consistency was scored weekly for each pen on a subjective visual scale of 1 to 5 (1 very loose to 5 very solid).
Skin lesions and cleanliness
Hygiene status of focal pigs was scored weekly by visual estimation of the % whole body surface area which was clean (as
opposed to soiled).
Body lesions were counted weekly on each of the focal pigs. Seven areas of the body were assessed: face and ears, neck, shoulders,
flank, rump, buttocks and tail. For each area (excluding the tail), lesions on the left and right hand sides were recorded separately.
Bursitis of the hock in focal pigs was visually scored weekly on a subjective scale of 0 to 5 according to Lyons et al. (1995) as
follows: 0 no bursitis, 1 small raised swelling, 2 moderate swelling, 3 fairly extensive swelling, 4 very severe swelling and 5
eroded/ulcerated bursa with infection.
Behavioural recording
Behavioural time budgets for focal pigs were recorded concurrently by time sampling at 10 minute intervals for three 2-hour
periods (09.00-11.00, 12.00-14.00, and 15.00-17.00hrs).This was repeated 3 times for each room: in the week of entry, the week
prior to stocking density reduction and the week before slaughter. Data were entered onto a standard recording sheet using an
ethogram.
A 24-hour video record of behaviour at the feed trough was taken in each of the 3 weeks detailed above. Focal pigs within each
pen were uniquely spray marked so that they could be recognised individually.
The number of pigs feeding and queuing for the trough was recorded at 5 minute intervals.The feeding bouts of focal pigs were
individually documented. For each bout, the start and end time and method of initiation and termination were recorded.
38
Slaughter assessments
Foot damage of focal pigs was subjectively evaluated on the slaughter line based on the method described by Lyons et al. (1995).
Both claws of the left hind foot were inspected for the presence of white line lesions, false sandcracks, toe erosions, sole erosions,
and heel flaps (torn heels).These conditions were scored on a scale of 0 to 3, with 0 no damage and 3 as severe damage.
The hearts and lungs of all pigs were removed and scored for lesions by a Veterinary Surgeon.All seven lung lobes were scored: 4
were scored out of 10, and 3 scored out of 5 to give a maximum total score of 55 for any given pig (Goodwin and Whittlestone,
1979). Lesions on the lobes were scored proportionately; if lesion covered 20% of the surface area of a lobe it was scored as 2. If
other conditions were present (for example pleurisy, scarring), they were scored on an increasing severity scale (+,++ or +++).
The heart was inspected for evidence of pericarditis and scored on an increasing severity scale (+,++ or +++).
The gastrointestinal tract of focal pigs was scored for gastric ulceration (including hyperkeratosis of the gastric pars oesophagus)
according to Potkins and Lawrence ( 1989). Any digesta was removed from the pars oesophagus and its surface condition was
subjectively scored on a scale of 0 to 5: 0 apparently normal, 1 hyperkeratosis just beginning, 2 slight hyperkeratosis, 3 moderate
hyperkeratosis, 4 severe hyperkeratosis and 5 severe hyperkeratosis and ulcer (active or healed).
The dressed carcases of focal pigs were scored for skin damage using the standard MLC subjective scale of 1 to 5: 1 unblemished
to 5 severely blemished.
The leg joints of 2 pairs (equal sexes) of focal pigs per pen were dissected to expose the joint.The extent of osteochondrosis was
scored according to Slevin et al. (2001) on a scale of 0 normal (no gross lesion) to 4 generalised dulling, deep depressions and
extensive erosion, ulceration or absence of cartilage.
Microbial status
Gut contents on entry and at slaughter, individual feed ingredients, complete diets (dry and liquid), fresh straw, drinking water,
fresh faeces, effluent and dust were sampled during the trial for microbial evaluations by the Veterinary Laboratories Agency (VLA,
Bury St Edmunds). Sterilised equipment and sample containers were used to avoid cross contamination. Blood samples were taken
from all pigs on entry and during exsanguination at slaughter, plus additional samples were taken from focal pigs at mid-point for
Salmonella ELISA testing as described by Heijden (2001).
Sampling
Gut contents (ileum, caecum and colon) were sampled from 2 randomly selected pigs per batch on entry (Tuesday) and from all
focal pigs at slaughter. Caecal contents were sampled from all pigs at slaughter. Ligated segments of the ileum, caecum and colon
were removed and placed in an insulated box with cool packs. Segments were transported to the VLA for sampling.
All feed ingredients (except soya oil) were sampled during delivery to Stotfold Pig Development Unit. Pelleted dry compound
diets were sampled from unopened bags from each new batch of delivered feed.Weekly samples of dry pelleted diets from
unopened bags and liquid diets (grower and finisher mix) from the feed tanks (Tanks 1 and 2, see Appendix III) were taken.
Bales used for bedding the straw based system were sampled on 9 separate occasions during the course of the trial.
Each room was fitted with a water tap from which samples were taken on 3 separate occasions (on stocking with pigs, mid-point
and on emptying).Taps were flushed and cleaned using 70% alcohol prior to sampling.
Pens were sampled for fresh faeces on 3 separate occasions (on stocking with pigs, mid-point and on emptying). Each pen was
sampled from 4 locations and these sub-samples were pooled for analysis. Samples were taken from the dunging area and slatted
flooring of the straw based fully slatted systems.
39
Sal
mo
nella
Tota
l Aer
obi
c V
iabl
e C
oun
t
Tota
l Ana
ero
bic
Via
ble
Co
unt
Lac
tic
acid
bac
teri
a
Ent
ero
bact
erac
iae
coun
t
Co
lifo
rm c
oun
t
Yeas
t co
unt
Law
soni
a an
d B
rach
yspi
ra
Effluent samples were taken weekly from each room within the fully slatted system.The pit under each pen was sampled from 4
locations and pen sub-samples were pooled to represent the room sample for analysis.
Dust samples were taken weekly from each room. Samples were taken from the windowsills along the outer walls of the room
using a sterile Petri dish exposed for 2 hours.
Microbial evaluations
The samples were evaluated for the following microbial organisms.
Table 4 Summary of microbial evaluations of samples
Gut contents at entry (8 pigs)
Ileum � � � � �
Caecum � � � � � �
Colon � � � � � �
Gut contents at slaughter
Ileum (focal pigs only) � � � � �
Caecum (focal pigs only) � � � � �
Colon (focal pigs only) � � � � �
Caecum (all pigs) �
Feed ingredients � � � � � �
Complete feeds � � � � � �
Fresh straw �
Drinking water �
Fresh faeces � � � � �
Effluent � �
Dust � � �
40
Table 5 Media and conditions for microbial counts performed on samples
Microbial organism Media and inoculation Supplement Incubation Reference
Salmonella Buffered peptone, 37°C for 18h;
Diassalm semi-solid agar, 30°C/41.5°C Netten et al. (1991)
Rambach agar, for 24/48h;
Columbia agar, 37°C for 24h
MacConkey agar serial incubations
Total aerobic bacteria Plate count agar, 5% defibrinated sheep Aerobic, for 72 h ISO (1991)
viable count pour plate blood for gut samples
only
Total anaerobic Wilkins-Chalgren 5% defibrinated sheep Anaerobic, 37°C
bacteria viable count Anaerobe agar, blood for 48 h
spread plate
Lactic acid bacteria MRS agar, spread 5% CO2, 30°C
plate for 48 h
Enterobacteraciae Violet red bile Aerobic, 37°C Mackie and
count glucose agar, pour for 24 h MacCartney (1965)
plate
Coliform count VRBL agar, Aerobic, 37°C
MacConkey broth for 18 to 24 h
Yeast Rose Bengal agar Chloramphenico Aerobic, 25°C
l, Oxoid SR78 for 4 days
Lawsonia and PCR Jones et al. (1993),
Brachyspira Moller et al. (1998) and
Leser et al. (1997)
Limits of detection; for pour plates, 10 cfu per g: for spread plates, 100 per g.
Environmental impact
The table below summarises systems monitoring for the assessment of environmental impact of housing and feeding system
during Production Trials 1, 2 and 4.
Table 6 Summary of environmental monitoring
Parameter monitored Frequencya
Ammonia concentration at the entry to the exhaust Once per hour per room, continuously
fan in each room
Dust concentration at one position in each room 14 occasions, each nominally of 3 days duration, nominally once aweek
Ventilation rate of each room Hourly averages, computed from a large number of basic readings
Ammonia emission rate from each room One value per hour per room, continuously
Dust emission rate from each room 14 occasions, each nominally of 3 days duration, nominally once a week
Effluent volume from each slatted room Each occasion of emptying slurry pit
Effluent composition from each slatted room Each occasion of emptying slurry pit
Farm Yard Manure production from whole straw Each occasion of cleaning out the straw based building
based building
FYM composition from whole straw based building Analysis carried out on a pooled sample, once every 14 daysa In trials 2 and 4 dust concentration will be measured at a reduced frequency of once per fortnight during the period when both buildings are
fully stocked.
41
Ventilation rate
Ventilation rate was continuously measured for each room using a fan-wheel anemometer installed in the exhaust duct, between
the inlet damper and the exhaust fan (Demmers et al., 1999). The rate of rotation of the fan wheel as well as the opening angle of
the inlet damper were continuously monitored electronically, to give an accurate log of the instantaneous ventilation rate of each
room. Each fan-wheel anemometer was calibrated by installation in an identical ventilation chimney fitted to a fan test rig at Silsoe
Research Institute before the start of Trial 1 (Moulsley and Randall, 1990).This calibration will be checked at the end of trial 4.Any
variation in the calibration curve and hence ventilation rate will be accounted for after trial 4.
Ammonia
Ammonia concentration was measured using a chemiluminescence-type nitric oxide analyzer (Demmers et al., 1999), following
catalytic conversion of ammonia to nitric oxide at 750˚C. Measurements were taken at 12 locations, at entry to the exhaust fan
within each room of the straw based and fully slatted housing and at four placed immediately outside the buildings, to correct for
ambient ammonia entering the buildings.The analyzer was calibrated regularly using certified standard gas mixtures.
Net ammonia emission rate for each room was estimated as a function of hourly ammonia concentration and hourly ventilation
rate, corrected for any incoming concentration of ammonia.The ammonia emission was normalised to the live weight of pigs in
each room.The ammonia emission factor (g NH3-N per live weight unit per hour) was calculated from the cumulative emission.
One live weight unit corresponds to 500 kg live weight.
Dust
Dust concentration was measured at entry to the exhaust fan within each room of the straw based and fully slatted housing
(Takai et al., 1998). Dust concentration was also measured at one of the air inlets in the sidewalls of one room to correct for dust
entering the buildings.
The average ventilation rate over the period of exposure of each set of dust concentration samplers (normally 3 days) was
multiplied by the average dust concentration (corrected for any incoming dust), to give average dust emission rate for each room.
Waste
The volume and weight of waste (effluent and manure) produced were monitored as described on page 36.
Slurry samples were taken immediately before pit emptying for the determination of dry matter, total nitrogen and ammoniacal
nitrogen and phosphorous content according to APHA (1985).Analysis was carried out on a pooled sample representing the
content of the slurry pits within each room.
Four grab samples of manure were taken from the trailer, at randomly selected points, at 14 day intervals for the determination of
dry matter, total nitrogen, ammoniacal nitrogen and phosphorous content.The samples were combined, coned and quartered to
give a 1 kg sample for analysis.
42
Meat quality
Carcase measurements and sampling
Pigs were transported to the abattoir and slaughtered (day 1) under commercial conditions and the carcases were conditioned
using achilles suspension.
The carcases were graded using the Hennessy Grading Probe for the estimation of carcase lean content using the following EU
approved (88/234/EEC) equation:
Y = 62.5 – 0.62X1 – 0.46X3 + 0.16X4
where,
Y = the estimated percentage of lean meat in the carcase,
X1 = the thickness of backfat (including rind) in mm, measured at 6 cm off the midline of the carcase at the last rib (commonly
known as P2),
X3 = the thickness of backfat (including rind) in mm, measured at 6 cm off the midline of the carcase between the 3rd and 4th
last ribs (known as ‘rib-fat’),
X4 = the thickness of muscle in mm, measured at the same time and in the same place as X3 (known as ‘rib-muscle’).
Carcases were chilled overnight under commercial slaughter house conditions (1°C).The left side of the carcase from 4 out of 6
focal pigs (see selection Table 7) were transported (day 2) to MLC Winterhill House, Milton Keynes, under controlled refrigeration
and stored in a chiller at 1°C for subsequent evaluation.
On day 3, firmness measurements were taken of the subcutaneous fat by penetrometer over the shoulder and leg. Subjective fat
firmness scores, on scale of 1 to 8 (1= very soft (oily), 8 = very hard), over the shoulder and leg were assessed by depressing the
subcutaneous fat with the tip of a finger or thumb.
The sides will were butchered to provide the following samples:
Shoulder fat (200g); vacuum packed and frozen for subsequent analysis of skatole and indole levels.
Shoulder fat (100g); vacuum packed and frozen for subsequent analysis for fatty acid profile.
Single steak (20 mm); from the anterior end of the loin for immediate assessment of drip loss according to the following method.
The steak was weighed and suspended in a polythene bag for 24 hours at 1°C.The steak was removed from the bag and
reweighed.The drip was weighed.The eye-muscle was removed from the steak and weighed. Per cent drip loss was calculated as
(weight of drip loss/(weight of drip + weight of eye-muscle))*100.
43
Table 7 Selection of focal pigs for carcase and meat quality evaluations
Housing system Room Pen Meat quality evaluationsa Chemical analysisb
Fully slatted 1 32 2 mixed sex pairs 1 male and 1 female
31 2 mixed sex pairs 1 female
30 2 mixed sex pairs 1 male
29 2 mixed sex pairs 1 female
2 28 2 mixed sex pairs 1 female
27 2 mixed sex pairs 1 male
26 2 mixed sex pairs 1 female and 1 male
25 2 mixed sex pairs 1 male
3 24 2 mixed sex pairs 1 male
23 2 mixed sex pairs 1 female and 1 male
22 2 mixed sex pairs 1 male
21 2 mixed sex pairs 1 female
4 20 2 mixed sex pairs 1 female
19 2 mixed sex pairs 1 male
18 2 mixed sex pairs 1 female
17 2 mixed sex pairs 1 male and 1 female
Straw based 1 1 2 mixed sex pairs 1 male and 1 female
2 2 mixed sex pairs 1 female
3 2 mixed sex pairs 1 male
4 2 mixed sex pairs 1 female
2 5 2 mixed sex pairs 1 female
6 2 mixed sex pairs 1 male
7 2 mixed sex pairs 1 female and 1 male
8 2 mixed sex pairs 1 male
3 9 2 mixed sex pairs 1 male
10 2 mixed sex pairs 1 female and 1 male
11 2 mixed sex pairs 1 male
12 2 mixed sex pairs 1 female
4 13 2 mixed sex pairs 1 female
14 2 mixed sex pairs 1 male
15 2 mixed sex pairs 1 female
16 2 mixed sex pairs 1 male and 1 female
Total 64 pairs = 128 20 males and 20 females = 40a Evaluations include: fat firmness, drip loss, Minolta Chroma Meter readings, simulated retail display and sensory evaluations.b Analysis includes: skatole, indole, fatty acid profile and TBARS.
44
Remainder of the boneless primal loin was vacuum packed and held in refrigerated storage (0-3ºC) until Day 8.
Minolta Chroma Meter readings were taken on the cut surface of each loin, at the anterior end, following a period of blooming
and prior to vacuum packing.
On Day 8 the primal loin was butchered to provide the following samples (from the anterior end):
Three over-wrapped retail packs, each of two steaks (20 mm) for simulated retail display.
Two steaks (20 mm) vacuum packed and frozen for subsequent sensory evaluation.
Chemical analysis
Skatole and indole were determined according to the method described by Whittington et al. (1995). Fatty acid profiles were
determined by direct saponification according to Enser et al. (1998).
Simulated retail display
The three retail packs per side were placed in a chiller for a period of simulated retail display (at 0-3ºC). The packs were opened
in sequence at 1, 3, 4, 5 and 7 days. On opening, Minolta Chroma Meter readings were taken and the steaks vacuum packed and
frozen. Following the end of the trial, day 1 and day 7 samples were frozen for subsequent TBARS (thiobarbituric acid values)
assessment according to Vyncke (1970).
Sensory evaluation
Trained sensory panellists were used to evaluate lean and fat samples from cooked loin steaks for the attributes presented in
Table 8.
Panel sessions were structured so that samples from each housing system x feeding treatment were compared in each session.
Six samples were allocated to each session in an incomplete block design so that there were male and female pigs represented in
each session. (Not all treatments were represented in both sexes).This resulted in a total of 22 single panel sessions for the trial.
In each session all samples were assessed by six experienced sensory panellists. Cooking and sampling procedures are
documented below.
Vacuum packed steaks (2 per carcase) were selected from the freezer and thawed for 24 hours in a chiller at 3°C.
Steaks were removed from the packs about an hour before cooking and where necessary trimmed to a uniform thickness of 20
mm and weighed. Steaks were placed on a cooking turntable.The grill (Stot Benham Supergrill 600 gas grill) was set at the highest
temperature and the turntable was placed under the burners.
45
Table 8 Sensory evaluation of cooked loin chops
Sample Attribute Method
Lean
Juiciness Tasting
Tenderness
Pork flavour
Abnormal flavour
Boar flavour
Fat
Pork flavour
Abnormal flavour
Boar flavour
Lean and fat
Overall acceptability
Fat
Pork odour Smelling
Abnormal odour
Androstenone
Skatole
Steaks were grilled to an internal temperature of 75°C (monitored at the end of cooking using a Comark probe C9003
thermometer,Welwyn Garden City, Herts), about 5 minutes on each side. During cooking, the turntable was rotated
approximately 60 degrees every 25 seconds.After cooking, the steaks were removed and placed on coded plates and each steak
was re-weighed on a clean plate (one plate per steak to avoid transfer of flavour components between samples) to establish
cooking loss. Each steak was loosely wrapped in aluminium foil, returned to its coded plate and held in a hot cabinet (54°C) until
sub-sampling for sensory evaluation.
Steaks were removed from the cabinet, one at a time, and placed on a clean chopping board.The fat was separated from the lean.
Six cubes, one per trained sensory panellist, about 1.5 to 2.0 cms in size, were cut from the lean, discarding the outside edges. Six
unbrowned fat samples, about 1 cm were also cut. One sample of lean and another of fat was wrapped in aluminium foil. Excess
fat from each pair of chops was placed in a coded, screw-top, wide-mouth glass jar for odour assessment.The wrapped samples,
one from each allocation within sensory session, were placed in individual wells of a circular microwave bun-tray and returned to
the hot cabinet until all samples were ready for sensory evaluation.
The bun-trays were transferred to the sensory booths within the panelling room. Each booth was illuminated by a green light (to
eliminate bias from sample colour differences) and was equipped with a hot plate onto which a bun-tray was placed. Panellists
were provided within each booth with a small white plate, knife, fork, glass of warm water and a piece of white toast (to cleanse
residual flavour between sampling) and a disposable cup for residues.The jars containing fat samples, were placed on a hot plate,
for assessment by all panellists.
The six trained sensory panellists were asked to score wrapped lean and fat samples and fat samples within jars, on a psuedo line
24 point scale (1 = weak/low to 24 = strong/high) for the attributes listed in Table 8. For statistical analysis, individual panellist
scores were averaged to give a single score per attribute per pig sampled.
46
Data processing
Production
Feed intake (kg/pig day) was derived from total intake per pen divided by total pig days per pen specific to the grower and finisher
stages and overall (grower plus finisher stages).
Growth rate (g/pig day) was derived from total net weight gain per pen divided by total pig days per pen specific to the grower
and finisher stages.The overall growth rate was calculated for only those pigs left in the pens for finishing after the numbers were
reduced at the end of the grower stage (week 6).
Feed conversion (intake/gain), was derived from total intake per pen divided by net weight gain per pen specific to the grower and
finisher stages and overall (grower plus finisher stages).
All other inputs (labour, medicine, power, water and straw) and farm yard manure production were calculated overall (combined
grower and finisher stages) from total input (or manure produced) per housing system divided by total pig days specific to each
feeding system. Effluent production was measured for each pen and total output was divided by total pigs days for each pen over
the combined grower and finisher stages.
Pig health and welfare
Health, hygiene and lesion scores were averaged across pigs within each pen, and across recording weeks for each pen. Behaviour
data were expressed as the proportion of observations at which that behaviour was expressed. These data were
subsequently averaged across pigs within each pen, and across recording weeks for each pen. All of the post-slaughter
assessments were averaged across pigs within each pen.
Microbial status
All microbial counts were transformed to log10 before analysis.
Salmonella tests on blood (ELISA) and caecal contents (laboratory incubation) were recorded as either positive or negative and
present or absent respectively.These data were used to calculate the proportion of pigs that tested positive/present per pen, by
dividing the number of positive/present results by the total recorded samples in each pen.
Meat quality
Sensory scores for individual panellist were averaged to give a single score per attribute per pig sampled for statistical analysis.
Sensory score sample means and all other sample assessments were considered as independent experimental units in the
statistical analysis of meat quality data.
47
Statistical analysis
Production
Pen means for live weight, feed intake, growth rate, feed conversion ratio, slaughter weight, carcase quality measurements and
within pen standard deviation for growth and carcase quality measurements were subjected to Analysis of Variance (ANOVA)
using the General Linear Model (GLM) in Minitab Statistical Software (Minitab Inc., State College, PA, U.S.A.). Model inputs
included housing system (H), feeding system (F) and an interaction term for feeding and housing (I).
Pen effluent data were subjected to one-way ANOVA to establish the effect of feeding system on waste production.
Pig health and welfare
Pen means for hygiene, lesion, health, behaviour and post-slaughter measurements were subjected to a two-way ANOVA. Model
inputs included housing system (H), feeding system (F) and an interaction term for feeding and housing (I).
Microbial status
All microbial counts from gut samples at the start of the trial were subjected to two-way ANOVA and for colon samples GLM
was used. Model inputs included H, F and I.All microbial counts from gut samples at slaughter were subjected to ANOVA using
GLM. Model inputs included H, F and I.
Viable counts in complete feed samples were subjected to one-way ANOVA for the effect of feeding system.
Bacterial counts in faecal samples were subjected to two-way ANOVA. Model inputs included H, F and I.
Enterobacteraciae in effluent samples were subjected to ANOVA using GLM for the effect of feeding system.
Data obtained for total aerobic and coliform counts in dust samples were subjected to ANOVA using GLM. Model inputs included
H, F and I.
Pen positive rates for Salmonella ELISA and caecal presence were subjected to two-way ANOVA. Model inputs included H, F and I.
Environmental impact
Room results for dust and ammonia were subjected to two-way ANOVA, with H and F as model inputs. Pen results were
subjected to ANOVA using GLM for the effect of feeding system (F) on effluent production. Room sample results were subjected
to ANOVA for the effect of feeding system (F) on effluent composition (F).
Meat quality
Sample data from physical, chemical and sensory measurements of meat quality were subjected to ANOVA using GLM. Model
inputs included pig gender, H, F and I.
48
APPENDIX III SYSTEMS TECHNICAL SPECIFICATIONS
Finishing system
Buildings
The finishing buildings have identical shells constructed of a steel frame (33.8m long, 12.30m wide with 2m eaves height at a 15
degree pitch). External walls are constructed from Durox insulated blocks (215mm, U value of 0.6) finished using Fibrocem plaster
coating (3mm).The roofs are constructed with fibre cement with fibreglass insulation giving a U value of 0.7.
Ventilation system
The ventilation and environment in each room is automatically controlled (Euromatic DOL34H, Skov, Denmark) to set maximum
and minimum ventilation, relative humidity (RH) and temperature against occupancy day.
Table 1 Settings for the environmental control system in the finishing buildings
Day Max. ventilation (%) Relative humidity (%) Straw based system: Fully slatted system:
Target temperature (°C) Target temperature (°C)
1 65 55 24 25
7 75 60 22 23
14 85 - 20 21
21 - - 19 20
42 100 75 18 20Minimum ventilation: Summer 20% and Winter 5%.
Each room is equipped with temperature and humidity sensors.
Fresh air is ventilated into each room through three side vents allocated in the external wall above each pen.The vents are fitted
with adjustable flaps controlled by the Skov system.
Stale air is extracted from each room by a single fan located centrally in the roof. Fan speed and airflow are controlled
automatically by the Skov system through adjustment of the exhaust inlet flap under negative air pressure.
Additional heating is provided by two heaters above each pen.These are also automatically controlled by the Skov system.
If in the event of a power cut the flaps and fan go to a default position and the building operates as an ACNV (Automatically
Controlled Natural Ventilation) system.
Environmental data is captured on a computer using Skov software.
49
Internal construction of the fully slatted building,
each pen with independent shallow effluent pit (10 to
14 days storage) for waste monitoring.
Internal layout of the fully slatted building, complete
with concrete slats, central passage and internal
walls, pen divisions and gates made from recycled
high density polypropylene (PP), Panel Plus (51mm).
Internal construction of the straw based building,
with central passage and scraped dunging areas.
Internal layout of the straw based building, with solid
concrete for strawed lying and scraped dunging
areas. Internal walls, pen divisions and gates
(incomplete) made from recycled high density
polypropylene (PP), Panel Plus.
50
Figure 1 Pen layout within each room of the fully slatted building
Figure 2 Pen layout within each room of the straw based building
Location of ad libitum hoppers for pen groups on pelleted dry feed (Trial 1)
X
X
X
1.0m 5.5m
3.7m
X
1.0m 5.8m
3.7m
51
Liquid feeding troughs in the fully slatted (left) and straw based (right) buildings with delivery pipes and sensors
fitted.
Liquid feeding trough
Figure 3 Design and specification of the ad libitum liquid feeding trough
Three dimensional view
SectionShowing detail of divider
Side Elevation300mm deep with lip heightof 220mm. Base and backfixings.
Front Elevation1200mm wide with 2 dividers, 10mm ‘chin bar’ to reduce spillage,Front lip folded down to form safe edge, all other exposed edges with 5mm wire as protection.
52
Feed centre
Figure 4 Schematic layout of feed centre (not to scale)
See page 53 (opposite) for details
27 28 29 30
1 2 3 4 24
13
7 8 95
14
6
10 11 1222
25
23
26
21 20 19 18 17 16 15
Entrance
Fire Exit
Fire Exit
53
System ID Capacity Description
Dry feed storage and milling
1 DS1 5 tonnes Reserve cloth silo
2 DS2 19 tonnes Cloth silo holding whole grain wheat
3 DS3 19 tonnes Cloth silo holding pelleted wheatfeed
4 DS4 19 tonnes Cloth silo holding whole grain barley
5 DS5 5 tonnes Cloth silo holding rapeseed meal
6 DS6 19 tonnes Cloth silo holding soya bean meal
7 S7 1.3 tonnes Cloth bin with load cells holding milled wheat
8 S8 1.3 tonnes Cloth bin with load cells holding milled barley
9 S9 1.3 tonnes Cloth bin with load cells holding milled wheatfeed
10 DS15 0.5 tonnes Metal bin holding mineral and vitamin supplement mix (grower)
11 DS11 0.5 tonnes Metal bin holding mineral and vitamin supplement mix (finisher)
12 DS10 0.5 tonnes Metal bin holding fish meal
13 Hammer mill
14 Dust valve and filter assembly
Liquid feed processing and delivery system (Meyer Lohne, Germany)
15 3000 litres Waste storage tank
16 Tank 3 3000 litres Central processing tank with load cells, receiving all feed ingredient
components, with heating and chilling facilities
17 Tank 4 1500 litres Protein tank with load cells
18 Tank 5 (L1) 3000 litres Insulated fermentation/storage tank with load cells and heating & chilling
facilities
19 Tank 6 (L2) 3000 litres Insulated fermentation/storage tank with load cells and heating & chilling
facilities
20 Tank 1 1000 litres Feeding tank with load cells
21 Tank 2 1000 litres Feeding tank with load cells
22 S44 1000 litres Soya oil pumped into central process tank
23 Positive displacement pumps for liquid feed transfer and delivery
Heating, refrigeration and water supply
24 S41 Water tank
25 Boiler
26 Chiller
Co-product storage and delivery
27 - 30 37, 38, 39 22 tonnes each Tanks for separate storage and delivery of four co-products to central process
and 40 tank
54
GLOSSARY
Nutritional
Enzymes In the context of pig nutrition, enzymes help to breakdown dietary substances, such as starch and protein,
so that they can be more easily absorbed as nutrients.
pH A measure of the acidity or alkalinity of liquids, such as liquid feed.As pH decreases from a neutral value of
7.0, acidity increases.The pH of liquid feed samples from Trial 1 ranged between 4.4 and 5.3.
DE Digestible energy.The total energy in the pig’s food minus that lost in the faeces. DE is usually around 85%
of the total energy present in the pig’s diet.
Lysine The first limiting essential amino acid in a cereal based diet, which must be provided for lean growth by
supplementation with protein rich feed ingredients (e.g. soya bean meal) or synthetic lysine.
NDAF Neutral detergent plus amylase fibre.The cell wall fraction of plant derived feed ingredients, which the pig
is unable to readily digest.
Ethanol Alcohol.
Lactic acid Produced predominately by lactic acid bacteria as a by-product from the fermentation of carbohydrates
(e.g. lactose and glucose). Lactic acid at a concentration of between 100 and 150mmol per litre (or 1 to
1.3%) is highly desirable in the control of Salmonella and other undesirable bacteria such as coliforms in
liquid feeds.
Acetic acid Vinegar acid, which can also be generated during microbial fermentation of liquid feeds. Concentrations
(>30mmol per litre or 0.16%) are undesirable and can reduce feed palatability.
Lipid fatty acids The individual fatty acids found in oils and fats.These are usually a mixture of saturated, mono-saturated
and polyunsaturated fatty acids.
Health and welfare
Acute Phase Proteins Acute-Phase Proteins (APP) are produced mainly by liver cells.The production of these proteins is
dramatically changed by infection, inflammation, and malignancy. Levels are generally regarded as being
sensitive, although non-specific, indicators of inflammation.
PRRS virus Porcine Respiratory and Reproductive Syndrome virus commonly known as “Blue-ear” causes pneumonia
in grower-finishers and abortions, infertility and stillbirths in sows.
C-Reactive protein C-reactive protein (CRP) is considered one of the "major" Acute-Phase Proteins. Increases in response to
insults.
Haptoglobin Haptoglobins are Acute-Phase Proteins and are a group of substances produced by the liver, which bind
free haemoglobin circulating in the blood. Increases in response to insults.
Hyperkeratosis Thickening of tissues such as the skin.
Osteochondrosis Abnormal growth of the cartilage particularly on joint surfaces, which may cause lameness.
Microbiology
Salmonella ELISA An enzyme-linked immunosorbent assay (ELISA) or test, which detects the presence of circulating
antibodies in the pig resulting from exposure to the Salmonella group (or genus) of bacteria.A positive test
does not necessarily indicate that the pig is carrying Salmonella.
Salmonella A group of rod-shaped bacteria found in the pig’s food, gut or faeces, which can be transmitted to humans
through the consumption of contaminated pig meat products and which may cause food poisoning.To
detect the presence of Salmonella in pig feed, the gut or in pig meat, the sample must be subjected to
microbial culture techniques in the laboratory.
Bacterial counts Counts of viable bacteria are made by serially diluting a sample in 10-fold steps, then plating these samples
on agar containing appropriate nutrients. Bacterial colonies are assumed to arise from single cells and the
number of cells is then calculated through the degree of dilution of the sample.
55
Total Aerobic The total aerobic count provides a measure of the number of bacteria capable of growth in air on a
Viable Count general-purpose growth medium.
Total Anaerobic The total anaerobic count provides a measure of the number of bacteria capable of growth in the absence
Viable Count of oxygen on a general-purpose growth medium. Facultative bacteria will appear in both aerobic and
anaerobic total counts.
Lactic acid bacteria A group of Gram-positive lactic-acid-producing bacteria capable of anaerobic growth on MRS agar. In
porcine intestinal samples this includes predominately Lactobacilli with some Bifidobacteria, Streptococci
and Lactococci.
Enterobacteraciae A group of Gram-negative short rod-shaped bacteria found in the intestine of most animals.The group
includes the coliform bacteria as well as related bacteria such as Klebsiella.
Coliform A subgroup of the Enterobacteriaceae which includes Escherichia coli and a number of pathogenic species
such as Salmonella.
Yeast A spore-forming single-celled fungal group with few pathogenic members.Yeast may cause problems in feed
storage and excessive alcohol levels in liquid feeds.
Lawsonia Lawsonia intracellularis is the agent which causes the disease porcine ileitis. It is difficult to isolate from
faeces or gut contents.Their presence is normally detected using molecular techniques.They are rarely
enumerated, the molecular techniques provide only presence or absence data.
Brachyspira Brachyspira (formerly known as Serpulina) is a group (or genus) of bacteria some of which cause colitis
and/or dysentery in pigs. Disease causing species for pigs include B. pilosicoli and B. hyodysenteriae.These
pathogens are difficult to isolate from faeces or gut contents.Their presence is normally detected using
molecular techniques.They are rarely enumerated, the molecular techniques provide only presence or
absence data.
Log 10 As bacteria occur in their millions, laboratory counts are transformed using log 10 so that large numbers
transformation are more manageable. For example 1,000,000 (1 million) in log 10 is expressed as 6, and 100,000 is
expressed as 5 and so forth.All microbial analysis results are presented as Log10 colony forming units (cfu)
per gram or per ml of sample as appropriate.
Environmental impact
Emission The release of a potential pollutant, such as dust and ammonia, into the environment from pig production.
Ammonia Ammonia is produced from the microbial breakdown of nitrogen rich compounds found in the pig’s faeces
and urine.Ammonia can be found in the liquid fraction of waste, such as manure and slurry, and is readily
released into the atmosphere.Ammonia is a potential environmental pollutant and there are regulations,
which aim to control emissions from intensively housed pigs.
Ammoniacal nitrogen Nitrogen present within ammonia.
Kjeldahl nitrogen Nitrogen present in all other substances present within effluent (e.g. protein) excluding ammonia.
Meat quality
Minolta Chroma A device used to measure colour based on a light source and silicon photocells to measure reflected light.
Meter This gives a set of numeric values for sample colour. The value given in the results is the saturation value,
which is a measure of the intensity of colour. Higher values indicate a more intense colour (i.e. darker pink
in the case of pork).
Skatole and indole Principle components of boar taint in pig meat, produced in the pig’s gut by bacterial fermentation.A
skatole level greater than 0.25ppm is considered undesirable for consumers.
TBARS "Thiobarbituric acid reactive substances" values are a measure of the degree of rancidity of pig meat fat
samples.Values higher than 1 are generally considered as undesirable in pork.
56
Statistical
Mean Means or averages in the report are weighted means of the observation.They are values from the
statistical analysis, which ensures that no biases have resulted from, for example, an uneven distribution of
animals to a particular treatment.
Level of significance A single asterisk denotes significance at the five per cent level, meaning that such differences could arise by
chance alone, with a probability (P) of 1 in 20.A double asterisk is at the 1% level and a triple asterisk is at
the 0.1% level. Significance between the 5 and 10% level of probability is given as the P value. P values
greater than 10% are left blank.
Lack of significance does not necessarily imply that real differences do not exist, only that in the work
conducted they were not demonstrated or were not large enough to distinguish from the effects of
random variation.
Interaction An interaction (I) between housing system (H) and feeding system (F) implies that the difference between
the two feeding systems was not the same for both housing system. For example in Trial 1, the growth
benefits from liquid feeding over dry feeding were much greater in the straw based compared with the fully
slatted system, giving a statistically significant interaction.
Standard deviation Standard deviation (SD) is a measure of how variable the data are for a given measurement of interest, say
growth rate. In most data sets, around 94% of all values fall within +/- 2 standard deviations either side of
the mean.
Standard error of The standard error of difference (s.e.d.) is a function of the standard deviation and the number of
difference independent observations per treatment mean.As a general guide, two treatment means tend be
significantly different if the difference between the means is twice the s.e.d.
57
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59
ACKNOWLEDGEMENTS
The Finishing Systems Research Programme is funded by Defra and BPEX.
The research participants are:
Acorn House Veterinary Surgery1
Liquid Feeders Research Group2
Meat and Livestock Commission3
Scottish Agricultural College4
Silsoe Research Institute5
University of Newcastle upon Tyne6
University of Nottingham7
University of Plymouth8
Veterinary Laboratories Agency9
This report was compiled by Dr Pinder Gill3, co-ordinator of the research programme, with the support of the following
participants:
Dr Jane Beal8, Professor Peter Brooks8, Dr Phil Cain6, David Chennells1, Dr Rob Davies9, Dr Theo Demmers5, Professor Sandra
Edwards6, Peter Heath9, Dr Kevin Hillman4, Brian Hunt9, Kim Matthews3, Philip McTiffin2, Mike Owen3, Martin Sage2, Kamara Scott6,
Lisa Taylor3, Dr Jayne Thompson3, John Tingey2, Barry Weigleb3, Dr Julian Wiseman7.
The following companies participated in the development of the Stotfold Finishing Systems Research Unit and their provision of
technical support is gratefully received:
Quality Equipment, G.E. Baker (UK) Ltd, Bury St Edmunds, Suffolk
Meyer Lohne GmbH, Lohne, Germany.
© (May 2004) Meat and Livestock Commission.All rights reserved.
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BRITISH PIG EXECUTIVE
PO Box 44,Winterhill House
Snowdon Drive
Milton Keynes MK6 1AX
www.bpex.org.uk
www.stotfoldpigs.co.uk
Telephone: 01908 844368 Fax: 01908 844289
For technical enquiries contact MLC’s Technical Division
Tel: 01908 844734 Fax: 01908 844214
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