J. J. Wagner

The effect of rumen degradable and rumen undegradable intake protein on feedlot performance and carcass merit in heavy yearling steers.

A total of 432 crossbred yearling steers (395 kg +/- 6.35) were used in a randomized block experiment to study the effects of rumen degradable intake protein (DIP) and rumen undegradable intake protein (UIP) concentration on feedlot performance and carcass merit. The 6 dietary treatments used for this study included 1) a 10.5% CP diet with 5.1% UIP and 5.4% DIP (DIP5); 2) an 11.5% CP diet with 5.1% UIP and 6.4% DIP (DIP6); 3) a 12.5% CP diet with 5.1% UIP and 7.4% DIP (DIP7); 4) a 13.5% CP diet with 5.1% UIP and 8.4% DIP (DIP8); 5) a 14.5% CP diet with 5.1% UIP and 9.4% DIP (DIP9); and 6) a 14.5% CP diet with 6.1% UIP and 8.4% DIP with the additional UIP provided by corn gluten meal. There was a linear increase in final BW and ADG and a trend for a linear increase in DMI associated with increasing DIP concentration within the 5.1% UIP treatments. Feed efficiency and NE recovered from the diet were not influenced by dietary DIP concentration. As dietary DIP concentration increased, carcass fat depth and average yield grade increased linearly and the percentage of yield grade 1 and 2 carcasses decreased linearly. Dietary UIP treatment had no effect on final BW, ADG, DMI, G:F, and calculated NE recovery. For the 14.5% CP diets, marbling score tended to be reduced for steers fed 6.1% UIP as compared with 5.1% UIP. The remaining carcass traits were not affected by dietary UIP. The results of this study show that the DIP requirement in the finishing diet for heavy yearling steers fed steam-flaked corn is greater than 7.4% of dietary DM but likely is not more than 8.4% of dietary DM when dietary UIP is approximately 5.1% of dietary DM. Increasing UIP above 5.1% of dietary DM did not improve feedlot performance or HCW. Expressed on a CP basis, it appears as though the requirement for CP for heavy yearling steers fed steam-flaked corn-based finishing diets is 13.5% of DM, with approximately 62% of CP from DIP.

Alpharma Beef Cattle Nutrition Symposium: Alternative energy sources for beef cattle finishing diets1

The Alpharma Beef Cattle Nutrition symposium was held at the joint annual meeting of the American Society of Animal Science, the American Dairy Science Association, and the Canadian Society of Animal Science in Montreal, Quebec, Canada, July 12 to 16, 2009. The symposium was organized to discuss the increased incorporation, challenges, and management options when alternative energy sources are incorporated into high-energy diets for finishing beef cattle. Much of the dietary energy in feedlot diets for beef cattle has and continues to originate from the inclusion of corn grain. However, as the more traditional sources of energy for cattle are being diverted to supply substrates for other purposes (e. g., ethanol production), feedlot diet formulation must adapt. Concurrently, price volatility of grain sources, increases in cost per unit of energy, and locally availability of coproducts affect the formulation of high-energy feedlot diets for finishing cattle. These challenges to the continued use of traditional high-energy feedlot diets for beef cattle have compelled the beef cattle feeding industry to identify and utilize a greater array of coproducts from other production systems as alternative energy sources in feedlot diets. Incorporation of alternative energy sources presents opportunities and challenges to diet formulation, determination of feed energy content, practical feed delivery and utilization, beef cattle performance, digestive physiology, and carcass characteristics. Owens et al. (2010) reviewed the impact of feedstuff nutrient composition on digestibility and energy supply for cattle. The variability of the chemical composition in feed ingredients is a major issue in feedlot diet formulation and predication of cattle performance. The ability to identify and adapt to the variation in chemical composition can have great economic importance. Crude fiber appears to most closely estimate TDN and metabolic fecal loss of OM associated with a variety of feedstuffs. Crude fiber content of feedstuffs may exert an adverse effect on apparent digestibility of other nutrients that could have a greater nutritional impact than the energy derived from fiber digestion itself. The influence of fiber, as well as other feed components, on the metabolic fecal loss of OM, total energy expenditure, influence on digestibility, and utilization in cattle warrants further investigation. The review by Owens et al. (2010) portended the importance of the discussion about the incorporation of coproducts into diets of feedlot cattle. Berger and Singh (2010) described evolutions in the processing methods of corn and the resulting coproducts. Innovative technologies are being utilized in ethanol production facilities that fractionate the corn or distillers dried grains with solubles (DDGS) or both for recovering additional coproducts, alter the nutritional composition of DDGS, and reduce the volume of DDGS. Corn components including the germ, pericarp fiber, endosperm fiber, and oil are used as sources for other coproducts or directly as ingredients in animal feeds. The modification of the DDGS chemical composition has important implications for the formulation of high-energy feedlot diets and the resulting cattle performance. Feedlot research reviewed in Berger and Singh (2010) indicated that new DDGS can replace corn in feedlot diets and still maintain or improve beef cattle performance and carcass characteristics. Wet coproducts other than corn-based products are an important component of many high-energy feedlot diets. Wet coproducts fed to beef cattle include those from the fruit, vegetable, juice, and brewing industries. Quantitatively, potato (Solanum tuberosum) may be the most important because of the estimated 4.3 million t of coproduct produced (Nelson, 2010). The incorporation of potato coproducts into beef cattle diets is contingent Alpharma Beef Cattle Nutrition Symposium: Alternative energy sources for beef cattle finishing diets

Effects of winter growing program on visceral organ mass, composition, and oxygen consumption of beef steers during growing and finishing

The purpose of this experiment was to investigate the effects of winter growing program on organ mass, composition, and oxygen consumption in beef steers. A total of 46 steers were used for the experiment. Four steers were randomly selected as an initial slaughter group. Remaining steers were randomly allotted to 1 of 4 treatment groups: 1) fed a high-concentrate diet for ad libitum intake (CF); 2) grazed on wheat pasture (WP); 3) fed a sorghum silage-based growing diet (SF); or 4) program fed a high-concentrate diet (PF). Steers in the WP, SF, and PF groups were managed to achieve approximately equal rates of BW gain during the growing phase. After the growing phase (112 d), steers in the WP, SF, and PF treatments were adapted to a high-concentrate diet for finishing. Steers from all treatments were slaughtered at a fat thickness of 1.27 cm as estimated by ultrasound. In addition, 6 steers from each treatment were randomly selected for slaughter at the end of the growing phase. Weights of all individual organs were measured and tissue samples of duodenum and liver collected. At the end of the growing phase, WP steers had greater (P < 0.05) small intestine, liver, and kidney mass than SF and PF steers. In contrast, mesenteric fat mass and total visceral fat content were greatest (P < 0.01) for PF, intermediate for SF, and least for WP steers. Mass of total viscera and total splanchnic tissues (TST) did not differ (P > 0.10) among treatments. At final slaughter, mass of mesenteric fat, total viscera, and TST were similar among treatments, but liver weights remained greatest (g/kg of empty BW; P < 0.01) for WP steers. There were no differences in oxygen consumption of duodenum or liver tissue on an equal weight basis (microL.min(-1.)g(-1)) at the end of either period. Growing program affected mass of components of the TST at the end of the growing phase, which contributed to differences in rate of splanchnic organ growth during finishing. We conclude that program feeding a high-concentrate diet during the growing phase may result in greater ADG and G:F during the subsequent finishing period compared with forage-based diets due to less accretion of visceral organ mass resulting in reduced maintenance energy requirements during finishing.

The Modern Feedlot for Finishing Cattle

The modern beef feedlot has evolved into a complex system that is very dependent upon technology. Modern feedlots are organized into departments, often including the office, cattle, yard, feed milling, and feed departments, that allow for improvements in production efficiency through the specialization of management and labor. Regardless of size, feedlots must succeed at the following tasks: cattle procurement, cattle receiving, cattle processing, daily cattle observations, health treatments, cattle marketing, feed procurement, feed commodity receiving, feed commodity storage, diet formulation, diet delivery, bunk management, and environmental management. Apart from cattle ownership, feedlots create most of their gross income from feed sales, yardage, inventory gain on flaked grain, and combinations of these sources. The future of the industry is filled with economic and political challenges, including high grain prices owing to competition from the ethanol industry, environmental regulations, excess feedlot capacity, and a diminishing labor pool owing to declining rural populations.

Effect of feeding frequency on feedlot steer performance123

ABSTRACT Crossbred yearling steers (n = 270; mean initial BW = 318 kg) were used to determine the effect of feeding frequency on feedlot performance and carcass characteristics. Steers were stratified by BW and randomly assigned to pens. Pens were then randomly assigned to 1 of 3 treatment groups: once-daily feeding (1X), twice-daily feeding (2X), or 3-times-a-day feeding (3X). Steers were fed a standard high-concentrate steam-flaked-corn based finishing ration for 170 d. Steers were housed in pens measuring 6.1 × 18.3 m. Feed was delivered to steers in fence-line (3.7 m in length) concrete bunks (0.31 m per steer). Pen served as the experimental unit, and cattle were slaughtered at a constant days on feed. Average daily gain was similar for steers fed 1X or 2X per day; however, ADG (P

The effect of medicinal feed additive programs and dietary sulfur concentrations in steam-flaked corn diets containing wet distillers grains on performance and carcass merit in yearling feedlot steers123

ABSTRACT A total of 432 crossbred yearling steers (329 ± 10.5 kg) were used in an unbalanced randomized block design to examine the effects of a medicinal feed additive (MFA) program and dietary sulfur (S) concentrations on feedlot performance and carcass merit. Treatments were arranged in a 2 × 2 factorial, with main factors being ionophore and antibiotic combination consisting of feed additive program monensin/tylosin or laidlomycin propionate/chlortetracycline and dietary S concentration [constant (CST) or variable (VAR)]. High-S diets (0.60% S) were fed on randomly assigned days to the VAR treatment, with low-S diets (0.48% S) fed on remaining days and to the CST treatment throughout the experiment. No interactions between S and MFA treatment were apparent for feedlot performance. Steers receiving VAR had greater (P

An evaluation of 10-G brand direct-fed microbial for yearling steers fed finishing diets containing wet distillers grains12

ABSTRACT One hundred forty-four Charolais crossbred yearling steers (335.5 kg ± 12.2) were used to determine the effect of 10-G brand direct-fed microbial product (10-G contains Lactobacillus acidophilus, Enterococcus faecium, Pediococcus acidilacticii, Lactobacillus brevis, and Lactobacillus plantarum) in a finishing diet containing steam-flaked corn and wet distillers grains with solubles (WDGS) on performance and carcass characteristics. Cattle were fed twice daily with dietary treatment applied only to the first feeding. Dietary treatments included 1) 10-G (TRT) product in the first round of feeding and 2) control (CON). The CON diet received a placebo in place of the 10-G product. Each diet contained 6% wheat straw (WS) and 15% WDGS and the finishing diet contained 68% steam flaked corn on a DM basis. Prior to the initiation of the experiment, WS and WDGS were mixed together using a vertical screw-type truck-mounted mixer box in the ratio of 2:5 (kg:kg) WS to WDGS on a DM basis, stored in a single pile, packed with a tractor, and covered with plastic. The WS and WDGS mixture was added to each batch of feed as one commodity during diet manufacturing. Overall ADG, DMI, G:F, and NE recovery were similar across treatments (P > 0.10). Hot carcass weight, YG, QG, maturity, and marbling score were similar across treatments (P > 0.10). Carcasses from steers receiving 10-G had a greater (P

Nutritional depletion of total mixed rations by European starlings: Projected effects on dairy cow performance and potential intervention strategies to mitigate damage

European starlings are an invasive bird species in North America that are known to cause damage to commercial dairies through the consumption of total mixed rations (TMR) destined for dairy cows. We hypothesized that large foraging flocks of starlings alter the physical composition of TMR, and that this change may be significant enough to affect milk production. To better determine if production losses could potentially occur in commercial dairies as a consequence of feed consumption by foraging flocks of starlings, we conducted controlled feeding experiments using a TMR sourced from a commercial dairy that is chronically plagued with seasonal starling damage. European starlings selected the high-energy fraction of the TMR and reduced starch and crude fat availability. Using the dairy National Research Council production model equations, the nutritional changes measured in the controlled feeding experiments could potentially reduce the productivity of dairies. Model output suggests that for Holsteins producing 32 kg of milk/d, total required net energy intake (NEI) was 31.5 Mcal/d. Within the reference TMR, NEI supplied was 29.3 Mcal/d, whereas within the starling-consumed TMR NEI supplied was 27.7 Mcal/d. Following our nutrition experiments, we assessed the efficacy of pelleted feed as a deterrent strategy for bird damage management in commercial dairies. Six different pelleted feed treatments of differing diameter were offered to starlings. All pellets of 0.95 cm diameter or larger inhibited starling consumption by ≥79%.

The effects of molybdenum water concentration on feedlot performance, tissue mineral concentrations, and carcass quality of feedlot steers

Thirty cross-bred steers (initial BW 452.0 ± 12.1 kg) were used to investigate the effects of Mo water concentration on performance, carcass characteristics, and mineral status of feedlot steers. The experimental design was a randomized complete block design. Steers were blocked by weight and then divided into 2 weight blocks each consisting of 15 steers. Steers were randomly assigned within block to one of 5 treatments (3 steers/treatment per block). Water treatments consisted of: 1) 0.0 µg/L, 2) 160 µg/L, 3) 320 µg/L, 4) 480 µg/L, and 5) 960 µg/L of supplemental Mo added as Na2MoO4 to the drinking water. Steers were housed in individual pens (steer = experimental unit) that contained individual 265 L water tanks for monitoring water intake. Steers were fed a growing diet for 28 d and then transitioned to a finishing diet. Block 1 steers were fed for a total of 151 d and block 2 steers were fed for a total of 112 d. Daily water intake was recorded for each steer. Steers were individually weighed on 2 consecutive days at the beginning and end of the experiment and interim weights and jugular blood samples were obtained every 28 d. Liver biopsies were obtained on d 0 and 84 from each steer within each block. Steers were transported to a commercial abattoir, slaughtered, and individual carcass data and liver samples were collected. Initial BW was used as a covariate for statistical analysis of data and significance was determined at P ≤ 0.05. No differences were observed for final BW (P > 0.98). Overall ADG (P > 0.91), DMI (P > 0.92), feed efficiency (P > 0.94), water intake (P > 0.40), hot carcass weight (P > 0.98), dressing percentage (P > 0.98), yield grade (P > 0.91), and marbling score (P > 0.29) did not differ across treatments. Lastly, no treatment differences were observed for liver concentrations of Cu (P > 0.93), Mo (P > 0.90) and Zn (P > 0.86) or plasma concentrations of Cu (P > 0.42), Mo (P > 0.43) and Zn (P > 0.62). These data indicate that water Mo concentration, within the range studied, had no impact on performance, mineral status, water intake, and carcass characteristics in feedlot steers.

Effect of feed bunk management on feedlot steer intake1

Twelve pens of yearling steers were used to determine the effects of bunk management on DMI and the pattern of feed disappearance from the feed bunk. Three 0630 h target bunk scores were compared: 0 = a bunk devoid of feed particles; 1/2 = a bunk containing up to 0.25 kg of feed/steer; and 1 = a bunk containing greater than 0.25 and up to 1.0 kg of feed/steer. Steers were fed twice daily at 0700 (round 1) and 1130 h (round 2), and bunks were observed by a single observer at 1630, 2200, 0200, and 0630 h. Daily DMI for steers fed to a target score of 0 (9.74 kg) was lower (P < 0.05) than that for steers fed to a target score of 1/2 (10.37 kg), which was lower (P < 0.01) than that for steers fed to a target score of 1 (11.21 kg). In addition, a treatment-by-time interaction (P < 0.001) for the estimated disappearance of feed from the bunk suggests that eating patterns differed by treatment. Even though adequate feed was available in all bunks from 0700 until 1600 h to support similar DMI during this time period for all treatments, steers fed to a target score of 0 consumed less feed during the day (0730 until 1600 h) than did steers fed to a target score of 1/2 (P < 0.001), which consumed less feed from delivery through 1600 h than did steers fed to a target score of 1 (P < 0.01). These data indicate that slick bunk management systems may restrict DMI in feedlot steers and alter feed consumption patterns.