J. E. Rossi, S. C. Loerch2, S. J. Moeller, and J. P. Schoonmaker
The Ohio State University Department of Animal Sciences
Crossbred steers (n = 107, 681 lb) were used in a 2 x 2 factorial experiment to determine effects of ad libitum (AL) or prescription-intake (PI) and days fed (168 vs. 203) on performance, carcass characteristics, and gross profits. Steers were fed a 92% concentrate, 13% crude protein diet. Prescription-intake steers were fed to gain 2.5 lb/day for the first 171 lb of gain, 3.0 lb/day for the next 274 lb of gain, and were offered feed ad libitum for the final 118 and 228 lb of gain before slaughter for PI-168 d and PI-203 d steers, respectively. Overall, ADG from day 0 to 168 was greater (P < 0.03) for AL (3.55 lb/day) vs. PI (3.31 lb/day) steers. Feed efficiency was improved (P < 0.02) for PI (0.193) vs. AL (0.183) steers. From day 169 to 203, PI steers had greater (P < 0.06) ADG (3.53 vs. 3.04 lb/day); greater (P < 0.02) DMI (23.2 vs. 20.7 lb/day); and similar (P = 0.38) feed efficiency (0.152 vs. 0.147) compared with AL steers. Total DMI was greater (P < 0.01) for AL vs. PI steers (3,230, 4,040, 2,895, and 3,691 lb for AL-168 d, AL-203 d, PI-168 d, and PI-203 d, respectively). Hot carcass weight was greater (P < 0.01) for AL vs. PI steers (781, 853, 741, and 822 lb for AL-168, AL-203 d, PI-168 d, and PI-203 d, respectively). Percentage of carcasses grading choice was greater for AL vs. PI steers (74, 81, 48, and 67% choice for AL-168 d, AL-203 d, PI-168 d, and PI-203 d, respectively). Gross profit per steer was $15.05 greater for AL steers at 168 days fed and $1.65 greater for PI steers at 203 days fed. Increasing days fed increased gross profits $46.30 for PI steers and $29.06 for AL steers. Increasing days fed increased percentage choice 40% in PI and 9% in AL steers.
Increasing days on feed to improve carcass marbling and the percentage of carcasses grading choice may reduce average daily gain and feed efficiency as cattle near finishing weights, thus making this option not cost effective. Goodrich and Anderson (1993) fed steers for 136 or 192 days and found that average daily gain was not decreased to a level that would be unprofitable (4.01 and 3.44 lb/day for 136 and 192 days fed, respectively). When intake is restricted to achieve step-wise increases in rate of gain, more rapid rates of gain are maintained until the end of the feeding period compared with cattle offered feed ad libitum throughout the feeding period (Knoblich et al., 1997). However, restricting intake for a portion of the feeding period tends to decrease the percentage of carcasses grading choice. Thus, increasing days on feed may be more beneficial for limit-fed steers compared with ad-libitum-fed steers through improved quality grades and greater performance near the end of the feeding period. Objectives were to determine effects of days fed and feeding regimen on performance, carcass characteristics, and gross profits in feedlot steers.
One hundred seven Angus crossbred steer calves (initial weight = 681 lbs) were used in a completely randomized design experiment with a 2 x 2 factorial arrangement of treatments to determine effects of feeding regimen (ad libitum or prescription intake) and days fed (168 or 203) on performance, carcass characteristics, and gross profits.
Steers were allotted to 12 pens with eight or nine steers per pen and three pens per treatment. Steers in Treatments 1 and 2 were offered ad libitum consumption of a 92% concentrate diet for either 168 (AL-168) or 203 days (AL-203). Steers in Treatments 3 and 4 were fed the same ad libitum diet, except intake was restricted using a prescription-intake feeding strategy for either 168 (PI-168) or 203 days (PI-203). For prescription-intake steers, intake was restricted for the first 171 lb of gain to achieve a predicted (NRC, 1984) gain of 2.5 lb/day. For the next 274 lb of gain, intake was restricted to achieve a predicted gain of 3.0 lb/day. Steers were then offered feed ad libitum for the final 118 lb of gain for steers fed 168 days and 228 lb of gain for steers fed 203 days. The diet was formulated to contain 13% crude protein, 27 grams Rumensin/ton, and 10 grams Tylan/ton. Steers were implanted with Synovex-S7 on day 0 and Revalor-S7 on day 70 (provided by the courtesy of Fort Dodge Animal Health, Overland Park, Kan., and Hoechst-Roussel Agri. Vet. Co., Overland Park, Kan., respectively). Feedstuffs were analyzed weekly for dry matter to adjust for dietary moisture content. Pens had slatted floors and were located in an open-sided barn.
Steers were fed once daily beginning at 0800 hours. Steers were weighed every 14 days, and intake of prescription-intake steers was increased to meet maintenance requirements as body weight increased. Initial and final weights were determined using the average weight from two consecutive days. Carcass data were collected by trained university personnel and by a USDA grader.
Data were analyzed using GLM procedures of SAS (1988). The model contained effects due to feeding regimen, days fed, and the interaction between the two. The model for performance data from 168 to 203 days in AL-203 and PI-203 contained effects due to treatment. Pen served as the experimental unit for all analyses. Research animal-care protocols followed guidelines recommended in the Guide for the Care and Use of Agricultural Animals in Agriculture Research and Teaching (Consortium, 1988).
Diet composition is shown in Table 1. Effects of feeding regimen and days fed on performance are shown in Table 2. There were no significant interactions (P > 0.25) between feeding regimen and days fed, therefore only main effect means are presented for performance data. Steers offered feed ad libitum gained approximately 1.2 lb/day faster (3.78 lb/day; P < 0.01) than prescription-intake steers (2.59 lb/day) when predicted gain was 2.5 lb/day. Prescription-intake steers consumed 25% less (P < 0.01) dry matter per day than steers offered feed ad libitum during this period, and feed efficiency was improved (P < 0.05) 11% for steers offered feed ad libitum compared with prescription-intake steers. When predicted gain was 3.0 lb/day, prescription-intake steers gained 29% more than predicted. Daily dry-matter intake was 11% lower (P < 0.01), and feed efficiency was improved (P < 0.01) 20% for prescription-intake steers compared with steers offered feed ad libitum. When all steers were offered feed ad libitum prior to the first slaughter date (168 days), prescription-intake steers gained 26% faster (P < 0.01) than steers offered feed ad libitum throughout the experiment. In addition, dry-matter intake per day was greater (P < 0.01) for prescription-intake than for steers offered feed ad libitum, and feed efficiency was improved 14% (P < 0.01) in prescription-intake vs. ad-libitum-intake steers. Overall ADG to the first slaughter date was greater (P < 0.03) for steers offered feed ad libitum compared with prescription-intake steers; likewise, total gain was 42 lb greater (P < 0.03) for steers offered feed ad libitum. Dry-matter intake per day was 13.4% greater (P < 0.01) for steers offered feed ad libitum compared with prescription-intake steers. Feed efficiency was improved 5% (P < 0.02) for prescription-intake steers compared with steers offered feed ad libitum, and prescription-intake steers consumed 381 lb less (P < 0.01) of total feed than steers offered feed ad libitum. For the entire experiment (0 to 203 days), ADG was greater (P < 0.06) for steers offered feed ad libitum compared with prescription-intake steers. Therefore, total weight gain was 33 lb less (P < 0.06) for prescription-intake steers vs. steers offered feed ad libitum. Daily dry-matter intake was 10% lower (P < 0.01), and feed efficiency was improved (P < 0.02) 4.5% for prescription-intake steers compared with steers offered feed ad libitum. Total feed consumed was 341 lb less (P < 0.01) for prescription-intake steers than for steers offered feed ad libitum.
Table 1. Diet Composition. |
|
|---|---|
| Item | % Dry-Matter Basis |
| Ingredient | |
|
Whole shelled high-moisture corn |
70 |
|
Corn silage |
15 |
|
Ground corn |
2.90 |
|
Soybean meal |
8.62 |
|
Urea |
0.70 |
|
Animal-vegetable fat |
0.40 |
|
Dicalcium phosphate |
0.35 |
|
Limestone |
1.40 |
|
Tace mineral salta |
0.50 |
|
Rumensin, 176 g/kg |
0.016 |
|
Tylan, 220 g/kg |
0.010 |
|
Selenium, 201 mg/kg |
0.050 |
|
Vitamin A, 30,000 IU/g |
0.010 |
|
Vitamin D, 3,000 IU/g |
0.010 |
|
Vitamin E, 44 IU/g |
0.030 |
|
Nutrient composition |
|
|
Crude proteinb, % |
13.00 |
|
Calcium, % |
0.63 |
|
Phosphorus, % |
0.60 |
|
Potassium, % |
0.42 |
|
NEm, Mcal/kg |
2.07 |
|
NEg, Mcal/kg |
1.42 |
| aContained:
> 93%NaCl, 0.35% Zn, 0.28% Mn, 0.175% Fe, 0.035% Cu, 0.007% I, and 0.007%
Co. bCrude protein was determined by analysis; remaining composition values were calculated. |
|
Table 2. Effects of Feeding Regimen and Days Fed on Performance of Feedlot Steers. |
|||||||
|---|---|---|---|---|---|---|---|
|
Feeding Regimena |
Days Fed | P-Valueb | |||||
| Item | AL | PI | 168 | 203 | SE | FR | DF |
| No. of steers | 27 | 26 | 27 | 27 | |||
|
Initial wt., lb |
681 | 682 | 682 | 681 | 1.32 | 0.93 | 0.40 |
|
Final wt., lb |
1,332 | 1,299 | 1,262 | 1,369 | 14.59 | 0.05 | 0.00 |
|
Predicted Gain, 2.5 lb/day |
|||||||
|
Gain, lb/day |
3.77 | 2.58 | 3.23 | 3.14 | 0.130 | 0.00 | 0.52 |
|
DM intake, lb/day |
18.1 | 13.5 | 15.7 | 16.0 | 0.33 | 0.00 | 0.35 |
|
Feed efficiency, lb gain/lb feed |
0.209 | 0.192 | 0.205 | 0.196 | 0.0065 | 0.03 | 0.20 |
|
Total gain, lb |
265 | 171 | 220 | 216 | 8.3 | 0.00 | 0.72 |
|
Total feed, lb |
1267 | 892 | 1060 | 1098 | 25.3 | 0.00 | 0.17 |
|
Days |
70 | 66 | 68 | 69 | 0.8 | 0.01 | 0.20 |
| Predicted Gain, 3.0 lb/day | |||||||
|
Gain, lb/day |
3.59 | 3.86 | 3.68 | 3.78 | 0.166 | 0.14 | 0.56 |
|
DM intake, lb/day |
20.3 | 18.3 | 19.3 | 19.4 | 0.50 | 0.00 | 0.75 |
|
Feed efficiency, lb gain/lb feed |
0.176 | 0.211 | 0.192 | 0.196 | 0.0089 | 0.01 | 0.68 |
|
Total gain, lb |
251 | 274 | 259 | 265 | 5.3 | 0.00 | 0.33 |
|
Total feed, lb1 |
426 | 1305 | 1363 | 1368 | 53.2 | 0.05 | 0.93 |
|
Days |
70 | 72 | 71 | 71 | 2.2 | 0.57 | 0.89 |
| Ad Libitum Intake | |||||||
|
Gain, lb/day |
2.91 | 3.66 | 3.40 | 3.19 | 0.14 | 30.00 | 0.19 |
|
DM intake, lb/day |
20.7 | 22.7 | 21.6 | 21.8 | 0.47 | 0.00 | 0.60 |
|
Feed efficiency, lb gain/lb feed |
0.141 | 0.162 | 0.158 | 0.146 | 0.0077 | 0.03 | 0.17 |
|
Total gain, lb |
82 | 111 | 101 | 91 | 7.5 | 0.01 | 0.23 |
|
Total feed, lb |
579 | 691 | 641 | 629 | 58.7 | 0.09 | 0.85 |
|
Days |
28 | 31 | 30 | 29 | 2.7 | 0.37 | 0.76 |
| Overall Performance, Day 0 to 168 | |||||||
|
Gain, lb/day |
3.55 | 3.31 | 3.46 | 3.42 | 0.087 | 0.02 | 0.63 |
|
DM intake, lb/day |
19.4 | 17.2 | 18.2 | 18.4 | 0.39 | 0.00 | 0.64 |
|
Feed efficiency, lb gain/lb feed |
0.183 | 0.193 | 0.190 | 0.186 | 0.0031 | 0.02 | 0.23 |
|
Total feed, lb |
3270 | 2889 | 2896 | 2879 | 65.9 | 0.00 | 0.64 |
|
Total gain, lb |
598 | 556 | 581 | 573 | 14.6 | 0.02 | 0.63 |
| Overall Performance, Day 0 to 203 | |||||||
| Gain, lb/day | 3.52 | 3.33 | 3.46 | 3.39 | 0.082 | 0.06 | 0.46 |
|
DM intake, lb/day |
19.6 | 17.7 | 18.2 | 19.0 | 0.38 | 0.00 | 0.07 |
|
Feed efficiency, lb gain/lb feed |
0.180 | 0.188 | 0.190 | 0.179 | 0.0028 | 0.02 | 0.00 |
|
Total feed, lb |
3635 | 3294 | 3063 | 3865 | 67.1 | 0.00 | 0.00 |
|
Total gain, lb |
651 | 618 | 581 | 689 | 14.7 | 0.05 | 0.00 |
| aAL-168 and AL-203 = offered feed ad libitum for
168 and 203 days, respectively. PI-168 and PI-203 = prescription intake
of feed for 168 and 203 days, respectively. bFR = feeding regimen; DF = days fed. |
|||||||
Performance of AL-203 and PI-203 steers from the first (day 168) to second slaughter date (day 203) is shown in Table 3. Average daily gain was 16% greater (P = 0.08) in PI-203 steers compared with AL-203 steers. Daily dry-matter intake was 11.5% higher (P < 0.02) in prescription-intake steers, and feed efficiency was similar (P = 0.38) between treatments. Cost of gain was $0.02 lower for PI-203 steers than for AL-203 steers.
Table 3. Performance of Steers Fed for 203 Days From the First (168 days) to the Second Slaughter Date (203 Days). |
||||
|---|---|---|---|---|
| Treatmenta | ||||
| Item | AL | PI | SE | P-value |
| Gain, lb/day | 3.05 | 3.53 | 0.145 | 0.08 |
|
DM intake, lb/day |
20.8 | 23.2 | 0.42 | 0.02 |
|
Feed efficiency, lb gain/lb feed |
0.147 | 0.152 | 0.0040 | 0.38 |
|
Total gain, lb |
106.9 | 123.7 | 5.07 | 0.08 |
|
Total feed, lb |
729 | 812 | 14.8 | 0.02 |
|
Cost of Gain, $/lbb |
$0.392 | $0.372 | ||
| aAL = offered
feed ad libitum for 203 days, PI = prescription intake of feed for 203 days.
bCalculated using the following prices: corn = $0.043/lb ($2.40/bu), corn silage = $0.013/lb ($25/ton), supplement = $0.104/lb ($208/ton). |
||||
Effects of feeding regimen and days fed on carcass characteristics are shown in Table 4. Dressing percentage and hot carcass weight was greater (P < 0.01) for steers offered feed ad libitum compared with prescription-intake steers, and both were greater (P < 0.01) for steers fed 203 days compared with 168 days. Backfat was greater (P < 0.04) for steers offered feed ad libitum compared with prescription-intake steers and also increased (P < 0.06) as days fed increased from 168 to 203 days. Ribeye area and percentage of kidney, pelvic, and heart fat were not affected (P > 0.26) by feeding regimen or days fed. Yield grades followed a similar pattern in that steers offered feed ad libitum had less desirable (P < 0.04) yield grades than prescription-intake steers, and yield grades were less desirable (P < 0.06) for steers fed 203 vs. 168 days. Percentage of steers grading choice was greater (P < 0.05) for steers offered feed ad libitum compared with prescription-intake steers. Days fed did not affect percentage USDA Choice (P > 0.16); however, increasing days fed from 168 to 203 days in prescription-intake steers increased percent choice 39%.
Table 4. Effects of Feeding Regimen and Days Fed on Carcass Characterisitcs of Feedlot Steers. |
||||||||
|---|---|---|---|---|---|---|---|---|
| Treatmenta | P-valueb | |||||||
| Item | AL-168 | AL-203 | PI-168 | PI-203 | SE | FR | DF | FR*DF |
|
Dressing % |
60.8 | 61.7 | 59.6 | 60.7 | 0.16 | 0.00 | 0.00 | 0.52 |
|
Hot carcass wt, lb |
779.6 | 852.4 | 740.7 | 823.3 | 9.22 | 0.01 | 0.00 | 0.61 |
|
Backfat, in |
0.48 | 0.54 | 0.35 | 0.47 | 0.040 | 0.04 | 0.05 | 0.47 |
|
KPH fat, % |
3.15 | 3.26 | 3.09 | 3.15 | 0.070 | 0.28 | 0.28 | 0.70 |
|
Ribeye area, in2 |
12.77 | 12.88 | 12.84 | 12.39 | 0.234 | 0.39 | 0.49 | 0.27 |
|
Yield grade |
3.00 | 3.01 | 2.56 | 2.96 | 0.094 | 0.03 | 0.06 | 0.07 |
|
Choice, % |
74.1 | 81.0 | 48.1 | 66.7 | 8.44 | 0.04 | 0.17 | 0.51 |
| aAL-168 and
AL-203 = offered feed ad libitum for 168 and 203 days, respectively; PI-168
and PI-203 = prescription intake of feed for 168 and 203 days, respectively. bFR = feeding regimen; DF = days fed. cKPH = Kidney, pelvic, and heart fat. |
||||||||
Effects of feeding regimen and days fed on economic returns are presented in Table 5. Steers offered feed ad libitum had a $37.39 higher sale price compared with prescription-intake steers at 168 days and a $20.26 higher sale price at 203 days. Likewise, feed costs were $21.95 lower for prescription-intake steers vs. steers offered feed ad libitum at 168 days fed and $20.43 lower at 203 days fed. Gross profit per steer was $15.05 higher for steers offered feed ad libitum compared with prescription-intake steers at 168 days; however, gross profit per steer was $1.65 higher for prescription-intake vs. steers offered feed ad libitum at 203 days fed. Increasing days fed from 168 to 203 days increased profit per steer by $45.76 for prescription-intake steers and $29.06 for steers offered feed ad libitum. Therefore, cost of gain was $0.02/lb lower for prescription-intake than for steers offered feed ad libitum. Overall cost of gain was $0.017/lb lower for prescription-intake steers and was $0.106/lb lower for steers fed 168 vs. 203 days.
Table 5. Effects of Feeding Regimen and Days Fed on Economic Returns. |
||||
|---|---|---|---|---|
| Treatmenta | ||||
|
Item |
AL-168 | AL-203 | PI-168 | PI-203 |
|
Purchase Priceb |
$531.65 | $531.26 | $532.27 | $530.79 |
|
Sale Pricec |
$807.39 | $880.63 | $770.00 | $860.37 |
|
Feedcostsd |
$189.28 | $232.84 | $167.33 | $212.41 |
|
Gross Profit |
$86.46 | $115.52 | $71.41 | $117.17 |
|
Cost of Gain, $/lbd |
$0.315 | $0.332 | $0.299 | $0.314 |
| aAL-168 and
AL-203 = offered feed ad libitum for 168 and 203 days, respectively. PI-168
and PI-203 = prescription intake of feed for 168 and 203 days, respectively. bCalculated using initial wt. at $0.78/lb. cCalculated using hot carcass weight and the following average prices from the two slaughter dates: Choice YG 2 and 3 = $1.055/lb; Choice YG 4 = $0.9555/lb; Select YG 2 and 3 = $1.025/lb; Select YG 4 = $0.925/lb; and over 950 lb carcass weight = $0.8555/lb. dCalculated using the following prices: corn = $0.043/lb ($2.40/bu), corn silage = $0.013/lb ($25/ton), and supplement = $0.104/lb ($208/ton). |
||||
Performance of both Al-203 and PI-203 steers was maintained at a profitable level during the last 35 days of the experiment (Table 3), and overall performance of steers at 203 days fed was similar to performance at 168 days fed (Table 2). Steers in the PI-203 treatment gained 0.48 lb/day more than AL-203 steers from 168 to 203 days fed. Feed efficiency was similar between PI-203 and AL-203 during the last 35 days fed; therefore, the difference in ADG was due to a 12% higher intake per day in the PI-203 vs. AL-203 steers. Improved performance in PI-203 steers was expected because restricting feed intake to achieve step-wise increases in growth rate maintains higher feed intake and a more rapid rate of gain until the end of the feeding period compared with steers offered feed ad libitum. Furthermore, the increase in gross profit during the last 35 days was much greater for PI-203 ($45.76) than for AL-203 steers ($29.06).
Increasing days fed from 168 to 203 days was expected to increase the percentage of carcasses grading choice. In steers offered feed ad libitum, few differences were observed in percentage of carcasses grading choice. However, the percentage of carcasses from prescription-intake steers grading choice increased from 48% to 67%. Therefore, the only economic advantage to extending the feeding period in AL-203 steers was to increase carcass weight, whereas prescription-intake steers improved economic returns through an increased quality grade and larger carcass weights. Prescription-intake steers received no discounts for yield grade 4 carcasses compared with 9.5% of steers offered feed ad libitum. In addition, one carcass in the AL-203 treatment was discounted for being greater than 950 lb. Because of discounts, carcasses of prescription-intake steers were worth $0.01/lb more than carcasses from steers offered feed ad libitum despite fewer carcasses grading choice. However, the difference in price between choice and select would have a large impact on economic returns of prescription-intake steers compared with steers offered feed ad libitum.
Increasing days fed 35 days increased gross profits of both prescription-intake and steers offered feed ad libitum. Steers offered feed ad libitum were $15.05 more profitable than prescription-intake steers at 168 days fed, and prescription-intake steers were $1.65 more profitable than steers offered feed ad libitum at 203 days fed. Using a prescription-intake feeding strategy reduced carcass weights, but eliminated yield grade and overweight carcass discounts. Increasing days fed improved percentage choice in prescription-intake steers but had minimal influence on percentage choice carcasses in steers offered feed ad libitum. Three main factors will dictate the profitability and advisability of increased time on feed – additional cost of feed, additional weight of beef sold, and carcass value of the longer-fed animal (quality premiums vs. yield and heavy weight discounts). In our study, steers offered feed ad libitum that were fed an additional 35 days (AL-203) gained 107 lb more and sold for $73.24 more than steers fed for 168 days (value of this gain was $0.67/lb). Additional feed costs were $43.56/steer. In this situation, the break-even daily gain would be 1.86 lb/day. Assuming the same feed costs and the same carcass value per pound, it would be more profitable to keep feeding the steers if gains were greater than 1.86 lb/day. Maintaining acceptable performance is required if cattle are fed to heavier body weights.
Consortium. 1988. Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Consortium for Developing a Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching, Champaign, Ill.
Goering, H. K., and van Soest, P. J. 1970. Forage fiber analyses (apparatus, reagents, procedures, and some applications). Agric. Handbook No. 379. ARS, USDA, Washington, D.C.
Goodrich, R. D. and Anderson, P. T. 1993. Influence of Synovex and Finaplex-s on daily gain and carcass characteristics of steers marketed at varying weights. Minnesota Beef Cattle Research Report B-399. p. 32. Minnesota Extension Service and Department of Animal Science, St. Paul, Minn.
Knoblich, H. V., Fluharty, F. L., and Loerch, S. C. 1997. Effects of programmed gain strategies on performance and carcass characteristics of steers. J. Anim. Sci. 75:3094—3102.
Loerch, S. C. and Fluharty, F. L. 1998. Effects of programming intake on performance and carcass characteristics of feedlot cattle. J. Anim. Sci. 76:371—377.
NRC. 1984. Nutrient Requirements of Beef Cattle. 6th Ed. National Academy Press, Washington, D.C.
SAS. 1996. SAS/STAT7 User’s Guide. Release 6.12. SAS Institute, Inc., Cary, N.C.
1 Partial support was provided by Moyer Packing Co.,
Souderton, Pa.
2 For more information, contact at: The Ohio State University, Ohio
Agricultural REsearch and Developement Center, 1680 Madison Avenue, Wooster,
OH 44691; (330) 263-3900; email:loerch.1@osu.edu