The nutritive value for ruminants of thin stillage and distillers' grains derived from wheat, rye, triticale and barley

Journal of the Science of Food and Agriculture J Sci Food Agric 80:607±613 (2000)

The nutritive value for ruminants of thin stillageand distillers’ grains derived from wheat, rye,triticale and barleyArif F Mustafa,1* John J McKinnon,1 Michael W Ingledew2 and David A Christensen1

1Department of Animal and Poultry Science, University of Saskatchewan, 72 Campus Drive, Saskatoon, SK, S7N 5B5, Canada2Department of Applied Microbiology and Food Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada

(Rec

* CoSK, SCont

# 2

Abstract: A study was conducted to determine nutrient degradabilities of thin stillages and distillers'

grains derived from wheat-, rye-, triticale- and barley-based ethanol production. In vitro protein

degradabilities of wheat, rye, triticale and barley thin stillages were determined using a protease

enzyme assay. One ruminally ®stulated cow was used to determine ruminal nutrient degradabilities

for wheat, rye, triticale and barley distillers' grains. Results of the in vitro study showed that the soluble

protein fraction was highest for rye thin stillage and lowest for barley thin stillage. The degradation

rate of the slowly degradable protein fraction was higher for wheat and triticale thin stillage than rye

thin stillage and was higher for rye than barley thin stillage. Effective degradability of crude protein

followed the order rye (659g kgÿ1)> triticale (632g kgÿ1)>wheat (608g kgÿ1)>barley (482g kgÿ1) thin

stillage. Ruminal degradability of dry matter was highest for rye and lowest for barley distillers' grains.

Ruminal degradability of dry matter was also higher for wheat than triticale distillers' grains. Crude

protein from barley distillers' grains had a lower ruminal degradability relative to crude protein from

wheat and rye distillers' grains. Ruminal degradability of neutral detergent ®bre was highest for rye

distillers' grains (470g kgÿ1), intermediate for wheat and triticale distillers' grains (average 445g kgÿ1)

and lowest for barley distillers' grains (342g kgÿ1). It was concluded that thin stillage and distillers'

grains derived from barley had a lower nutritive value for ruminants compared with those derived

from wheat, rye and triticale.

# 2000 Society of Chemical Industry

Keywords: nutrient degradability; thin stillage; distillers' grains; cereal grains

INTRODUCTIONAlcohol production from cereal grains involves the

conversion of starch to alcohol through enzymatic

hydrolysis and yeast fermentation.1 The by-product

remaining after fermentation and distillation is known

as whole stillage, which is usually screened or

centrifuged to produce thin stillage and wet distillers'

grains.2 Distillers by-products have been recognised as

excellent energy and protein sources for ruminants

owing to the concentration of unfermented nutrients

such as ®bre and protein as well as residual yeast

cells.3±5 Corn (maize) is the most common substrate

for ethanol production in North America owing to its

abundance and its greater yield of ethanol relative to

other cereal grains.6 In western Canada, wheat is the

preferred cereal grain for ethanol production owing to

its availability. The economics of wheat-based ethanol

production, however, is very much dependent on the

price of wheat. Cyclic ¯uctuations in wheat prices will

often lead to opportunities for use of other sources of

starch such as barley, triticale or rye. The feeding value

of wheat-based thin stillage and distillers' grains is well

eived 18 March 1999; revised version received 22 August 1999; acce

rrespondence to: Arif F Mustafa, Department of Animal and Poultry S7N 5B5, Canada

ract/grant sponsor: Western Grains Research Foundation

000 Society of Chemical Industry. J Sci Food Agric 0022±5142/2

documented,3,4,7,8 but data on the nutritive value of

barley-based distillers' grain and thin stillage are

limited and no information is available on distillers'

by-products from other cereal grains such as rye or

triticale. Weiss et al9 evaluated barley-based distillers'

grains derived from a mix of 65% barley and 35% corn

for dairy cows. These authors found that feeding

barley-based distillers' grain up to 130g kgÿ1 of the

diet dry matter did not affect milk yield or milk fat

percentage. The objective of this study was to

determine the chemical composition and nutrient

degradability of wet distillers' grains and thin stillages

derived from ethanol fermentations of rye, tricale and

barley relative to those derived from wheat mash

fermentation.

MATERIALS AND METHODSSample preparation and chemical analysisWet distillers' grains and thin stillage samples were

obtained from the fuel alcohol research laboratory in

the Department of Applied Microbiology and Food

pted 1 December 1999)

cience, University of Saskatchewan, 72 Campus Drive, Saskatoon,

000/$17.50 607

AF Mustafa et al

Science at the University of Saskatchewan. To prepare

mashes for fermentation, grain samples were ground

with a plate grinder (Disk Mill S.500, Glen Mills Inc,

Clifton, NJ, USA) at a setting of 5. Milled grain was

slurried into 14.7 l of 75°C distilled water. Novozyme

348 (pentosanase/glucanase enzyme, 0.95g) and

Novo BAN 240L (low-temperature a-amylase,

0.95g) were added and the temperature was held at

75°C for 1h, after which it was raised to 100°C for

15min, then reduced to 90°C. Novo liquozyme 120L

(high-temperature a-amylase, 270ml) was added and

the mash was held for 2h, then lowered to 30°C for

fermentation.

For fermentation, Novo spirizyme 300L (glucoa-

mylase, 2.9ml), Allprotease (59mg) and Alltech

Superstart yeast (1.6g) were added to each mash,

then, after 2h, urea was added (5.9g). Fermentations

were controlled near 28°C using cooling water.

Distillation was carried out to remove the alcohol

from the mashes, with 15min of additional boiling

carried out after the temperature rose to 98°C. Thin

stillage and wet distillers' grains were then separated

by a screen and both were frozen.

Mash preparation for all samples followed the strict

protocol described above. However, differences in

viscosity prevented equal separation of the four thin

stillage fractions from the corresponding wet distillers'

grains. In order to have a fair comparison of all by-

products, it was thus necessary to take samples (400g)

of the four distillers' grains and wash them with

distilled water. This procedure was carried out twice

with equal portions (400ml) of distilled water.

Following each wash, the distillers' grains were

squeezed through two layers of cheesecloth. The wash

was then added to the corresponding thin stillage.

Thin stillage/wash material and wet distillers' grain

samples were subsequently freeze-dried to determine

dry matter content.

Distillers' grain and thin stillage samples were

analysed for moisture, ether extract, crude protein

(CP, Kjeldahl nitrogen�6.25), acid detergent ®bre

and acid detergent lignin according to the procedures

of the Association of Of®cial Analytical Chemists.10

Neutral detergent ®bre was determined according to

Van Soest et al. 11 Total starch was determined using

the a-amylase/amyloglucosidase method.12 Total and

non-structural carbohydrates were estimated accord-

ing to the equations of Sniffen et al. 13 Non-protein

nitrogen, soluble CP, neutral and acid detergent

insoluble CP were determined according to the

procedures of Licitra et al. 14

In vitro protein degradability of thin stillageThe procedure of Roe et al15 was used to estimate invitro crude protein degradability of the four thin

stillage samples. Duplicate samples containing the

equivalent of 0.2g of air-dry crude protein were

weighed into 125ml Erlenmeyer ¯asks and incubated

in 40ml of borate phosphate buffer (pH 6.7) at 39°Cfor 1h. Following incubation, 10ml of fresh protease

608

solution (0.33unitsmlÿ1 protease enzyme from Strep-tomyces griseus, type XIV, Sigma Chemical Co, St

Louis, MO, USA) was added to each ¯ask and the

samples were incubated for 2, 4, 8, 12, 18, 24, 36 and

48h at 39°C. Zero-hour disappearance was estimated

by soaking samples in 40ml of borate phosphate buffer

for 1h at 39°C. At the end of each incubation time,

insoluble residues were ®ltered and residual nitrogen

was determined using the Kjeldahl method.10 The

experiment was repeated three times for replication.

In vitro crude protein disappearance at each

incubation time was calculated from crude protein in

the residues and the original samples. The data were

then used to estimate in vitro crude protein kinetic

parameters using the equation of érskov and Mc-

Donald:16

P � a� b�1ÿ eÿct�where P is crude protein disappearance at time t, a is

the soluble fraction, b is the slowly fraction and c is the

rate of degradation of the b fraction. The parameters a,b and c were estimated by an iterative least squares

method using a non-linear regression procedure of the

Statistical Analysis System17 with the constraint that

a�b�100. Effective degradability (ED) of crude

protein was then calculated according to the equation

of érskov and McDonald:16

ED � a� bc=�k� c�where k is the rumen out¯ow rate, assumed to be

5%hÿ1, and a, b and c are as described above.

In situ nylon bagRuminal degradabilities of dry matter, crude protein

and neutral detergent ®bre for wheat, barley, rye and

triticale distillers' grains were determined using one

non-lactating Holstein cow ®tted with a ¯exible rumen

cannula. The cow was fed a 50:50 barley silage/

concentrate diet. Dry matter intake was restricted at

1.5% of body weight. All feed samples were ground

through a 2mm screen prior to rumen incubation.

Duplicate (7g) feed samples were weighed into nylon

bags (9cm�21cm, 41mm pore size) and incubated in

the rumen for 6, 12, 18, 24, 48, 72 and 96h. Zero-hour

disappearance was estimated by washing duplicate

bags containing the feed samples in cold water.

Following the removal from the rumen, bags were

washed and dried as described by McKinnon et al. 18

Incubations were repeated three times for replication.

The disappearances of dry matter, crude protein

and neutral detergent ®bre at each incubation time

were calculated from the concentration of these

nutrients in the original samples and the residues,

and used to estimate ruminal kinetic parameters

according to the equation of érskov and McDonald16

as described in the in vitro trial. Ruminal effective

degradabilities of dry matter, crude protein and

neutral detergent ®bre were estimated using the

J Sci Food Agric 80:607±613 (2000)

Nutritive value for ruminants of thin stillage and distillers' grains

equation of érskov and McDonald,16 assuming a

rumen ¯ow rate of 5%hÿ1.

Statistical analysisData of the in vitro and the in situ trial were analysed as

a completely randomised design using the General

Linear Model of SAS.17 Incubations (n =3) were used

as replicates. When a signi®cant difference (P<0.05)

was found, means were separated using the Student±

Newman±Keuls procedure.19

RESULTS AND DISCUSSIONChemical composition of thin stillageOnly one mash fermentation and distillation run was

carried out for each grain and thus no replicates were

available to statistically test differences in chemical

composition between the different thin stillages and

distillers' grains. However, it was evident that the four

thin stillage samples differed in their chemical compo-

sition (Table 1). Crude protein was 33, 44 and 12%

higher in wheat, triticale and barley thin stillage

respectively than in rye thin stillage. The lower value

for rye thin stillage may result from the viscous nature

of the by-products from this grain. Even though the rye

wet distillers' grains were washed in the same manner

as the other samples, some of the thin stillage may have

remained with the distillers' grains and thus lowered

the crude protein value in the thin stillage. Ojowi et al3

reported wheat thin stillage to contain 485g kgÿ1

crude protein, while Wu20 reported a crude protein

level of 241g kgÿ1 for barley thin stillage. However,

the four thin stillages in the present study had higher

crude protein contents than that reported for corn thin

stillage.5 Lee et al21 have also reported that wheat thin

stillage had a higher crude protein content than corn

thin stillage. Soluble crude protein was highest for rye

and triticale, intermediate for wheat and lowest for

barley thin stillage. Acid and neutral detergent

insoluble crude protein levels were similar in wheat,

Table 1. Chemical composition of thin stillagederived from different cereal grains (DM basis)

Ash (g kgÿ1 of DM)

Ether extract (g kgÿ1

Carbohydrate comp

Total carbohydrate (

Non-structural carbo

Neutral detergent ®b

Acid detergent ®bre

Acid detergent lignin

Starch (g kgÿ1 of DM

Protein composition

Crude protein (CP) (

Soluble protein (g kg

Non-protein nitrogen

Neutral detergent in

Acid detergent insol

J Sci Food Agric 80:607±613 (2000)

rye and triticale thin stillage. However, barley thin

stillage had higher concentrations of neutral and acid

detergent insoluble crude protein than the other thin

stillage samples.

Carbohydrate analyses showed low acid detergent

®bre, acid detergent lignin and starch levels in the four

thin stillage samples (Table 1). Neutral detergent ®bre

was lowest for rye thin stillage and highest for wheat

and barley thin stillage. Total and non-structural

carbohydrates were higher in rye thin stillage relative

to the other samples. These results suggest that rye

thin stillage contained more rapidly degradable carbo-

hydrate than the other thin stillage samples. Ojowi etal3 reported a similar neutral detergent ®bre and a

lower acid detergent ®bre value for wheat thin stillage

relative to the values reported for wheat thin stillage in

the present study. However, the neutral detergent ®bre

values for wheat, rye, triticale and barley thin stillage in

our study were higher than that reported for corn thin

stillage by Ham et al. 5 The relatively high neutral

detergent ®bre values of the four thin stillage samples

can be attributed to the high levels of neutral detergent

insoluble crude protein. When corrected for the

associated crude protein, the neutral detergent ®bre

contents of wheat, rye, triticale and barley thin stillage

were 175, 114, 143 and 161g kgÿ1 respectively.

Chemical composition of distillers’ grainsCarbohydrate was the main constituent of the four wet

distillers' grains, with non-structural carbohydrate

contributing less than 20% of the total carbohydrate

(Table 2). Neutral detergent ®bre and acid detergent

lignin levels were similar in the four distillers' grains

(average 713 and 62.6g kgÿ1 of dry matter respec-

tively). However, barley distillers' grains contained

more acid detergent ®bre than the other three

distillers' grains. Similar neutral and acid detergent

®bre values were previously reported for wheat

distillers' grains.4 The average neutral detergent ®bre

level of the four distillers' grains was 38% higher than

Thin stillage

Wheat Rye Triticale Barley

64 69 87 77

of DM) 59 22 61 60

osition

g kgÿ1 of DM) 522 634 455 555

hydrate (g kgÿ1 of DM) 341 520 312 394

re (g kgÿ1 of DM) 352 232 316 367

(g kgÿ1 of DM) 85 81 72 87

(g kgÿ1 of DM) 16 12 8 28

) 30 20 13 13

g kgÿ1 of DM) 366 275 397 308ÿ1 of CP) 237 358 321 174

(g kgÿ1 of CP) 200 341 277 160

soluble CP (g kgÿ1 of CP) 483 428 437 669

uble CP (g kgÿ1 of CP) 61 55 62 143

609

Table 2. Chemical composition of wet distillers’grains derived from different cereal grains (DMbasis)

Wet distillers' grains

Wheat Rye Triticale Barley

Ash (g kgÿ1 of DM) 18 22 25 41

Ether extract (g kgÿ1 of DM) 44 45 66 51

Carbohydrate composition

Total carbohydrate (g kgÿ1 of DM) 663 671 611 707

Non-structural carbohydrate (g kgÿ1 of DM) 91 125 83 129

Neutral detergent ®bre (g kgÿ1 of DM) 739 700 712 700

Acid detergent ®bre (g kgÿ1 of DM) 216 197 211 307

Acid detergent lignin (g kgÿ1 of DM) 58 71 58 63

Starch (g kgÿ1 of DM) 24 97 27 6

Protein composition

Crude protein (CP) (g kgÿ1 of DM) 275 262 298 201

Soluble protein (g kgÿ1 of CP) 40 45 39 36

Non-protein nitrogen (g kgÿ1 of CP) 36 44 49 34

Neutral detergent insoluble CP (g kgÿ1 of CP) 606 590 617 607

Acid detergent insoluble CP (g kgÿ1 of CP) 46 65 62 147

AF Mustafa et al

the neutral detergent ®bre value of corn wet distillers'

grains as reported by Ham et al. 5 As expected, all the

distillers' grains had low residual starch contents.

As noted for thin stillage, crude protein was

numerically highest for triticale, intermediate for rye

and wheat and lowest for barley distillers' grains

(Table 2). A lower crude protein content for barley

distillers' grains would be expected based on the high

hull content of barley relative to the other cereal grains.

Bell et al22 found that barley hulls contained 51g kgÿ1

crude protein. Similar crude protein values for wheat

distillers' grains were reported by Ojowi et al4 and Wu

et al. 2 The crude protein content of wheat, rye and

triticale distillers' grains in our study was comparable

with that of corn distillers' grains as reported by Ham

et al. 5 All the distillers' grains samples contained low

levels of soluble crude protein and non-protein

nitrogen (Table 2). This is likely the result of the

washing of distillers' grain samples prior to analysis.

This procedure would have resulted in a more

complete separation of thin stillage and distillers' grain

dry matter than what normally occurs at ethanol

production facilities. Neutral detergent insoluble

crude protein was similar in the four distillers' grains

(average 605g kgÿ1 of crude protein). These results

indicate that most of the protein in distillers' grains is

bound to the cell wall. Acid detergent insoluble crude

protein was higher in barley than in wheat, rye and

triticale distillers' grains. This is consistent with the

carbohydrate analysis that showed more differences in

acid than neutral detergent ®bre content between the

different distillers' grain samples.

In vitro protein degradability of thin stillageThe results of the in vitro protein degradability study

showed signi®cant differences in protein kinetic par-

ameters and effective degradability among the differ-

ent thin stillage samples (Table 3). In vitro soluble

crude protein content was highest (P<0.05) for rye

and lowest (P<0.05) for barley thin stillage. Wheat

610

thin stillage had a higher (P<0.05) in vitro soluble

crude protein content than barley thin stillage and

lower (P<0.05) than triticale thin stillage. Degrada-

tion rate of crude protein was higher (P<0.05) for

wheat and triticale than rye and was higher (P<0.05)

in rye thin stillage than barley thin stillage. Effective

degradability of crude protein ranged from 659g kgÿ1

in rye thin stillage to 482g kgÿ1 in barley thin stillage

and followed the order (P<0.05) rye> triticale>wheat>barley. The results of this experiment suggest

that barley thin stillage is a better source of rumen

undegraded protein than rye, triticale and wheat thin

stillage. However, it should be mentioned that about

50% of thin stillage derived from cereal grains

bypasses the rumen and thus serves as a source of

rumen undegraded protein.8,23

The protein kinetic parameters and effective de-

gradability of crude protein for wheat thin stillage

obtained in this study are in good agreement with

those reported by Iwanchysko et al. 8 The variations in

protein degradability between the different thin

stillages can largely be attributed to differences in the

soluble crude protein fractions. High levels of acid

detergent insoluble crude protein in barley thin stillage

can explain its lower crude protein degradability

relative to the other thin sillage samples. High levels

of acid detergent insoluble crude protein are usually

associated with a reduced protein degradability.24,25

In situ nutrient degradability of distillers’ grainThe results of the in situ nutrient degradability of the

four distillers' grains are presented in Table 4.

Degradability of dry matter was highest (P<0.05)

for rye distillers' grains and lowest (P<0.05) for barley

distillers' grains. A higher rate of degradation of the

slowly degradable fraction may explain the higher

ruminal degradability of dry matter for rye distillers'

grains relative to the other distillers' grains. Ruminal

degradability of dry matter was also higher (P<0.05)

for wheat than triticale distillers' grains.

J Sci Food Agric 80:607±613 (2000)

Table 3. In vitro crude protein kinetic parametersand effective degradability of thin stillage derivedfrom different cereal grainsa

Thin stillage

SEMWheat Rye Triticale Barley

Protein kinetic parameters b

Soluble fraction (g kgÿ1 of CP) 288.0c 445.0a 350.0b 190.0d 3.8

Slowly degradable fraction (g kgÿ1 of CP) 431.0a 306.0c 379.0b 449.0a 9.2

Degradation rate (%hÿ1) 14.2a 11.5b 14.9a 9.3c 0.4

Effective degradability (g kgÿ1) 608.0c 659.0a 632.0b 482.0d 5.9

a Means in the same row followed by different letters are signi®cantly different (P<0.05).b Soluble=a fraction, slowly degradable=b fraction, rate of degradation=c in the equation

P =a�b(1ÿeÿct).


Differences in ruminal degradability of crude

protein between the four distillers' grains were smaller

than those observed for dry matter (Table 4). Ruminal

degradability of crude protein was higher (P<0.05)

for wheat and rye than for barley distillers' grains. This

is likely a combination of low crude protein and high

acid detergent insoluble crude protein levels in barley

relative to wheat distillers' grain. It has been shown

that high levels of acid detergent insoluble crude

protein reduce rumen degradability of crude protein in

wheat and corn distillers' grains.5,26 No differences

were observed in crude protein degradability between

triticale and the other distillers' grains. The effective

crude protein degradability for wheat distillers' grains

was lower than that reported by Ojowi et al. 4 This

discrepancy is likely a result of washing the distillers'

grains in the present study. The procedure would

reduce the soluble protein fraction of the distillers'

grains. This was evident by the higher soluble crude

protein fraction reported in that study (371g kgÿ1 of

crude protein) relative to our value (152g kgÿ1 of

crude protein). These results indicate that ruminal

degradability of washed distillers' grains will be

different from the unwashed distillers' grains which

are likely to be available as ruminant feeds. However,

Table 4. In situ rumen nutrient kineticparameters and effective degradability ofdifferent wet distillers’ grainsa

Dry matter (DM) kinetic

Soluble fraction (g kgÿ1

Slowly degradable frac

Degradation rate (%hÿ1

Effective degradability o

Crude protein (CP) kine





Neutral detergent ®bre





a Means in the same row follb Soluble=a fraction, slow

P =a�b(1ÿeÿct).

J Sci Food Agric 80:607±613 (2000)

the relative ranking of distillers' grains for ruminal

degradability from this study is likely to be similar to

that of commercial distillers' grain samples.

Despite the fact that washing might have reduced

ruminal degradability of distillers' grains, our values of

effective crude protein degradability for wheat, rye and

triticale distillers' grains were higher than reported for

wheat-based dried distillers' grains (488g kgÿ1) by

Boila and Ingalls.26 These results together with those

of Ojowi et al3 indicate that wet distillers' grains have

lower rumen undegradable crude protein values than

dried distillers' grains.

Rate of degradation of neutral detergent ®bre was

highest (P<0.05) for rye and lowest (P<0.05) for

triticale and barley distillers' grain (Table 4). Effective

degradability of neutral detergent ®bre was highest

(P<0.05) for rye distillers' grains followed by wheat

and triticale distillers' grains and lowest (P<0.05) for

barley distillers' grains (Table 4). A similar effective

degradability of neutral detergent ®bre for wheat

distillers' grains was reported by Ojowi et al. 4 The

most likely explanation of the lower ruminal neutral

detergent ®bre degradability for barley distillers' grains

is the high hull content of barley relative to the other

cereal grains. It has been shown that barley hulls are

Wet distillers' grains

SEMWheat Rye Triticale Barley

parameters b

of DM) 122.0c 184.0a 189.0a 159.0b 6.1

tion (g kgÿ1 of DM) 734.0a 616.0b 687.0a 53.2c 17.9

) 3.6b 6.4a 3.6b 3.7b 0.3

f DM (g kgÿ1) 431.0c 528.0a 474.0b 381.0d 4.5

tic parameters b

of CP) 152.0 146.0 174.0 149.0 6.7

tion (g kgÿ1 of CP) 812.0a 786.0a 803.0a 685.0b 8.5

) 4.6a 5.0a 3.6a 5.0a 0.2

f CP (g kgÿ1) 539.0a 541.0a 512.0ab 492.0b 7.8

(NDF) kinetic parameters b

of NDF) 91.0a 50.0b 120.0a 105.0a 9.9

tion (g kgÿ1 of NDF) 701.0a 696.0a 705.0a 549.0b 11.5

) 5.2b 7.6a 4.2c 3.8c 0.3

f NDF (g kgÿ1) 450.0b 470.0a 439.0b 342.0c 6.2

owed by different letters are signi®cantly different (P<0.05).

ly degradable=b fraction, rate of degradation=c in the equation

611

AF Mustafa et al

poorly digested in the rumen.27,28 Nordkvist et al29

reported that the highest concentration of phenolic

acids (particularly p-coumaric acid) in barley grain is

found in the hull. Several studies have indicated that p-

coumaric acid is the most important lignin component

negatively related to digestion.30±32 These results also

indicate that the difference in ruminal dry matter

degradability between barley and the other three

distillers' grains samples is largely due to differences

in the ruminal degradability of neutral detergent ®bre

rather than crude protein.

CONCLUSIONSResults of this study showed little difference in protein

degradability between wheat, rye or triticale thin

stillage samples, although that from rye was 8% more

degradable than wheat thin stillage. Thin stillage from

barley-based fermentation was 28% less degradable

than rye-based thin stillage, primarily owing to a high

level of acid detergent insoluble protein. Despite some

statistical differences, distillers' grains derived from

wheat, rye and triticale had similar ruminal degrad-

ability. However, the high hull content of barley

resulted in lower ruminal degradability relative to the

other distillers' grain samples. As such, it can be

concluded that relative to wheat, rye and triticale, by-

products from barley-based ethanol production will be

of lower nutritive value for ruminants. However,

owing to the washing procedure, kinetic parameters

and nutrient degradabilities for thin stillage and

distillers' grain samples evaluated in the present study

could be different from commercial samples.

ACKNOWLEDGEMENTSThe authors wish to acknowledge aid provided by Mrs

S Hynes and Dr KC Thomas in the mash preparation,

fermentation and distillation procedures. The Western

Grains Research Foundations and Pound Maker

Agventures Ltd, Lanigan, SK, are thanked for their

research support.

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The nutritive value for ruminants of thin stillage and distillers' grains derived from wheat, rye, triticale and barley