Subsequent Feedlot Performance Research Articles

PSIV-A-11 Effects of Supplementing Extruded Dried Distillers' Grains Cubes to Stocker Cattle Grazing Introduced Pastures on Subsequent Feedlot Performance and Carcass Characteristics

Abstract This research evaluated the effects of supplementing extruded dried distillers’ grains (DDG) cubes to grazing steers on subsequent finishing performance and carcass characteristics. Steers (n = 140) grazed tall fescue (Festuca arundinacea)/bermudagrass (Cynodon dactylon) pastures from 14 April to 17 September 2020 with supplementation treatments (n = 3 pastures/treatment) that included: 1) Fertilized Control (FC), no supplementation on N fertilized pastures (112 kg N/ha); 2) Fertilized Supplement (FS), supplemented DDG cubes at 2.9 kg/d prorated for 3-d/wk feeding on N fertilized pastures; and 3) Supplement (S), supplemented DDG cubes at 0.75% of BW/d prorated for 5-d/wk feeding on unfertilized pastures. All animals were followed through the finishing phase in a commercial feedyard to investigate carryover effects on feedlot performance in 2 pens comingled across supplemental treatment. Carcass characteristics were evaluated via ultrasonography on d0 and d84 of finishing, and measurements were obtained at harvest. Feed DMI were segregated to individual animals according to Guiroy et al. (2001) and Tedeschi and Fox (2020b). Supplemented animals were heavier (P < 0.01) at feedlot entry than FC, but harvest BW did not differ (P = 0.23). However, S and FS required 37 fewer days on feed (P = 0.01) than FC. Supplementation on pasture reduced total feed required (P = 0.02) and feed costs (P = 0.01) relative to FC. Gains were greater (P = 0.02) for FC and FS than S from d0 to d84, but did not differ thereafter (P ≥ 0.15). At harvest, FC had the greatest dressing percent (P < 0.01) and lower yielding carcasses than FS (P = 0.01), but did not differ (P = 0.11) from S. Overall, extruded DDG cube supplementation during grazing did not negatively affect subsequent feedlot performance or carcass characteristics, but reduced the total feed required for finishing.

Feedlot performance and carcass characteristics of steers managed with growth-promoting technologies while grazing toxic, endophyte-infected fescue during autumn and winter months

Our objective was to evaluate subsequent feedlot performance and carcass characteristics of steers that previously grazed endophyte-infected fescue and received either a mineral only (MIN) supplement or a cumulative management (CM) strategy. Grazing occurred in autumn and winter of 2018 and 2019 with feedlot finishing after grazing. Within year, 60 fall-weaned steers (282 ± 7.7 kg) were randomly assigned to either MIN (n = 3) or CM (n = 3) pastures. The CM strategy include a steroidal growth implant, monensin, and 1% BW (as-fed basis) of 1:1 corn gluten feed:soybean hull mix. During feedlot finishing, steers were penned to maintain pasture groups. Steers receiving CM were heavier ( P = 0.002) entering the feedlot and finished 40 d earlier than MIN (161 vs. 201 ± 5.7 d, P < 0.001). The CM steers gained more BW the first 28 d ( P = 0.005) in the feedlot. Both treatments showed similar overall ADG ( P ≥ 0.23), but MIN steers showed a tendency for greater G:F ( P = 0.06). Finished live weight and carcass traits did not differ ( P ≥ 0.18). Pens were 78 and 80 ± 5.4% USDA Choice for MIN and CM, respectively. A CM strategy increases weight of steers grazing toxic fescue. This additional weight can reduce the days required for feedlot finishing without influencing carcass characteristics. Improved grazing performance and fewer days for feedlot finishing may reduce environmental impact.

Effects of Encapsulated Methionine on Skeletal Muscle Growth and Development and Subsequent Feedlot Performance and Carcass Characteristics in Beef Steers.

Simple SummaryResearch investigating the effects of amino acids in growing and finishing beef cattle is not a new topic. Many studies suggest that in cattle fed a concentrate-based diet, lysine is the most limiting amino acid followed by methionine. When considering supplementing amino acids to growing-finishing beef cattle, the amino acids must be protected from ruminal microbial consumption for the beef animal to be able to absorb the amino acids in the small intestine. The regulation of skeletal muscle growth is a multifaceted, complex process controlled through many signaling cascades. One major process involved in muscle growth is the mammalian target of the rapamycin (mTOR) signaling pathway. The objectives of these studies were to investigate the role of encapsulated methionine on feedlot growth performance and carcass characteristics and to elucidate the role of methionine supplementation on the mTOR signaling pathway and skeletal muscle development in feedlot steers during the finishing phase.Two studies were conducted to evaluate the effect of encapsulated methionine on live performance, carcass characteristics, and skeletal muscle development in feedlot steers. In Experiment 1, 128 crossbred steers (body weight [BW] = 341 ± 36.7 kg) were used in a randomized complete block design and supplemented with 0, 4, 8, or 12 g/(head day [d]) of ruminally protected methionine (0MET, 4MET, 8MET, and 12MET, respectively) for 111 d or 139 d. In Exp. 2, 20 steers (BW = 457 ± 58 kg) were stratified by BW and randomly assigned to either the 0MET or 8MET treatment; longissimus muscle (LM) biopsies were collected on d 0, 14, 28, 42, and 56, and analyzed for mRNA and protein expression. Additionally, immunohistochemical analysis was performed to measure fiber type area and distribution as well as the density of muscle nuclei and satellite cells (Myf5, Pax7, and Myf5/Pax7). In Experiment 1, no significant differences were observed for live performance (p ≥ 0.09). There was, however, a linear relationship between LM area and methionine supplementation (p = 0.04), with a 9% increase in the area when steers were supplemented with 12MET compared to 0MET. In Exp. 2, There were no treatment × day interactions (p ≥ 0.10) for expression of mRNA or protein abundance. Although mRNA expression and protein abundance of all genes were influenced by day (p ≤ 0.04), methionine supplementation did not have a significant effect (p ≥ 0.08). There was a significant treatment × day interaction for distribution of MHC-I fibers (p = 0.03), where 8MET supplemented cattle had a greater proportion of MHC-I fibers after 56 d of supplementation than did 0MET steers. Cross-sectional area was increased over time regardless of fiber type (p < 0.01) but was unaffected by treatment (p ≥ 0.36). While nuclei density was not impacted by treatment (p = 0.55), the density of myonuclei increased nearly 55% in 8MET supplemented cattle (p = 0.05). The density of Myf5 positive satellite cells tended to decrease with methionine supplementation (p = 0.10), while the density of Pax7 expressing cells tended to increase (p = 0.09). These results indicate that encapsulated methionine supplementation may influence markers of skeletal muscle growth, and potential improvements in the LM area may exist.

95 Multi-Specie cover crop bale grazing effect after annual forage grazing on yearling steer grazing and feedlot performance, muscling, carcass measurements and carcass value

Abstract Yearling crossbred steers (n = 144) were randomly assigned to native range (NR) or annual forage (ANN&amp;gt;: native range plus field pea-barley, corn, 13-species cover crop) to evaluate grazing season extension by feeding (“Grazing”) cover crop bales (field pea, forage barley, clover, sorghum sudan 12.8% CP, 54.4% NDF, 31.4% ADF, 59.0% TDN) before feedlot entry to measure the effect on steer grazing and subsequent feedlot performance and economics. Grazing was extended 43.6 days (177.9 to 221.5 days). ANN plus bale grazing ADG was 0.95 kg/day; NR was 0.77 kg/day (P = 0.01). Ending ANN grazing gain was 43.0 kg heavier (P = 0.001). Grazing muscling was measured using ultrasound. The ratio for REA:45.4 kg live weight did not differ (P = 0.53). End grazing ANN steer REA (P = 0.002) and percent intramuscular fat (IMF) were greater (P = 0.05) than NR steers. End grazing marbling score did not differ (489.0 vs. 470.0). In the feedlot, steers were fed 95.7 days. The ANN steer feedlot arrival weight was heavier (P = 0.04), but ending weight did not differ between ANN and NR treatments (717.6 vs. 684.0 kg; P = 0.19). ANN steer hot carcass weight (HCW) was 25.6 kg heavier (P = 0.03). The NR steer dressing percent was greater (P = 0.01) and muscling (REA:HCW) was greater for the NR steers (P = 0.007), resulting in improved USDA yield grade (P = 0.01). Quality grade did not differ (98.6% Choice or better; P = 1.00). ANN steer HCW resulted in $92.26 more per carcass (P = 0.031) than NR. Grazing medium forage quality cover crop bales is an effective method for increasing gain and live animal muscle and intramuscular fat quality before feedlot entry, and ANN steer weight advantage entering the feedlot carried over to greater ending HCW and subsequently, greater carcass value.

20 Polyclonal antibody preparations from avian origin improves growth performance of beef cattle during the first fourteen days of the backgrounding phase

Abstract This study aimed to evaluate the effects of feeding avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40, 35, and 25% of the preparation, respectively) on growth performance of beef cattle during the backgrounding phase. From d 0 to 56, Angus crossbreed heifers (n = 80; 360 ± 60 kg of BW; 470 ± 26 d of age) and steers (n = 20; 386 ± 65 kg of BW; 465 ± 30 d of age) were blocked by BW and randomly assigned to 1 of 16 concrete-floored pens (108 m2), equipped with 2 GrowSafe (GrowSafe Systems Ltd., Airdrie, Alberta, Canada) feed bunks each. Animals received a common ad libitum diet (76% TDN, 15.9% CP, DM basis) with the addition of 1 (PAP1), 3 (PAP3), or 0 g (CON) of PAP per d. Feed intake was recorded daily and BW were obtained on d -1, 0, 14, 28, 42, 55, and 56, to assess changes in BW, ADG, DMI, and G:F. Based upon orthogonal contrasts (CON vs. PAP1, and PAP1 vs. PAP3), BW and ADG on d 14, and DMI from 0 to 28, and 0 to 42 were greater for PAP1 vs. CON (P ≤ 0.03), whereas PAP3 animals were intermediate (P ≥ 0.20). No differences in final BW, DMI, and ADG from d 0 to 56 were detected among treatments (P ≥ 0.22). In conclusion, feeding 1g of polyclonal antibody preparations against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides in a backgrounding diet, improved growth performance in the first 14 d of feeding suggesting that feeding these PAP for longer than 14 d may not be necessary. The effects on subsequent feedlot performance when using PAP should be evaluated in future studies

74 Stocker management and impacts on health and subsequent feedlot performance

Abstract The stocker segment of the beef industry provides significant enterprise services. The stocker industry provides a shock absorber to absorb the bulk of the cattle not ready for finishing in the numbers glut in the fall and helps provide a year around supply of feeder cattle. Other benefits include adding size to small and medium frame cattle to allow them to finish at acceptable weights, grouping cattle from small herds into semiload lots, and improved health and resilience to the stressors of changing diets, management, and environment. Health during receiving to the finishing phase has been shown to impact finishing performance and carcass quality, so the effects of stocker management can have serious implications on long-term economics of the feedlot enterprise and consumer acceptance of beef products. Ratliff et al. (2014) compiled data from Arkansas receiving and stocker grazing experiments and found that calves coming into the receiving unit as bulls were more likely to experience 2nd and 3rd pulls for bovine respiratory disease and had lower gains during grazing than calves coming in as steers. Records from research trials conducted in Mississippi and Arkansas found a 6 to 14% reduction in ADG for calves that had been treated for BRD once vs two times or more, respectively. There is much less data that considers the health outcomes of calves received as light weight stocker cattle and how this impacts subsequent performance during finishing. Timing of application of growth promoting technologies during the stocker phase has been shown to affect response to implants during finishing and carcass quality, but little data is available regarding stocker cattle health and finishing performance. More research is needed to ascertain what determines the quality of the health intervention outcomes for individual animals and the subsequent implications of health in the stocker phase

184 Effect of monensin intake during a stocker phase and subsequent finishing phase on performance and carcass characteristics of feedlot steers

Abstract Three experiments were conducted to determine the effects of monensin supplementation during the stocker and finishing phase on feedlot performance and carcass characteristics of beef steers. In Exp. 1 and 2, steers (n = 61, BW = 345 ± 20 kg and n = 70, BW = 298 ± 26 kg) were fed hay and supplement or grazed wheat pasture (Exp. 1) or bermudagrass (Exp. 2) and then were transported 1,068 km to Canyon, TX, for finishing. For Exp. 3 steers (n = 59, BW = 322 ± 31 kg) grazed wheat pasture and then transported 636 km to Stillwater, OK, for finishing. Treatments were arranged as a 3 × 2 factorial with three monensin levels during the stocker phase (0, 800, 1600 g/ton fed in a free choice mineral) and two levels during finishing [0 (UN) or 37.5 mg/kg diet DM (RUM). There were no location × treatment interactions (P ≥ 0.19) for performance or carcass measurements, therefore data were pooled across locations. Stocker × feedlot treatment interactions were not observed for performance data (P ≥ 0.50), but were observed for carcass characteristics. Cattle consuming RUM in the feedlot had decreased (P &lt; 0.01) DMI and increased (P &lt; 0.01) G:F compared with UN. Cattle on 1600UN treatment had the greatest LM area whereas 0U had the least (103.4 vs 96.3 cm2). Steers on the 800UN and 1600UN treatments had decreased YG and 800RUM had the greatest (2.31 and 2.22 vs 2.75). Cattle consuming RUM during finishing had increased (P = 0.03) fat thickness compared to UN. Supplementation of monensin to stocker cattle may have minimal impact on subsequent feedlot performance. Providing monensin in feedlot diets still decreases DMI and improves feed efficiency of feedlot cattle.

116 Polyclonal antibody preparations from avian origin improves growth performance of beef cattle during the first fourteen days of the backgrounding phase

Abstract This study aimed to evaluate the effects of feeding avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40, 35, and 25% of the preparation, respectively) on growth performance of beef cattle during the backgrounding phase. From d 0 to 56, Angus crossbreed heifers (n = 80; 360 ± 60 kg of BW; 470 ± 26 d of age) and steers (n = 20; 386 ± 65 kg of BW; 465 ± 30 d of age) were blocked by BW and randomly assigned to 1 of 16 concrete-floored pens (108 m2), equipped with 2 GrowSafe (GrowSafe Systems Ltd., Airdrie, Alberta, Canada) feed bunks each. Animals received a common ad libitum diet (76% TDN, 15.9% CP, DM basis) with the addition of 1 (PAP1), 3 (PAP3), or 0 g (CON) of PAP per d. Feed intake was recorded daily and BW were obtained on d -1, 0, 14, 28, 42, 55, and 56, to assess changes in BW, ADG, DMI, and G:F. Based upon orthogonal contrasts (CON vs. PAP1, and PAP1 vs. PAP3), BW and ADG on d 14, and DMI from 0 to 28, and 0 to 42 were greater for PAP1 vs. CON (P ≤ 0.03), whereas PAP3 animals were intermediate (P ≥ 0.20). No differences in final BW, DMI, and ADG from d 0 to 56 were detected among treatments (P ≥ 0.22). In conclusion, feeding 1g of polyclonal antibody preparations against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides in a backgrounding diet, improved growth performance in the first 14 d of feeding suggesting that feeding these PAP for longer than 14 d may not be necessary. The effects on subsequent feedlot performance when using PAP should be evaluated in future studies

Effects of distillers dried grains with solubles supplementation on yearling heifers grazing Northern Great Plains rangeland: impacts on subsequent feedlot performance and meat quality.

Eighty-two yearling crossbred heifers (318.8 ± 1.03 kg) were utilized in a completely randomized design to evaluate the effects of distillers dried grains with solubles (DDGS) supplementation on animal performance, while grazing on rangeland of the Northern Great Plains, and subsequent feedlot performance, carcass characteristics, and meat quality traits. Treatments were: 1) 0% DDGS supplementation (CONT) and 2) 0.6% of body weight (BW) DDGS supplementation (SUP). Heifers received treatments for 70 d (6 June to 16 August) while grazing, and then were acclimated to and fed a common corn-based finishing diet for 109 d. Average daily gain (ADG) of SUP heifers was greater (P ≤ 0.01), resulting in heavier BW (P ≤ 0.03) following grazing compared with CONT heifers. Heifer performance, including ADG (1.91 ± 0.05 kg/d), gain to feed (G:F) (0.15 ± 0.003 kg), dry matter intake (DMI) (12.6 ± 0.20 kg), and final BW (572.4 ± 7.43 kg) were not different (P ≥ 0.13) during finishing. Hot carcass weight (335.7 ± 4.39 kg), Longissimus muscle area (81.30 ± 1.24 cm2), 12th rib fat thickness (1.24 ± 0.06 cm), and kidney, pelvic, heart fat (KPH) (1.85 ± 0.08%) were not different (P ≥ 0.47) between treatments. There were no differences (P ≥ 0.24) between treatments in yield grade (2.9 ± 0.10) or marbling (492 ± 22.3; Small00 = 400). Results from Warner–Bratzler shear force indicated that strip loin steaks from SUP heifers tended (P = 0.07) to have increased tenderness compared with strip loin steaks from CONT heifers (3.3 vs. 3.7 ± 0.12 kg, respectively). Inclusion of 0.6% BW supplementation during grazing increased (P = 0.01) strip loin steak muscle lightness (L*) compared with CONT steaks (46.5 vs. 45.5 ± 0.27, respectively). Strip loin steaks from heifers supplemented DDGS during grazing were perceived to be more tender by taste panelists (P = 0.02) than strip loin steaks from CONT heifers (5.9 vs. 5.5 ± 0.11; eight-point scale). Supplementation of DDGS during grazing improved ADG of yearling heifers with no effect on feedlot performance or carcass characteristics but did improve tenderness and steak sensory attributes.

Effects of extended-release eprinomectin on productivity measures in cow–calf systems and subsequent feedlot performance and carcass characteristics of calves

The objective of this study was to estimate the impact of a single injection of extended-release eprinomectin on economically relevant production variables in beef cows and calves as well as subsequent feedlot health, performance, and carcass traits of calves compared with a traditional, short duration anthelmintic. Animals from 13 cooperator herds across seven states were stratified within herd and assigned to one of two treatments; injectable doramectin (DOR; Dectomax; n = 828) or injectable eprinomection (EPR; Longrange; n = 832). Fecal samples were randomly collected from a subset of cows at both treatment and the end of grazing to evaluate fecal egg count (FEC). Continuous and categorical data were analyzed using the MIXED and GLIMMIX procedures of SAS, respectively. Cow treatment body weight (BW) and final BW were not different (P ≥ 0.40) between treatments. There were no differences (P ≥ 0.12) between treatments in cow ADG, change in BW, or body condition scores during the grazing season. While FEC at treatment did not differ (P = 0.18), cows treated with EPR had lower final FEC at the end of the grazing season (P = 0.02) and a greater reduction of FEC over the grazing season (P = 0.01). Calf treatment BW, weaning BW, and ADG did not differ between treatments (P ≥ 0.34). Incidence of pinkeye tended to be less (P = 0.06) for cows treated with EPR but was not different for calves (P = 0.43). Conception to AI, overall pregnancy rates, and calving interval were not different between treatments (P ≥ 0.45). A subset of calves from each herd was sent to Tri-County Steer Carcass Futurity (TCSCF) feedlot for the finishing phase. Calf BW did not differ at initiation of feeding (P = 0.20). While EPR calves tended to be heavier at reimplantation (P = 0.07), final BW and overall ADG were not different between treatments (P ≥ 0.13). Health records indicated lower morbidity for EPR calves (P = 0.05). Carcass performance including HCW, dressing percent, backfat, KPH, REA, YG, were not different between treatment groups (P ≥ 0.12). However, EPR calves had a greater marbling score, greater average quality grade (P < 0.01), and higher proportion of calves that graded average choice or greater (P = 0.03). Results of this study indicate no difference in cow or preweaning calf performance, however, carcass quality in the feedlot phase was improved. Thus, economic analysis indicates opportunities for return on investment if animals treated with EPR have improved health status and/or carcass quality during the feeding phase.

Effects of dry or wet conditions during the preweaning phase on subsequent feedlot performance and carcass composition of beef cattle

Our objective was to determine the effects of dry and wet conditions during the preweaning on subsequent feedlot performance and carcass characteristics of beef cattle. Steers (n = 7,432) and heifers (n = 2,361) finished in 16 feedlots in southwestern Iowa through the Tri-County Steer Carcass Futurity Cooperative were used for a retrospective analysis. Cattle originated in the Midwest (Iowa, Missouri, Indiana, Illinois, and Minnesota) and were born in February, March, or April of 2002 through 2013. Feedlot performance and carcass composition data were obtained for each animal. Palmer Drought Severity Index (PDSI) values were obtained for each animal’s preweaning environment on a monthly basis. Mean PDSI values were used to classify conditions as dry (≤−2.0), normal (>−2.0 and <2.0), or wet (≥2.0) for the cool (April and May), warm (June through August), and combined (April through August) forage growing seasons preweaning. Mixed models were used to evaluate the effects of PDSI class on subsequent performance. Calf sex, date of birth (as day of year), year, and feedlot were also included as fixed effects. When considering PDSI class during the cool season, cattle from normal and wet classes had a greater feedlot delivery BW (P < 0.0001) than dry. Dry and normal classes had greater (P ≤ 0.02) delivery BW than wet during the warm and combined seasons, however. For the cool season, average daily gain was greater (P < 0.0001) for the dry class than normal and wet. Cattle from the normal class for the cool season had greater (P = 0.001) final BW than wet, but the wet class had the greatest (P < 0.04) and dry class had the lowest (P < 0.01) final BW during the warm season. During the cool season, HCW was greater (P < 0.007) for the normal than wet class, although HCW was greater (P ≤ 0.02) for wet compared with dry and normal during the warm season. Calculated yield grade was lower (P ≤ 0.006) for the normal class during the cool season compared with dry and wet. For both the warm and combined seasons, the dry class had lower (P ≤ 0.004) calculated yield grade compared with normal and wet. Carcasses from cattle that experienced normal or wet warm seasons had greater (P ≤ 0.0005) marbling scores than dry, and normal had greater (P = 0.0009) marbling score than dry for the combined seasons. In conclusion, these data indicate that both dry and wet conditions during the preweaning phase may impact ultimate feedlot performance and carcass composition.

1181 WS Effects of dry and wet conditions during the pre-weaning phase on subsequent feedlot performance and carcass composition of beef cattle

1181 WS Effects of dry and wet conditions during the pre-weaning phase on subsequent feedlot performance and carcass composition of beef cattle

Subsequent Feedlot Performance and Carcass Quality of Steers that Grazed Tall Fescue with Different Endophyte Types

Research was conducted to determine subsequent feedlot performance and carcass quality of steers that grazed tall fescue [Lolium arundinaceum (Schreb.) Darbysh.; Schedonorus phoenix (Scop.)] pastures with different endophyte types. Three breed and gender groups of cattle grazed wild‐type endophyte‐infected (E+), novel endophyte‐infected (MaxQ), or endophyte‐free (E−) tall fescue pastures for about 100 days. Twenty‐four animals (four head/paddock; two paddock replicates/endophyte type) from each of the three groups were transported to a feedlot in Stillwater, OK, after the completion of the grazing phase. At arrival to the feedlot, cattle within pasture replicate were maintained in pens and fed a high‐concentrate diet for 112 days in Year 1 and 102 days in Year 2. Live weights of cattle off pasture were 59 kg greater for MaxQ than for E+, and similar to E−. Transit shrink on a percentage basis did not differ among MaxQ and E+ or E−. Rectal temperatures at feedlot arrival and processing were higher for E+ than for MaxQ. In the feedlot, overall average daily gain did not differ among MaxQ and E+ or E−, and averaged 1.99 ± 0.13 kg/day across all treatments. Overall feed efficiency was greater for E+ than for MaxQ. Hot carcass weight was 35 kg heavier for MaxQ than for E+. Other carcass traits did not differ among MaxQ and E+, or MaxQ and E−. Grazing E+ tall fescue decreased gains during the grazing phase that resulted in lighter cattle going into the feedlot, and this weight differential continued after finishing due to similar gains in the feedlot period.

Comparison of ivermectin and extended-release eprinomectin deworming treatment on stocker and subsequent feedlot performance and carcass characteristics of fall-born Angus heifers

The effect of deworming beef heifers with either ivermectin or extended-release eprinomectin on performance and carcass characteristics of stocker and feedlot cattle was assessed. Sixty Angus heifers (610 +/- 50 lb initial body weight; 277 +/- 23 kg) were blocked by body condition score and body weight, and allotted to 1 of 2 injectable deworming treatments after grazing summer pasture for 35 days: (1) ivermectin (IVM) or (2) extended-release eprinomectin (ERE). After 63 days grazing, heifers were placed in a feedlot and fed a finishing ration for 150 days. Heifers were stratified by BW within grazing treatment and allotted to receive ivermectin (dewormed; DWRM) or no treatment during processing (NO) at feedlot entry. Although fecal egg counts did not differ at treatment initiation, egg counts were greater in the IVM group (5.138 eggs per gram) than in the ERE group (0.073 EPG) at the end of the grazing period (P less than 0.01). Heifers in the ERE group had greater average daily gain and greater body weight change (P=0.01) during the grazing period. There were no differences in feedlot performance or carcass characteristics (P greater than or equal to 0.09) between treatment groups. Based on this study, there may be no benefit to deworming at feedlot arrival when cattle are effectively managed to minimize internal parasite infection during the grazing period. However, even at extremely low levels of infection during grazing, parasites can significantly impact performance.

Effect of forage type in the stocker phase and its effect on subsequent feedlot performance and carcass characteristics of beef steers

ABSTRACT The focus of most research on beef weaning programs is to evaluate effects of age and diet on calf performance with a particular interest on preconditioned health program to maximize BW gain. In support of the forage-based production system, research needs to be conducted to evaluate the potential of different forages to facilitate weaning and continuation into forage-based development programs. In each of 2 yr, 48 weaned beef steers were used to evaluate performance when grazing monocultures of endophyte-free tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire = Festuca arundinacea Schreb.; TF] and alfalfa (Medicago sativa L.; ALF) and the effect of these stocker treatments on subsequent performance and carcass characteristics. Forages were not limiting in terms of mass produced and nutritive value. The greater nutritive value of ALF resulted in greater performance and pounds of beef produced per hectare compared with steers grazing TF. Steers grazing ALF tended to be heavier at the beginning of the feedlot phase, and the difference resulted in heavier (P

Effects of Digestible Fiber and Yellow Grease Supplementation to Steers Grazing Small-Grain Pastures on Grazing and Feedlot Finishing Performance

<h2>ABSTRACT</h2> A performance experiment was replicated in 2yr to evaluate the effects of yellow grease supplementation on grazing and subsequent feedlot performance and carcass characteristics of beef steers grazing small-grain pasture. British crossbred steers (yr 1=February 15, 2006, n=45, initial BW=329±14.8kg; yr 2=February 24, 2007, n=45, initial BW=276±20.1kg) were allowed to graze irrigated small-grain pasture. During the grazing periods, steers received 1 of 3 supplements: 1) mineral supplement (MS) offered at 114g/animal daily, 2) MS plus a supplement based on soybean hulls and wheat middlings (MF) offered at 0.50% of BW, and 3) MF plus yellow grease supplement (MFY), consisting of the supplement offered at 0.50% of BW and yellow grease offered at 0.125% of BW. Grazing ADG was greater (P=0.01) for the steers receiving supplement compared with those receiving only MS (1.09, 1.25, and 1.31±0.06kg/d, for MS, MF, and MFY, respectively). Feedlot ADG (P=0.47; 1.38, 1.45, and 1.40±0.04kg/d for MS, MF, and MFY, respectively) and DMI (P=045; 10.6, 104, and 10.1±0.26kg/d for MS, MF, and MFY, respectively) were not affected by the supplemental treatment offered during grazing. Carcass characteristics were not altered (P≥0.41) by supplemental treatments. In conclusion, adding yellow grease to the digestible fiber supplement did not further improve performance on pasture or in the finishing phase.

Erratum to “Effects of winter growing programs on subsequent feedlot performance, carcass characteristics, body composition, and energy requirements of beef steers” (J. Anim. Sci. 88:1564–1576)

McCurdy, M. P., G. W. Horn, J. J. Wagner, P. A. Lancaster, and C. R. Krehbiel. 2010. Effects of winter growing programs on subsequent feedlot performance, carcass characteristics, body composition, and energy requirements of beef steers. J. Anim. Sci. 88(4):1564–1576. Erratum to “Effects of winter growing programs on subsequent feedlot performance, carcass characteristics, body composition, and energy requirements of beef steers” (J. Anim. Sci. 88:1564–1576)

Effect of bovine respiratory disease during preconditioning on subsequent feedlot performance, carcass characteristics, and beef attributes1,2

Heifers with expected increased risk of bovine respiratory disease (BRD; n = 360; initial BW = 241.3 +/- 16.6 kg) were assembled at a Kentucky order-buyer facility and delivered to Stillwater, OK, in September 2007 to determine the effects of clinical BRD observed during preconditioning on subsequent feedlot performance, carcass characteristics, and meat attributes. During a 63-d preconditioning period, morbidity and mortality attributed to BRD were 57.6 and 8.6%, respectively. Immediately after preconditioning, heifers were grouped according to health outcome category and allotted to finishing pens (5 to 7 heifers/pen). Heifers were never treated for BRD (0X; n = 9 pens), treated 1 time (1X; n = 9 pens), 2 times (2X; n = 6 pens), 3 times (3X; n = 6 pens), or designated as chronically ill (CI; n = 2 pens). Arrival BW was not different (P = 0.21) among treatment categories. However, disease incidence during preconditioning decreased (P < 0.001) growth, resulting in BW of 318, 305, 294, 273, and 243 kg for 0X, 1X, 2X, 3X, and CI, respectively, at the start of the finishing phase. Estimates on the LM, taken by ultrasound on d 65 and 122, were combined with BW and visual appraisal to target common average endpoint within category and block. On average, heifers were slaughtered on d 163 for 0X, 1X, and 2X, d 182 for 3X, and d 189 for CI (P < 0.01). Final BW was similar (P > or = 0.18) for heifers treated 0, 1, 2, or 3 times, but heifers deemed CI weighed less (P = 0.01) than 3X heifers. Considering the finishing phase only, ADG was linearly increased (P < 0.001) with increasing BRD treatments, but was linearly decreased (P = 0.003) as BRD treatments increased from arrival to slaughter. Therefore, G:F was greater (P = 0.007) for CI than 3X and linearly increased (P = 0.002) from 0X to 3X. Similar to BW, HCW was less (P = 0.03) for CI than 3X. Marbling score tended (P = 0.06) to decrease linearly as the number of treatments increased, but no other differences (P > or = 0.24) in carcass traits were detected. No differences were observed in beef tenderness (P = 0.65), and no consistent trends were noted in retail display or palatability data. Less than 20 additional days on feed were required for heifers treated 3 times to have similar BW and carcass characteristics to heifers never treated for BRD. Segregating animals with multiple BRD treatments and feeding them to an acceptable carcass endpoint may be a viable strategy for increasing value of animals treated for BRD.

Effects of winter growing programs on subsequent feedlot performance, carcass characteristics, body composition, and energy requirements of beef steers12

The purpose of this study was to investigate the effects of winter growing program on subsequent finishing performance, carcass merit, and body composition of beef steers. Four steers were slaughtered to determine initial body composition. Remaining steers (n = 256) were blocked by BW and randomly allotted to 1 of 4 treatment groups: 1) ad libitum fed a high-concentrate diet (CF), 2) grazed on wheat pasture (WP), 3) fed a sorghum silage-based 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. After the growing phase (112 d), 6 steers were randomly selected from the WP, SF, and PF treatments for determination of body composition. Remaining steers were adapted to a high-concentrate diet for finishing and slaughtered at 1.27 cm of 12th-rib fat. Six steers from each treatment were used to determine carcass, offal, and empty body composition. During the growing phase, WP, SF, and PF steers gained 1.15, 1.10, and 1.18 kg/d, respectively, and ME intake did not differ (P = 0.50) among treatments. Program-fed and SF steers had greater (P < 0.05) offal and empty body fat content than WP steers. Gain in offal and empty body fat was greatest (P < 0.05) for PF steers, intermediate for SF steers, and least for WP steers. During the finishing phase (123, 104, 104, 196 d for WP, SF, PF, and CF, respectively) DMI was greater (P < 0.01) for SF steers (10.9 kg/d) than for PF steers (10.1 kg/d); WP steers were intermediate (10.4 kg/d). Daily BW gain was greatest (P < 0.05) for SF steers (2.02 kg/d), intermediate for PF steers (1.85 kg/d), and least for WP and CF steers (1.64 and 1.63 kg/d, respectively). Accretion (kg/d) of carcass and empty body mass was less (P < 0.05) for WP and CF steers compared with PF and SF steers. Calf-fed steers had greater (P < 0.05) fat content of offal than SF and PF steers; WP steers were intermediate. Gain in empty body and carcass energy (Mcal/d) was greater (P < 0.05) for PF steers than CF steers with SF and WP steers being intermediate. At slaughter, SF steers had reduced (P < 0.01) yield grades and greater marbling scores compared with CF and WP steers; PF steers were intermediate. In conclusion, growing programs that increase fat composition of feeder calves did not negatively affect subsequent finishing performance. Finishing steers as calves may reduce retained energy of carcass tissues and increase internal fat during high-grain feeding compared with steers that previously underwent a growing program.

Growing rate of gain on subsequent feedlot performance, meat, and carcass quality of beef steers1

Eighty Angus and Angus x Simmental steer calves were used in a completely random design to determine the effect of rate of BW gain during the backgrounding period on subsequent feedlot performance, carcass characteristics, Warner-Bratzler shear force (WBSF), and sensory analysis. Animals were stratified by BW and allotted randomly to 1 of 10 pens (5 pens/treatment). Dietary treatments were formulated for an ADG of 0.91 kg/d [low BW gain (LG), 1.06 Mcal of NE(g)/kg] diets and 1.25 kg/d [high BW gain (HG), 1.19 Mcal of NE(g)/kg]. Steers were fed 70 d during the growing period. The LG diet consisted of 52.5% barley silage, 39.0% whole shell corn, and 8.5% supplement, whereas the HG diet contained 43.9% barley silage, 47.4% whole shell corn, and 8.7% supplement (DM basis). Initial BW (226 kg) was not different (P = 0.70) between treatments. Steers fed the HG diet had increased ADG (1.67 vs. 1.40 kg/d; P < 0.001) compared with steers fed LG diet. Dry matter intake was greater (9.49 vs. 8.35 kg/d; P < 0.001) for steers fed the HG vs. LG diet. Total backgrounding cost ($/animal) was less (P < 0.001) for those steers fed LG diet compared with HG diet ($126.00 vs. $140.35, respectively); however, total cost per kilogram of BW gain was not different (P = 0.24; $0.485/kg of BW gain). After the backgrounding period, steers were fed a common finishing diet for 135 d. During the finishing period, LG steers had similar (P = 0.12; 10.73 vs. 10.35 kg/d) DMI compared with those fed HG diets; however, ADG was not different (1.55 kg; P = 0.72) among treatments. Hot carcass weight, marbling score, 12th-rib fat, LM area, and USDA yield grade were not different (P > 0.12) between treatments and averaged 363 kg, Sm(30), 1.33 cm, 83.8 cm(2), and 2.7, respectively. There were no differences (P = 0.77; 3.63 +/- 0.12 kg) in WBSF tenderness of rib-eye steaks. Percent cooking loss was increased in LG diets (P = 0.017). No differences were observed in consumer sensory analysis of tenderness, juiciness, and flavor intensity (P > or = 0.276; 5.43 +/- 0.12, 5.07 +/- 0.13, and 5.17 +/- 0.05, respectively). These data suggest that feeding steers diets that differ in energy concentration and result in ADG of 1.4 and 1.7 kg/d during the growing period results in minimal changes in subsequent finishing performance and does not affect meat quality.