6

Maataloustieteellinen Aikakauskirja
VoL 60: 711—721, 1988

Response of silage intake and milk production to replacement of barley
by barley fibre derived from integrated starch-ethanol process

PEKKA HUHTANEN, HANNELE ALA-SEPPÄLÄ and MATTI NÄSI
Department of Animal Husbandry, University of Helsinki
SF-00710 Helsinki, Finland

Abstract. A duplicated 4x4 Latin Square experiment was conducted to determine the ef-
fects of a gradually increased level of barley fibre in the diet on ad libitum grass silage intake
and milk production. Barley fibre is a fibrous ethanol-starch by-product (120 g crude protein,
550 g neutral detergent fibre (NDF) and 120 g starch/kg dry matter (DM)). The four supple-
ments, given at the rate of 6.5 kg/d on DM basis, were barley (B) and barley of which 333
g/kg (BF), 667 g/kg (FB) and 1000 g/kg (F) were replaced by barley fibre. In addition the
cows were given I kg of rapeseed meal and 0.25 kg of mineral mixture.

As the proportion of barley fibre in the diet increased there was a linear (P<0.001) in-
crease in silage DM intake. The cows ate less concentrate at the higher levels of barley fibre
inclusion, so that there was a tendency for higher total DM intake only when the intermediate
levels of barley fibre (diets BF and FB) were given (quadratic effect; PcO.I).

Milk yield and fat corrected milk yield were not significantly affected by the level of barley
fibre. However, as the proportion of barley fibre in the diet was increased, milk protein con-
tent decreased (linear effect; P<0.01), there was a trend towards lower milk fat content (line-
ar and quadratic effect; P<o.l) and milk protein yield decreased (Pc0.05). At the same time
the digestibility of organic matter (OM) decreased from 0.742 to 0.661 (P < 0.001). Digestibili-
ties of ether extract and nitrogen were not affected by the diet but digestibilities of cell wall
components decreased with the level of barley fibre. Calculations of energy balance suggested
that the metabolizable energy of barley was either utilized less efficiently for milk production
or, more likely, cows given barley partitioned more energy to body fat stores than those given
barley fibre.

Index words: barley, barley fibre, silage, milk production

introduction

Traditionally, Finnish dairy concentrates nutritional shortcomings arising mainly from
have been based on cereal grains. Although its suppressive effect on silage intake (Castle
the energy value of barley is high, it has some 1982). To avoid this problem there has been

711

JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND

https://www.c-info.fi/en/info/?token=KDN-x235WN7hMmt1.VtLqExZGDJyfJXXwB5jYYQ.GwBdqf0VM5-A7tVgVeWnCA0u_bh0EcVH7eIT6SjFsqvPzZKI31x_fyx7kNQTEpJKCwXFnwlvRiLMCI2kc6nlZXXxd369SAtsV2PMyOaDpIIWtwfi9al1riL1mOLTjpUl06Y_DEe7ouTYM0NqBGS2YgqV9U5SJuKTlbDntI0A4UK7mPwB2uSjFVcn-L4pcz-tfrHLZGwq_a0KlxhWiomDOd1WgtynYSnrYTCYMoEtNg


Table 1. Composition of experimental diets.

Treatment

B BF FB F

Grass silage ad lib ad lib ad lib ad lib
Rapeseed meal (kg/d) 1.00 1.00 1.00 1.00
Concentrate (kg DM)

Barley 6.50 4.36 2.15
Fibre 2.15 4.36 6.50

Minerals' (kg/d) 0.25 0.25 0.25 0.25

In mineral mixture (g/kg): Ca 170, P 80, Na 60, Mg 80

interest in replacing barley by fibrous by-
products. At high level of concentrate inclu-
sion, cows given fibrous concentrate have
been found to consume more forage than
those given starchy concentrates (Thomas et
al. 1986, Sutton et al. 1987, Phipps et al.
1987). However, at lower level of supplemen-
tation (ca. 400 g/kg DM) no differences in si-
lage intake have been observed between barley
and sugar beet pulp (Castle et al. 1981.
Huhtanen 1987 a).

At present, sugar beet pulp and wheat bran
are the most important by-products incorpo-
rated in dairy concentrates in Finland, but new
fibrous by-products from integrated starch-
ethanol production from barley are becoming
available. These products, consisting mostly
of the cell walls of the endosperm, are
produced by a process corresponding to the
wet milling of maize, as described in detail by
Nasi (1988). Production started in 1987 and
is expected to climb to 35 millionkg in the next
few years. The objectives of the present study
were to compare the effects of barley fibre,
relative to barley, on feed intake, milk produc-
tion and diet digestibility.

Materials and methods

Animals and management

The experiment was conducted with eight
lactating Finnish Ayrshire cows. Four of the
cows were in their second of fifth lactation
and four were heifers. The multiparous cows

had calved 43 days (SE 2) and the heifers 103
days (SE 13) before the start of the experi-
ment. The animals were fed and housed in-
dividually and had free access to water. Silage
was given ad libitum and concentrates were
given at 5 and 14 h. Feed refusals were re-
moved and weighed after the morning feed-
ing.

Design and treatments

The experimental design was a duplicated
4x4 Latin Square with eight animals, four
treatments and four three-week experimental
periods. The heifers and the multiparous cows
were allocated to separate squares. The four
treatments consisted of grass silage ad libitum,
1 kg of rapeseed meal (RSM), 0.25 kg of
mineral mixture and one of the supplementary
feeds. The basal supplement was barley (B),
which in three treatments was replaced by 333
g/kg (BF), 667 g/kg (FB) and 1000 g/kg (F)
barley fibre (Table 1). RSM was treated to
reduce the ruminal degradability (Öljyn-
puristamo Oy, Helsinki). All the supplements
were given at the rate of 6.5 kg/d on dry mat-
ter (DM) basis. The ingredients of the concen-
trate mixture were weighed separately and
mixed before feeding. Direct-cut silage was
made from timothy-meadow fescue sward,
harvested with a precision-chop forage har-
vester and ensiled with a formic acid additive
(5 1/t).

Feed intake and milk yield were recorded
daily. Milk has taken for analysis at morning

712



Table 2, Chemical composition of experimental feeds (g/kg DM) and estimated feed values.

Silage Barley Fibre Rapeseed meal

Dry matter (g/kg) 210 872 936 888
In dry matter

Ash 74 23 104 75
Crude protein 152 137 118 353
Ether extract 53 37 78 93
Crude fibre 312 45 158 129
NFE 1 409 758 542 349
NDF 560 179 556 239
ADF 324 37 151 169
ADL 13 2 19 70
Cellulose 311 35 132 97
Hemicellulose 236 142 406 72
Starch nd. 551 119 nd.

Feed values
FFUVkg DM 0.706 1.184 0.909 1.027
ME MJ/kg DM 9.95 13.84 10.85 12.27
DCP J g/kg DM 104 103 90 293

nd. =not determined, 1 NFE =nitrogen free extracts, 2 FFU =fattening feed unit =0.7 kg starch, 5 DCP =digestible
crude protein. In silage: pH 3.88; in dry matter (g/kg): sugars 23, lactic acid 41, acetic acid 19, propionic acid 1.0,
butyric acid 0.6; in total nitrogen (g/kg): NH,-N 49, soluble N 548; D-value 0.622.

and evening milking on days 16 and 17of each
experimental period and bulked to provide a
sample. Live weights were determined at the
beginning of the experimental and on days 6,
7, 20 and 21.

Apparent digestibility of the diets was de-
termined using acid-insoluble ash (AIA) as a
natural maker (Van Keulen and Young

1977). Faecal grab samples were taken during
the last 5 days of each period at 7 and 16 h.

Chemical analyses

Samples of feeds were determined for DM
by drying at 103°C, and for organic matter
(OM) by ashing at 550°C. Feed analyses were
made according to standard procedures. Si-
lage DM content was corrected for volatile
losses of lactic acid, volatile fatty acids (VFA)
and ammonia according to Porter et al.
(1984). OM digestibility of silage was deter-
mined by the method of Tilley and Terry

(1963). Fermentation quality of the silage was
determined by methods described by Huhta-
nen (1987 a). Other analyses were for neutral
detergent fibre (NDF), acid detergent fibre

(ADF) and acid detergent lignin (ADL) ac-
cording to Goering and Van Soest (1970),
for starch by polarimetric method and for
AIA according to Van Keulen and Young

(1977). Feed values (feed units = FFU, digest-
ible crude protein = DCP) were calculated ac-
cording to Finnish Feed Tables (Salo et ai.
1982) and metabolizable energy according to
the Ministry of Agriculture, Fisheries and
Food (Maff 1975). Digestibility coefficients
for barley fibre determined in sheep were ob-
tained from Näsi (1988). Chemical composi-
tion of experimental feeds and estimated feed-
ing values are presented in Table 2.

Milk fat and protein contents were analysed
with an infrared milk analyser.

Energy utilization
The energy requirements for maintenance

were calculated according to the Agricultural
Research Council (ARC 1980) and the require-
ments for live weight change according to
Maff (1975). Milk energy was calculated
from equations of Tyrrel and Reid (1965).
ME intake was estimated from digestible OM

713



Table 3. Feed intake (kg DM/d) and estimated nutrient consumption in cows given grass silage ad libitum with in-
creasing levels of barley fibre.

Treatment SEM
18 df

Statistical
significance

of effect
B BF FB F L Q

Grass silage

Barley

9.91 10.56 11.25 11.56
2.09

0.23 NS
6.47 4.29 0.05

Fibre 2.13 3.97 5.10 0.29

Rapeseed meal
Concentrate total
Total DM intake
DM intake as %

of live weight

0.88 0.87 0.82 0.71 0.04

7.35 7.29 6.87 5.82 0.34 *• NS
NS NS17.26 17.86 18.12 17.38 0.35

3.12 3.27 3.31 3.15 0.06 NS •

DM intake as
g/kg W»” 151.2157.9 159.9152.5

15.5515.36 14.8613.53
198.8198.2 194.0179.1

1955 1989 1984 1874

3.04 NS *

••• NS
•• NS

NS NS

FFU/d 0.31
ME MJ/d
DCP g/d

3.72

38.9

SEM =standard error of means
Significance: NS (non-significant), * (P<0.05), ** (PcO.Ol), (P<0.001)
L, Q =linear and quadratic effect of the level of barley fibre

(DOM) as described by Huhtanen (1987 a)
and according to Mate (1975).

Statistical analyses

Statistical analyses were based on the results
for the last 7 days of each period except for
live weight and live change. The model used
to analyse the data was

yijklm -Si+ Cj (S) +Pk +T, + eUklm.

where S, C, P and T represent square, cow,
period and treatment effects. The sums of
squares for treatment effects were further par-
titioned using polynomial contrast into line-
ar, quadratic and cubic effects of the level of
barley fibre in the diet (Snedecor and
Cochran 1967).

Results

Feed intake

Replacement of barley with gradually in-
creasing levels of barley fibre led to a linear

increase (P< 0.001) in silage DM intake (Ta-
ble 3). At the same time, however, the cows
ate less concentrate mixture, SO that the to-
tal DM intake was not significantly affected.
There were large individual differences be-
tween the animals in the intake of the supple-
ments with the two highest levels of barley
fibre. The total DM intake tended, however,
to be higher when the intermediate levels (diets
BF and FB)) of fibre were given (quadratic
trend, P<o.l), and when expressed in terms
of kg DM/100 kg live weight the quadratic
trend reached statistical significance (P<
0.05). As the proportion of barley fibre in-
creased there was a linear decrease in esti-
mated FFU and ME intakes (P< 0.001;
PC0.01).

Because of the different carbohydrate com-
positions of barley and barley fibre, there were
marked differences in the intake of the vari-
ous carbohydrates (Table 4). As the propor-
tion of barley fibre in the diet increased, the
intake of starch decreased and the intakes of
cellulose and especially hemicellulose in-
creased.

714



Table 4, Daily intake (kg) of crude protein, ether extract, starch, crude fibre, NFE, NDF, ADF, cellulose and hemicel-
lulose in cows given grass silage ad libitum with increasing levels of barley fibre.

Treatment SEM Statistical
18 df significance

of effect

B BF FB F L Q

Crude protein 2.71 2.76 2.76 2.62 0.05 NS NS
Ether extract 0.85 0.97 1.06 1.08 0.03 NS
Starch 3.56 2.61 1.62 0.60 0.05 ••• NS
Crude fibre 3.50 3.94 4.34 4.51 0.08 NS
NFE 9.26 9.03 8.63 7.75 0.17 *** NS
NDF 6.91 8.08 9.07 9.48 0.18 *** NS
ADF 3.60 4.05 4.46 4.63 0.08 *** NS
Cellulose 3.39 3.80 4.17 4.33 0.07 **» NS
Hemicellulose 3.32 4.02 4.62 4.84 0.12 *** NS

For significance: see Table 3.

Table 5. Milk yield, milk composition and feed conversion in cows given grass silage ad libitum with increasing
levels of barley fibre.

Treatment SEM Statistical
18 df significance

of effect
B BF FB F L Q

Milk yield (kg/d) 24.4 25.1 24.6 24.0 0.41 NS NS
FCM yield (kg/d) 26.3 27.5 26.2 25.3 0.58 NS NS
Fat yield (g/d) 1105 1165 1089 1043 31 NS NS
Protein yield (g/d) 771 776 745 731 13 * NS
Milk composition

Fat (g/kg) 45.3 46.3 44.4 43.5 0.90 NS NS
Protein (g/kg) 31.9 31.3 30.5 30.6 0.28 •• NS

Live weight
Mean (kg) 555 550 550 554 2.66 NS NS
Change (kg/d) 0.14 0.30 0.13 0.07 0.19 NS NS

Feed conversion
FFU/kg FCM 1 0.417 0.382 0.392 0.356 0.02 NS NS
kg DM/kg FCM 0.663 0.663 0.697 0.694 0.01 * NS
DCP g/kg FCM 2 62.6 61.9 63.9 61.8 1.25 NS NS

1 Production feed units; intake corrected for maintenance and live weight change.
1 Production DCP; intake corrected for maintenance. For significance: see Table 3.

Milk yield and milk composition

There were no significant differences be-
tween the treatments in milk yield or 4 %-fat
corrected milk (FCM) yield (Table 5). Milk
protein content decreased linearly (PcO.Ol)
and there was a tendency (linear effect,
P<0.07) for lower milk fat content as the
proportion of barley fibre increases. Milk pro-

tein yield decreased (linear effect, P< 0.005),
but milk fat yield was not significantly af-
fected although there was a tendency for lin-
ear (P<0.07) and quadratic (P<0.10) effects,
with a maximum value being observed when
diet BF was fed and a minimum value when
diet F was fed. There were no differences be-
tween cows and heifers in their response to the
dietary treatments and the treatment * square

715



716

term in statistical analyses was small. No sig-
nificant differences were observed in live
weight. Live weight changes were positive for
all treatments, but they were variable between
the animals and no consistent diet effect was
observed.

Feed conversion expressed in terms of
production FFU/kg FCM tended to improve
as the proportion of barley fibre in the diet
increased. However, the amount of DM con-
sumed per kg of FCM, increased lineary at the
same time (P<0.05).

Digestibility

The digestibility of DM and OM decreased
linearly (P< 0.001) as the Wei of barley fibre
increased (Table 6), while the digestibilities of
N and ether extract did not change NDF and
ADF digestibilities decreased (linear effect,
PcO.OOl; quadratic effect, P<0.05), with the
minimum value being observed when diet FB
was fed. Likewise, the digestibilities of cellu-
lose and hemicellulose decreased with the level
of barley fibre (linear effect, PcO.Ol). The
digestibility of barley fibre calculated as a
difference averaged 0.669 (SE 0.021) and was
not significantly affected by the level of barley
fibre.

Energy balance

In spite of the slightly higher OM intake
when diets BF and FB were fed (Table 7),
DOM and estimated ME intakes decreased as
the proportion of barley fibre in the diet in-
creased (linear effect, PcO.OOl). Milk ener-
gy output tended to decrease (linear effect,
P<0.06), although the reduction was evident
only when diet F was fed. The efficiency of
transferring surplus ME into milk (k,) im-
proved with the level of barley fibre (linear ef-
fect, P< 0.001) when live weight change was
ignored. Including live weight change, the ef-
ficiency of utilization of ME averaged 0.628
(SE 0.017) and tended to improve as the
proportion of barley fibre increased. The
difference did not reach statistical significance

because of the wide variation in estimated ME
output from live weight change.

Discussion

The increased silage DM intake with in-
creased level of barley fibre was confounded
by the reduced intake of the supplement.
However relative to the diet of barley alone,
there were increases of 0.60and 0.86kg in the
total DM intake when diets BF and FB were
fed. The reasons for higher feed intakes with
diets BF and FB are uncertain but may be
related to less pronounced post-prandial
depression in rumen pH and more efficient
cellulolysis in the rumen. The adverse effects
of barley on silage intake have their origin in
reduced cellulolytic activity in the rumen
(Thomas and Chamberlain 1982). Dietary
starch content decreased from 206 to 35 g/kg
DM as the proportion of barley fibre in the
diet increased. Huhtanen (1988), however,
did not find any differences between barley
and unmolassed sugar beet pulp supplements
in their effects on rumen pH or on the degra-
dation of silage or hay DM when the supple-
ments comprised 520 g/kg of the total DM in-
take.

There is some contradiction in the literature
regarding the effect of different carbohydrate
supplements on silage intake. Thomas et al.
(1986) observed 0.9 kg higher silage DM in-
take with a mixture of unmolassed sugar beet
pulp and rice bran than with barley based con-
centrate. Phipps et al. (1987) reported 0.5 kg
higher silage DM intake for cows given fibrous
concentrates than for those given starchy con-
centrates. In experiments where the supple-
ment comprised 400—500 g/kg of the total
DM intake, no differences were found be-
tween sugar beet pulp and barley supplements
(Castle et al. 1981, Huhtanen 1987 a). In
the present study the supplements comprised
from 335 (diet F) to 426 (diet B) g/kg of the
total DM intake.

The present results are in agreement with
a number of other trials in which starchy and
fibrious concentrates had the same effect on



Table 6. Digestibility of different dietary constituents in cows given grass silage ad libitum with increasing levels
of barley fibre.

Treatment SEM
18 df

Statistical
significance

of effect
B BF FB F L Q

Dry matter 0.726 0.700 0.658 0.639
0.742 0.718 0.679 0.661
0.696 0.706 0.695 0.682
0.581 0.655 0.624 0.590
0.763 0.726 0.680 0.663
0.688 0.670 0.639 0.656
0.696 0.676 0.643 0.660
0.742 0.729 0.701 0.717
0.679 0.665 0.636 0.651

0.006 NS
... NS
NS NS
NS NS

NS
*** *

Organic matter
Crude protein
Ether extract
Crude carboh. 1
NDF

0.006
0.007
0.026
0.006
0.007

ADF
Cellulose
Hemicellulose

0.008 ***

0.007 ** NS
*» NS0.007

1 Crude carbohydrates =NFE +crude fibre.
For significance: see Table 3.

Table 7. Calculated energy balance (MJ/day) and efficiency of conversion of surplus to maintenance into milk in
cows given grass silage ad libitum with increasing levels of barley fibre.

Treatment SEM Statistical
18 df significance

of effect

B BF FB F L Q

OM intake (kg/d) 16.32 16.70 16.79 15.95 0.32 NS NS
DOM 1 intake (kg/d) 12.15 12.01 11.40 10.57 0.26 *•» NS
DE intake2 230.8 228.1 216.6 200.9 4.91 NS
ME intake 198.5 196.2 186.2 172.7 4.23 ••* NS
ME from change of
live weight 3 —5.7 —11.3 —4.9 —2.8 6.14 NS NS
Energy output

Maintenance 51.9 51.6 51.6 51.9 0.19 NS NS
Milk 80.3 83.3 79.3 76.7 1.61 NS NS

Efficiency
Ignoring live
weight change 0.556 0.577 0.593 0.637 0.014 *** NS
Including live
weight change 0.574 0.649 0.628 0.662 0.036 NS NS

NE/DE 4 0.510 0.543 0.539 0.562 0.018 NS NS

1 DOM =digestible organic matter.
2 DE = digestible energy.
3 Allowing 28 MJ for each kg lost and subtracting 34 MJ for each kg gained.
4 NE = net energy for milk, live weight gain (20 MJ/kg) and maintenance (0.3 MJ/kg W 0 75 ).

For significance: see Table 3.

the milk yield of cows given grass silage based
diets (Castle et al. 1981, Mayne and Gordon
1984, Thomas et al. 1986, Phipps et al. 1987,
Sloan et al. 1987). The effect of barley fibre
on milk production has not been studied

earlier, but feeding of a corresponding by-
product from the corn wet-milling industry,
maize gluten feed, led to lower milk yield
when it replaced maize and soybean meal in
complete mixted diets (Staples et al. 1984,

717



Macleod et al. 1985). The lower yield was at-
tributable to the reduced feed intake. Replac-
ing maize and soybean meal by maize gluten
feed in dry form increased feed intake and
thereby increased FCM yield (Macleod et al.
1985).

A tendency for lower milk fat content with
increasing level of barley fibre agrees with the
observations of Thomas et al. (1986) and
Huhtanen (1987 a) for experiments where
unmolassed sugar beet pulp based supple-
ments was substituted for barley at the level
of 420—440 g/kg of the total DM intake,
similar to the present study. Likewise Castle
et al. (1975) reported a higher milk fat con-
tent in cows given barley supplements than in
those given dried grass supplements with grass
silage ad libitum. Higher milk fat content in
cows given silage and barley may be related
to a high proportion of butyrate in rumen
VFA (Huhtanen 1987 b). Supplementation
of silage diets with barley leads to a marked
increase in the number of total protozoa in the
rumen (Chamberlain et al. 1985) which may
explain the high proportion of butyrate in ru-
men VFA. In contrast to the present results,
Staples et al. (1984) and Macleod et al.
(1985) reported higher milk fat content with
on maize gluten than on diets of maize.

Linear decrease in milk protein content as
the proportion of barley fibre in the diet was
increased agrees with the results of Staples et
al. (1984) and Macleod et al. (1985). The
reasons for the decrease are uncertain but
threepoints need to be considered. First, there
where differences in the intakes of supplement
and RSM, too. However, the reduction in the
intake of supplement was small, and in fact
the total DM intake tended to be higher when
diets BF and FB were given. Second, the di-
gestibility of OM decreased with the level of
barley fibre in the diet and consequently DE
intake decreased. The reduction in DE intake
was rather small when diets BF and FB were
given and it is unlikely that differences in the
intake of supplement or DE can explain the
lower milk protein content totally.

The third point is the difference in fat con-

tent of the supplements: the fat content of
barley fibre was 41 g/kg higher than that of
barley. It is well recognised that increasing the
fat content of dairy cow diets leads to a lower
milk protein content (see Thomas 1984). In a
number of trials the energy source of the sup-
plement was found not to affect milk protein
content (Castle et al. 1981, Mayne and Gor-
don 1984, Sloan et al. 1987, Huhtanen
1987 a). However, Thomas et al. (1986) and
Phipps et al. (1987) found a tendency for
concentrates based on highly digestible fibre
sources to decrease milk protein content. The
lower milk protein content associated with the
use of concentrate based on sugar beet pulp
and rice bran (Thomas et al. 1986) may well
have been due to inclusion of fat in the con-
centrate and not the digestible fibre per se.
Also Thomas and Robertson (1987) observed
a large reduction in milk protein content when
of 60 g fat/kg was included in concentrate
containing a large proportion of fibrous by-
products.

The reduction in the digestibility of DM and
OM with increasing level of barley fibre is
similar to that reported by Staples et al.
(1984) when the proportion of wet maize glut-
en feed in the diet was increased. On the oth-
er hand, when barley was replaced by sugar
beet pulp (Mayne and Gordon 1984, Huhta-
nen 1987 a) or starchy concentrate by fibrous
concentrate (Phipps et al. 1987), no differ-
ences in OM digestibility were observed. OM
digestibility of barley fibre calculated by
difference was markedly lower in the present
experiments than was found in sheep (0.67 v.
0.74) fed at the maintenance level (Nasi
1988). The size of barley fibre particles is small

and they were available for passage without
further comminution. The small particle size
is necessary for the starch process. Because the
level of feed intake in dairy cows was 3—4
times higher than in sheep, digesta retention
time is shorter (Growum and Williams 1977),
with reduced digestibility. The lower digesti-
bility of barley fibre in lactating dairy cows
than in sheep is in agreement with results of
Steg et al. (1985) and Sutton et al. (1987),

718



who reported a greater reduction in the digest-
ibility of diets based on fibrous by-products
than of diets based on starchy supplements
when the level of feeding was raised.

In contrast to the present results, Staples

et al. (1984) found that digestibilities of NDF,
ADF and especially hemicellulose were linear-
ly increased by substitution of wet maize
gluten feed for maize and soybean meal. This
may indicate that the digestibilities of cell wall
carbohydrates of maize gluten feed are higher
than those of barley fibre. It seems unlikely
that barley fibre reduced the digestibility of
grass silage because silage intake was increased
with increasing level of barley fibre. Rather,
this argues that the cell wall components of
barley fibre were less digestible than those of
grass silage. As the proportion of barley fibre
in the diet increased, the supplement con-
tributed proportionately more to the intake of
cell wall components.

The difference in ME intakes estimated
from feed tables and based on digestibility
measurements increased with the proportion
of barley fibre in the diet. This can partly be
attributed to the use of the same energy value
for DOM (19 MJ/kg DOM) for all diets ir-
respective of fat content and partly to the
reduced digestibility of barley fibre at high
level of intake in dairy cows. The value of
0.637 for the efficiency of utilization of ME
for milk production when diet F was given is
similar to values of Maff (1975) and ARC
(1980), suggesting that the cows were close to
energy balance. On the other hand, lower
values with higher levels of barley in the diet
indicate either lower efficiency of ME utiliza-
tion or, more likely, a change in energy parti-

tioning. In a previous trial, plasma insulin
concentration was significantly higher in cows
given barley than in those given sugar beet
pulp (Miettinen and Huhtanen 1987, unpub-
lished), which would be expected to increase
the uptake of nutrient by adipose tissue while
depressing lipolysis.

Subtracting ME requirements from ME in-
take gives the ME available for production
(ME

P
), and the ME used for milk production

was calculated as milk energy/k, (a value of
0.62 was used for k„ Maff 1975). The differ-
ence between MEP and milk energy/k, was
considered to be associated with body weight
change. Estimates for body energy balance in-
dicate that, as the proportion of barley fibre
in the diet increased, the cows were storing less
energy in the body. ME balance estimates were
17, 10, 7 and —3 MJ for diets B, BE, FB and
F, respectively.

Conclusions

The productive value of barley fibre in lac-
tating dairy cows given grass silage ad libitum
was better compared with barley than could
be estimated from digestibility values deter-
mined in sheep. Calculation of energy balance
suggested that, relative to other diets, cows
given barley partitioned more energy to adi-
pose tissue and cows given increasing amounts
barley fibre partitioned a greater proportion
of the production energy to milk. Because the
cows refused to eat all the supplement con-
taining barley fibre alone, we do not recom-
mend using this kind of barley fibre alone as
energy supplement.

References

Arc. (Agricultural Research Council) 1980. The Nu-
trients Requirements of Ruminants. Commonwealth
Agricultural Bureaux. 351 p. London.

Chamberlain, D.G. Thomas, P.C., Wilson, W., New
hold, C.J. & MacDonald, J.C. 1985. The effects of

carbohydrate supplements on ruminal concentration of
ammonia in animals given grass silage. J. agric. Sci.,
Camb. 104: 47—58.

Castle, M.E. 1982. Feeding high-quality silage. Silage
for milk production. (Ed. Rook, J.A.F. & Thomas,

719



P.C.). Technical Bulletin 2. pp. 127—150. National Re-
search Institute for Research in Dairying, Read-
ing/Hannah Research Institute, Ayr.
, M.E., Gill, M.S. & Watson, J.N. 1981. Silage and
milk production: a comparison between barley and
dried sugarbeet pulp as silage supplements. Grass and
Forage Science 36: 319—324.
& Watson, J.N. 1975. Silage and milk production: a
comparison between barley and dried grass as supple-
ments to silage of high digestibility. J. Br. Grassl. Soc.
30: 217—222.

Goerino, H.R. & Van Soest, P.J. 1970. Forage fiber
analyses. Agriculture Handbook No. 379. United States
Dept, of Agric. Washington.

Grovum, W.L. & Williams, V.J. 1977. Rate of passage
of digesta in sheep. 6. The effect of level of food in-
take on matematical predictions of the kinetics of diges-
ta in the reticulorumen and intestines. Br. J, Nutr. 30;
313—329.

Huhtanen, P. 1988. The effects of barley, unmolassed
beet pulp and molasses supplements on organic mat-
ter, nitrogen and fibre digestion in the rumen of cattle
given silage diet. Anim. Feed Sci. Technol. (In Press)

1987 a. The effect of dietary inclusion of barley, un-
molassed sugar beet pulp and molasses on milk produc-
tion, digestibility and digesta passage in dairy cows given
silage based diet. J. agric. Sci Finl. 59: 101—ll9.

1987 b. The effect of carbohydrate supplements on the
utilization of grass silage diets, pp. 1—45. Academic
Dissertation. Department of Animal Flusbandry,
University of Helsinki SF-00710 Helsinki.

Macleod, G.K., Droppo, T.E. Grieve, D.G., Barney,
D.J. & Rafalowski, W. 1985. Feeding value of wet
corn gluten feed for lactating dairycows. Can. J. Anim.
Sci. 65: 125: 134.

Maff (Ministry of Agriculture, Fisheries and Food).
1975. Energy allowances and feeding systems for

ruminants. Technical Bulletin 33. 79 p. London.
Mayne, C.S. & Gordon, F.J. 1984. The effect of type of

concentrate and level of concentrate feeding on milk
production. Anim. Prod. 39: 65—76.

Miettinen, H. & Fluhtanen, P. 1987. The effect of the
type of supplement on blood metabolites in dairy cows
given grass silage ad libitum. Unpublished.

Näsi, M. 1988.Evaluating of barley feed fractions from
integrated barley ethanol-starch process in diets of
ruminants. J. agric. Sci Finl. 60: 701—709.

Phipps, R.H., Sutton, J.D., Weller, R.F. & Bines, J.A.
1987. The effects of concentrate composition and meth-
od of silage feeding on intake and performance of lac-
tating dairy cows. J. agric. Sci., Camb. 109: 337—343.

Porter, M. G., Patterson, D.C., Steen, R.W. & Gor-

don, F.J. 1984. Determination of dry matter and gross
energy of grass silage. Proc. 7th Silage Conf. Queens’s
Univ. Belfast. (Ed. Gordon, F.J. & Unsworth, E.F).
pp. 89—90.

Salo, M-L., Tuori, M. & Kiiskinen, T. 1982, Re-
hutaulukot ja ruokintanormit. 70 p. Helsinki.

Sloan, B.K. & Rowlinson, P. 1987. A note on concen-
trate energy source for dairy cows in mid lactation.
Anim. Prod. 45: 321 —323.

Snedecor, G.W. & Cochran, W.C. 1967. Statistical
methods. 6th Ed. 593 p. The lowa State Univ. Press.
Ames, USA.

Staples, C.R., Davis, C.L., McCoy, G.C. & Clark,
J.H. 1984. Feeding value of wet corn gluten feed for
lactating dairy cows. J. Dairy Sci. 67: 1214—1220.

Steg, A., Honig, Y. Van Der & Visser, H. De. 1985. Ef-
fect of fibre in compound feed on the performance of
ruminants. Recent Advances in Animal Nutrition. (Ed.
Haresign, W. & Cole, D.J.A.) pp. 113—129. Butter-
worths.

Sutton, J.D., Bines, J.A., Morant, S.V., Napper, D.J.
& Givens, D.I. 1987. A comparison ofstarchy and fi-
brous concentrates for milk production, energy utili-
zation and hay intake by Friesian cows. J. agric. Sci.,
Camb. 109: 375—386.

Thomas, C., Aston, K., Daley, S.R. & Bass, J, 1986.
Milk production from silage. 4. The effect of the com-
position of the supplement. Anim. Prod. 42: 315—325.

Thomas, P.C. 1984. Feeding and milk protein produc-
tion. In Milk Compositional quality and its Importance
in Future Markets (Ed. Castle, M.E. & Gunn, R.G.),
Occ. Pubi. Br. Soc. Anim. Prod, No. 9, Pp. 53—67.

Thomas, P.C. & Robertson, S. 1987. The effect of lipid
and fibre source and content on silage intake, milk
production and energy utilization. In Eighth Silage
Conference, Summary of Papers. Sept. 1987. pp.
173—174.
& Chamberlain, D.G. 1982. Silage as a foodstuff. In
Silage for Milk Production (Ed. Rook, J.A.F. & Tho-
mas, P.C.) pp. 63—101. National Research Institute
for Research in Dairying. Reading/Hannah Research
Institute, Ayr.

Tilley, J.M.A. & Terry, R.A. 1963. A two-stage tech-
nique for in vitro digestion of forage crops. J. Br.
Grassl. Soc. Society 18: 104—111.

Tvrrel, H.F. & Reid, J.T. 1965. Prediction of energy
value of cow’s milk. J. Dairy Sci. 48: 1215—1223.

Van Keulen, J. & Young, B.A. 1977. Evaluation of acid-
insoluble ash as a natural marker for digestibility
studies. J. Anim. Sci. 44: 282—287.

Ms received

720



SELOSTUS

Ohran ja integroidusta tärkkelys-
etanoliprosessista saatavan ohrarehun
vaikutus säilörehun syöntiin ja
maidontuotantoon

Pekka Huhtanen, Hannele Ala-Seppälä ja
Matti Näsi
Helsingin yliopisto, kolieläinlieleen laitos,
00710 Helsinki

Tutkimuksessa verrattiin ohran ja integroidusta tärk-
kelys-etanoliprosessista saatavan ohrarehun (120 g raa-
kavalkuaista, 550 neutraalidetergenttikuitua, 120gtärk-
kelystä/kg kuiva-ainetta (ka)) vaikutusta säilörehun syön-
tiin, maidontuotantoon ja rehun sulavuuteen lypsylehmil-
lä. Koe-eläiminä oli 8 Ay-lehmää, joistapuolet oli ensik-
koja. Koe tehtiin kaksinkertaisena 4x4 latinalaisena ne-
liönä. Perusväkirehuna oli ohra (A), josta 1/3 (B), 2/3
(C) tai 3/3 (D) korvattiin ohrarehulla. Näitä rehuja an-
nettiin 6.5 kg ka/pv, minkä lisäksi lehmät saivat I kg:n
rypsirouhetta ja 0.25 kg kivennäisseosta päivässä. Säilö-
rehua oli vapaasti saatavilla 24 tuntia vuorokaudessa.

Ohrarehun osuuden lisääntyessä säilörehun kuiva-ai-
neen syönti lisääntyi 9.91 kg:sta 11.56 kg:aan/pv
(P< 0.001). Ohrarehun huonomman maittavuuden vuoksi
lehmät söivät runsaasti ohrarehua sisältäviä väkirehuja
(C; D) vähemmän kuin pelkkää ohraa, joten erot kuiva-
aineen syönnissä yhteensä olivat pienempiä eivätkä olleet
tilastollisesti merkitseviä. Ruokinnoilla B ja C kuiva-ai-
neen syönti oli keskimäärin 0.73 kg (P<o.l) suurempi
kuin pelkkää ohraa saaneilla lehmillä.

Ohrarehun osuudella ei ollut merkitsevää vaikutusta
maitotuotokseen (keskimäärin 24.6 kg/pv) eikä rasvakor-
jattuun maitotuotokseen. Maidon valkuaispitoisuus ale-
ni merkitsevästi (P< 0.01) ohrarehun osuuden lisääntyessä
ja sama suuntaus(P<o.l) oli todettavissa myös rasvapi-
toisuuden osalta.

Väkirehun muuttuessa pelkästä ohrasta pelkkään
ohrarehuun maitovalkuaisen tuotanto väheni 5.2 °7o
(P<0.05).

Ohrarehun sulavuus oli huonompi kuin ohran ja diee-
tin orgaanisen aineen sulavuus laski 0.742:5ta 0.661 :een
(PcO.OOl) lisättäessä ohrarehun osuus o:sta 100 %:iin
väkirehussa. Raakavalkuaisen ja raakarasvan sulavuuteen
ohrarehulla ei ollut vaikutusta, multa solunseinämäainei-
den sulavuus huononi ohrarehun osuuden lisääntyessä.
Laskelmat energian hyväksikäytöstä osoittavat, että oh-
ran muuntokelpoisenenergian hyväksikäyttö maidontuo-
tantoon oli huonompi kuin ohrarehun tai todennäköisem-
min, ohraa saaneet lehmät käyttivät suuremman osan
energiasta kudosvarastojen kasvattamiseen maidontuo-
tannon sijasta kuin ohrarehua saaneet.

721