The influence of partial replacement of barley with dietary fat sources
on growth and feed conversion efficiency of growing bulls

Alem Tsehai Tesfa, Mikko Tuori and Liisa Syrjälä-Qvist

Tesfa, A.T., Tuori, M. & Syrjälä-Qvist, L. 1992. The influence of partial replace-
ment of barley with dietray fat sources on growth and feed conversion efficiency
of growing bulls. Agric. Sei. Finl. 1: 267-278. (Univ. Helsinki, Dept. Anim. Sei., SF-
-00710 Helsinki, Finland.)

This paper presents animal performance and carcass quality in an experiment con-
ducted to observe the effect of replacing some of the barley in a concentratemixture
with different fat sources and wheat bran. The treatments were: concentrate mixture
with no added fat (control); in the test feeds, some of the barley was replaced with 5 %

of a fat source plus 10 % wheat bran, 1 % wheat molasses and 1 % Ca-lignosulphonate.
The fat sources were rapeseed oil (RSO), calcium salt palm fatty acids (CaSFA), or tal-
low (TS). These four concentratemixtures were fed to growing bulls with hay (45:55)
at a rate of 85 g dry matter kg' 1 metabolic body weight (W075).

Partial replacement ofbarley with different fat sources slightly decreased dry matter
intake and thereby reduced the daily intake of estimated metabolizable energy in all fat
containing diets. Average daily weight gain was 1.20; 1.05; 1.05 and 1.08 kg for the
control as to RSO; CaSFA and TS, respectively. Carcass weight was similar forall fat
sources but slightly higher for the control diet, while dressing percentage was slightly
lower for the control diet. Feeding RSO, TS or CaSFA had no effect on feed conver-
sion efficiency in comparison to the control. No apparent difference was observed
between treatments on carcass quality and palatability scores of the meat. Oleic and
stearic acids were increased for RSO and TS containing diets as compared to the con-
trol and CaSFA containing diets.

Key Words: Weight Gain, Longissimus dorsi, carcass composition, Fatty Acids

Introduction

The effects of adding fat to the diet of ruminants is
a complex subject involving the levels, sources and
forms of fats as well as their interactions with
rumen metabolism. Generally, nutritional benefits
obtained from replacing grain with fat are often
below the theoretical benefits due to the removal of
carbohydrates from the ration. Replacing 30 % of
flaked com with 14 % protected tallow improved
the performance of steers in short term feeding
(Haaland et al. 1981), while replacing 8-28 % of

corn-grain mixture with 10-30 % protected safflo-
wer oil decreased daily weight gain (Dinius et al.
1975). On the other hand, Boucque et al. (1990)

reported no effect on live weight gain ofbeef cattle
when 17% ofwheat was replaced with 2.5 % or 5.0
% hydrolysed animal-vegetable fat. Adverse
effects of fat on feed intake and feed conversion
efficiency have also been reported (Haaland et al.
1981; Oltjen and Dinius 1975).
If replacing grain increases energy intake by the

animal, the level of animal performance can be
increased per cost of gain (feed/weight gain) thus

267

Agric. Sei. Fin!. 1 (1992)

https://www.c-info.fi/en/info/?token=4BNfFw58PCSIOVA5.fGc8pWsdjS2hdmvXw-ePmg.k7GgOwFJBxlcB7rYYk_uFI68Yeu4BnBuFMHJ8zIC35kQO7OfFHvYiY9xpU6d5xAa4FqZXIxmsXS1zwTkVT2aXsU6wVfTTeZdNqleAfPeJTjD8tNPWkt5o2akocTV9zHIZq__a0WgEqr6FLkb0zxHZgrwJtyIHJhjuhoWE31dS4fOXty8BdUNonP0EzsXAlgC3HuyvXSKiWIc_NG4SS48nFFcQime8vctFvd-K4y0A7KMWHOcoCEFNFZ1dkuYVqA06uVr57xbYTMXhh4sDR8W23wA7vnkUwkrM0gCbBKLCWLUv7c53XuWhftyzzk9zIhbYkeQESt2yg


improving feed conversion efficiency. The object-
ives of this experiment were to determine the effect
of partial replacement of barley with RSO, TS and
CaSFA on feed conversion efficiency, carcass and
meat quality of growing bulls.

Material and methods

Animals

Twenty eight dairy breed (Friesian-Ayrshire)
growing bulls with average initial weights of 123
kg were randomly allotted into four treatment
groups with seven animals in each group. The an-
imals were individually penned and fed the treat-
ments for a period of 256 days. The animals
remained on the prescribed treatment until the ter-
mination of the experiment except for two animals,
one in the control group and the other in the CaSFA
group.

Feeds and feedings

The dietary treatments were; commercial concen-
trate mixture with no added fat (Control); in the test
feeds, part of the barley was replaced by 5 % rape-
seed oil (RSO); or 5 % calcium salt palm fatty acids
known by the trade name of Megalac produced by
Volac Ltd, Cambridge (CaSFA); or 5 % tallow
(TS). In addition, the test feeds contained 10 %

wheat bran, 1 % wheat molasses and 1 % Ca-ligno-
sulphonate. The forage was timothy ( Phleum pra-
tense) hay. The bulls were fed with 85 g DM
(concentrate:hay ratio, 45:55 on DM basis) kg' 1
metabolic body weight (W075 ) given in two equal
portions a day. The hay was chopped before it was
given to the animals. Water was available freely at
all time. A mineral mixture was given at a rate of
100 g d' 1 throughout the trial. Feed allowances were
adjusted every 28 days on the basis of live weight
changes.

Digestibility and fermentation study

A digestion trial was conducted with all the experi-

mental animals using acid insoluble ash (AIA) as
an internal marker (Van Keulen and Young,
1977). Faecal grabs were collected rectally twice

daily at 07.30 and 15.30 h for a period of 7 days at
the end of the trial. Daily samples were frozen until
the end of collection period. All samples were
thawed, mixed and sub-sampled per animal per diet
at the end of the collection period.

The gross energy of the feeds and faeces was
determined in an adiabatic bomb calorimeter. The
digestible energy (DE) of the diets was determined
in vivo on the bulls. The metabolizable energy
(ME) of the diets was calculated as 81 %ofthe DE
of the diet. The efficiency of feed energy utilization
was calculated according to the equations proposed
by the Agricultural Research Council (ARC 1980)
to estimate energy retained as gain.

The effects of fat sources on rumen fermentation
were tested in vitro in a continuous culture fermen-
ter according to Miettinen and Setälä (1989).
Twenty three grammes of hay and concentrate
mixture (50:50) and 5 % of each fat source were fed
to the fermentation vessels daily. The fermentation
culture was stabilized for 3 days followed by a 2-
day sampling. The concentrations of the total and
individual volatile fatty acids (VFA) were deter-
mined.

Weighing and feed sampling

Upon the initiation of the trial and subsequently at
28 day intervals, the animals were weighed before
the morning meal and the weight change of each
animal was recorded. Concentrate feeds and hay
were sampled every week and pooled for each
month.

Chemical analysis

The chemical composition of the feeds and VFA
from in vitro fermentation study were analyzed as
explained previously (Tesfa et al. 1991a). Faecal
and feed samples were analyzed for the AIA (Van
Keulen and Young 1977).

268

Agric. Sei. Finl. 1 (1992)



Slaughtering and sampling

At the termination of the trial, the final live weight
of the bulls was recorded and the animals were
slaughtered after 24 h fasting. Pelvic fat including
kidney knobs were totally removed from both sides
of the carcasses and weighed. The cold carcasses
were weighed and graded visually for fatness and
conformation using the five-point scale of the Fin-
nish Slaughter House Classification Scheme. Dres-
sing percentage for each animal and for the group
was calculated as a proportion of cold carcass
weight to final live weight.

Right half sides of three bulls from each group
were randomly selected, cooled for 24 hours at
+4°C and measured for specific gravity (sg) in
water at +4°C according to Kraybill et al. (1952).
Empty body weight (EBW) was calculated accord-
ing to Garrett and Hinman (1969) using the equa-
tion EBW = 1.362 X + 30.26, X being carcass
weight.

The carcasses were then cut to retail cuts. The rib
cuts were marked to obtain samples of longissimus
dorsi muscle between the 9-12th ribs and trimmed
to determine physically separable fat, lean and
bone. The lean part of the section of the longissi-
mus dorsi muscle at the end of the 12th rib was
used for the determination of moisture, ether
extract, crude protein and fatty acids composition.

Sensory assessment

Boneless rib roasts from the longissimus dorsi
muscle between 9-12thribs were vacuum packed in
polyethylene bags, aged for 20 days at +4°C and
were roasted to an internal temperature of70°C in a
microwave oven. The roasts were removed from
the oven and allowed to stand at room temperature
for approximately 15 minutes. A cut of about 1.5
cm2 were served on a preheated plate to an experi-
enced six member sensory panel for assessment of
palatability differences.Panellists scored the samp-
les for visual acceptance, tenderness, flavour and
juiciness using an eight point hedonic scale.

Instron testing

Three cooked cuts (1.5 cm diameter) from each car-
cass were prepared and each cut was sheared once
at the right angles of the muscle fibres with an
Instron Universal Testing Machine (INSTRON
1140).

Meat chemical composition

Moisture content was measured by oven drying at
105°C for 24 h, crude protein was analyzed by the

Kjeldhal method and fat by extracting with
petroleum-ether. The lipid portion of the adipose
tissue was extracted with chlorofomrmethanol (2; 1
v/v) and an aliquot of the total lipid extract was
evaporated under nitrogen. Approximately 100 mg
of the total lipid extract was mixed with the internal
standard (Cl2:0 methyl ester) and methylated
according to Christie (1982). Fatty acids methyl
esters were analyzed with gas chromatography.
The nitrogen carrier gas and hydrogen flow rates
were 20 ml min' 1 and the air flow rate was 300 ml
min 1. The chromatography was operated with a
thermal gradient from 80°C to 200°C at a rate of
16°C min 1 . Peak areas were computed using a
microcomputer connected to the chromatography.

Statistical analysis

The data were analyzed by a one-way analysis of
variance with dietary treatment as the only effect
and tested with the Tukey test. The dietary effect
was further partitioned using orthogonal contrast to
test the differencesbetween control and fat sources
and between fat sources as follows: control against
others, rapeseed oil against CaSFA and TS, and
CaSFA against TS.

Results

The mean chemical composition of the feeds and
fatty acid composition of the concentrates offered
to the bulls during the trial is given in Table 2. Pal-
mitic acid (C 160)

is considerably higher in CaSFA

269

Agric. Sei. Finl. 1 (1992)



due to its origin from fat. The control diet contained
higher concentrations of linoleic acid (C ]S,2). Stea-
ric acid (C |g 0)

levels were quite similar except for
TS. There was a wide variation in oleic acid (C lg l)

among treatments, ranging from 12.0 g 100 g-1 in
TS to 39.3 g 100 g ' in RSO.

Mean dry matter intake (DMI) tended to decrease
with fat inclusion compared to the control. CaSFA

Table 1. Concentrate feed ingredients, g kgl

Dietary groups
Control RSO CaSFA TS

Ingredients:
Barley 498 328 328 328
Oat 250 250 250 250
Soybean meal 120 120 120 120
Wheat bran - 100 100 100
Wheat molasses 40 50 50 50
Skim milk 30 30 30 30
Rapeseed oil - 50
Calcium salt fatty acids - - 50
Tallow - - - 50
Ca-Ligninsulphonate 20 30 30 30
Mineral mix 35 35 35 3535 35 35 35
Vitamins, ADE 7 7 7 7

Table 2. Diet chemical composition.

Dietary groups
Hay Control RSO CaSFA TS

Dry matter.g kg’ 1 838 868 874 872 882

In DM, g kg-1 DM
Crude protein 116 171 173 174 169
Ether extract 23 42 95 87 104
Ash 62 62 73 76 69
Neutral detergent fibre 683 172 218 216 213
Acid detergent fibre 366 53 84 79 84

GE, MJ kg' 1 DM 19.1 19.2 19.6 19.4 19.819.1 19.2 19.6 19.4 19.8

Fatty acid content, g 100 g 1 of total fatty acids
C16:0 19.9 11.2 319.9 11.2 39.7 18.4
C16:l 0.3 0.3 0.3 0.1
cl8:0 1.9 2.0 3.8 40.9
C 18:1 18.9 41.1 29.1 12.5
C18:2 48.2 33.9 18.7 19.8
cl8:3 5.7 7.3 1.6 1.9
C20:0-C24:0 0.6 0.8 0.7 1.8
C20:l-C24:l 1.1 1.5 0.5 0.5

GE, gross energy.
270

and TS fed animals consumed about the same
amount (7.1 and 8.2 % less than the control) of DM
while the RSO group consumed 13.2 % less than
the control group and 6 % less than the two fat
groups (Table 3). Fat (from concentrate) intake (g
d 1) was 113 (control), 241 (RSO), 228 (CaSFA),
and 279 (TS). The mean daily intake of neutral
detergent fibre (NDF) and crude protein (CP) was

Table 3. Daily feed and feed energy intake by bulls.

Dietary groups
Control RSO CaSFA TS
n=6 n=7 n=6 n=7

Intake, kg DM d' 1
Total DMI 6.44 5.65 5.98 5,91
Hay 3.74 3.06 3.37 3.22
Concentrate 2.70 2.59 2.61 2.69

Neutral detergent fibre, kg d' 1 3.02 2.65 2.86 2.77
Acid detergent fibre, kg d’ 1 1.51 1.34 1.44 1.41
Crude protein, g d" 1 894 802 845 828894 802 845 828
Total fat, g d- 1 217 326 321 368
Fat:DMI, % 3.36 5.77 5.36 6.23
Energy intake, MJ d 1
Digestible energy 83.0 75.6 83.1 75.5
Metabolizable energy 67.3 61.2 67.3 61.1

DMI, dry matter intake.

higher for animals fed on the control than fat fed
animals whereas ME intake was higher both for the
control and CaSFA fed animals.

Nutrient digestibility

The digestibility coefficients of the diets are given
in Table 4. There was no difference (P>0.10)
between the control and diets containing fat or
among different fat sources in DM, NDF, acid
detergent fibre (ADF) and energy digestibility. CP
digestibility was higher (P<0.05) for RSO and
CaSFA containing diets than the control diet or TS
containing diet. RSO and CaSFA had higher
(P<0.01) ether extract (EE) digestibility than TS.

The fermentation pattern from continuous culture

Agric. Sei. Fin!. 1 (1992)



Table 4. Apparent digestibility ofdietary components, g kg' 1.

Dietary groups
Control RSO CaSFATS SE
n=6 n=7 n=6 n=7

Dry matter 687 703 697 681 21.0
Organic matter 700 716 711 695 20.8
Crude protein 718 743 748 724 23,1
Ether extract 519 724 726 598 38.1
Neutral detergent fibre 625 608 633 606 33.5
Acid detergent fibre 574 559 587 562 38.7
Cellulose 633 618 642 619 36.2633 618 642 619 36.2
Hemicellulose 667 650 674 644 29.7
Energy 674 692 688 667 22.5

SE, standard error of estimates.

Table 5. The effect ofpartial replacement ofbarley with 5 %

fat on continuous culture in vitro rumen fermentation.

Dietary groups
ControlRSO CaSFATS SE

VFA mmol I' 1 103.5 74.4 89,0 93.9 18.09
Individual VFA,
mmol mol' 1
Acetate 638 594 637 633 20.3
Propionate 176 255 183 189 46,9
Butyrate 165 132 158 154 27.9
Valerate 21.9 19.3 22.3 23.7 3.51
Acetate/propionate 3.6 2.3 3.5 3.4 0.21

Values for total VFA includes other minor volatile fatty
acids.

showed an altered molar proportion of individual
VFA with non significant (P>0.10) differences in
total VFA concentration between treatments (Table
5).

Animal performance

Means for the growth traits are presented in Table
6. The mean daily weight gain was higher (P<0.05)
for the control group. There was no difference
(P>0.10) in the final live weight of bulls between
treatments though the control animals were slightly
heavier. However, the control bulls with higher

daily weight gains had slightly lower (48.8 vs 49.1
kg) dressing percentage compared to the RSO
group. Kidney and pelvic fat of the bulls fed on TS
and CaSFA increased by 20 % and that of those fed
on RSO decreased by 16 % compared to the con-
trol. There was no difference in estimated empty
body weight or specific gravity of the carcass
between treatments.

Dry matter intake per body weight gain was high-
er (5.72 vs 5.35) for bulls fed on CaSFA containing
diet than that of the control diet. The feed conver-
sion rate (ME intake as MJ kg' 1 gain) did not differ
between the control, RSO and TS the control bulls
displaying a MJ:kg gain ratio of 55.9, and the RSO
and TS bulls showing 58.6 and 57.1, respectively.
Bulls fed on CaSFA showed the highest consump-
tion of MJ:kg gain (61.2) and lowest partial effi-
ciency ofME in gain compared to others. However,
none of these values were statistically significant
(P>0.10).

Carcass quality, shear and taste panel
evaluation

Results of qualitative and quantitative measures of
the longissimus dorsi are shown in Table 7. There
was no difference among treatments on fleshiness,
leanness and round development scores of visual
analysis. Sensory panel evaluations of the meat
showed that fat feeding did not affect meat payab-
ility or acceptability. The shear force required to
cut the meat samples was higher for control ani-
mals compared to fat fed animals indicating that
meat from animals fed with fat containing diets was
more tender than meat from control fed animals.

On the basis of objective measures, separable
lean, fat and bone in the 9 -12th rib cuts showed
that the bulls fed on the control diet had higher
(P<0.05) rib cut than TS fed bulls. TS fed animals
had a higher (P<0.05) lean meat and a lower
(P<0.05) fat proportion in comparison to CaSFA
fed animals. Apart from the estimated ash content,
there was no significant (P>0.10) difference in che-
mical composition of the Longissimus dorsi
between the dietary treatments.

271

Agric. Sei. Finl. 1 (1992)



Table 6. Effect of dietary fat sources on daily weight gain, carcass merit and feed ME utilization by growing bulls.

Dietary groups
Control RSO CaSFA TS
n=6 n=7 n=6 n=7 SE

Body weight, kg
Initial 123.0

430.8
1,20

210.5
48.8

123.3
391.7

1.05
192.9
49.1

123.8
393.5

1.05
192.8
49.0

123.4 28.6
Final 400.1 53.8
Gain, kg d' 1.08 0.122

Carcass wt, kg 191.7 28.4
Dressing percentage
Kidney and pelvic fat,
percentage of carcass
DMI, kg" 1 gain,

48.0 2.1

2.5
5.35

55.98
0.53

1.067
229.0
342.2

2.1
5.40

58.61
0.49

1.081
214.0
321.7

3,0
5.72

61.26
0.44

1.070
214.7
322.6

3.0 0.30
5.45 0.57

ME, MJ kg" 1 gain 6.2957.14
k 2K i 0.52 0.101
Specific gravity"
Carcass, kg"

1.073 0.008
200.0 21.63

Empty body weight, kg" 302.6 29.47

DMI, dry matter intake; ME, metabolizable energy; kf
2, partial efficiency of ME in gain = Estimated energy retention/(ME

intake - ME requirement for maintenance (ARC 1980); n =number of observation is 3 in each group.

Table 7. Composition and hedonic scores ofLongissimus dorsi from bulls fed on hay based diets supplemented with different
fat sources.

Dietary groups
Control RSO CaSFA TS
n=3 n=3 n=3 n=3 SE

Rib cut 9-12 ,h
, kg

Proportion of, %

Separable fat

13.7 11.4 11.6 10.8 1.54

20.7
67.6
11.7

20.8
69.0
10.2

20.5
69.4
10.1

14.9 3.05
Separable lean
Separable bone

75.3 3.90
9.8 0.35

Chemical compositions
pH 5.5

71.5
7.2

19.0
2.33

5.5
73.0
4.7

20.0
2.33

5.6
72.4

6.7
19.0
1.95

5.6 0,05
Water
Fat

72.5 1.30
5.6 2.45

Protein
Ash'

20.3 2.64
1.85 0.18

Sensory panel score
Juiciness 3.8

5.3
5.6

18.8

4.3
5.5
6.0

17.6

4.7
5.7
6.0

14.2

5.7 1.02
Flavour 6.0 0.61
Panel tenderness
Shear force, kg

5.7 0.40
11.8 6.91

1. calculated by difference; tenderness, 8= very tender, 1= very tough; flavour, 8 =no off flavour, 1= tasteless; juiciness, 8=
very juicy, 1= very dry.

272

Agric. Sei. Finl. 1 (1992)



Table 8. Major fatty acid profile of longissimus dorsi from bulls fed on hay based diet supplemented with different fat
sources.

Dietary groups
Control RSO CaSFA TS
n=3 n=3 n=3 n=3 SE

C 16:0 28.10 22.10 31.12 23.66 1.482
C 16:1 2.50 2.00 3.70 2.38 0.468
C 17:0 2.50 2.09 2.16 0.1261.75
C 17:1 0.56 0.42 0.49 0.55 0.037
CI8:0 23.09 25.13 20.65 26.50 2.858
Cl 8: lei's 31.43 33.56 31.73 35.54 1.001
Cl 8: l Irans
C18:2n6

2.77 6.22 2.68 3.22 0.639
2.07 2.15 1.90 1.47 0.167

ClB:2conj.
C18:3n3

0.18 0.38 0.16 0.16 0.022
0.49 0.35 0.34 0.26 0.058

C20:0 0.22 0.33 0.19 0.32 0.029
Saturated 53.91 49.66 53.71 52.65 1.168
Unsaturated 40.00 45.08 41.01 43.59 2.174

SE, standard error of estimate.

Fatty Acid Composition

The fatty acid compositions of Longissimus dorsi
revealed differences between control and fat
sources in the fatty acid profile (Table 8). Major
differences in fatty acid composition due to fat
sources were: decreased palmitic acid (C 16. 0), in-
creased stearic (C lg0

), oleic acid (C
lgl) and trans-

isomer of oleic acid on RSO and TS diets. Total
saturated fatty acids decreased by 8 % and total
unsaturated fatty acids increased by 13 % with
RSO compared to the control. The C lg.. trans acid
and conjugated linoleic (C ]g2) acids on RSO were
high compared to the other dietary groups whereas
C l 6 oacid was high in bulls fed on CaSFA compared
to the other two fat sources.

Discussion

Feed intake and digestibility

Total DMI was depressed by replacing barley with
fat and the animals fed on RSO and TS diets consu-
med less ME than the control and CaSFA fed an-
imals. Total DMI may have been depressed simply

because the animals fed on fat containing diets
tended to sort out the hay while consuming the
concentrate feed. This observation is similar to the
results of several other studies (Boucque et al.
1990; Dinius et al. 1975) where fat was fed either
protected or unprotected to beef animals. When
Dinius et al. (1975) replaced 8, 1 8 and 28 %ofcom
by 10, 20 and 30 % protected safflower oil in the
diet of steers, the steers refused to consume the
concentrate feed.

Free fatty acids may have organoleptic characte-
ristics which affect feed palatability but the reason
for the depressed feed intake with protected fat is
not known. Although the RSO and TS used in our
trial were not protected from hydrogenation, the
bulls consumed fat containing concentrates without
any major adaptation problem. No exact physiolo-
gical reason has so far been proposed for reduced
feed intake when fat is included in the ration of
ruminants however, rumen infusion of individual
and mixtures of VFA in goats and sheep indicated
thatpropionate infusion depresses feed intake more
than to acetate and butyrate infusion (Baile and
Mayer 1970). Besides the probable reduction in
gastro-intestinal tract movement caused by the free

273

Agric. Sei. Fin!. 1 (1992)



fatty acids (Nicholson and Omer 1983) which
tend to delay passage of feed through the digestive
tract, an increased proportion of propionate in the
rumen due to dietary fat could be another factor for
reduced feed intake.

The absence of depressed digestibility of DM,
OM and energy in our trial demonstrates that fat
sources, saturated or unsaturated, fed at 5 % of
concentrate mixture have no significant effect on
non fibre component digestibility. The absence of
significant depression in OM, DM and fibre observ-
ed with 5 % RSO feeding in this trial is not consis-
tent with the results obtained with fistulated bulls
(Tesfa 1991) where the digestibility of all the die-
tary components was depressed. The discrepancy
could be due to differences in the markers used
(AIA or Chromium oxide). Using the total col-
lection of faeces, Jenkins and Palmquist (1984)
observed a depression in DM digestibility when 5
% added tallow was fed with 50 % hay to steers.
Moore et al. (1986) noted depressed NDF and
ADF digestibility with steers fed a forage diet con-
taining 6.3 % cottonseed oil, which is consistent
with the result for RSO feeding in this trial.

Calcium soap fatty acids are insoluble at normal
rumen pH and thus inert to fermentative digestion
in vitro (Chalupa et al. 1984). In the abomasum at
lower pH, the calcium and the fatty acids disso-
ciate, leaving free fatty acids and calcium ions to be
utilized in the subsequent normal digestion and
absorption. Jenkins and Palmquist (1984) have
provided evidence that the feeding of preformed
calcium soaps of tallow and soya oil fatty acids to
dairy cows allowed normal rumen digestion of the
cell wall, whereas, non-saponified tallow fatty
acids caused reduced cell wall digestibility. Al-
though fat supplement increases microbial effi-
ciency, calcium soaps however failed to improve
microbial protein synthesis when fed to lactating
milking cows (Jenkins and Palmquist 1984). Pre-
sumably the CaSFA did not inhibit protozoa, both
in their and our study, to increase efficiency of
microbialprotein synthesis forefficient animal per-
formance.

In vitro studies with tallow fatty acids have

shown that they have only mild effects on VFA
production or on acetate:propionate ratio compared
to controls (Chalupa et al. 1984). The effect of TS
on rumen fermentation was mild compared to RSO
due to highmelting point and saturation level of tal-
low fatty acids. The overall changes in rumen fer-
mentation observed are consistent with in vivo stu-
dies with increasing levels of RSO (Tesfa et al.
1991a) and in vitro with com oil and tallow fatty

acid (Jenkins 1987). RSO containing high C, g2

fatty acids caused a more depressive effect on all
fermentationparameters.

The addition of calcium to a high fat diet has
been shown to reverse depressed fibre digestibility
in vitro (Jenkins and Palmquist, 1982) and in vivo
with steers (Palmquist and Jenkins, 1982). How-
ever, in the present study, no improvement was
observed in overall digestibility of the diet with
CaSFA compared to the other two fat sources. Our
data indicates that CaSFA was not totally inert in its
effect on the rumen environment.

Dietary fat inclusion in the diet of ruminants
increases propionate concentration with simulta-
neous reduction in methane formation (Van Nevel
and Demeyer 1981) and thus increases the meta-
bolizability of the gross energy (whitelaw et al.
1984). Although, the in vitro results revealed that
dietary fat increases glucogenic compound, the
efficiency of feed energy utilization by the bulls
remained low.

Animal performance

Marked reduction in feed intake has been the most
consistent effect observed with fat containing diets
which affects growth rate and animal performance.
Although we observed a decrease in daily weight
gain, we did not notice any difference in animal
performance between fat sources, even with
CaSFA, which is supposed to have a mild effect on
rumen environment. There are conflicting reports
from the literature on the effect of dietary fat on
animal growth rate. For example, Boucque et al.
(1990) reported that replacing 17 % or 33 % of
wheat with 2.5 % or 5.0 % blended animal-veget-

274

Agric. Sei. Finl. 1 (1992)



able fat had no effect on daily weight gain of beef
cattle. Short term feeding of steers with 14 % or
25.5 % protected tallow replacing 30 % or 57 % of
flaked com was noted to improve animal perform-
ance (Haaland et al. 1981). In contrast to this,
Dinius et al. (1975) reported a decreased daily gain
with steers when replacing 8-28 % corn-grain
mixture with 10-30 % protected safflower oil. Dif-
ferences in fat source on animal performance has
also been reported in the work of Boucque et al.
(1990) where 5 % lard decreased daily weight gain
compared to 5 % blended animal-vegetable fat.

Supplementing the ration of feedlot steers with 4
% yellow grease or 4 % blended animal-vegetable
fat increased the efficiency of microbial protein
synthesis (Zinn 1989) and improved animal
performance. In trials where grain was replaced by
fat, depressed animal performance seems to be
associated with a reduced availability of readily
fermentable carbohydrate. A reduced availability
of carbohydrates, combined with the negative
effect of fat on rumen metabolism, may lead to a
shortage of energy for rumen microbial energy
generation because fat cannot be fermented (apart
from glycerol) by rumen microbes to be used as
energy sources. Therefore, even ifrecycling of nit-
rogen can be reduced as the effect of fat on rumen
protozoa to improve microbial efficiency, replace-
ment of grain with fat does not seem to increase
animal performance due to the above mentioned
shortage of energy.

Carcass quality

Meat quality varies from muscle to muscle within
an animal. A single muscle, therefore, cannot be
representative of the whole animal under all
circumstances. In our study, Longissimus dorsi
muscle was considered as "representative" of the
whole carcass because ofits relative uniformity and
the fact that the sampling position can be defined
exactly by indicating the adjacent vertebrae. Sen-
sory evaluation of the boneless rib roast indicated
no major differences in flavour or tenderness. The
physical force required to test the tenderness of

meat however was high for the control bulls.
Increased carcass fat content (Boucque et al.

1990), as well as increased empty body weight,
kidney and heart fat (Zinn 1989) and kidney and
pelvic fat (Haaland et al. 1981) have been report-
ed for animals fed fat supplemented diet or partial
replacement of grain with fat. Increasing the level
of blended animal-vegetable fat in the diet from 4
%to 8 % increased the kidney-pelvic fat by 17 %

(Zinn 1989). Consistent with Zinn's observation
was an increase of 20 % in the kidney-pelvic fat
observed with 5 % TS and CaSFA inclusion where-
as RSO inclusion decreased it. This difference may
indicate that saturated fatty acids stimulate the
deposition of pelvic fat more than unsaturated oil
sources. TS fed bulls deposited more fat around the
kidney and pelvic region and less fat in intramuscul-
ar tissue.

Fatty acid composition

The C |6o
acid content was decreased by RSO and

TS feeding as compared to the control but was high
for bulls fed with CaSFA because CaSFA contained
higher proportion ofpalmitic acid and palmitic acid
is not sensitive to rumen hydrogenation. The decre-
ase in C,,„acid was 21 % with RSO and 16 % with

lo:U

TS feeding. When safflower containing polyunsatu-
rated fatty acids was infused into the abomasum of
steers, the C |B., content of Longissimus dorsi was
increased by 2.4 to 5 % compared to 0.9 % increase
when steers were fed orally (Dinus et al. 1974). In
the same work, the infusion of oil had no effect on
tissue C lg.,.

Regarding C lB2 , our results agree with
Dinus et al. (1974) and it is probable that this fatty
acid, whether fed in the form of oil supplement or as
a grain constituent, undergoes complete hydrogena-
tion in the rumen. In practice, the increase in C lg, 2
acid in milk or meat creates storage problems due to
its sensitivity to oxidative rancidity which produces
"oily" flavours (McDonald and Scott 1977). C lg2

has a low (-5°C) melting point compared to that of
acid (13.4-16.3°C), and this low melting point

affects the firmness of the meat at a particular tem-
perature (Wood 1984).

275

Agric. Sei. Finl. 1 (1992)



The increase in C
lg { was much higher with RSO

feeding contrary to the report of Dinius et al.
(1974) with safflower feeding but in agreement
with Robert and McKirdy (1964), who demon-
strated that the feeding ofrapeseed oil increased the
percentage ofmonounsaturated (C |8 | ) fatty acid by
3.5 % in prerenal fat. In contrast to our observation,
Garret et al. (1976) observed a decrease in C ]g.0
and C |g|

content ofLongissimus dorsi from steers
fed on a diet containing 15 and 30 % protected
vegetable oil. The increases in C lg,o and C lg.,

acids
content with RSO feeding correspond to the in-
crease in these acids observed in milk fat ofmilking
cows fed RSO (Tesfa et al. 1991 a & b). According
to Dryden and Marchello (1973), the fatty acid
content of intermuscular and intramuscular fat of
Longissimus dorsi, Semimembranosus and Triceps
hrachii muscles responded similarly to dietary
supplementation of 6 % sunflower oil or animal tal-
low. The only difference was that animals fed with
animal fat had more saturatedfatty acids than sun-
flower oil fed animals.

Dryden and Marchello (1970) reported low
and variable correlations between fatty acid com-
position and quality characteristics. However, in
studies with steers fed non fat supplemented diets,
Westerling and Hedrick (1979), reported a posi-
tive correlation between oleic acid and flavour
score, suggesting that the concentration ofC lg.,

acid
has a specific effect on the flavour of the meat. In

our study, the panel evaluation did not observed
any major difference in the flavour of meat from
RSO fed bulls though the C lB-l acid was high com-
pared to other treatments.

Conclusion

The current study showed thatreplacing grain with
fat and feeding it with hay tends to depress total
feed intake. Although partial replacement of barley
with fat had no significant effect on nutrient digest-
ibility, the feed intake of the animal and efficiency
of feed conversion by the animals was depressed.
Weight gain per feed intake was observed to be low
for fat containing diets compared to the control. A
lowered growthrate seems to be due to the reduced
availability of readily fermentable carbohydrates as
a consequence of the replacement of grain by fat.
Therefore, although fat increases the energy den-
sity of the diet, since it cannot be catabolized in the
rumen, thereplacement ofgrain with fat in the diets
of growing bulls has no economic benefit.

Acknowledgements.The authors are grateful to Prof. Eero
Puolanne, Olavi Törmä, M.Sc. Agric., and the technical staff
of the Department of Meat Technology for their advice and
assistance in meat quality evaluation. We would also like to
express our warm gratitude to Tore Storgårds, M.Sc. Agric.,
for his excellent technical assistance during the experiment.
We also wish to express our sincere gratitude to Seppo Kart-
tunen and the technical staff in Suitia experimental farm for
their contribution to this experiment.

References

ARC 1980. The nutrient requirements ofruminant livestock.
Agricultural Research Council. Commonwealth Agri-
cultural Bureaux, Slough, England, p. 351.

Bail, C.A. & Mayer, J. 1970. Hypothalamic centres: Feed-
backs and receptors sites in the short-term control of
feed intake. In: Phillipson, A.T. (ed.). Physiology of
digestion and metabolism in the ruminant, p. 254-263.

Boucque, Ch.V., Fiems, L.O. Cottyn, B.G. & Buysse, F.X.
1990. Effect of dietary fats on animal performance,

carcass quality and lipid composition of kidney fat in
beef bulls. J. Anim. Physiol. Anim. Nutr. 63: 213-219.

Chalupa, W., Rickabaugh, 8., Kronfield, D.S. & Sklan,
D. 1984. Rumen fermentation in vitro as influenced by
long chain fatty acids. J. Dairy Sci. 67: 1439-1444.

Christie, W.W. 1982. The procedure for rapid transmethy-
lation of glycolipids and cholesteryl esters. J. Lipid Res.
23: 1072-1075.

Dinius, D.A., Oltjen, R.R & Sätter, L.D. 1974. Influence

276

Agric. Sei. Fin!. 1 (1992)



of abomasally administered safflower oil on fat compo-
sition and organoleptic evaluation of bovine tissue. J.
Anim. Sci. 38: 887-892.

, Edmondson, L.F., Kimoto, W & Oltjen, R.R. 1975.
Growth, blood parameters and tissue lipids of finishing
cattle fed a formaldehydetreated casein-safflower oil
complex. J. Anim, Sci, 40: 358-365.

Dryden, F.D. & Marchello, J.A. 1970. Influence of total
lipid and fatty acid composition upon the palatability of
three bovine muscles. J. Anim. Sci. 31: 36-41,

& Marchello, J.A. 1973. Influence of dietary fats upon
carcass lipid composition of the bovine. J. Anim. Sci. 37:
33-39.

Garrett, W.N. & Hinman, N. 1969. Re-evaluation of the
relationship between carcass density and body composi-
tion of beef steers. J. Anim. Sci. 28: 1-5.

—, Yang, Y.T., Dunkley, W.L. & Smith, L.M. 1976.
Energy utilization, feedlot performance and fatty acid
composition ofbeef steers fed protein encapsulated tal-
low or vegetable oils. J. Anim. Sci. 42: 1522-1533.

Haaland, G.L., Matsushima, J.K., Johnson, D.E. &

Ward, G.M. 1981. Effect ofreplacement ofcom by pro-
tected tallow in a cattle finishing diet on animal perfor-
mance and composition. J. Anim. Sci. 52: 696-702.

Jenkins, T.C. 1987. Effect of fats and fatty acid combina-
tions on ruminal fermentation in semi-continuous in
vitro cultures. J. Anim. Sci. 64: 1526-1532.
& Palmquist, D.L. 1982. Effect ofadded fatand calcium
on in vitro formation of insoluble fatty acid soaps and
cell wall digestibility. J. Anim. Sci. 55: 957-963.
& Palmquist, D.L. 1984. Effect of fatty acids or calcium
soaps on rumen and total nutrient digestibility of dairy
rations, J. Dairy Sci. 67: 978-986.

Kraybill, H.F., Bitter, H.L. & Hankins, O.G. 1952. Body
composition of cattle. 11. Determination of fat and water
content from measurement of body specific gravity. J.
Appi. Physiol. 4: 575-583.

McDonald, I.W. & Scott, T.W. 1977. Foods of ruminant
origin with elevated content of polyunsaturated fatty
acids. World Rev. Nutr. Diets. 26: 144-207.

Miettinen, H. & Setälä, J. 1989. Design and development
of a continuous culture system for studying rumen fer-
mentation. J. Agric. Sci. Finl. 61: 463-473.

Moore, J.A., Swingle, R.S. & Hale, W.H. 1986. Effects of
whole cottonseed, cottonseed oil or animal fat on diges-
tibility ofwheat straw diets by steers, J. Anim. Sci. 63:
1267-1273.

Nicholson, T. & Omer, S.A. 1983. The inhibitory effect of
intestinal infusions of unsaturated long-chain fatty acids
on forestomach motility of sheep. Br. J. Nutr. 50: 141-
149.

Oltjen,R.R. & Dinius, D. A. 1975. Production practices that
alter the composition of foods ofanimal origin. J. Anim.
Sci. 41:703-722.

Palmquist, D.L., & Jenkins, T.C. 1982.Calcium soaps as a
fat supplement in dairy cattle feeding. Page 477 in Proc.

XII World Congr. Dis. Cattle. Vol. I. Amsterdam, the
Netherlands.

Roberts, W.K. & McKirdy, J.A. 1964. Weight gains,
carcass fat characteristics and ration digestibility in
steers as affected by dietary rapeseed oil, sunflowerseed
oil and animal tallow. J. Anim. Sci. 23: 682-687.

Snedecor, G.W. & Cochean, W.G. 1967., Statistical met-
hods, Sixth edition. The lowa State University Press.
U.S.A.

Tesfa, A T. 1991. Effects of rapeseed oil supplementation
on site of digestion, microbial protein synthesis and duo-
denal amino acid composition. (In press. Anim. Feed
Sci. Technol.).

—, Tuori, M. & Syrjälä-Qvist, L. 1991a. High rapeseed
oil feeding to lactating cows and its effects on milk yield
and composition. Finn. J. Dairy Sci. 49: 65-81.

—, Syrjälä-Qvist, L. & Tuori, M. 1991b. Replacement of
grain by tallow or rapeseed oil in the diet of lactating
cows and its effects on milk yield and composition. Finn.
J. Dairy Sci. 49: 54-64.

Zinn, R.A. 1989. Influence of level and source of dietary fat
on its comparative feeding value in finishing diets for
steers: Feedlot cattle growth and performance. J. Anim.
Sci. 67: 1029-1037,

Van Nevel, C.J. & Dmeyer, D.I. 1981. Effect of methane
inhibitors on the metabolism ofrumen microbes in vitro.
Arch. Tieremährung. 31: 141-151.

Van Keulen, J. & Young, B.A. 1977. Evaluation of acid-
insoluble ash as a natural marker in ruminant digestibi-
lity studies. J. Anim. Sci. 44: 282-287.

Westerling, D.B. & Hedrick, H.B. 1979. Fatty acid com-
position ofbovine lipids as influenced by diet, sex and
anatomical location and relationship to sensory characte-
ristics. J. Anim. Sci. 48: 1343-1348.

Whitelaw,F.G., Eadie, J.M., Bruce, L.A. & Shand, W.J.,
1984. Methane formation in faunated and ciliate-free
cattle and its relationship with rumen volatile fatty acid
proportions. Br. J. Nut. 52: 261-275.

Wood, J. D. 1984.Fat deposition and the quality of fat tissue
in meat animals. In: Wiseman, J.(ed.). Fats in Animal
Nutrition p. 407-435.

Manuscript received January 1992

Alem Tsehai Tesfa
Mikko Tuori
Liisa Syrjälä-Qvist
University ofHelsinki
Department of Animal Science
SF-00710 Helsinki, Finland

277

Agric. Sei. Fin!. 1 (1992)



SELOSTUS

Ohran osittainen korvaaminen erilaisilla rasvoilla kasvavan lihanaudan ruokinnassa

Alem Tsehai Tesfa, Mikko Tuori jaLiisa Syrjälä-Qvist
Helsingin yliopisto

Kasvavilla ay- ja fr-sonneilla suoritetussa 256 päivän pitui-
sessa ruokintakokeessa oli 24 sonnia, joidenkeskimääräinen
elopaino kokeen alussa oli 123 kg. Eläimet olivat rajoitetulla
ruokinnalla ja saivat 85 g kuiva-ainetta metabolista elopai-
nokiloa kohti. Karkearehuna oli heinä, väkirehuna ohra,
josta korvattiin osa erilaisilla rasvoilla. Dieetin väkirehu-
korsirehusuhde oli 45:55. Kontrolliryhmällä väkirehu oli
ohraa, RSO-ryhmällä 32 % ohrasta korvattiin 5 %:lla rypsi-
öljyä, CaSFA-ryhmässä sama määrä ohraakorvattiin 5 %:lla
palmuöljyn kalsiumrasvahapposuoloja, ja TS-ryhmässä
ohraa korvattiin 5 % ;lla talia.

Rasvan sisällyttäminen ruokintaan alensi lievästi rehun-
syöntiä ja energiansaantia kaikissa rasvaryhmissä. Dieetin
orgaanisen aineen, raakavalkuaisen tai solunseinämäainei-
den sulavuuteen rasvoilla ei ollut vaikutusta. Keskimääräiset
lisäkasvut olivat 1.20, 1.05, 1.05 ja 1.08 kg/d kontrolli,
RSO-, CaSFA-ja TS-ryhmissä, erot eivät olleet merkitseviä.
Myöskään rehun muuntosuhteessa ei dieettien välillä ollut
merkitsevää eroa (3.91, 4.20, 4.44 ja 4.33 ry/lisäkasvukg).

Ruhon laatu- tai maittavuusarvostelussa ei tullut eroja
dieettien välille. Longissimus dorsi -lihaksen rasvan koostu-
mus analysoitiin. RSO-ja TS-dieetit lisäsivät öljy-ja stearii-
nihappojen osuuttarasvassa.

278

Agric. Sei. Fint. 1 (1992)