Addition of increasing doses of ricinoleic acid from castor oil (Ricinus communis L.) in diets of Nellore steers in feedlots

The aim of this study was to evaluate the performance and blood parameters of feedlot Nellore cattle fed increasing doses of ricinoleic acid (RA) in the diet. Ninety-six Nellore steers divided into 12 groups of 8 animals were used. The animals were randomly assigned to four treatments: 0, 1, 2, or 4 g of RA/animal/day, with three replicates per treatment. The experimental period consisted of 84 days divided into three 28-day periods preceded by three step-up diets. A quadratic effect was found for average daily gain and final body weight, as well as for leukocyte and lymphocyte counts, and for urea and blood urea nitrogen. A linear effect was observed for albumin, alkaline phosphatase, and gamma glutamyl transferase. The inclusion of 2 g of RA daily improved the performance of feedlot Nellore steers.

Acid-base status of ammonia-poisoned steers

Although several studies on ammonia poisoning have been carried out, there is a lack of information on acid-base balance status in ammonia-poisoned cattle. Twelve crossbred steers received intraruminally 0.5 g of urea per kg of body weight in order to induce a clinical picture of ammonia poisoning. Blood samples were collected throughout the trials in order to determine the blood ammonia, lactate, and perform blood gas analysis. All cattle presented a classical clinical picture of ammonia poisoning, with a blood ammonia concentration rising progressively from the beginning until reaching higher values at 180 min (27 ± 3 to 1719 ± 101 μmol L-1), with a similar pattern occurring with blood L-lactate levels (1.7 ± 0.3 to 26.0 ± 1.7 mmol L-1). The higher the blood ammonia concentration the higher the blood L-lactate levels (r = 0.86). All animals developed metabolic acidosis, as blood pH lowered to 7.24 0.03. The steers tried to compensate the metabolic acidosis mainly through the use of blood buffers and respiratory adjustments by lowering the pCO2 levels in the blood to 32.8 ± 2.0 mm Hg.

Cow-Calf Production from Alfalfa-Grass or Smooth Bromegrass Pastures Rotationally Grazed at Three Stocking Rates

Pastures containing alfalfa-grass or smooth bromegrass were stocked with .6, .8, or 1.0 cow-calf units per acre to compare cow and calf production in rotational grazing systems managed for optimum forage quality. To remove excess forage early in the grazing season, yearling heifers or steers grazed with the cows in each pasture at a stocking rate of .6 ccu per acre for the first 28, 37, and 40 days of grazing in years one, two, and three. Live forage density and days of grazing per paddock were estimated by sward height. Cows, calves, and yearlings were weighed and cows condition scored every 28 days. All cows grazed for 140 days unless forage became limiting. The cows on the smooth bromegrass pasture stocked at 1.0 cow-calf units per acre were removed after 119 days in 1994, 129 days in 1995, and 125 days in 1996. Cows on one of the alfalfagrass pastures stocked at 1.0 ccu per acre were removed after 136 days of grazing in 1996 because of lack of forage. Alfalfa-grass pastures tended to have a more consistent supply of forage over the grazing season than the bromegrass pastures. Cows grazing the alfalfa-grass pastures had greater seasonal weight gains and body condition score increases and lower yearling weight gains than the smooth bromegrass pastures. Daily and total calf weight gains and total animal production also tended to be greater in alfalfa-cool season grass pastures. Increasing stocking rates resulted in significantly lower cow body condition increases and yearling weight gains, and also increased the amounts of calf and total growing animal produced.

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.

Substituting Wet Distillers Grains or Condensed Distillers Solubles for Corn Grain in Finishing Diets for Yearling Heifers

A feeding trial was conducted with 790-lb yearling heifers fed an average of 121 days to evaluate replacing cracked corn and supplemental urea with wet distillers grains or condensed distillers solubles. Wet distillers grains were evaluated at 16%, 28% and 40% of diet dry matter. Condensed distillers solubles were added at 6.5% of diet dry matter. Control diets were supplemented with urea or a combination of urea and soybean meal. Feeding 16% wet distillers grains or condensed distillers solubles increased gain of heifers compared with those fed the control urea diet. Increasing the amount of wet distillers grains tended to decrease feed intake and reduce gain. The calculated apparent net energy based on gain of the heifers was greatest for the heifers fed 16% wet distillers grains. The apparent energy of the wet distillers grains declined as the quantity fed was increased. The calculated net energy values were 1.09 and 1.35 Mcal/lb of dry matter for the average of the three concentrations of wet distillers grains and condensed distillers solubles. These results confirm the high energy values of wet distillers grains relative to cracked corn as observed in a previous steer feeding trial.

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.

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.

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.

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.

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.

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.

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.

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.