Effect of Optimum® High Oil Corn on Performance and Carcass Characteristics of Finishing Yearling Steers

Steers fed Optimum® high oil corn had statistically similar live performance as steers fed isogenetic control corn or the control corn + fat. Numerically steers fed high oil corn gained 3% faster during the 107-day study with similar feed conversion. During the first half of the experiment, steers fed high oil corn did not perform as well as those fed control corn. During the second half of the experiment, steers fed high oil corn gained 21% faster and were 17% more efficient. There were no effects of feeding high oil corn on carcass characteristics, except there were more Choice carcasses from the steers fed high oil corn as compared with control corn (57% vs. 43% Choice).

Effect of Feeding Procedure and Intake Level on Steer Feedlot Performance and Carcass Composition: A Progress Report

Two feedlot trials were conducted to evaluate the effects of feeding frequency (once daily in the morning, once daily in the afternoon or twice daily) and feeding level (ad libitum, 95% of ad libitum, or 90% of ad libitum) on the feedlot performance and carcass composition of beef steers. Data were collected using 196 yearling beef steers. In both trials cattle fed once daily in the morning tended to have higher gains and better feed efficiencies than cattle fed once daily in the afternoon or cattle fed twice daily. Overall, cattle restricted to 95% and 90% of ad libitum intake levels had better feed efficiencies than cattle with ad libitum access to feed. Cattle fed once daily in the morning tended to have less backfat than cattle fed once daily in the afternoon or cattle fed twice daily.

Effects of Sorting Steer Calves on Feedlot Performance and Carcass Value

Three groups of steer calves totaling 480 head were sorted into smaller and larger frame sizes, and those groups were sorted into groups with more and less backfat. There was no difference in age among the four sorted groups. The larger steers and steers with less fat had faster rates of gain and tended to have superior feed efficiencies. Steers with more initial fat were fed fewer days. The larger framed steers and steers with less fat had heavier carcasses, less carcass backfat, more yield grade 1 carcasses and a lower percentage of Choice carcasses, but they also had greater value per carcass when evaluated using a grid paying premiums for quality and yield grades. The greatest profit to the feedyard was realized from the smaller framed steers and those with less initial backfat. For similar profit it was calculated that the larger steers should have been discounted as feeders $3.50 per hundred compared with the smaller steers and the steers with more fat discounted $5.00 per hundred compared with those having less initial fat. The results of this study suggest that sorting based on initial fat thickness may have more potential for enhancing the value of finished cattle than sorting based on frame score.

Effects of Feeding Cobalt Dextro Lac (CDL) on Feedlot Performance and Carcass Value of Finishing Steers Fed Wet Corn Gluten Feed

A 192-day experiment involving 144 young Angus steers fed growing and finishing diets containing 20% corn gluten feed was conducted to evaluate feeding a soluble source of readily available cobalt. No benefits were observed in rate of gain, feed intake or carcass value by feeding the available source of cobalt.

The Effects of Feeding a Live Microbial Product on Feedlot Performance and Carcass Value of Finishing Steers Fed Wet Corn Gluten Feed

This experiment was conducted to evaluate the efficacy of daily feeding a live microbial preparation containing two live organisms to finishing cattle. One organism was a lactobacillus, and the other was a propionibacterium, thought to work in concert to improve fermentation in the rumen and overall digestion. The study was conducted with Angus steers with an average initial weight of 550 lbs that were fed a finishing ration containing 50% wet corn gluten feed on a dry basis for 184 days. Feeding the microbial product improved daily gain and feed efficiency 1.7% and 2.4%, respectively, but the differences were not statistically significant. The microbial preparation increased carcass weights 1% but had no effects on quality or yield grades. It is concluded that potential benefits of this product are more likely to be greater when cattle are fed high grain rations rather than diets containing high concentrations of corn gluten feed.

Effect of Supplemental Vitamin E and A on Reproductive Performance and Serological Profiles of Ewes Managed in Drylot

Forty Hampshire and 40 Suffolk ewes were allotted to one of four groups (VitA, VitE, VitA&E, Control) in a 2 x 2 factorial treatment arrangement to evaluate the effect of supplemental vitamin E (0 or 300 IU) and vitamin A (0 or 250,000 IU) on reproductive performance. Laparoscopy and ultrasonography were used to measure ovulation rate, embryonic loss, and fetal loss. Serum profiles of a-tocopherol (vitamin E) and retinol (vitamin A) also were monitored. There were no differences (P>.05) among treatment groups in any reproductive trait. Suffolk ewes exhibited a higher (P<.02) ovulation rate than Hampshire ewes, and yearling ewes incurred higher (P<.001) embryonic loss than other age groups, resulting in a lower (P<.001) litter size. Serum levels of a-tocopherol were higher (P<.05) for Hampshire than for Suffolk ewes and were lower (P<.001) in yearling ewes versus ewes two years of age and older. Serum levels of a-tocopherol declined (P<.01) throughout the study in VitA and Control ewes but remained unchanged in VitE and VitA&E ewes. Serum level of retinol remained unchanged in VitA ewes, whereas the level increased (P<.01) initially in VitE, VitA&E, and Control ewes before declining toward initial levels. Correlations were detected between ovulation rate and the change of pre-mating a-tocopherol serum level (r=-.29; P<.02), the change in pre-mating retinol serum level (r=-.50; P<.02) and the interval from vitamin A injection (r=-.60; P<.05). These data indicate significant influences of breed, age, and treatment on a-tocopherol and retinol serum levels in ewes and suggest that the timing of vitamin A administration may influence ovulation rate; however, vitamin supplementation, administered at random stages of the estrous cycle, was unable to alter flock reproductive performance.

Effect of Frame Size and Hormone Implant on Performance and Carcass Characteristics of Finishing Yearling Heifers: Returns to a Value-Based Market

Four groups of yearling heifers representing different frame sizes—small, medium, and large Angus and medium Simmental—were fed high-grain finishing diets to average Low Choice quality grade. Half the heifers were implanted with estrogen and trenbolone acetate. Backfat and ribeye area were measured by ultrasound four times during the study to assess growth of muscle and fat. Increasing frame size resulted in increased feed intake, greater rates of gain, and a trend towards reduced feed conversion. Greater returns would have been realized from each of the four groups had they been sold in a premium market based on yield grade rather than the conventional grade and yield market. Increasing frame size resulted in greater returns to the value-based market. Implants increased rate of gain and improved feed conversion but did not result in significantly greater returns to the value-based market compared with the grade and yield market. Ribeye area and backfat increased with body weight and time on feed. Increase in ribeye area was linear with time, whereas accumulation of backfat was exponential. Rate of increase in area of ribeye tended to increase and backfat tended to decrease as frame size increased. Implants increased rate of increase in ribeye area but had no effect on rate of deposition of subcutaneous fat. Equations describing growth of ribeye area and backfat for each group predicted average growth for the heifers but did not predict growth of individual heifers. Final carcass yield grade was related to initial thickness of backfat but not to initial ribeye area. These results indicate that the type of cattle selected to be fed for a premium market based on yield grade is important to the success of the program. More work is needed to develop growth equations from ultrasound measurements, but ultrasound will likely be a useful tool in selecting feeder cattle for a value-based market.

Effects of Bovine Somatotropin and Revalor-S® on Growth Performance and Carcass Leanness in Beef Cattle

Twenty crossbred steers were used to evaluate bovine somatotropin (bST) and an anabolic steroid implant, Revalor-S® (REV), to improve growth and increase carcass leanness. During the first 70 days on feed, bST-treated steers tended to improve live weight gains, consume more feed, and numerically improve feed utilization for growth. The implanted steers grew faster and utilized feed better than steers not implanted with REV. The improvement in gain and feed utilization for growth was maintained throughout the feeding period for REV-implanted steers. At slaughter, REV steers had heavier carcasses which resulted in more pounds of muscle, bone, and fat. When adjusted for hot carcass weight, bST increased leanness of the carcass as evident by the increased weight of the semitendinosus muscle, more pounds of dissected lean, and fewer pounds of dissected fat. Thus, REV and bST can be used to improve growth performance and increase carcass leanness.

Effect of Early Weaning of Beef Calves on Performance and Carcass Quality

A study was conducted to evaluate early weaning of beef calves at 60-70 days of age on feedlot performance and carcass characteristics. One hundred twenty steer calves sired by either Simmental or Angus sires were weaned at an average age of 67 (early weaned, EW) or 147 (late weaned, LW) days. Calves were allotted to 16 feedlot pens by weaning treatment and sire breed at approximately 750-800 lb. EW calves were heavier (P < .05) in initial feedlot weight. There were no differences due to weaning age on daily gain, dry matter intake, feed efficiency or slaughter weights. Simmental steers required more days on feed than Angus steers (P < .05). Early-weaned calves had a higher percent intramuscular fat (5.7 vs. 5.1%), higher average marbling scores (Small78 vs. Small20, P < .05), a higher percentage of cattle grading average USDA Choice and higher (38% vs. 14%, P < .05) and a higher percentage of USDA Prime (10% vs. 0%, P < .05). These data confirm observations in previous studies that early weaning and placing calves on a higher grain diet improves marbling at slaughter. In this study, the effect was shown in calves weaned at an average of 67 days.