Programmed Feeding of Protein to Finishing Beef Steers

Six-hundred pound Angus steer calves were fed cornbased finishing diets for 180 days to determine the effects of stepwise reduction of protein in the diet on performance and carcass characteristics. Reducing protein in the diet, but satisfying the requirements projected by the National Research Council model for Nutrient Requirements of Beef Cattle, did not affect performance or carcass measurements. Further reduction in protein content of the diet, so the projected requirement of the rumen microorganisms was not being met, did not affect performance or carcass measurements. It is concluded that quantity of protein fed to finishing cattle can be programmed and abstantially reduced. These reductions will result in substantially less nitrogen excreted in manure from larger feedlots.

Effects of Feeding Calcium Salts of Conjugated Linoleic Acid (CLA) to Finishing Steers

Thirty crossbred steers were randomly assigned to three treatment groups and fed corn-based finishing diets (88% concentrate) containing 0, 1.0 or 2.5% conjugated linoleic acid (CLA) for an average of 130 days. Steers fed 2.5% CLA consumed less feed and had lower daily gains than control steers. Carcass weights tended to be reduced, and marbling scores were decreased by feeding 2.5% CLA. There were no significant effects of feeding CLA on dressing percentages, yield grades and backfat measurements. The rounds from each animal were physically separated into tissue components. Rounds from steers fed CLA contained a higher percentage of lean tissue and a lower percentage of fat. Feeding CLA increased concentrations of CLA in lipids from fat and lean in rib steaks and rounds. Increasing CLA in beef had no effects on shelf life, tenderness, juiciness, flavor or flavor intensity of rib steaks. Although results indicated that feeding calcium salts of CLA to beef steers decreased performance, concentrations of CLA in tissues could be increased offering the availability of a leaner, more healthful meat product.

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.

Evaluation of Dietary Laidlomycin Propionate and Synovex Plus Implants for Enhancing Performance of Feedlot Steers

One hundred fifty crossbred yearling steers with an average weight of 876 pounds were used in a 111-day experiment. Steers received either 1) no implant and no ionophore, 2) Synovex Plus¨ and no ionophore, 3) Cattlyst¨ and no implant, 4) Synovex Plus¨ and Cattlyst¨, or 5) Revalor S¨ and Rumensin¨. Implanting steers with ) Synovex Plus¨ increased gain and improved feed efficiency compared with control steers. Compared with steers not implanted, steers implanted with Synovex Plus¨ had heavier carcasses and larger ribeye areas, but similar fat thickness and yield grades. Feeding Cattlyst¨ alone did not increase gain or improve feed conversion, but there was some improvement in feedlot performance when Cattlyst¨ was fed to steers implanted with Synovex Plus¨. Steers implanted with Synovex Plus¨ and fed Cattlyst¨ had superior gains to steers implanted with Revalor S¨ and fed Rumensin¨.

Intensive Rotational Grazing of Steers at the Andrew Jackson Demonstration Farm

Fifty head of crossbred steers started grazing 51 acres of pasture on May 1 in a rotational grazing system using a variable density paddock system. Twenty-two head grazed 92 days, 27 grazed 140 days, and one steer died. A total of 11,922 pounds was produced on 5,804 animal-days of grazing. The average daily gain was 2.02 pounds for group 1 and 2.07 for group 2. The stocking rate for the first 92 days was .98 steers per acre and .53 for the final 48 days. The animal days of grazing per acre was 113 and the pounds of gain per acre was 233. Total return for land, labor and management for the demonstration was $2,829.76 or $55.49/acre.

Evaluation of Synovex Plus, Synovex S and Revalor S Implants in Feedlot Steers

One hundred forty-four crossbred yearling steers with an average weight of 841 pounds were used in a 116- day experiment. Steers received either 1) no implant, 2) Synovex S¨, 3) Revalor S¨, or 4) Synovex Plus¨. All implanted groups consumed more feed and gained faster and more efficiently than non-implanted steers. There were no significant differences in gain, feed intake or feed efficiency among implanted groups, though steers with the estrogen + trenbolone acetate combination implants were numerically superior to those implanted with Synovex S¨. There were no differences in feedlot performance between the two combination implants. Implants increased carcass weight with no significant effects on fat thickness or carcass quality grades. The combination implants containing trenbolone acetate increased ribeye area and increased masculinity of the carcasses. These results indicate Synovex Plus¨ is an effective implant for finishing steers.

Evaluation of Wet Distillers Grains in Finishing Diets for Yearling Steers

A feeding trial was conducted with 940-lb yearling steers fed 113 days to determine the feeding value of distillers grains relative to corn grain. Replacing corn and urea with wet distillers grains for 20% of the diet dry matter tended to increase gain with no increase in feed consumption, resulting in improved feed conversion. Replacing 40% of diet dry matter with wet distillers grains decreased feed intake without affecting gains, and improved feed efficiency. The overall average estimated net energy value of wet distillers grains was 1.20 Mcal NEg per pound dry matter. This experiment confirmed the observations in previous cattle feeding experiments, that for finishing cattle wet distillers grains have a high energy value compared with cracked corn grain. Another objective of the study was to determine if cattle being fed wet distillers grains could be suddenly changed to a different diet if the supply of wet feed was suddenly disrupted. It was found that if intake is managed during the change, that distillers grains portion of the diet can be suddenly changed from wet to dry and then changed back to wet after a week, without sacrificing performance of the cattle.

Effects of Initial Body Condition, Frame Size and Concentration of Dietary Energy on Carcass Value of Finished Steers

Yearling steers were sorted into four groups based on hip height and fat cover at the start of the finishing period. Each group of sorted steers was fed diets containing 0.59 or 0.64 Mcal NEg per pound of diet. The value of each carcass was determined by use of the Oklahoma State University Boxed Beef Calculator. Sorting to increase hip height decreased the percentage of Choice carcasses and fat cover, increased ribeye area, and had no effect on carcass weight or yield grades 1 and 2. Sorting to decrease initial fat cover decreased carcass weight, carcass fat cover, and percentage of choice carcasses and increased the proportion of yield grades 1 and 2 carcasses. Concentration of energy in the finishing diet had no effect on carcass measurements. Increasing the percentage of yield grades 1 and 2 carcasses did not result in increased economic value of the carcasses when quality grades were lower and when there was a wide spread between Choice and Select carcasses, as occurred in 1996. With less spread between Choice and Select, as in 1997, sorting the cattle to increase yield grades 1 and 2 resulted in increased value, especially for close-trim boxed beef. The results of this study emphasize the importance of knowing how carcasses will grade before selecting a valuebased market for selling cattle.

Effects of Supplementing High or Low Quality Forages with Corn or Corn Processing Co-Products Upon Digestibility of Dry Matter and Energy by Steers

A digestibility trial, utilizing eight crossbred steers weighing initially 741 lbs. was conducted in an 8 x 8 Latin square design. High-fiber corn by-products were compared with corn as energy sources when fed in mixed diets with either lowor high-quality forage. Ground, dry corn stover and ground alfalfa hay were both fed alone or with corn grain, dried corn gluten feed (CGF), and dried corn distillers grains plus solubles (DDG) in a 1:1 ratio (dry basis). Total tract dry matter digestibility (DMD) was increased for both forages when fed with concentrates. Total tract DMD was similar in stover-based and alfalfa-based diets fed with CGF and DDG. However, stover+corn was lower in DMD than either stover+CGF and stover+DDG. Conversely, alfalfa+corn was higher in DMD than alfalfa+CGF or alfalfa+DDG. Feeding stover with corn tended to decrease digestibility of neutral detergent fiber (NDF), while feeding stover with CGF or DDG increased NDFD. There was no effect upon NDF digestion of alfalfa-based diets when fed with any of the concentrates. Feeding either forage with a concentrate increased digestible energy (DE). Stover+CGF and stover+DDG were similar in DE and were both higher in DE than stover+corn. Alfalfa+DDG tended to be higher than alfalfa+CGF and was similar to alfalfa+corn in DE. Alfalfa+CGF was lower in DE compared with alfalfa+corn. Results are interpreted to indicate that stover is more susceptible to negative feed interactions caused by corn grain than is alfalfa. Additionally, highfiber corn co-products fed with stover resulted in a positive associative effect but essentially had no associative effect when fed with alfalfa.

Evaluation of Condensed Porcine Solubles as a Source of Supplemental Nitrogen in Corn-Based Finishing Diets for Yearling Steers

A feeding trial was conducted with 860-lb yearling steers fed 121 days to evaluate Condensed Porcine Solubles (Porcine Solubles) as a source of supplemental nitrogen for finishing cattle. Diets containing 5% soybean meal, 1.46% urea, and 2% or 4% Porcine Solubles were compared. When first offered, cattle did not want to consume feed containing the Porcine Solubles. Following adaptation, feed containing up to 4% Porcine Solubles was readily consumed. During the first 56 days, steers fed soybean meal gained faster and were more efficient than steers fed urea or Porcine Solubles. At the end of the trial there were no differences among the nitrogen supplements in feed intake, gain, or feed conversion. There were no significant differences in carcass weight or measures of carcass quality.

Effects of Initial Fat Thickness, Hip Height, and Concentration of Dietary Energy on Growth of Area of the Longissimus dorsi Muscle and Subcutaneous Fat of Yearling Steers

Steers were sorted into four groups based on hip height and fat cover at the start of the finishing period. Each group of sorted steers was fed diets containing 0.59 or 0.64 Mcal NEg per lb. of diet dry matter. Steers with less initial fat cover (0.08 in.) compared with those with more (0.17) had less carcass fat cover 103 days later. The steers with less fat cover accumulated fat at a faster rate, but this was not apparent prior to 80 days. Accretion of fat was best predicted by an exponential growth equation, and was not affected by the two concentrations of energy fed in this study. Steers with greater initial height accumulated fat cover at a slower rate than shorter steers. This difference was interpreted to mean that large-frame steers accumulate subcutaneous fat at a slower rate than medium-frame steers. Increase in area of the ribeye was best described by a linear equation. Initial fat cover, hip height, and concentrations of energy in the diet did not affect rate of growth of this muscle. Predicting carcass fat cover from the initial ultrasound measurement of fat thickness found 46 of the 51 carcasses with less than 0.4 in. of fat cover. Twelve carcasses predicted to have less than 0.4 in. of fat cover had more than 0.4 in. Five carcasses predicted to have more than 0.4 in. actually had less than that. Accurate initial measurements of initial fat thickness with ultrasound might be a useful measurement to sort cattle for specific marketing grids.

Effects of Initial Body Condition, Frame Size and Concentration of Dietary Energy on Performance of Finishing Steers

Steers were sorted into four groups based on hip height and fat cover at the start of the finishing period. Each group of sorted steers was fed a diet containing 0.59 or 0.64 Mcal NEg per pound of diet. Steers with less initial fat cover (.08 in.) gained slightly faster, consumed less feed, and therefore tended to be more efficient than steers with greater finish (.16 in.). Steers fed the lower-energy diet consumed more feed, gained similarly, and were less efficient than steers fed the higher-energy diet. The NRC computer model to evaluate beef cattle diets underpredicted performance of cattle in this experiment, but accurately predicted the differences in gain and feed efficiency observed between the leaner and fatter steers and between the two diets. In this study, the shorter steers (49.4 vs 52.2 in. initial height at the hip) gained faster with slightly greater feed intake and the same feed conversion.

Potential Economic Returns from Selling Beef in a Specified Value-Based Market

Three groups of steers--one theoretical group and two experimental groups—were evaluated for marketing cattle live, as boxed beef, and grade and yield when the live price was $71 to $73/cwt, grade and yield price $125/cwt for Choice yield grade 3 carcasses with $20/cwt discount for Select carcasses, and in a commodity-trim or close-trim boxed beef market. The results show that the value of highyielding steers can be significantly increased if sold in a close-trim boxed beef market. The close-trim premiums ranged from $5.06 per head for Select close-trim yield grade 4 carcasses to $87.18 per head for close-trim Choice yield grade 1 carcasses. A group of experimental steers averaging 82% Choice and 60% yield grades 1 and 2 returned an additional $104 in the close-trim boxed market compared with selling live for $73/cwt. Another group of experimental steers averaging 21% Choice, 18% Standard, and 93% yield grades 1 and 2 had $29 per head greater return than if the steers had been sold live for $71/cwt. These comparisons emphasize the importance of knowing how cattle will potentially grade before selecting an alternative marketing strategy. This prior knowledge is most important when the spread in price between Choice and Select is high. Producers need to learn more about their cattle to predict how the cattle may grade for a specified value-based market.

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).