- Email: [email protected]
Performance of Holstein-Friesian Steers Fed an All-Concentrate Ration Diluted with Ground Hay1
Performance of Holstein-Friesian Steers Fed an All-Concentrate Ration Diluted with Ground Hay E. E. LISTER, D. P. HEANEY, and W. J. PIGDEN Animal Research Institute, Canada Department of Agriculture, Ottawa, Canada Abstract Thirty-six Holstein-Friesian steers (two pens of six animals each per treatment) were group fed a barley-based all-concentrate diet (C), Diet C diluted with 20% ground hay (D), or Diet C diluted with 40% ground hay (E) from an initial live weight of 200 kg to a final live weight of 385 kg. Average daily gain was significantly (P < .05) depressed by Diet E (0.99 vs. 1.13 and 1.12 ± 0.02 kg for E vs. C and D, respectively). Feed efficiency was significantly (P ~ .05) different among all diets (6.36, 7.30, and 8.82 ~+ 0.08 kg feed per kilogram gain for C, D, E, respectively). The digestibility of energy, determined with sheep, was significantly (P ~ .05) different among the three diets (77.2, 70.9, and 64.2 ± 1.3% for C, D, E, respectively). Based on these digestion coefficients, steers on Diet E consumed significantly (P ~ .05) more digestible energy per kilogram of weight gain than those on C or D (17.58, 18.70, and 21.31 ± 0.31 Meal for Diets C, D, E, respectively). Ration E produced a significantly (P ( . 0 5 ) higher yield of prime rib and lower yield of chuck (per cent o f chilled carcass) than C or D (9.8, 27.1; 9.7, 26.7; 10.4--0.11, 25.0-+-0.34 for Diets C, D, E, respectively).
I t was firmly established in commercial practice that British-Friesian steers will grow rapidly and efficiently when fed all-concentrate rations (5, 11) following the experimental work of Preston et al. (9, 10). However, as roughages are generally available at a comparatively lower cost than concentrates, more information on their maximum utilization in concentrate mixtures for dairy steers is required. Lamming et al. (7) recently reported that the inclusion of up to 30% ground barley straw in a maize-based, pelleted ration resulted in rate of gain and £eed efficiency comparable to that obtained from an all-concentrate ration when fed to British-Friesian steers.
Our work was designed to determine the effect of diluting a barley-based, all-concentrate diet with low-quality ground hay on growth rate, feed intake, and carcass yield of HolsteinFriesian steers. Experimental Procedure
Preliminary period. At approximately one week of age 36 male Holstein-Friesian calves were individually penned and fed a reconstituted high-fat milk replacer" for 28 days. Beginning five days after starting on milk replacer, Ration A (Table 1) was fed ad libitum for 44 days. The calves were then allotted to six pens of six calves each and group fed Ration B (Table 1) for 63 days, when their average weight reached 130 kg. For the next 63 days a high-barley concentrate Ration C (Table 1) was fed. All grain rations were fed ad libitum. Calves were dehorned and castrated before weaning from the milk replacer. While group fed, the calves were housed in an uninsulated barn with forced-air ventilation. Fresh water was always available and pens were bedded with wood shavings. Experimental period (175 days to market). The 36 steers (average live weight, 200.5 kg), 2Lactoveau, Canada Packers Ltd., Toronto. TABLE I. Ration ingredient
Physical composition of rations. Ab
]3b
Cc
Dc
E~
(%) Maize Oat groats Barleya Linseed meal Soybean meal Ground hay Molasses Iodized cobaltized salt Steamed bonemeal
35 30
15 10
................
s
45
ga
66
55
'5
'5
'2
20
40
1
1
1
.8
.6
3
3
2
1.6
1.2
1.6
a Slightly moistened and crushed. b Contained 1.8 g chlortetracycline, 1.1 million IU of vitamin A, and 275,000 IU vitamin D per 100 kg of diet. Received for publication May 13, 1968. ¢ Vitamins A and D were added as follows: Ra~Contribution no. 302, Animal Research Insti- tion C, 1.1 a~d .28; Ration D, .88 and .24; Ration E, .66 and .17 million IU per 100 kg of diet. tute. 1946
ALL-CONOENTRATE
reared as described under Preliminary period, were group fed Rations C, D, and E (Table 1) from November 1, 1965, until the animals reached market weight (386 kg), the last animal going off in mid-June, 1966. Each ration treatment was applied to two pens of six animals each, and all rations were fed ad libitum with weekly weighback recorded and discarded. Ration C was a high-barley, all-concentrate ration, similar to that fed by Preston et al. (10); Rations D and E were prepared by diluting Ration C with 20 and 40% ground hay, respectively. The hay was a low-quality grass-legume mixture (38% crude fiber, 11% crude protein), ground in a hammermill through a 0.32-cm screen. Weekly live weights were taken and steers slaughtered within three days of reaching a full live weight of 386 kg, except two unthrifty animals slaughtered at 377 and 301 kg. After slaughter, weights of warm and cold carcasses and untrimmed wholesale cuts were fallen. The variance in growth rate, feed intake, and efficiency due to treatments was tested against that of pens within treatments after adjustment by covariance for initial or final liveweight (6). Sheep digestion trial. Eighteen mature wethers, previously fed all-concentrate rations, were housed in individual metabolism crates in an air-conditioned room. They were assigned at random to Rations C, D, and E and fed at a level approaching ad libitum, resulting in little or no weighback. After a preliminary period of one week, feces were collected daily for 14 days. The feces were frozen, accumulated for the 14-day period, weighed, mixed, and sampled for chemical analysis. Samples were taken of feed offered and refused. The proximate composition of these samples was determined by standard methods (2). The gross energy content of feed and feces was determined in an adiabatic bomb calorimeter. Variance due to treatments was tested against variance of animals within treatments.
1947
RATION
Results and Discussion
Average daily gain (ADG). Average daily gains during the experimental period were not different between Rations C and D (1.13 vs. 1.12 kg per day), but both rations produced significantly (P < .05) greater daily gains than Ration E (0.99 kg/day) (Table 2). As a result, animals fed Ration E required significantly (P < .05) more days to reach market weight. Similarly, Preston et al. (10) showed that 35% ground roughage decreased daily gains and resulted in a longer time for British-Friesian stee~ to reach maxket. Lamming et al. (7) showed no difference in gains due to inclusion of up to 30% ground barley straw, but obtained a depression in gains, as we did with hay, when 40 or 50% ground straw was included in a maize-based, pelleted ration fed to older Friesian steers. During much of the expel4mental period the temperature in the barn was below 0 C. I n spite of this, the daily gains of the all-concentrate-fed steers were comparable to those reported by British workers (10) under much milder climatic conditions. Feed intake and e~ciency. During the experimental period, feed intake/day (corrected for final weight) was greater (P < .05) for Ration D than Ration C (7.95 vs. 7.04 k g / day) and steers fed Ration E consumed significantly (P < .05) more daily (9.07 kg) than those fed either Ration C or Ration D (Table 2). Feed per unit gain was significantly (P < .95) greater for Ration D (7.30) versus Ration C (6.36), and Ration E (8.82) was greater (P < .05) than either C or D. Total intake (corrected for final weight) during the experimental period followed the same pattern. Efficiency obtained with Ration C (6.36) was similar to that reported by Preston et al. (9) when 10% straw was included in the diet, but was greater than that reported by this group (10) in a later experiment when an all-concentrate barley diet was fed. This was likely due to their experimental period covering an
TABLE 2. Growth and feed intake by steers on Rations C, D, and E during the experimental period. Ration fed Starting wt (kg) Finalwt (kg) Days on experiment Total feed intake/animal~ (kg) Avg daily gain (kg) Feed intake/animal per day2 (kg) Kilograms feed/kg gain
C
D
198.2 391.1 171" 1,202a 1.13" 7.04" 6.36"
200.0 391.8 171a 1,366b 1.12" 7.95b 7.30b
E 203.1 383.6 183b 1,654e 0.99b 9.07~ 8.82~
SE 1 ± 1.0 ± 5.0 ± 1.0 ±12.5 ± 0.02 ± 0.09 ± 0.08
l Based on pen means. 2Adjusted by covarianc~ for final weight. ,. b. c Means within same line with differing superscripts were significantly different (P < .05). 7. DAIRY SCIENCE "VOL. 51, NO. 12
1948
LISTER, HEANEY, AlqD PIGDEN
earlier and more efficient period of growth. L a m m i n g et al. (7) demonstrated no difference in daily feed intake or in efficiency when up to 30% ground barley straw was included in a maize-based, pelleted ration, contrary to our results, but in their second experiment noted an increase in daily intake when the inclusion of 30, 40, and 50% ground barley straw was compared to 20% and an increased feed p e r u n i t gain at the two highest straw levels.
Chemical composition and digestibility of ration components. There was a marked decrease in crude protein and nitrogen-free exTABLE 3. Chemical composition and apparent digestibility coefficients for Rations C, D, and E. Ration fed Apparent digestibility coefficient Dry matter Crude protein Crude fiber Nitrogen-free extract Gross energy Chemical composition (dry matter basis) Crude protein (%) Crude fiber (%) Crude fat (%) Ash (%) Nitrogenfree extract (%) Gross energy (cal/g)
C
D
E
SE of mean
77.5 a
71.5 b
65.3 ¢
±1.1
79.9 a 18.2 ~
76.1 ab 28.9 b
73.3 b 36.1 b
+1.6 --+3.0
85.3 ~
81.9 b
75.7 ~
-+0.8
77.2 ~
70.9 b
64.2 ¢
___1.3
19.5
18.0
16.1
5.7
12.0
18.9
1.4 5.7
1.5 5.9
1.6 5.7
67.7
62.6
57.7
4.13
4.14
4.26
a. b. (. Means within same line with differing superscripts were significantly different (P < .05).
tract and an increase in crude fiber associated with increasing dilution by ground hay (Table 3). Decreasing crude protein content f r o m Ration C to Ration E was considered to be unimportant, since the lowest level exceeded the highest requirements f o r r a p i d l y growing steers according to the Agricultural Research Council (1) and the National Research Council (8) standards. Also, the average daily intake of digestible crude protein was similar f o r all three rations, 1,096, 1,089, 1,070 g / d a y f o r Rations C, D, E, respectively. The p e r cent a p p a r e n t digestibility of dry matter, nitrogen-free extract, and gross energy was significantly (P < .05) different between Rations C, D, and E, with C being digested to a greater extent than D and both greater than E (Table 3). A p p a r e n t digestibility of crude protein of C was significantly ( P < .05) greater than E but not D. Crude fiber a p p a r e n t digestibility was significantly (P < .05) less f o r Ration C than for Rations D and E. L a m m i n g et al. (7) reported a depression in dry matter digestibility with increasing levels of ground roughage, similar to our results. Likewise, Brent et al. (3) and D o n e f e r et al. (4) found that the digestibility of energy of a concentrate-roughage ration decreased with increasing levels of roughage. Efficiency of energy utilization. The digestible energy intake and efficiency of its utilization by the steers were calculated f r o m the app a r e n t digestibility coefficients determined with the sheep (Table 4). Although there was a trend toward higher average daily digestible energy intakes as fiber level of the rations increased, the differences between rations were not significant (.10 > P > .05). On the other hand, both average total digestible energy intake f o r the entire experimental period (171 days for C and D, 183 days for E ) and digestible energy p e r kilogram gain were significantly (P < .05) higher f o r steers fed Ration E than for those fed either of the two other rations. These results indicate that steers consuming essentially the same daily amounts of digestible energy f r o m rations containing
TABLE 4. Digestible energy intake and efficiency of utilization by steers. Ration fed
C
Digestible energy : Total intake per animal (meal) 2 3,341.3 ~ Intake per animal per day (meal) 2 19.50 Per kilogram gain (mcal) 17.58 a
D
E
SE 1
3,514.5 a 20.46 18.70 a
3,985.2 b 21.86 21.31 b
±32.2 + 0.29 ___ 0.31
a Standard error based on pen means. 2 Adjusted by covarianee for final weight. ,. b Means within same line with differing superscripts were significantly different (P < .05). J. I)AIRY SCIENC~ VOL. 51, No. 12
ALL-CONCENTRATE
high levels of ground roughage (40% of total diet) utilize this energy less efficiently than those on low fiber diets. S t e e r c a r c a s s data. Dressing per cent (cold carcass of full live weight) was low in all cases, since animals were not shrunk prior to slaughter, but compared f a v o r a b l y with results reported by Preston et al. (9, 10). There was a trend toward decreasing dressing p e r cent with increasing levels of fiber in the diet (54.8, 53.9, and 51.9% f o r Rations C, D, and E, respectively), but the differences were nonsignificant (.10 > P > . 0 5 ) . The yield of untrimmed wholesale cuts showed differences due to rations f o r prime rib and chuck, with the f o r m e r being significantly (P < .05) greater and the latter significantly ( P < .05) smaller for animals fed Ration E versus Rations C and D.
Acknowledgments The authors acknowledge the assistance of Mr. P. S. Ha.ydon, A. R. I., for supervision of slaughter and carcass measurements, and assistance and cooperation of C. H. Thomas Ltd., Ottawa., for slaughter and carcass cutting. Additionally, W. Emend and J. C. Batty and staffs, all of A. R. I., are acknowledged for their work in carrying out the digestion trial and the steerfeeding trial. Analytical Chemistry Research Services carried out all proximate analyses.
References (1) Agricultural Research Council. 1965. The nutrient requirements of farm livestock. Number 2. Ruminants. Agricultural Research Council, London. (2) Association of Official Agricultural Chemists. 1960. Official Methods of Analysis. 9th ed. Washington, D.C.
RATION
1949
(3) Brent, B. E., D. Richardson, W. A. Tsien, and C. S. Menzies. 1961. Digestibility studies on levels of concentrates in complete pelleted rations for fattening lambs. J. Ar~im. Sci., 20: 526. (4) Denefer, E., L. E. Lloyd, and E. W. Crampton. 1963. Effect of varying alfalfa:barley ratios on energy intake and volatile fatty acid production by sheep. J. Anim. Sci., 22 : 425. (5) Foil,: N. J. 1965. Super beef: A report on details on an inte~sive dairy beef production system in Eng]aitd. Feedstuffs, 37(10) : 26. (6) Henderson, C. R. 1960. Design and analysis of animal husbandry experiments. Techniques and procedures in animal production research. Amer. Soe. Anita. Sci., Q. Corporation, Albany, N.Y. (7) Lamming, G. E., H. Swan, and R. T. Clarke. 1966. Studies on the nutrition of ruminants. I. Substitution of maize by milled barley straw in a beef fattening diet and its effect o~ performance and carcass quality. Anlm. Prod., 8: 303. (8) ~qational Research Council. 1963. Nutrient requirements of domestic animals. IV. Nutrient requirements of beef cattle. Natl. Acad. Sci., Publ. 1137. Washington, D.C. (9) Preston, T. R., F. G. Whitelaw, J. N. Airken, A. Macdearmid, and Euphemia B. Char]son. 1963. Intensive beef production. I. Performance of cattle given complete ground diets. Anita. Prod., 5:47. (10) Preston, T. R., J. N. Aitken, F. G. Whitelaw, A. Macdearmid, Euphemia B. Philip, and N. A. MacLeod. 1963. Intensive beef production. 3. Performance of Friesian steers given low-fibre diets. Anim. Prod., 5 : 245. (11) Preston, T. R. 1964. Barley beef production in the United Kingdom. Feedstuffs, 36 (40) : 66.
J. DAIRXSCIENCEYOL. 51, NO.
12
I t was firmly established in commercial practice that British-Friesian steers will grow rapidly and efficiently when fed all-concentrate rations (5, 11) following the experimental work of Preston et al. (9, 10). However, as roughages are generally available at a comparatively lower cost than concentrates, more information on their maximum utilization in concentrate mixtures for dairy steers is required. Lamming et al. (7) recently reported that the inclusion of up to 30% ground barley straw in a maize-based, pelleted ration resulted in rate of gain and £eed efficiency comparable to that obtained from an all-concentrate ration when fed to British-Friesian steers.
Our work was designed to determine the effect of diluting a barley-based, all-concentrate diet with low-quality ground hay on growth rate, feed intake, and carcass yield of HolsteinFriesian steers. Experimental Procedure
Preliminary period. At approximately one week of age 36 male Holstein-Friesian calves were individually penned and fed a reconstituted high-fat milk replacer" for 28 days. Beginning five days after starting on milk replacer, Ration A (Table 1) was fed ad libitum for 44 days. The calves were then allotted to six pens of six calves each and group fed Ration B (Table 1) for 63 days, when their average weight reached 130 kg. For the next 63 days a high-barley concentrate Ration C (Table 1) was fed. All grain rations were fed ad libitum. Calves were dehorned and castrated before weaning from the milk replacer. While group fed, the calves were housed in an uninsulated barn with forced-air ventilation. Fresh water was always available and pens were bedded with wood shavings. Experimental period (175 days to market). The 36 steers (average live weight, 200.5 kg), 2Lactoveau, Canada Packers Ltd., Toronto. TABLE I. Ration ingredient
Physical composition of rations. Ab
]3b
Cc
Dc
E~
(%) Maize Oat groats Barleya Linseed meal Soybean meal Ground hay Molasses Iodized cobaltized salt Steamed bonemeal
35 30
15 10
................
s
45
ga
66
55
'5
'5
'2
20
40
1
1
1
.8
.6
3
3
2
1.6
1.2
1.6
a Slightly moistened and crushed. b Contained 1.8 g chlortetracycline, 1.1 million IU of vitamin A, and 275,000 IU vitamin D per 100 kg of diet. Received for publication May 13, 1968. ¢ Vitamins A and D were added as follows: Ra~Contribution no. 302, Animal Research Insti- tion C, 1.1 a~d .28; Ration D, .88 and .24; Ration E, .66 and .17 million IU per 100 kg of diet. tute. 1946
ALL-CONOENTRATE
reared as described under Preliminary period, were group fed Rations C, D, and E (Table 1) from November 1, 1965, until the animals reached market weight (386 kg), the last animal going off in mid-June, 1966. Each ration treatment was applied to two pens of six animals each, and all rations were fed ad libitum with weekly weighback recorded and discarded. Ration C was a high-barley, all-concentrate ration, similar to that fed by Preston et al. (10); Rations D and E were prepared by diluting Ration C with 20 and 40% ground hay, respectively. The hay was a low-quality grass-legume mixture (38% crude fiber, 11% crude protein), ground in a hammermill through a 0.32-cm screen. Weekly live weights were taken and steers slaughtered within three days of reaching a full live weight of 386 kg, except two unthrifty animals slaughtered at 377 and 301 kg. After slaughter, weights of warm and cold carcasses and untrimmed wholesale cuts were fallen. The variance in growth rate, feed intake, and efficiency due to treatments was tested against that of pens within treatments after adjustment by covariance for initial or final liveweight (6). Sheep digestion trial. Eighteen mature wethers, previously fed all-concentrate rations, were housed in individual metabolism crates in an air-conditioned room. They were assigned at random to Rations C, D, and E and fed at a level approaching ad libitum, resulting in little or no weighback. After a preliminary period of one week, feces were collected daily for 14 days. The feces were frozen, accumulated for the 14-day period, weighed, mixed, and sampled for chemical analysis. Samples were taken of feed offered and refused. The proximate composition of these samples was determined by standard methods (2). The gross energy content of feed and feces was determined in an adiabatic bomb calorimeter. Variance due to treatments was tested against variance of animals within treatments.
1947
RATION
Results and Discussion
Average daily gain (ADG). Average daily gains during the experimental period were not different between Rations C and D (1.13 vs. 1.12 kg per day), but both rations produced significantly (P < .05) greater daily gains than Ration E (0.99 kg/day) (Table 2). As a result, animals fed Ration E required significantly (P < .05) more days to reach market weight. Similarly, Preston et al. (10) showed that 35% ground roughage decreased daily gains and resulted in a longer time for British-Friesian stee~ to reach maxket. Lamming et al. (7) showed no difference in gains due to inclusion of up to 30% ground barley straw, but obtained a depression in gains, as we did with hay, when 40 or 50% ground straw was included in a maize-based, pelleted ration fed to older Friesian steers. During much of the expel4mental period the temperature in the barn was below 0 C. I n spite of this, the daily gains of the all-concentrate-fed steers were comparable to those reported by British workers (10) under much milder climatic conditions. Feed intake and e~ciency. During the experimental period, feed intake/day (corrected for final weight) was greater (P < .05) for Ration D than Ration C (7.95 vs. 7.04 k g / day) and steers fed Ration E consumed significantly (P < .05) more daily (9.07 kg) than those fed either Ration C or Ration D (Table 2). Feed per unit gain was significantly (P < .95) greater for Ration D (7.30) versus Ration C (6.36), and Ration E (8.82) was greater (P < .05) than either C or D. Total intake (corrected for final weight) during the experimental period followed the same pattern. Efficiency obtained with Ration C (6.36) was similar to that reported by Preston et al. (9) when 10% straw was included in the diet, but was greater than that reported by this group (10) in a later experiment when an all-concentrate barley diet was fed. This was likely due to their experimental period covering an
TABLE 2. Growth and feed intake by steers on Rations C, D, and E during the experimental period. Ration fed Starting wt (kg) Finalwt (kg) Days on experiment Total feed intake/animal~ (kg) Avg daily gain (kg) Feed intake/animal per day2 (kg) Kilograms feed/kg gain
C
D
198.2 391.1 171" 1,202a 1.13" 7.04" 6.36"
200.0 391.8 171a 1,366b 1.12" 7.95b 7.30b
E 203.1 383.6 183b 1,654e 0.99b 9.07~ 8.82~
SE 1 ± 1.0 ± 5.0 ± 1.0 ±12.5 ± 0.02 ± 0.09 ± 0.08
l Based on pen means. 2Adjusted by covarianc~ for final weight. ,. b. c Means within same line with differing superscripts were significantly different (P < .05). 7. DAIRY SCIENCE "VOL. 51, NO. 12
1948
LISTER, HEANEY, AlqD PIGDEN
earlier and more efficient period of growth. L a m m i n g et al. (7) demonstrated no difference in daily feed intake or in efficiency when up to 30% ground barley straw was included in a maize-based, pelleted ration, contrary to our results, but in their second experiment noted an increase in daily intake when the inclusion of 30, 40, and 50% ground barley straw was compared to 20% and an increased feed p e r u n i t gain at the two highest straw levels.
Chemical composition and digestibility of ration components. There was a marked decrease in crude protein and nitrogen-free exTABLE 3. Chemical composition and apparent digestibility coefficients for Rations C, D, and E. Ration fed Apparent digestibility coefficient Dry matter Crude protein Crude fiber Nitrogen-free extract Gross energy Chemical composition (dry matter basis) Crude protein (%) Crude fiber (%) Crude fat (%) Ash (%) Nitrogenfree extract (%) Gross energy (cal/g)
C
D
E
SE of mean
77.5 a
71.5 b
65.3 ¢
±1.1
79.9 a 18.2 ~
76.1 ab 28.9 b
73.3 b 36.1 b
+1.6 --+3.0
85.3 ~
81.9 b
75.7 ~
-+0.8
77.2 ~
70.9 b
64.2 ¢
___1.3
19.5
18.0
16.1
5.7
12.0
18.9
1.4 5.7
1.5 5.9
1.6 5.7
67.7
62.6
57.7
4.13
4.14
4.26
a. b. (. Means within same line with differing superscripts were significantly different (P < .05).
tract and an increase in crude fiber associated with increasing dilution by ground hay (Table 3). Decreasing crude protein content f r o m Ration C to Ration E was considered to be unimportant, since the lowest level exceeded the highest requirements f o r r a p i d l y growing steers according to the Agricultural Research Council (1) and the National Research Council (8) standards. Also, the average daily intake of digestible crude protein was similar f o r all three rations, 1,096, 1,089, 1,070 g / d a y f o r Rations C, D, E, respectively. The p e r cent a p p a r e n t digestibility of dry matter, nitrogen-free extract, and gross energy was significantly (P < .05) different between Rations C, D, and E, with C being digested to a greater extent than D and both greater than E (Table 3). A p p a r e n t digestibility of crude protein of C was significantly ( P < .05) greater than E but not D. Crude fiber a p p a r e n t digestibility was significantly (P < .05) less f o r Ration C than for Rations D and E. L a m m i n g et al. (7) reported a depression in dry matter digestibility with increasing levels of ground roughage, similar to our results. Likewise, Brent et al. (3) and D o n e f e r et al. (4) found that the digestibility of energy of a concentrate-roughage ration decreased with increasing levels of roughage. Efficiency of energy utilization. The digestible energy intake and efficiency of its utilization by the steers were calculated f r o m the app a r e n t digestibility coefficients determined with the sheep (Table 4). Although there was a trend toward higher average daily digestible energy intakes as fiber level of the rations increased, the differences between rations were not significant (.10 > P > .05). On the other hand, both average total digestible energy intake f o r the entire experimental period (171 days for C and D, 183 days for E ) and digestible energy p e r kilogram gain were significantly (P < .05) higher f o r steers fed Ration E than for those fed either of the two other rations. These results indicate that steers consuming essentially the same daily amounts of digestible energy f r o m rations containing
TABLE 4. Digestible energy intake and efficiency of utilization by steers. Ration fed
C
Digestible energy : Total intake per animal (meal) 2 3,341.3 ~ Intake per animal per day (meal) 2 19.50 Per kilogram gain (mcal) 17.58 a
D
E
SE 1
3,514.5 a 20.46 18.70 a
3,985.2 b 21.86 21.31 b
±32.2 + 0.29 ___ 0.31
a Standard error based on pen means. 2 Adjusted by covarianee for final weight. ,. b Means within same line with differing superscripts were significantly different (P < .05). J. I)AIRY SCIENC~ VOL. 51, No. 12
ALL-CONCENTRATE
high levels of ground roughage (40% of total diet) utilize this energy less efficiently than those on low fiber diets. S t e e r c a r c a s s data. Dressing per cent (cold carcass of full live weight) was low in all cases, since animals were not shrunk prior to slaughter, but compared f a v o r a b l y with results reported by Preston et al. (9, 10). There was a trend toward decreasing dressing p e r cent with increasing levels of fiber in the diet (54.8, 53.9, and 51.9% f o r Rations C, D, and E, respectively), but the differences were nonsignificant (.10 > P > . 0 5 ) . The yield of untrimmed wholesale cuts showed differences due to rations f o r prime rib and chuck, with the f o r m e r being significantly (P < .05) greater and the latter significantly ( P < .05) smaller for animals fed Ration E versus Rations C and D.
Acknowledgments The authors acknowledge the assistance of Mr. P. S. Ha.ydon, A. R. I., for supervision of slaughter and carcass measurements, and assistance and cooperation of C. H. Thomas Ltd., Ottawa., for slaughter and carcass cutting. Additionally, W. Emend and J. C. Batty and staffs, all of A. R. I., are acknowledged for their work in carrying out the digestion trial and the steerfeeding trial. Analytical Chemistry Research Services carried out all proximate analyses.
References (1) Agricultural Research Council. 1965. The nutrient requirements of farm livestock. Number 2. Ruminants. Agricultural Research Council, London. (2) Association of Official Agricultural Chemists. 1960. Official Methods of Analysis. 9th ed. Washington, D.C.
RATION
1949
(3) Brent, B. E., D. Richardson, W. A. Tsien, and C. S. Menzies. 1961. Digestibility studies on levels of concentrates in complete pelleted rations for fattening lambs. J. Ar~im. Sci., 20: 526. (4) Denefer, E., L. E. Lloyd, and E. W. Crampton. 1963. Effect of varying alfalfa:barley ratios on energy intake and volatile fatty acid production by sheep. J. Anim. Sci., 22 : 425. (5) Foil,: N. J. 1965. Super beef: A report on details on an inte~sive dairy beef production system in Eng]aitd. Feedstuffs, 37(10) : 26. (6) Henderson, C. R. 1960. Design and analysis of animal husbandry experiments. Techniques and procedures in animal production research. Amer. Soe. Anita. Sci., Q. Corporation, Albany, N.Y. (7) Lamming, G. E., H. Swan, and R. T. Clarke. 1966. Studies on the nutrition of ruminants. I. Substitution of maize by milled barley straw in a beef fattening diet and its effect o~ performance and carcass quality. Anlm. Prod., 8: 303. (8) ~qational Research Council. 1963. Nutrient requirements of domestic animals. IV. Nutrient requirements of beef cattle. Natl. Acad. Sci., Publ. 1137. Washington, D.C. (9) Preston, T. R., F. G. Whitelaw, J. N. Airken, A. Macdearmid, and Euphemia B. Char]son. 1963. Intensive beef production. I. Performance of cattle given complete ground diets. Anita. Prod., 5:47. (10) Preston, T. R., J. N. Aitken, F. G. Whitelaw, A. Macdearmid, Euphemia B. Philip, and N. A. MacLeod. 1963. Intensive beef production. 3. Performance of Friesian steers given low-fibre diets. Anim. Prod., 5 : 245. (11) Preston, T. R. 1964. Barley beef production in the United Kingdom. Feedstuffs, 36 (40) : 66.
J. DAIRXSCIENCEYOL. 51, NO.
12