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).

Value of High-Oil Corn Grain for Finishing Steers

Rolled high-oil corn in comparison with rolled isogenetic control corn was fed to finishing steers as 33%, 66% and 100% of the corn grain in their diet in a 134-day feeding trial. During the first 75 days of the trial, steers fed highoil corn had numerically lower rates of gain and tended to have poorer feed conversions compared with the control corn. At the end of the trial, there were not statistically significant differences in performance or carcass measurements of the steers fed the different amounts of high-oil or control corns. The results of this study indicated that the steers did not respond to the higher energy content of high-oil corn.

The Effects of High-Oil Corn or Typical Corn with or without Supplemental Fat on Diet Digestibility in Finishing Steers

Two 3 x 3 latin squares were utilized in an 84-day digestion trial with ruminally- and duodenallycannulated steers. Diets consisted of 73 to 78% whole corn grain, 12.3% corn silage and 2.0% N, with treatment differences being high-oil corn- (HOC), isogenetic typical-corn- (TC), or isogenetic typical-corn + fat- (TC+F) based diets. The HOC and TC+F diets were formulated to provide the same ether extract (EE) content. All diets were fed at 90% of ad libitum intake. Chromic oxide was used as a digestibility marker. Total tract dry matter (DM) (P=.08), organic matter (OM) (P=.08) and nitrogen (N) (P=.06) digestibilities tended to be greater for TC than HOC diets, whereas starch neutral detergent fiber (NDF), acid detergent fiber (ADF), and ether extract digestibilities were similar (P>.10). There were no differences (P>.10) in total tract dry matter, organic matter, starch, NDF, ADF, ether extract, or nitrogen digestibilities between TC+F and HOC diets or TC and TC+F diets. Ruminal digestion of dry matter, organic matter, starch, NDF, ADF, and feed nitrogen was similar (P>.10) among treatments. Microbial-nitrogen flow and efficiencies were also similar (P>.10) among treatments. Results indicate finishing steer diets composed of primarily HOC are equally or less digestible than similar diets composed of TC, and adding fat to TC diets did not affect the digestibility of the diet when fed to finishing steers.

Forage-Based Beef Production Research at the Armstrong Outlying Research Farm

Fifty-five yearling crossbred steers and 3C cow-calf pairs were used in a forage-based beef production system demonstration project at the Armstrong Outlying Research Farm. From May 11 to June 13, steers rotationally grazed a 41-acre grass pasture that was divided into eight paddocks. From June 13 to August 24, steers were placed in a drylot and fed berseem clover/oat soilage from a strip-intercropping system. Beginning June 5, 36 cow-calf pairs were allowed to rotationally graze the 41-acre pasture until September 18. Calf weight gains for the 110 days were 1.57 pounds per day, and total production from the pasture was 151 pounds per acre. No cow weight change or condition score change was measured. Total steer production was 29 and 580 pounds per acre or average daily gains were .67 and 2.23 pounds while grazing pasture and being fed in a drylot.

Responses to Adding Fat to Corn-Based Diets Supplemented with Urea and Soybean Meal for Finishing Steers

Yearling steers were fed corn-based diets supplemented with urea or soybean meal plus urea, and none, 2%, or 4% fat. All steers were implanted with Revalorâ-S and fed for 118 days. Adding fat did not improve performance of the steers in the feedlot or improve carcass characteristics. Feeding soybean meal increased rate of gain, improved feed efficiency, increased carcass weight, and tended to improve carcass quality grades compared with feeding urea. Adding 4% fat decreased feed intake, suggesting that corn-based diets may contain enough oil to approach the quantity of fat that can be utilized effectively in a ruminant diet.

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.

Evaluation of Proteferm® as a Nitrogen Supplement for Finishing Steers

Proteferm is a liquid by-product from the production of monosodium glutamate by fermentation that is 40% solids and contains 95% crude protein on a dry basis. Two trials were conducted with yearling steers to study the effects of different levels of Proteferm when added to 90% concentrate diets to replace corn and urea. Feeding Proteferm resulted in a decrease in urine pH, suggesting a metabolic acidosis that was probably caused by a negative cation–anion balance. Correcting the cation–anion imbalance resulted in an increase in feed intake and the performance of steers fed Proteferm as 1.5% of diet dry matter to be similar to the performance of control steers. Addition of sodium bicarbonate to the control diet or to the diet containing 1.5% Proteferm to produce a positive cation–anion balance did not improve performance. The results of these trials indicate that 1.5% Proteferm is the maximum that should be added to high concentrate diets fed to beef cattle without affecting performance or carcass value.

Use of Ultrasound Backfat Estimates to Form Marketing Groups Prior to Finishing for Feedlot Steers

An experiment was conducted using 95 Continental crossbred steers. The cattle were sorted by ultrasound 160 days before slaughter into a low backfat group (Low BF) and a higher backfat group (High BF). Half of the Low BF and half of the High BF were implanted whereas the other halves were not. Data from the experiment were used in two hypothetical markets. One market was a high yield beef program (HY) that did not allow the use of implants. The second market was a commodity beef program (CM) that allowed the use of implants. The cattle were priced as an unsorted group (ALL) and two sorted groups (Low BF and High BF) within the HY (non-implanted) and CM (implanted) markets. The CM program had a base price of $1.05/lb hot carcass weight (HCW) with a $0.15/lb HCW discount for quality grade (QG) Select and a $0.20/lb HCW discount for yield grade (YG) 4. The HY program used a base price of $1.07/lb HCW with premiums ($/lb HCW) paid for YG £ .9 (.15), 1.0 - 1.4 (.10), and 1.5 - 1.9 (.03). The carcasses were discounted ($/lb HCW) for YG 2.5 - 2.9 (.03), 3.0 - 3.9 (.15), and ³ 4.0 (.35). This data set provides good evidence that the end point at which to sell a group of cattle depends on the particular market. Sorting had an economic advantage over ALL in the HY Low BF and the CM High BF groups. The HY High BF cattle should have been sold sooner due to the discounts recieved for increased YG. The increased YG was directly affected by an increase in BF. Furthermore, the CM Low BF group should have been fed longer to increase the number of carcasses grading Choice.

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.