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“Optimal nutrition management targets for the transition ewe: Lessons learned in
the lab and field”
Richard Ehrhardt
Small Ruminant Specialist
Michigan State University
Overview:
• Flock nutrition in the 21st century• Opportunities for high performance and profitability with
optimized nutritional management• Importance of forage quality
• Energy intake issues observed in the field• Feeding recommendations to optimize
productivity and maternal health
Precise nutrition management:Nutritional investment at critical stages can
reap large dividends!
What stages and type of investment?•3 critical stages: flushing late pregnancyearly lactation
•Invest in energy, particularly that from highly digestible forage sources!
Precise nutrition management allows:
• Improved out of season conception• Larger litter sizes (birth percentage)• Higher colostrum and milk production• Reduced incidence of metabolic disease• Improved postnatal lamb/kid survival • Improved postnatal lamb/kid growth
Forage Quality
•
Forage Quality: determined by composition and digestibility of cell wall fraction
Cell wall component: Digestibility:
Cellulose 50-90%
Hemicellulose 20-80%
Lignin 0-20%
Fiber digestibility determines the amount of energy and protein available to the animal
Factors that determine fiber digestibility:
•Plant maturityVegetative to mature
•Growing conditionsTemperature
•Plant speciesGrasses (C3 vs. C4)Legumes
How do can you manage plant maturity?
•Time of cutting/harvest!!!!Grazing: length of pasture rotationMachine harvest: time of cutting
•Timing of forage harvest is the most critical factor to manage in optimizing animal health and performance in most sheep and goat farming systems!
Barriers to control of harvest timing:•Stored forage:
Lack of awareness!Great lakes weather: lack of lengthy drying periods!Silage harvesting systems allow much greater control over
harvest timing!Need only 6-24 h of dry weather in most instances
Cost of silage harvest equipment/farm scale
•Grazing systems: Lack of awareness!Lack of pasture infrastructure
Subdivision fencing, water
Feeding issues encountered with silage systems on sheep and goat farms:
• Quality and freshness: is the feeding rate sufficient to keep silage from spoiling?
• Animal number needed to keep silage sources fresh during cold weather (Dec to March):
Corn silage Haylage
Doe (125 lb) Ewe (170 lb) Doe (125 lb) Ewe (170 lb)
Silage bunk 1.86/ft2 1.37/ft2 2.92/ft2 2.15/ft24 ft W, 6 ft T: 268 197 420 3098 ft Ag bag: 94 68 147 108Baled silage
(4x4 ft bale for 4 days: 39 28
* Need twice as many animals during warm weather!!
Important measures of fiber quality:•NDF=neutral detergent fiber (cell wall fraction)
Negatively correlated with DM intake
•NDF digestibility =% of NDF digested in rumen
Best indicator of DM intake
•ADF=acid detergent fiber (cellulose and lignin)
Negatively correlated with DM digestibility
A primary goal is to maximize dry matter intake during critical production phases
% Moisture 58
% Crude Protein 19.8
% Acid detergent fiber 32
% Neutral detergent fiber 53
% TDN 72
NDFD 48 h, % of NDF 77
Relative Forage Quality 187
Relative Feed Value 120
Orchard grass, tall fescue, alfalfa “sheep pasture”May 21, 2011
Feeding issues encountered with fermented feeds (silages!) on sheep and goat farms:
• Obesity in low productivity states!
Non-pregnant ewes outside of the breeding period
Pregnant ewes: day 0 to day 100 of pregnancy
• Management solutions to prevent obesity in late pregnancy
1.Identify non-pregnant ewes with ultrasound (day 40-70) and sort them out of the late pregnancy feeding group.
2. Feed a diet lower in energy (60% TDN) in the day 40-100 period.
3. Alter diet energy density for the 40-100 day period according to body condition status.
Fetal and placental growth in single and triplet births
Triplet
Single
0
200
400
600
800
0 30 60 90 120 150
Gestational age, d
Pla
cen
tal w
eigh
t, g
Triplet
Single
0
1000
2000
3000
4000
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Feta
l wei
ght,
g
Early LateMid
Sir John Hammond 1944
Prevention of ketosis:
• Key concept is to increase energy density of diet in last 30 days
• Risk factors:
Plane of nutrition and body condition
Thin ewes in general-underfeeding exacerbates the problem
Fat ewes-that cannot consume enough energy in late pregnancy
Stress-winter storms, shearing, etc.
Evaluation of transition diets and their relationship to health status and performance
in large sheep flocks in 2014• Health status recorded by flock owners and CVM “Small ruminant
production medicine” clerkship students
• Feed intake recorded by flock managers during late pregnancy and early-mid lactation
• Diet components and complete total mixed rations were sampled
• Diet samples were analyzed by NIR methodologies to estimate dietary energy and protein concentration and to characterize fiber fractions
• 8 farms evaluated, results from 4 farms during the late pregnancy period will be presented
• All flocks were “prolific” with lamb drop >200%
• Average ewe mass (parity 2+ in average body condition- BCS 3) ranged from 165-180 lbs between flocks
• All flocks fed some form of silage as the main source of dietary dry matter
0
1
2
3
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5
6
7
A B C D NRC
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
A B C D NRC
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
A B C D NRC
Energy intakeME, (Mcal)
Feed dry matter intake, % of bodyweight
Diet energyConcentration
ME/lb.
0
5
10
15
20
A B C D
0
5
10
15
20
25
30
A B C D
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
A B C D NRC
Feed intake,% of bodyweight
Diet Starch, %
Diet ADF, %
0
10
20
30
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50
A B C D
0
20
40
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80
100
A B C D
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
A B C D NRC
Feed intake,% of bodyweight
Forage NDF Digestibility, % (48 h)
Diet NDFConcentration, %
Body condition score, incidence of ketosis and energy intake in large flocks during 2014
Energy intakeME, (Mcal)
0
1
2
3
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5
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A B C D NRC
0
2
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A B C D
Incidence of ketosis,% of late pregnant ewes
0
1
2
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A B C D
Flock body condition score(1=thin, 5=fat)
Improvement of dietary NDF digestibility in flock D and its impact on feed intake and
incidence of ketosis in late pregnancy
• Flock D had a high incidence of ketosis , 5.8%, during the April lambing period
• Ewes in flock D were also obese, BCS 4.0.
• Recommendations were made to improve dietary fiber quality and to reduce energy concentration of diet prior to late pregnancy
67% of poor quality “husklage” was replaced with a 50/50 mix of high quality corn silage and alfalfa haylage
Ration cost increased by 33%
0
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2
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Old silage New silage
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Old silage New silage
0
20
40
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80
Old silage New silage
00.20.40.60.8
11.21.4
Old silage New silage
Diet energyConcentration
ME/lb.
Diet NDFConcentration, %
Forage NDF Digestibility, % (48 h)
Feed intake,% of bodyweight
0
2
4
6
8
Old silage New silage
Incidence of ketosis,% of late pregnant ewes
Improvement of dietary NDF digestibility in flock D and its impact on feed intake and incidence of
ketosis in late pregnancy• Projected flock income due to reduction in ketosis
• 400 ewes @ 5.8%=22.4
• 400 ewes @ 1.0%=4.0
• 18.4 ewes and 32 lambs saved
18.4x$275 plus 32x$50=$6660
• Cost of preventative treatment:• Feed cost differential = $3564
• Benefit of changing feed to reduce ketosis= $3096
• Additional benefits not assigned a $ value: lambs grew faster
lamb mortality was reduced (birth to pre weaning)
Improved conception in next breeding cycle
Improved sheep welfare!
-50
0
50
100
150
200Maternal Tissues
Pregnant Uterus
Nit
roge
n (
g)
Protein changes in maternal tissues during late pregnancy according to dietary protein level
McNeill et al. 1997Journal of Animal Science 75:809-816
LP 8% HP 16%MP 11.5%
-80
-60
-40
-20
0
20
40
60
80
MuscleOrgansMammary GlandWool
Nit
roge
n (
g)
LP 8% HP 16%MP 11.5%
Protein changes in maternal tissues during late pregnancy according to dietary protein level
McNeill et al. 1997JAS 75:809-816
Summary of protein nutrition during late pregnancy:
• Fetal growth is optimized at a protein plane (% crude protein) of 11% and 13%, for single- and twin-pregnant animals, respectively.
•Supplementation of protein above these thresholds will improve maternal muscle protein retention during late pregnancy
Will supplemental protein increase milk production?
Is supplemental protein cost effective in terms of milk production and lamb growth?
Nutritional targets for late pregnancy:• Manage body condition before late pregnancy,<3.5 BCS• Target ration NDF <40% unless forage NDFd >70%• Maximize use of highly digestible fiber sources
Target intake= 3% of non pregnant BWMaximizes dry matter intake, maintains steady intake
• Limit use of high starch energy sources (i.e. corn and barley) <50% of energy content( <30% dietary starch)Minimizes acidosis, “going-off feed”
• Energy and Protein density targets(TDN, %) Crude Protein (%)
Single 58 11Twin 66 13Triplet 73 15
• Alter targets based on BCS and production system
Summary:• Forage quality is key to maximizing performance and profit in
prolific animals in high performance management systems (accelerated, machine milking, etc.).
• The timing of forage harvest is the most critical management factor in controlling forage quality.
• Silage harvest systems allow much greater control over the timing of forage harvest but silage feeding systems must be matched to farm size and may not be feasible for small flocks/herds..
• Energy form is especially important during late pregnancy as diets high in fermentable fiber will allow a steady, high level of intake thereby minimizing risk for metabolic disease.
• Managing body condition prior to late pregnancy will minimize incidence of metabolic disease (target of 3-3.5 BCS)
Contact information:Richard Ehrhardt Ph.D.Small Ruminant SpecialistAnimal Science / Large Animal Clinical Sciences
1287F Anthony Hall
Michigan State University
East Lansing, MI 48824-1225
Email: [email protected]
Office: (517) 353-2906
Cell: (517) 899-0040
