J. P. Schoonmaker, S. C. Loerch1, F. L. Fluharty, T. B. Turner,
S. J. Moeller, and J. E. Rossi
The Ohio State University Department of Animal Sciences
Sixty-three calves were allotted to a bull or a steer group based on sire, birth date, and birth weight. At 75 days of age (5-15-98), calves in the steer group were castrated. Calves were not creep fed prior to weaning. All calves were weaned and weighed at an average age of 115 days of age (6—24—98) and transported by truck to the Ohio Agricultural Research and Development Center (OARDC) feedlot in Wooster, Ohio. Performance information and carcass characteristics were measured in three phases. Phase 1 was from 6—25—98 to 9—17—98; Phase 2 was from 9—18—98 to 12—3—98; Phase 3 was from 12—4—99 to harvest. Calves averaged 115, 200, and 277 days of age on 6—25—98, 9—17—98, and 12—3—98, respectively. Before implantation, four bulls and four steers, were selected for serial slaughter and carcass evaluation. Steers were implanted with Synovex C at 130 days of age (7—9—98), Revalor S at 200 days of age (9—17—98), and Revalor S at 277 days of age (12—3—98). Bulls gained 9.7 % faster (3.86 vs 3.52 lb/day; P < 0.01), consumed 56 lb more DM (1,149 vs. 1,093 lb; P = 0.11), and were 3.3 % more efficient (0.282 vs. 0.273 lb/lb, P < 0.10) than steers in Phase 1. However, steers gained 10.5% faster (3.57 vs. 3.23 lb/day; P < 0.02), consumed similar amounts of DM and were 6.5% more efficient than bulls (0.214 vs. 0.201 lb/lb; P < 0.06) in Phase 2. Overall, gains and efficiency were similar between bulls and steers; however, bulls had to consume 309 lb more of DM (P < 0.05), gain 59 lb more of weight (P < 0.05), increase hip height growth 12.8% (P < 0.07), increase REA 12.3% (P < 0.03), and had to stay in the feedlot 18 more days (P < 0.05) than steers to achieve a similar amount of backfat. Eighty-five percent of both bulls and steers graded low choice or better. Placing early-weaned bulls and implanted steers on a high grain diet resulted in excellent feedlot performance and carcass characteristics in cattle marketed before a year of age.
Castration alters growth rate and carcass composition in cattle due to a change in hormonal status (Anderson et al., 1988a; Anderson et al., 1988b; Henricks et al., 1988; Lee et al., 1990; Hunt et al., 1991). Implants alter growth rate and carcass composition in steers due to a change in hormonal status as well (Hayden et al., 1992; Hongerholt et al., 1992; Johnson et al., 1996; Johnson et al., 1998; Trenkle, 1997). The hormonal control of muscle growth has not been elucidated and the biological mechanisms responsible for the anabolic effects of implants are also unknown (Hayden et al., 1992; Hongerholt et al., 1992; Johnson et al., 1996, 1998; Trenkle, 1997). All anabolic implants currently on the market contain active ingredients that can be classified as either estrogens (estradiol 17b, progesterone) or androgens (testosterone propionate, trenbolone acetate). Since the introduction of androgen/estrogen combination implants (Revalor-S) into the United States in 1987, improvements in performance over implants containing only estrogen have been realized. Measuring performance and carcass characteristics may help determine similarities in the pattern and extent of growth in bulls and implanted steers.
There are concerns that the use of implants, particularly those containing trenbolone acetate (TBA), may have detrimental effects on carcass quality grade and beef tenderness (Smith et al., 1992). Heightened concerns exist for these quality characteristics in bulls. Schoonmaker (1999) demonstrated that early weaning, by enabling steers to deposit intramuscular fat earlier in the feeding period, can complement an aggressive implant regimen and allow for rapid and efficient growth, as well as a lean high-quality carcass in steers marketed at less than a year of age. Carcass quality and behavior problems of bulls may be less significant if bulls are managed similarly and marketed around a year of age.
Performance, growth rate, and carcass characteristics in early weaned steers after multiple implants have not been compared with early-weaned bulls. The objective of this study was to compare performance, growth rate, and carcass characteristics between early-weaned bulls and implanted steers and to determine if early weaning bulls and feeding them a high concentrate diet could be a viable management option for profitable production of quality beef.
Sixty-three calves were allotted to a bull or a steer group based on sire, birth date, and birth weight. At 75 days of age (5—15—98), calves in the steer group were castrated. Calves were not creep fed prior to weaning. All calves were weaned and weighed at an average of 115 days of age (6—24—98) and transported by truck to the OARDC feedlot in Wooster, Ohio. Performance information and carcass characteristics were measured in three phases. Phase 1 was from 115 to 200 days of age (6—25—98 to 9—17—98, respectively), Phase 2 was from 201 to 277 days of age (9—18—98 to 12—3—98, respectively), and Phase 3 was from 278 days of age (12—4—98) to slaughter. Serial slaughter calves were weighed, hip-heighted, and selected for slaughter at the initiation of each phase. Remaining calves were weighed, hip-heighted, implanted and then scanned with an Aloka 500v ultrasound machine (Carometrics Medical Systems; Wallingford, Conn.) to determine backfat and loin- eye measurements within two weeks of the initiation of each phase. Composition of gain in each phase was then determined for all calves. To avoid confounding subsequent serial slaughter and final slaughter measurements by weight, bulls and steers were each divided (on paper) into four subgroups based on weight at each serial slaughter date (115, 200, 277 days of age, respectively). Before implantation, four bulls and four steers, one from each weight quadrant, were randomly selected for serial slaughter and carcass evaluation. Nineteen bulls and 20 steers remained in each treatment until final slaughter. Steers were implanted with Synovex C (provided through the courtesy of Fort Dodge Animal Health, Overland Park, Kan.) at an average age of 130 days (July 9), Revalor S (provided courtesy of Hoechst-Roussel Agri. Vet. Co., Overland Park, Kan.) at an average age of 200 days (9—17—98) and 277 days (12—3—98).
Calves received a 30% corn silage, 18% crude protein (CP) receiving diet for the first 14 days in the feedlot. After the first 14 days, all calves were fed a 30% corn silage, 14% CP diet until normal weaning time at 200 days of age (9—17—98). Corn silage was fed at 30% of the diet to lower energy intake and therefore minimize subcutaneous fat deposition from early weaning to normal weaning time (Schoonmaker, 1999). From normal weaning time (9—17—98) until slaughter, all calves were fed a 15% corn silage, 14% CP diet. For all diets, the concentrate portion of the diet consisted primarily of whole shelled corn and soybean meal (Table 1). Pen construction consisted of metal gates and a slatted concrete floor located inside a totally enclosed barn. Calves were penned individually with access to their own feed bunk and water cup. Therefore, each calf was an experimental unit. All steers were fed once daily, beginning at 0800 hours, and feed refusals were recorded daily for each steer. Initial and final weights were determined using two consecutive days average pre-feeding weight. Average daily gain (ADG), dry matter intake (DMI), and feed efficiency (gain/feed) was determined for 28-day periods, beginning at day 0 (108 days of age), as well as for the entire trial. Feed samples were collected every seven days throughout the trial and analyzed for dry matter according to the procedures of Goering and Van Soest (1970). Monthly composites of feed were analyzed for nitrogen (N) content by a Leco 2000 nitrogen analyzer.
Table 1. Diet Composition. |
|||
|---|---|---|---|
| Item | Receiving | Intermediate | Finishing |
|
Ingredient% |
Dry matter basis | ||
| Shelled corn | 40.0 | 45.0 | 65.0 |
|
Corn Silage |
30.0 | 30.0 | 15.0 |
|
Ground corn |
4.9 | 6.4 | 4.0 |
|
Soybean meal |
21.05 | 15.00 | 12.10 |
|
Urea |
0.85 | 0.40 | 0.70 |
|
Limestone |
1.33 | 1.33 | 1.33 |
|
Dicalcium phospate |
0.400 | 0.400 | 0.500 |
|
Trace mineral salta |
0.500 | 0.500 | 0.500 |
|
Vitamin A, 30,000 IU/g |
0.010 | 0.010 | 0.010 |
|
Vitamin D, 3,000 IU/g |
0.010 | 0.010 | 0.010 |
|
Vitamin E, 44 IU/g |
0.030 | 0.030 | 0.030 |
|
Selenium, 201 mg/kg |
0.050 | 0.050 | 0.050 |
|
Rumensin, 176 g/kg |
0.017 | 0.017 | 0.017 |
|
Potassium choride |
0.150 | 0.150 | 0.150 |
|
Dynamateb |
0.400 | 0.400 | 0.400 |
|
Animal-vegetable fat |
0.300 | 0.300 | 0.200 |
|
Nutrient composition |
|||
|
Crude proteinc |
17.280 | 15.043 | 13.90 |
|
Calcium |
0.689 | 0.670 | 0.65 |
|
Phosphorus |
0.450 | 0.430 | 0.46 |
|
Potassium |
1.054 | 0.949 | 0.81 |
|
NEm, Mcal/kg |
1.943 | 1.964 | 2.05 |
|
NEg, Mcal/kg |
1.31 | 1.33 | 1.40 |
| aContained
> 93% NaCl, 0.35% Zn, 0.28% Mn, 0.175% Fe, 0.035% Cu, and 0.007% Co. bMagnesium sulfate and potassium sulfate. Contained 22% S, 18% K, and 11% Mg (International Minerals and Chemical, Terre Haute, Ind). cCrude protein content was determined by analysis; remaining composition values were calculated. |
|||
Calves were removed from the trial and slaughtered on an individual basis when they reached a predetermined terminal fat thickness of 0.45 in. Marbling may be less developed in implanted animals than in non-implanted animals fed a similar number of days; however, it may be equally developed at a common compositional endpoint (Foutz, 1997). The same may be true when comparing bulls to steers. Calves were therefore slaughtered when backfat reached approximately 0.45 in. (0.40 to 0.50) so that quality grade was not biased by compositional endpoint. Calves were required to be a minimum weight of 1,100 lb when slaughtered. Hot carcass weight; backfat (BF) depth; percentage kidney, pelvic, and heart fat; rib-eye area (REA); and USDA quality and yield grades were determined at slaughter. Research protocols regarding animal care followed guidelines recommended in the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (Consortium, 1988).
Data were analyzed using the GLM procedures of SAS (SAS, 1996) for a completely randomized design comparing two treatments. The model included effects due to sex. Effects due to time and the sex X time interaction were analyzed using the PROC MIXED procedures of SAS (SAS, 1996). Animal was the experimental unit.
Phase 1 began at early weaning time, when calves averaged 115 days of age, and lasted for 84 days. Measurements were taken on 27 bulls and 28 steers during Phase 1. Four bulls and four steers were removed for serial slaughter at the end of Phase 1 (data not shown). Bulls gained 9.7 % faster than steers during Phase 1 (3.86 vs. 3.52 lb/day; P < 0.01), resulting in a 38-lb weight difference in bulls compared to steers (699 vs. 661 lb; P < 0.05) at the termination of Phase 1 (Table 2). Bulls consumed 56 lb more of feed (1,149 vs. 1,093 lb; P = 0.11), and were 3.3 % more efficient (0.282 vs. 0.273 lb/lb, P < 0.10). Steers did not receive their initial implant until 130 days of age, and it was a low potency, estrogen implant (Synovex C). This may have contributed to the decreased performance of implanted steers compared to bulls during this phase. Hip height, backfat, and REA were similar between bulls and steers at the initiation and termination of Phase 1 (P > 0.24), resulting in no difference in hip height, backfat, and REA change during Phase 1 (P > 0.48). This indicates that at an early stage of growth, implanted steers have similar skeletal, protein, and fat deposition as bulls under the influence of natural hormone production.
|
Table 2. Effect of Early Weaning on Performance and Carcass Characteristicsa of Bulls and Implanted Steers During Phase 1c. |
||||
|---|---|---|---|---|
|
Item |
Bulls | Steers | SE | P-value |
|
No. of Animals |
27 | 28 | ||
|
Days |
84 | 84 | ||
|
Initial age (6—25-98) |
118.9 | 115.6 | 3.5 | 0.43 |
| Gain | ||||
|
Initial weight, lb (6—25-98) |
375 | 364 | 8.4 | 0.33 |
|
Final weight, lb (9—17-98) |
699 | 661 | 12.1 | 0.03 |
|
Average daily gain, lb/day |
3.85 | 3.52 | 0.07 | 0.01 |
|
Intake |
||||
|
Daily DM intake, lb/day |
13.7 | 13.0 | 0.3 | 0.11 |
|
Total DM intake, lb |
1149 | 1093 | 24.0 | 0.11 |
|
Gain/feed, lb/lb |
0.282 | 0.273 | 0.004 | 0.10 |
|
Hip Height |
||||
|
Initial hip height, in. (6—25-98) |
39.8 | 40.4 | 0.4 | 0.24 |
|
Final hip height, in. (9—17-98) |
43.7 | 44.0 | 0.3 | 0.42 |
|
Hip height change, in |
3.9 | 3.6 | 0.3 | 0.48 |
|
Backfat |
||||
|
Initial backfat, ina (6—25-98) |
0.11 | 0.10 | 0.01 | 0.35 |
|
Final backfat, inb (9—17-98) |
0.25 | 0.23 | 0.01 | 0.37 |
|
Backfat change, in |
0.14 | 0.13 | 0.01 | 0.63 |
|
Rib-eye area |
||||
|
Initial REA, in2 a (6—25-98) |
5.9 | 5.9 | 0.1 | 1.00 |
|
Final REA, in2 b (9—17-98) |
8.5 | 8.3 | 0.2 | 0.36 |
|
REA change, in |
22.6 | 2.4 | 0.2 | 0.38 |
| aMeasured
via ultrasound (Aloka 500v, 12.5 cm 3.5 MHz linear transducer). bMeasured via ultrasound (Aloka 500v, 17.0 cm 3.0 MHz linear transducer). cFrom 6—25—99 to 9—17—99. |
||||
Phase 2 began at approximately 200 days of age and lasted for 77 days. Prior to the initiation of Phase 2, four steers and four bulls were removed for serial slaughter (data not shown), and an implant of Revalor-S was given to the remaining steers. Measurements were taken on 23 bulls and 24 steers. Performance (ADG, DMI, G/F) in Phase 2 was inversely related to perfromance in phase 1 (Table 3). Steers gained 10.5% faster than bulls during Phase 2 (3.57 vs. 3.23 lb/day; P < 0.02), resulting in similar weights at the termination of Phase 2. Dry-matter intake was not different between bulls and steers; however, steers were 6.5% more efficient than bulls (0.214 vs. 0.201 lb/lb; P < 0.06). The high potency TBA/E2 implant of Revalor-S may have contributed to the improved performance of steers during this phase. Hip height measurements and hip height change were not different between bulls and steers. Backfat was lower (nonsignificant) for steers at the initiation of Phase 2, but was higher (nonsignificant) for steers at the termination of Phase 2, resulting in increased (P < 0.04) fat deposition for implanted steers. Increased fat deposition in Phase 2 for implanted steers compared to bulls indicates that some of the increased gains experienced by implanted steers in Phase 2 was partitioned to fat. Rib-eye area measurements and REA change were not different (P > 0.16) between bulls and steers in Phase 2, indicating that implants in steers affect protein deposition in an intermediate stage of growth in a similar manner as natural hormone production in bulls.
Table 3. Effect of Early Weaning on Performance and Carcass Characteristicsa of Bulls and Implanted Steers During Phase 2b. |
||||
|---|---|---|---|---|
|
Item |
Bulls | Steers | SE | P-value |
|
No. of Animals |
23 | 24 | ||
|
Days |
77 | 77 | ||
| Gain | ||||
|
Initial weight, lb (9—17-98) |
699 | 660 | 13.2 | 0.04 |
|
Final weight, lb (12—3-98) |
949 | 935 | 15.4 | 0.52 |
|
Average daily gain, lb/day |
3.23 | 3.57 | 0.11 | 0.02 |
|
Intake |
||||
|
Daily DM intake, lb/day |
16.1 | 16.6 | 0.3 | 0.26 |
|
Total DM intake, lb |
1242 | 1281 | 24.5 | 0.26 |
|
Gain/feed, lb/lb |
0.201 | 0.214 | 0.005 | 0.06 |
|
Hip Height |
||||
|
Initial hip height, in (9—17-98) |
43.7 | 44.0 | 0.3 | 0.52 |
|
Final hip height, in (12—15-98) |
47.5 | 48.1 | 0.3 | 0.19 |
|
Hip height change, in |
3.8 | 4.1 | 0.2 | 0.30 |
| Backfat | ||||
|
Initial backfat, ina (9—17-98) |
0.25 | 0.23 | 0.02 | 0.34 |
|
Final backfat, ina (12—15-98) |
0.34 | 0.37 | 0.02 | 0.40 |
|
Backfat change, in |
0.10 | 0.14 | 0.02 | 0.04 |
|
Rib-eye area |
||||
|
Initial REA, in2 a (9—17-98) |
8.5 | 8.2 | 0.2 | 0.16 |
|
Final REA, in2 a (12—15-98) |
11.9 | 11.6 | 0.2 | 0.29 |
|
REA change, in2 |
3.5 | 3.5 | 0.2 | 0.97 |
| aMeasured via ultrasound (Aloka
500v, 17.0 cm 3.0 MHz linear transducer). bFrom 6—25—99 to 9—17—99. |
||||
Phase 3 began when calves were approximately 277 days of age and lasted until calves were slaughtered. Prior to the start of Phase 3, four steers and four bulls were removed for serial slaughter (data not shown), and an implant of Revalor-S was given to the remaining steers. Measurements were taken on 19 bulls and 20 steers. Average daily gain in phase 3 was not different between bulls and steers (Table 4); however, bulls were in the feedlot for 18 more days (249 vs. 231 days; P < 0.004), weighed 59 lb more at harvest (1,219 vs. 1,160 lb, P < 0.03), consumed 4.2% less DM per day (19.0 vs 19.8; P < 0.10), consumed 271 lb more of total DM (1,669 vs. 1,398 lb; P < 0.03), and were 26 days older than steers (367.7 vs. 341.9 days; P < 0.001). Steers had numerically greater hip heights throughout Phase 1 and 2. Bulls had a larger increase in hip height (2.6 vs. 1.7 in; P < 0.03) in Phase 3 compared to steers, thus reaching a similar final hip height. Backfat at slaughter (P > 0.59), as planned, and backfat change (P > 0.94) was not different between bulls and steers for Phase 3. Bulls had a larger REA than steers at harvest (12.3 vs. 11.6 in2; P < 0.03).
Table 4. Effect of Early Weaning on Performance and Carcass Characteristicsa of Bulls and Implanted Steers During Phase 3c. |
||||
|---|---|---|---|---|
|
Item |
Bulls | Steers | SE | P-value |
|
No. of Animals |
19 | 20 | ||
|
Days |
88 | 70 | 4.2 | 0.01 |
| Gain | ||||
|
Initial weight, lb (12-3-98) |
951 | 935 | 17.2 | 0.54 |
|
Harvest weight, lb |
1,219 | 1,160 | 18.5 | 0.03 |
|
Average daily gain, lb/day |
3.11 | 3.22 | 0.13 | 0.50 |
| Intake | ||||
|
Daily DM intake, lb/day |
19.0 | 19.8 | 0.4 | 0.10 |
|
Total DM intake, lb |
1,669 | 1,398 | 88.8 | 0.03 |
|
Gain/feed, lb/lb |
0.164 | 0.161 | 0.006 | 0.79 |
|
Hip height |
||||
|
Initial hip height, in (12-15-98) |
47.6 | 48.5 | 0.4 | 0.09 |
|
Hip height at harvest, in |
50.2 | 50.2 | 0.4 | 0.97 |
|
Hip height change, in |
2.6 | 1.7 | 0.3 | 0.03 |
|
Backfat |
||||
|
Initial backfat, ina (12-15-98) |
0.34 | 0.37 | 0.01 | 0.40 |
|
Backfat at harvest, inb |
0.48 | 0.50 | 0.03 | 0.59 |
|
Backfat change, in |
0.14 | 0.14 | 0.02 | 0.94 |
|
Rib-eye area |
||||
|
Initial REA, in.2 a (12-15-98) |
11.9 | 11.6 | 0.2 | 0.29 |
|
REA at harvest, in2 b |
12.3 | 11.6 | 0.2 | 0.03 |
|
REA change, in2 |
0.4 | 0.0 | 0.2 | 0.24 |
| aMeasured via ultrasound (Aloka
500v, 17.0 cm 3.0 MHz linear transducer). bMeasured on chilled carcass. cFrom 12-3-98 or 12-15-98 to harvest. |
||||
Overall, gains and efficiency were similar between bulls and steers (Table 5); however, bulls had to consume 309 more lb of DM (P < 0.05), gain 59 more lb of weight (P < 0.05), increase REA 12.3% (P < 0.03), and had to stay in the feedlot 18 more days (P < 0.05) than steers to achieve a similar amount of backfat. Increased DM intake and continued protein growth in bulls compared to steers are due in part to an extended stay in the feedlot (18 days longer) for bulls. However; differences in final REA and overall REA growth, coupled with similar backfats and backfat growth throughout the trial and at slaughter, indicate that the extent of carcass component growth and final carcass proportions are different between bulls and implanted steers, but the pattern of carcass component growth is similar. Hot carcass weight, percent KPH, liver weight, and percent of abcessed livers were similar between bulls and steers (Table 6). Steers had a 21% greater heart weight (4.0 vs. 3.3 lb; P < 0.01) than bulls. Quality grade and yield grade distributions were similar between bulls and steers; however, bulls had a 54-point increase in marbling score (421 vs. 367; P < 0.06) and a 15.2% increase in quality grade score (3.8 vs. 3.3; P < 0.07).
Table 5. Effect of Early Weaning on Performance and Carcass Characteristicsab of Bulls and Implanted Steers During the Entire Trialc. |
||||
|---|---|---|---|---|
|
Item |
Bulls | Steers | SE | P-value |
|
No. of Animals |
19 | 20 | ||
|
Days |
249 | 231 | 4.1 | 0.01 |
|
Initial Age (6-25-98) |
118.7 | 110.8 | 3.5 | 0.11 |
|
Age at Harvest |
367.7 | 341.9 | 5.1 | 0.01 |
|
Gain |
||||
|
Initial weight, lb (6-25-98) |
375 | 364 | 10.5 | 0.48 |
|
Weight at harvest, lb |
1,219 | 1,160 | 18.5 | 0.03 |
|
Average daily gain, lb/day |
3.40 | 3.46 | 0.07 | 0.59 |
|
Intake |
||||
|
Daily DM intake, lb/day |
16.3 | 16.2 | 0.3 | 0.89 |
|
Total DM intake, lb |
4061 | 3752 | 101.4 | 0.04 |
|
Gain/feed, lb/lb |
0.209 | 0.214 | 0.004 | 0.47 |
|
Hip Height |
||||
|
Initial hip height, in (6-25-98) |
39.6 | 40.8 | 0.5 | 0.10 |
|
Hip height at harvest, in |
50.2 | 50.2 | 0.4 | 0.97 |
|
Hip height change, in |
10.6 | 9.4 | 0.4 | 0.07 |
|
Backfat |
||||
|
Initial backfat, ina (6-25-98) |
0.11 | 0.10 | 0.01 | 0.35 |
|
Backfat at harvest, inb |
0.48 | 0.50 | 0.03 | 0.59 |
|
Backfat change, in |
0.37 | 0.40 | 0.03 | 0.45 |
|
Rib-Eye Area |
||||
|
Initial REA, in2 a (6-25-98) |
5.9 | 5.9 | 0.1 | 1.00 |
|
REA at harvest, in2 b |
12.3 | 11.6 | 0.2 | 0.03 |
|
REA change, in2 |
6.4 | 5.7 | 0.2 | 0.03 |
| aMeasured via ultrasound (Aloka
500v, 12.5 cm 3.5 MHz linear transducer). bMeasured on chilled carcass. cFrom 6-25-98 to harvest. |
||||
Table 6. Effect of Early Weaning on Performance and Carcass Characteristics of Bulls and Implanted Steers. |
||||
|---|---|---|---|---|
|
Item |
Bulls | Steers | SE | P-value |
|
No. of animals |
19 | 20 | ||
|
Weight at harvest, lb |
1,219 | 1,160 | 18.5 | 0.03 |
|
Hot carcass wt, lb |
745 | 721 | 12.3 | 0.15 |
|
Dressing, % |
61.1 | 62.1 | 0.3 | 0.03 |
|
Backfat, in |
0.48 | 0.50 | 0.03 | 0.59 |
|
Ribeye area, in2 |
12.3 | 11.7 | 0.2 | 0.03 |
|
KPH fata, % |
3.2 | 3.3 | 0.1 | 0.11 |
|
Heart wt, lb |
3.3 | 4.0 | 0.2 | 0.01 |
|
Liver wt, lb |
14.1 | 13.9 | 0.3 | 0.70 |
|
Testicle wt, lb |
1.72 ± 0.09 | |||
|
Abscessed livers, % |
5.3 | 0 | 3.7 | 0.31 |
|
Marbling score |
421 | 367 | 20 | 0.06 |
|
Quality grade |
3.8 | 3.3 | 0.2 | 0.07 |
|
Quality grade distribution, % |
||||
|
Select- |
0 | 0 | ||
|
Select+ |
15.8 | 15.0 | 8.4 | 0.95 |
|
Choice- |
26.3 | 50.0 | 11.1 | 0.13 |
|
Choice |
36.8 | 30.0 | 10.8 | 0.66 |
|
Choice+ |
21.1 | 5.0 | 7.6 | 0.14 |
|
Prime |
0 | 0 | ||
|
³Choice- |
84.2 | 85.0 | 8.5 | 0.95 |
|
Yield grade |
3.2 | 3.4 | 0.1 | 0.17 |
| Yield grade (YG) distribution, % | ||||
|
YG 1 |
0 | 0 | ||
|
YG 2 |
21.1 | 10.0 | 8.2 | 0.35 |
|
YG 3 |
73.7 | 75.0 | 10.3 | 0.93 |
|
YG 4 |
5.3 | 15.0 | 7.1 | 0.33 |
|
YG 5 |
0 | 0 | ||
| aKPH = Kidney, plevic, and heart fat. | ||||
Placing early-weaned bulls and implanted steers on a high grain diet resulted in excellent feedlot performance and carcass characteristics in cattle marketed before a year of age.
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