Feedlot Growth Performance Research Articles

PSLBI-9 The growth performance and total tract starch digestibility of finishing Nelore bulls fed flint corn-based diets are improved by the corn processing method and urea source

Abstract The aim of this study was to evaluate the flint corn processing method (CPM) and urea source for finishing Nellore bulls fed corn-based diets. In this study, 80 Nellore bulls [initial body weight (BW) = 388 ± 45.7 kg] were allocated into 28 pens (7 pens/treatment; 6 pens with 3 bulls + 1 pen with 2 bulls). A completely randomized design with a 2 × 2 factorial arrangement of treatments was used to test two CPMs: dry ground corn (DGC) and reconstituted and ensiled corn (REC), and two US: feed-grade urea (FGU) and post-ruminal release urea (PRU). Dietary inclusion (% DM) of flint corn (vitreousness = 86.0%) was 61.3% (DGC or REC), and urea source addition was 0.5% as non-protein nitrogen (NPN; as FGU or PRU). The PRU source (Trouw Nutrition, Netherlands) contained 82% urea on a DM basis. In an in vitro assay, 27% of this urea was released into the rumen. Experimental period lasted 100 d (with 14 d of adaptation). Fecal samples from each bull were collected in two periods of three consecutive days (d 44 to 46 and 94 to 96) at different time (0600, 1200, and 1800 h). Samples were composited by pen and analyzed for fecal starch (FS) and indigestible NDF as markers for fecal excretion. At the end of the experiment, bulls were slaughtered and the jejunum and pancreas were sampled from one bull per pen. Interaction effects were not found (P ≥ 0.31) for any feedlot growth performance variables (Table 1). Final BW, average daily gain, and feed efficiency (gain to feed; G:F) were greater for bulls fed REC and PRU than for those fed DGC and FGU (P < 0.02), respectively. As a result, observed dietary net energy (NE) for maintenance and BW gain were about 7.0% and 9.0% greater for bulls fed REC diets, and 4.3% and 5.6% greater for bulls fed PRU diets, respectively. Bulls fed DGC had 2.2 times greater FS compared with bulls fed REC, resulting in lower fecal pH and total tract starch digestibility (TSD) for bulls fed DGC compared with those fed REC (P < 0.01). Interestingly, a similar trend was observed in bulls fed PRU compared with those fed diets with FGU (P < 0.06). Jejunal gene expression of SLC5A1 was not affected by treatments (P > 0.14). Nevertheless, bulls fed diets with PRU presented greater jejunal α-amylase activity (P = 0.02). Pancreatic α-amylase activity was less when bulls were fed DGC + PRU diet. In conclusion, REC markedly improved TSD and growth performance compared with DGC. Additionally, independent of CPM, PRU inclusion as NPN source increased G:F and dietary NE concentration due to the positive effects on jejunal amylase activity and TSD.

509 Growth and health of Holstein and Holstein x Angus calves from birth to the end of the grower phase

Abstract Feedlot growth performance and carcass traits often differ between Holstein and dairy-beef crossbred calves. However, little is known about their performance and health during the growing phase when reared under similar conditions. This study aimed to compare purebred Holstein (n = 20) and Holstein x Angus crossbred (n = 20) steers from birth until the end of the grower phase. Male calves sourced from one commercial farm arrived at a calf rearing facility at 4.7 ± 1.94 d of age. Calves were fed milk replacer (24 % CP, 20% fat) twice daily at 12 % of birth body weight (BW) for the first 2 wk after arrival and 15 % BW thereafter until wk 6. Calves were gradually weaned from wk 7 to 9. Calves were offered starter (21 % CP, 28% starch) ad libitum until wk 12, and were fed a grower diet (15 % CP, 56 % starch) until wk 32. Milk intake was recorded daily and starter intake on a weekly basis. Once on the growing diet, feed intake was recorded daily using automated feed bins (Roughage Intake Control system, Hokofarm Group). Until wk 12, fecal and respiratory scores were recorded twice daily to estimate the incidence of disease, BW was measured weekly and frame measurements (hip and wither heights, and heart and chest girth) were recorded on wk 4, 7 and 12. From wk 12 to 32, BW and frame measurements were recorded monthly. Data were analyzed using PROC GLIMMIX (SAS 9.4), with breed as fixed, and calf and time as random effects. There were no differences between breeds in initial BW (P = 0.69), proportion of days with diarrhea (P = 0.21) or respiratory disease (P = 0.11), intake of milk (P = 0.45), starter (P = 0.83) or grower diet (P = 0.28). Crossbred calves tended to have greater average daily gain during the rearing phase (P = 0.07) and were growing 250 g/d faster than Holstein calves throughout the growing phase (P < 0.01). Thus, at the end of the growing phase, crossbred calves were 33.5 kg heavier than Holstein calves and had a better feed conversion rate (P < 0.01). During the growing phase, crossbred calves had larger heart and chest girths (P < 0.01) than Holstein calves, whereas hip and wither heights were higher (P < 0.01) for Holstein calves throughout the study. Overall, crossbred calves had greater average daily gain and improved feed conversion rate than Holstein calves during the growing phase, but it remains unknown if these differences will affect their feedlot performance.

Dose effects of encapsulated butyric acid and zinc on beef feedlot steer growth performance, dietary net energy utilization, rumen morphometrics, small intestine histology, and carcass characteristics.

The objective of this study was to determine the effects that increasing doses of encapsulated butyric acid and zinc (BZ) have on feedlot steer growth performance, rumen morphometrics and small intestine histology (data not statistically analyzed), dietary net energy utilization, and carcass characteristics. Steers [n = 272; shrunk body weight (BW) = 360 kg ± 74 kg] were assigned to dietary treatments [0 (CON), 1, 2, or 3g BZ/kg diet dry matter] in a randomized complete block design (RCBD) with pen (n = 32 total; n = 8 per treatment) as experimental unit. Pens were blocked by cattle source and location within the feedyard. Cattle were fed until visually assessed to have 1.27cm rib-fat and were shipped for harvest at a commercial beef abattoir. Carcass and liver health data were recorded. A subset of steers (n = 8 total; n = 2 per treatment) was harvested at the SDSU Meat Laboratory to collect empty body measurements, rumen samples for morphometric analysis, and duodenal and ileal samples for histological analysis to provide context to feeding trial outcomes. Feedlot growth performance data was calculated on a carcass-adjusted basis: hot carcass weight (HCW)/0.625. Data were analyzed as a RCBD with fixed effects of BZ inclusion level and block was considered a random effect; pre-planned contrasts for CON vs. BZ, plus linear, and quadratic responses were tested. No differences (P ≥ 0.11) were observed for final BW, dry matter intake, average daily gain (ADG), feed conversion efficiency (G:F), performance calculated dietary net energy, HCW, ribeye area, rib-fat thickness, marbling score, estimated empty body fat, or distribution of USDA yield grade (YG) 1, 3, 4, 5, and USDA quality grade among treatments. A tendency (P = 0.10) was observed for CON vs. BZ for calculated YG. Tendencies were detected for USDA YG 2 carcass distribution (linear; P = 0.07) and for normal and abscessed liver prevalence (quadratic; P = 0.08). Dressed yield tended to be greater (P = 0.08) for BZ vs. CON and increased with dose (linear; P = 0.05). Receiving period shrunk BW, ADG, and G:F was improved (P ≤ 0.02) for BZ-supplemented steers compared to CON. Data from this study suggests that the addition of BZ to feedlot finishing diets to improve receiving period growth performance and decreasing the prevalence of abscessed livers should be further investigated.

Effect of traditional roughage-based or limit-fed, high-energy diets on growth performance and digestion in newly received growing cattle and subsequent implications on feedlot growth performance and carcass characteristics.

The objective was to determine the effects of ad libitum-fed roughage-based diets or limit-fed high-energy diets on growth performance, behavior, health, and digestion in newly received growing cattle and subsequent implications on feedlot growth performance and carcass characteristics. In experiment 1, 409 crossbred heifers (initial body weight [BW] = 279 ± 24kg) in 32 pens were used in a randomized block design. Heifers were fed one of two dietary treatments: a total mixed ration with 0.99 Mcal net energy for gain (NEg)/kg dry matter (DM) fed ad libitum (0.99AL) or 1.32 Mcal NEg/kg DM limit-fed at 85% of intake of heifers fed 0.99AL (1.32LF85%). Both diets contained 40% DM as a branded wet corn gluten feed. In experiment 2, 370 crossbred heifers (initial BW = 225 ± 20kg) were used in a randomized block design and were fed a diet formulated to contain 0.99 Mcal of NEg/kg DM for ad libitum intake or a diet formulated to contain 1.32 Mcal of NEg/kg DM and fed at 2.2% of BW daily (DM basis; 1.32LF2.2). For experiments 1 and 2, treatment integrity was maintained through the finishing phase where cattle were fed a common diet. Cattle were sorted by BW into heavy and light groups prior to finishing, with light cattle fed longer than heavy cattle to reach similar harvest BW. In experiment 3, eight ruminally cannulated heifers (average BW = 305 ± 23kg) were used in a 2-period cross-over design and fed treatments from experiment 1 to assess digestibility and ruminal fermentation characteristics. Gain:feed was 47% and 35% greater (P < 0.01) in experiments 1 and 2, respectively, for limit-fed heifers compared with 0.99AL heifers. Rumination time was greater (P < 0.01) for 0.99AL compared with limit-fed treatments in experiments 1 and 2. Activity was greater (P < 0.01) for 1.32LF2.2 than for 0.99AL in experiment 2. In experiment 1, more (P = 0.03) carcasses from light-sort heifers than carcasses from heavy-sort heifers had livers with large, active abscesses. In experiment 2, finishing phase morbidity was greater (P < 0.01) for 1.32LF2.2 than for 0.99AL. Light-sort groups had fewer (P < 0.01) edible livers than heavy-sort groups, suggesting that greater number of days on feed may increase the risk of liver abscess prevalence and condemnation. In experiment 3, apparent total-tract DM and organic matter digestibilities were greater (P < 0.01) for 1.32LF85% than for 0.99AL. Overall, dietary treatments during the growing phase had little carryover effect on feedlot growth performance, carcass characteristics, or liver abscesses prevalence at harvest.

A novel production profile classification system for incoming calves that predicts feedlot growth performance

Context Mitigating financial risk in the feedlot environment is an ongoing occurrence, and good production is a key risk mitigator. However, production protocols are based on historic averages because of the inability to predict growth potential of incoming calves. Production profiling of individual incoming feeder calves could address these limitations. Aims The aim of this study was to establish criteria for optimal sorting of incoming feeder calves into various cattle groups in a feedlot that maximises feedlot profit. Methods South African feeder calves (n = 436) were classified into four production-profile (PP) categories according to a predetermined set of phenotypic traits: PP 3 (n = 72) representing feeder calves with the poorest feedlot growth potential, PP 2− (n = 191) with below-average potential, PP 2+ (n = 139) with above-average potential and PP 1 (n = 34) with above-average feedlot growth potential. After combining the data of PP 2− and PP 2+ into PP 2, mixed modelling of economically important feedlot growth traits (average daily gain (ADG), carcass ADG, and carcass exit weight) was performed to evaluate the effect of PP classification (PP 1 and PP 3), while adjusting for potential confounding effects such as starting weight (entry weight) and gender. Key results Carcass weights for calves with a PP classification of 3 and 1 were 15.54 kg less (P &lt; 0.000), and 11.34 kg more (P = 0.007) respectively, than those with a PP classification of 2 (261.27 kg, 95% CI 257.94–264.57), after adjusting for entry weight, calf gender and the random effect of the feeding pen. Similar to carcass weight, calves with a PP 3 classification were outperformed by other classifications in all the measured traits (P &lt; 0.05). Conclusions This is the first report demonstrating the ability of subjective production-profile classification to predict growth performance of individual feeder calves. Implications The opportunity of the PP classification system lies in value-based procurement of incoming feeder calves based on their growth potential at the start of the feeding period, and then to use technology to improve and finalise the current subjective PP classification system.

371 Effect of Calcium Magnesium Carbonate And/Or Tylosin Phosphate Supplementation on Behavior, Rumination Activity, Feedlot Growth Performance and Carcass Characteristics in Yearling Beef Steers

Abstract The objective of this study was to evaluate the effects of calcium magnesium carbonate (CMC) and/or tylosin phosphate (TYL) supplementation on behavior, rumination activity, growth performance and carcass characteristics of yearling beef steers. Treatments were arranged in a 2 × 2 factorial including CMC and TYL. Beef steers (n = 156; 469 ± 18 kg) were randomly assigned to treatment pens (7 to 8 steers/pen) with pen (n = 20 pens total, 10 pens/main effect mean, and 5 pens/simple effect mean) as experimental unit. Cattle were transitioned from a 30% roughage diet to a 7% roughage finishing diet based on dry-rolled corn, dried distillers grains plus solubles, liquid supplement, and oat silage over the initial 20 d period. The CMC was included at 1.5% of the diet (DM basis) in replacement of dry-rolled corn and TYL was provided at 90 mg·animal·d-1. Behavior and rumination activity were monitored during a 24 h period on d 42. Data was collected on a pen-basis, every 10 min from 0800 h to 0750 h the next day and included minutes spent drinking (DR), eating (EA), active (AC), ruminating (RU), and resting (RE). Cattle were shipped for harvest on d 105 to a commercial beef abattoir. Growth performance was calculated on a carcass-adjusted basis (HCW/0.625). Data were analyzed as a randomized complete block design with fixed effects of CMC, TYL, or their interaction; block was a random effect. An interaction was observed between CMC and TYL for time spent DR (P = 0.03) and RU (P = 0.01). Control steers ruminated 28% longer compared with CMC/-TYL steers (P = 0.05) and 20% longer than -CMC/TYL steers (P = 0.05). The main effect of CMC tended to increase time spent EA by 19.3% (P = 0.06). Dry matter intake was decreased (P ≤ 0.02) by 4.57% when CMC was fed and increased by 1.96% when TYL was fed. However, no difference (P ≥ 0.26) was observed for G:F or gain efficiency in either treatment. No differences (P ≥ 0.28) were observed in any dietary net energy utilization outcomes in either main effect treatment. Carcass weight tended (P = 0.07) to be lighter with CMC supplementation compared with CON (432 vs 439 kg). Supplementation of TYL resulted in a 11.7% reduction (P = 0.04) in percentage of abscessed livers. No differences (P ≥ 0.12) were observed in DP, marbling, YG, or EBF in either main effect treatments. These results indicate that supplementation of CMC did not result in any appreciable improvements in growth, carcass or dietary net energy utilization performance, but TYL supplementation resulted in a positive effect on liver abscess prevalence.

41 Growth Performance and Carcass Characteristics of Beef-Sired Steers Born to Holstein Dams

Abstract The objective of this study was to compare feedlot growth performance and carcass characteristics of F1 beef × Holstein steers (n = 124) sired by commercially available Angus (n = 19 from 7 sires), Charolais (n = 79 from 3 sires), SimAngus (n = 16 from 3 sires), or Wagyu (n = 10 from 2 sires) bulls. Male calves born from May to August of 2021, were sourced from 8 Pennsylvania dairy herds. Steers were raised by a commercial calf grower until April of 2021 (10.5 ± 1.5 months of age). Steers were then moved to the PA Department of Agriculture’s Livestock Evaluation Center (LEC) and transitioned to a high-energy ration. Individual feed intake was monitored using the GrowSafe Feed Intake Monitoring System (Model 4000E, Vytelle, Calgary AB, Canada). Steers were slaughtered after 90, 118, or 153 days on feed at the LEC. Pulls were based on a combination of visual appraisal and body weight. Linear models of growth performance traits and carcass characteristics included the fixed effects of sire breed, herd of origin, and birthdate. Binomial models of USDA Quality Grades and Yield Grades included a fixed effect of sire breed. Angus-sired steers were heaviest at feedlot entry (P &amp;lt; 0.01) and were on feed for the fewest days (P &amp;lt; 0.01). Angus × Holstein steers were heavier at slaughter (P &amp;lt; 0.01) than SimAngus and Wagyu-sired steers. Wagyu-sired steers had the least dry matter intake (DMI), average daily gain (ADG), and carcass ADG (P &amp;lt; 0.01) when compared with progeny of other sire breeds. No differences in gain to feed intake (G:F(; P = 0.90), back-calculated carcass G:F (P = 0.62), net energy of metabolism (P = 0.70) and net energy of gain (P = 0.70), nor hip height at harvest (P = 0.14) were detected between sire breeds. Wagyu × Holstein carcasses were the lightest (P &amp;lt; 0.01) and had the least amount of backfat (P = 0.01). Dressing percentage tended to be least (P = 0.10) in Charolais × Holstein carcasses (60.5%) and greatest in SimAngus × Holstein carcasses (61.7%); carcasses from Angus and Wagyu-sired steers were intermediate and not different. About 84% of Angus × Holstein carcasses graded Choice while only 31% of SimAngus × Holstein carcasses graded Choice (P = 0.03). However, there were no differences in called marbling scores between sire breeds (P = 0.15). Charolais × Holstein tended to have the lowest proportion (4%) of Yield Grade 1 carcasses (P = 0.05). Angus-sired steers were on feed for the fewest days when compared with steers sired by other beef breeds. Wagyu × Holstein steers had reduced ADG, DMI, and subsequent carcass weight in comparison with compared steers of other sire breeds.

Evaluation of long-term supplementation of a direct-fed microbial and enzymatically hydrolyzed yeast cell culture product on feedlot growth performance, efficiency of dietary net energy utilization, heat stress measures, and carcass characteristics in beef steers.

The objective of this research was to determine the influence of long-term supplementation (258 d) of a direct-fed microbial (DFM) and yeast cell wall (YCW) product used alone or in combination on growth performance, dietary net energy utilization, and carcass characteristics in beef steers finished under climatic conditions in the Northern Plains (NP). Single-sourced Charolais × Red Angus steers [n = 256; body weight = 246 ± 1.68 kg] were blocked by pen location in a 2 × 2 factorial arrangement of DFM and YCW. Steers were administered a series of diets common to the NP and administered ractopamine hydrochloride (RH; 300 mg/kg) during the last 28 d of the finishing phase. Steers were vaccinated and poured at processing and individually weighed on days 1, 14, 42, 77, 105, 133, 161, 182, 230, and 258. Temperature-humidity index (THI) was calculated during RH supplementation. For 98% of the experiment, the THI was lower than 72 and thus cattle were not under high-ambient temperature. On days 1, 2, 21, and 22 of RH supplementation, respiration rates (RR), and panting scores (PS) were determined before and after AM and PM feedings (0700 h, 1100 h, 1400 h, and 1700 h). A DFM + YCW interaction was noted for the proportion of steers categorized as PS 2.0 at 1100 h on day 21 (P = 0.03) and RR on day 21 at 1400 h (P = 0.02). Control steers had a greater proportion of PS 2.0 compared to DFM or YCW steers (P ≤ 0.05), while DFM + YCW steers did not differ from others (P ≥ 0.05); DFM + YCW steers had greater (P < 0.05) RR compared to DFM steers, while control and YCW steers did not differ from others (P ≥ 0.05). No DFM + YCW interactions or main effects (P ≥ 0.05) were observed for cumulative growth performance measures. However, YCW steers had 2% lower (P = 0.04) dry matter intakes compared to steers not fed YCW. No DFM + YCW interactions or main effects (P ≥ 0.05) were observed for carcass traits or liver abscess severity. However, a DFM + YCW interaction (P < 0.05) was noted for the distribution of USDA yield grade (YG) 1 and Prime carcasses. Control steers had a greater proportion (P < 0.05) of YG 1 carcasses compared to other treatments. DFM+YCW steers had a greater proportion (P < 0.05) of USDA Prime carcasses compared to DFM or YCW but were similar to control steers, which were also similar to DFM or YCW. Overall, the use of DFM and YCW alone or in combination had minimal effects on growth performance, carcass traits, and heat stress measures in steers finished in NP climatic conditions.

The effect of different implant programs on beef × dairy steer feedlot growth performance and carcass characteristics.

The objective of this study was to evaluate potency and timing of trenbolone acetate (TBA) administration on live performance and carcass characteristics of beef × dairy steers. A total of 6,895 beef × dairy steers [initial body weight (BW) = 157 ± 5.2 kg] were allotted into 30 pens, with pen as the experimental unit. Each pen was randomly assigned one of three implant treatments: 1) Revalor-IS (IS) at d 0, IS at d 80, and Revalor-XS (XS) at d 160 (IS/IS/XS); 2) Ralgro at d 0, IS at d 80, and XS at d 160 (Ral/IS/XS); or 3) Encore at d 0 and XS at d 160 (Enc/XS). Steers were blocked by arrival date, each pen was terminally sorted in three ways at 257 ± 22 days on feed and harvested at 329 ± 25 days on feed. For live and carcass outcomes, fixed effect of implant treatment and random effect of block was evaluated. Data are reported on a deads and removals out basis. Removals, morbidity, and mortality were similar (P ≥ 0.45). Steers administered TBA prior to d 160 were 5.8 kg heavier (P = 0.03) than Enc/XS steers at d 160. Final BW was not different (P = 0.78). Early administration of a TBA-containing implant resulted in an increased prevalence of bullers [2.40%, 5.18%, 6.86% (for Enc/XS, Ral/IS/XS, and IS/IS/XS) respectively; P < 0.01]. Dry matter intake (DMI) was 2.3% greater (P < 0.01) in steers administered Enc/XS compared to IS/IS/XS; however, DMI as a percentage of BW, average daily gain, and feed efficiency were not different (P ≥ 0.12). Dressing percentage, hot carcass weight, heavy carcass occurrence, Longissimus muscle area, and 12th rib fat thickness were similar among all steers (P ≥ 0.28). Marbling score tended to be greatest for Enc/XS and Ral/IS/XS (P = 0.09). Enc/XS graded a greater proportion of USDA Prime and fewer USDA Select carcasses than IS/IS/XS (P < 0.05). Enc/XS and Ral/IS/XS tended (P = 0.09) to have more USDA Yield Grade (YG) 1 carcasses. While delayed administration or decreased total potency of TBA-containing implants may decrease buller incidence and improve Quality Grade, few differences were observed in live or carcass outcomes.

Feedlot growth performance and carcass characteristics of steers backgrounded on buffel grass or buffel-Desmanthus mixed pastures.

Feedlot performance and carcass characteristics of tropical beef steers backgrounded on buffel grass (Cenchrus ciliaris) only or buffel grass oversown with desmanthus (Desmanthus spp. ; 11.5% initial sward botanical composition) were evaluated. It was hypothesized that tropical beef cattle steers backgrounded on buffel grass only or buffel grass oversown with desmanthus with similar backgrounding growth performance will not differ in feedlot growth performance and carcass quality. Three hundred and twelve Bos indicus × Bos taurus tropical composite steers, 20–23 months old and weighing 413 ± 24 kg, previously backgrounded on buffel grass only or buffel-desmanthus mixed pastures for 147 days were finished on a concentrate diet in the feedlot for 110 days before slaughter. Buffel–desmanthus backgrounded steers had a slightly higher average daily gain (ADG; 1.8 kg/day) than the buffel grass backgrounded steers that had 1.7 kg/day ADG (p < 0.01). However, the final live weight and dry matter intake were not different (p ≥ 0.59). All the carcass traits measured were not different (p ≥ 0.18). Only 4% buffel grass and 8% buffel-desmanthus backgrounded steers fell short of the Meat Standards Australia (MSA) index, a level that is within the 4–9% reported for cattle produced in Queensland and slaughtered between July 2019 and June 2020. These findings indicate that desmanthus can be used to background beef cattle in northern Australia vertosol soil regions, where there is a paucity of adapted pasture legumes, with no negative impact on feedlot performance and carcass quality. The hypothesis that tropical beef cattle steers backgrounded on buffel grass only pastures or buffel grass oversown with desmanthus with similar backgrounding growth performance will have similar feedlot growth performance and carcass quality was accepted.

The effect of supplementing CLOSTAT 500 (Bacillus subtilis PB6) to yearling steers in a commercial feedyard on health, Salmonella spp. prevalence, feedlot growth performance and carcass characteristics.

British and British × Continental crossbred beef steers, n = 2,100; 313 ± 38 kg of initial body weight (BW) were used to evaluate the effects of Bacillus subtilis PB6 supplementation to yearling steers in a commercial feedyard on health, prevalence of Salmonella spp., growth performance, and carcass characteristics. Steers were blocked by arrival date and assigned randomly to pens within the block; pens were randomly assigned to 1 of 2 dietary treatments within block. Treatments, replicated in 15 pens/treatment with 70 steers/pen, included: 1) control (CON), diets containing no supplemental direct-fed microbials; 2) CLOSTAT (CLO), diets supplemented with 0.5 g/steer/d Bacillus subtilis PB6 (CLOSTAT 500, Kemin Industries, Des Moines, IA) to provide 6.6 × 109 CFU/g of the active ingredient. Supplementing CLO decreased the overall incidence of morbidity (P = 0.03), 10.38% (CLO) vs. 13.43% (CON), decreased the percentage of steers treated once for bovine respiratory disease (BRD; P < 0.01), 9.14% (CLO) vs. 12.76% (CON), and decreased the incidence of BRD retreatment (P = 0.03) compared with CON. Mortality did not differ among treatments (P = 0.23); however, overall deads and removals tended to be less for CLO than CON (53 heads vs. 73 heads respectively, P = 0.06). Prevalence of fecal Salmonella did not differ among treatments, (P ≥ 0.35); overall fecal Salmonella counts tended to be less for CLO (1.59 log (10) CFU/g) than CON (2.04 log (10) CFU/g; P = 0.07). Salmonella concentration in subiliac lymph nodes (n =150/treatment) was not different (P = 0.62) between CON (0.22 log (10) CFU/g) or CLO (0.19 log (10) CFU/g); however, there was a 46% reduction in the overall mean prevalence of lymph node Salmonella (P = 0.46; 15.48% vs. 28.66%) for CLO and CON, respectively. With deads and removals included, final BW was heavier for CLO steers than CON, (654 kg vs. 641 kg, respectively, P = 0.05), and average daily gain (ADG; P = 0.08) and gain efficiency (G:F; P = 0.06) tended to be greater for CLO than CON. With deads and removals excluded, final BW, ADG, and G:F did not differ among treatments (P ≥ 0.30). Carcass traits were not different between treatments (P ≥ 0.15). Supplementing CLO throughout the feeding period in a commercial feedyard improved the health outcomes of yearling steers by decreasing BRD and overall treatment rates, reducing the overall abundance of Salmonella, and resulting in fewer steers removed from the study compared with CON.

Replacement of dietary corn with corn bran plus condensed distillers solubles effects on feedlot growth performance and carcass trait responses of beef steers.

Dry-corn milling biorefineries have the opportunity to install technology to fractionate corn prior to fermentation, which creates a product stream of fibrous bran that can be fed to cattle. The objective of this study was to determine the effects of replacing dietary corn with corn bran and condensed distillers solubles (CBCDS) or wet-corn gluten feed (WCGF) on growth performance, efficiency of dietary net energy (NE) utilization, and carcass characteristics in finishing steers. British × Continental steers (n = 240; initial body weight [BW] = 401 ± 43.2 kg) were assigned to the following dietary treatments in a randomized complete block design (RCBD): 1) a control finishing diet with no corn milling coproducts; 2) a finishing diet that contained CBCDS at 20% replacement of dietary corn; and 3) a finishing diet that contained WCGF at 20% replacement of dietary corn. Dietary corn (50:50 of dry-rolled corn and high-moisture corn) was included at 81.5% for control diet-fed steers and 61.5% for steers-fed CBCDS and WCGF. Steers were fed for 145.5 d until visually appraised to have 1.27 cm of rib fat (RF) and were harvested at a commercial abattoir where carcass data were collected. Data were analyzed as an RCBD with pen as the experimental unit, treatment as a fixed effect and block as a random effect. There were no significant differences (P ≥ 0.28) between treatments for final BW, average daily gain, dry matter intake, feed conversion efficiency, observed dietary NE for maintenance (NEm), and NE for gain (NEg), or observed-to-expected NEm and NEg. Additionally, no differences (P ≥ 0.16) were noted between treatments for hot carcass weight, ribeye area, RF, marbling score, kidney–pelvic–heart fat, estimated empty body fat (EBF), BW at 28% EBF (AFBW), and distribution of USDA Quality and Yield grades. Control steers tended (P = 0.10) to have the highest calculated yield grade followed by WCGF and CBCDS. Furthermore, WCGF steers tended (P = 0.08) to have the highest calculated retail yield followed by CBCDS and control steers. Replacement NEm and NEg values of corn coproducts were determined to be 2.14 and 1.42 for CBCDS and 2.09 and 1.37 for WCGF, respectively. Thus, CBCDS can be included in finishing steer diets at 20% replacement of corn without detriment to growth performance or carcass characteristics.

Comparing Blend of Essential Oils Plus 25-Hydroxy-Vit-D3 Versus Monensin Plus Virginiamycin Combination in Finishing Feedlot Cattle: Growth Performance, Dietary Energetics, and Carcass Traits.

Simple SummaryA primary objective in livestock production is the limitation of use of conventional antibiotics as feed additives for promoting growth. Due to their antimicrobial characteristics, essential oils are “generally recognized as safe” alternatives to conventional antibiotics. In this study, dietary supplementation of finishing cattle with essential oils combined with vitamin D3 improved dietary energy utilization comparable to that of the combination of ionophore monensin and antibiotic virginiamycin. Furthermore, supplementation with essential oils combined with vitamin D3 during the finishing phase may improve carcass Longissimus muscle area and carcass yield.Ninety crossbreed bulls (349.5 ± 8.25 kg initial weight) were used in an 87day trial to compare the effects of a blend of essential oils plus 25-hydroxy-Vit-D3 (EO + HyD) versus the combination of monensin with virginiamycin (MON + VM) on feedlot growth performance and carcass characteristics. Dietary treatments (nine replicates/treatment) were supplemented with 40 mg/kg diet dry matter of MON + VM (equal parts) or with 120.12 mg/kg diet dry matter of a combination of standardized mixture of essential oils (120 mg) plus 0.12 mg of 25-hydroxy-vitamin-D3 (EO + HyD). There were no treatment effects on dry matter intake (DMI, p = 0.63). However, the coefficient of variation in day-to-day DMI was greater for EO + HyD than for MON + VM (11.4% vs. 3.88%, p = 0.04). There were no treatment effects (p ≥ 0.17) on daily weight gain, gain-to-feed ratio, and estimated dietary net energy. Cattle supplemented with EO + HyD had greater Longissimus muscle area (7.9%, p < 0.01) and estimated retail yield (1.6%, p = 0.03), and tended to have heavier (1.7%, p = 0.10) carcass weight. Differences among treatments in dressing percentage, fat thickness, kidney–pelvic–heart fat, and marbling score were not appreciable (p > 0.10). It is concluded that growth performance response and dietary energetic are similar for finishing cattle supplemented with EO + HyD vs. MON + VM. However, compared with MON + VM, supplementation with EO + HyD during the finishing phase may improve carcass Longissimus area and carcass yield.

Influence of arrival weight of Holstein steers of similar age on feedlot growth performance, dietary energetics, and carcass characteristics.

Objective:Evaluate the effect of arrival weight on feedlot growth performance and carcass characteristics of Holstein steers of similar age.Material and Methods:Three hundred calf-fed Holstein steers (age 113 ± 1-day) were distributed in a completely randomly unbalanced design and divided into five categories (105, 112, 117, 123, and 129 kg) of shrunk initial weight (SIW). Calves were weighed on days 1, 112, 224, and 361. Calves were fed steam-flaked corn-based diets. Growth performance and dietary energy were evaluated for each period and the study as a whole (1–361-day).Results:During the rearing period, average daily gain (ADG) increased (linearly effect, p < 0.01) with increasing birth weight. Birthweight was positively associated (p < 0.05) with feedlot arrival weight (R2 = 0.47) and final harvest weight (R2 = 0.36). Overall ADG increased (p < 0.01) with increasing SIW. Dry matter intake increased linearly during the first 224-day but quadratically during the last 137 days. Overall, there was a quadratic effect (p < 0.05) of SIW on gain-to-feed and observed-to-expected dietary NE, with lower efficiencies (4%) for steers in both the lightest and heaviest SIW. Hot carcass weight, Longissimus muscle area, marbling score, and fat thickness increased (linear effect, p ≤ 0.03) as SIW increased, whereas kidney-pelvic-heart fat and yield-grade were unaffected.Conclusions:The initial arrival weight influences the growth performance, energetic efficiency, and carcass characteristics of Holstein steers of similar age. The effect is more pronounced in the lighter (<112 kg) steers.

Influence of supplemental condensed tannins on initial 112-d feedlot growth-performance and characteristics of digestion of calf-fed Holstein steers.

In experiment 1, 150 calf-fed Holstein steers (119±6kg) were used to evaluate the effects of level of supplemental condensed tannin (0, 14, and 28g/kg diet DM) in a conventional steam-flaked corn-based growing-finishing diet on feedlot growth performance. There were no treatment effects on growth performance during the initial 56-d period. However, during the subsequent 56-d period, supplemental condensed tannin tended to increase average daily gain (ADG; linear effect, P = 0.09). The increase in ADG was consistent with the tendency for increased dry matter intake (DMI; linear effect, P = 0.08). Hence, differences in gain efficiency during the second 56-d period were not appreciably affected (P = 0.80). Supplemental condensed tannin did not affect overall (112-d) ADG, DMI, gain efficiency, or dietary NE. In a second experiment, six Holstein steers (179.4±7.9kg) with cannulas in the rumen and proximal duodenum were used in a replicated 3×3 Latin square design to evaluate treatment effects on characteristics of ruminal and total tract digestion. Treatments were the same as in Trial 1. Tannin supplementation decreased (linear effect, P = 0.03) ruminal OM digestion and tended to decrease (linear effect, P = 0.06) ruminal feed N degradation. Tannin supplementation decreased (linear effect, P = 0.03) ruminal pH, but did not affect (P > 0.20) ruminal molar proportions of volatile fatty acids and estimated methane production. In current study, supplemental tannin had marginal effects on overall growth performance of calf-fed Holstein steers, but reduced ruminal, postruminal, and total tract nitrogen digestion.

A Limit-Fed, High-Energy Diet Fed During the Growing Phase Does Not Negatively Affect Subsequent Feedlot Growth Performance or Carcass Merit Compared to Feeding a Traditional Roughage-Based Diet Ad Libitum During the Growing Phase

Objective: The objective of this experiment was to compare the subsequent growth performance and carcass impacts of a high-energy diet limit-fed at 2.2% of body weight (BW) or a traditional roughage-based diet fed ad libitum during the growing phase.

Interaction of early metabolizable protein supplementation and virginiamycin on feedlot growth performance and carcass characteristics of calf-fed Holstein steers.

One hundred sixty-eight Holstein steer calves (133.4 ± 7.9 kg) were used to evaluate the influence of virginiamycin (VM) supplementation on cattle growth performance and liver abscess incidence, and the effect of feeding 100% vs. 87% of metabolizable protein (MP) requirements during the initial 112 d on growth performance, efficiency of energy utilization, and carcass characteristics. Steers were balanced by weight and assigned to 28 pens (6 steers/pen). During the initial 112-d feeding period, dietary treatments consisted of two levels of MP (100% vs. 87% of expected requirements) supplemented with or without 22.5 mg/kg VM in a 2 × 2 factorial arrangement. There were no VM × MP supplementation interactions (P ≥ 0.14) on any of the parameters measured in both experiments. Calf-fed Holstein steers supplemented with VM increased (P ≤ 0.03) overall average daily gain (ADG), feed efficiency (G:F), observed/expected net energy (NE) values for maintenance and gain, and final body weight (BW). Cattle fed VM also increased (P ≤ 0.04) carcass weight, dressing percent, and longissimus muscle area. However, there was no effect (P ≥ 0.22) of VM supplementation on any other carcass characteristics. Calf-fed Holstein steers fed 100% MP requirements during the initial 112-d feeding period had greater (P ≤ 0.02) ADG, G:F, observed/expected NE values for maintenance and gain, and live BW compared with steers fed 87% of the expected MP requirements. However, there was no effect (P ≥ 0.17) of MP supply during the initial 112-d period on overall (342 d) growth performance measurements. The incidence of liver abscesses was low (averaging 7.7%) and not affected by dietary treatments. We conclude that, independent of MP supplies, supplemental VM enhances overall growth performance and efficiency of energy utilization of calf-fed Holstein steers.

Effects of wet distillers bran plus solubles and corn oil in diets containing flint corn grain and citrus pulp for finishing Nellore bulls

Objectives were to evaluate the effects of de-oiled wet distillers bran plus solubles (WDBS) as a protein source [when included at 150 g/kg of diet dry matter (DM)] to replace soybean meal (SBM); or as a protein and energy source (when included at 300 and 450 g/kg of diet DM) to replace a mix of soybean meal, ground flint corn, and citrus pulp, and to evaluate the effects of corn oil inclusion (0vs 30 g/kg of diet DM) in diets containing 0 to 450 g/kg of WDBS (DM basis). Two hundred and thirty-two Nellore bulls (BW = 425 ± 25 kg) were used in a randomized complete block design with a 2 × 4 factorial arrangement of treatments consisting of diets supplemented or not with 30 g/kg of corn oil (DM basis) each one combined with 4 inclusions of WDBS (0, 150, 300, and 450 g/kg; DM basis). Bulls were blocked by initial shrunk BW and allocated into 40 pens (5 pens/treatment; 5 or 6 bulls/pen). Effects of corn oil × WDBS interaction were not detected (P ≥ 0.29) for feedlot growth performance, carcass traits, and dietary NE concentrations, except for dry matter intake (DMI; P = 0.03). Increasing inclusion of WDBS linearly decreased DMI (P = 0.004) of finishing bulls fed diets without corn oil supplementation, but quadratically decreased DMI (P = 0.002) in diets containing 30 g/kg of corn oil, resulting in the observed interaction (P = 0.03). Feeding WDBS did not affect average daily gain (ADG), hot carcass weight (HCW), and dressing percentage of finishing bulls regardless of corn oil supplementation (P ≥ 0.18). Feed efficiency (G:F) tended (linear; P = 0.09) to increase due to WDBS inclusion. The inclusion of 30 g/kg corn oil (DM basis) in the diet tended (P = 0.07) to decrease DMI by 3% and increase G:F by 7.5% compared with diets not supplemented with corn oil. Including 30 g/kg of corn oil (DM basis) in the diet increased (P = 0.05) observed net energy of maintenance (NEm) and net energy of gain (NEg). Corn oil supplementation had no effect (P ≥ 0.19) on final BW, ADG, HCW, and dressing percentage. In summary, WDBS is as a protein supplement alternative to SBM when fed at 150 g/kg of the diet DM. The supplementation with corn oil is an effective way to increase the energy density of finishing diets containing WDBS.

359 Intake and Growth Performance of Feedlot Lambs Fed Diets with Hi-a and Low-a Corn Cobs and Bermudagrass Hay

Abstract Hi-A™ corn is a unique type of lines and hybrids that were developed by the Texas A&amp;M AgriLife Corn Breeding Program and have high anthocyanin and antioxidants. A completely randomized design trial was used to evaluated effects of Hi-A and low-A (regular) corn cobs and bermudagrass hay (BGH) in feedlot diets fed to female Rambouillet lambs (n = 10/treatment), with initial body weight (BW) of 30.7+1.2 kg, on dry matter intake (DMI), BW, average daily gain (ADG), and growth:feed ratio (G:F). After 14 days of adaptation, lambs were individually fed a total mixed ration with 80% concentrate and 20% of one of the roughages (Hi-A, low-A, or BGH) for 63 days. Hay was chopped, while cobs were ground using a hammermill with a 9.52-mm screen. Data were analyzed using repeated-measures ANOVA. The BW was not affected by the diet but increased (P &amp;lt; 0.001) during the trial. Diet did not influence the ADG. However, the ADG was lower (P &amp;lt; 0.001) in the d-42 (0.12 kg/d) than the rest of the trial (0.22 kg/d), after a period of constant high temperatures. The interaction diet vs. day affected (P &amp;lt; 0.05) DMI. In general, lambs increased (P &amp;lt; 0.05) DMI (g/d) and decreased (P &amp;lt; 0.05) relative DMI (%BW) in the final part of the trial, when the animals were getting closer to the harvesting date. Lambs had lower (P &amp;lt; 0.05) DMI of BGH diets than Hi-A diets from d-42 to d-63 and Low-A diets from d-49 to d-56. The G:F ratio was not affected by the diet but decreased (P &amp;lt; 0.05) from the middle to the end of the trial. Corn cobs are valuable as alternative roughage for feedlot lambs, with intake and growth performance comparable to BGH.

Influences of timing of liver abscess control and early metabolizable amino acid supplementation on feedlot growth-performance and digestive function of calf-fed Holstein steers

Our objective was to examine the influence of timing of liver abscess control and early rumen-protected AA supplementation on cattle growth performance (Exp. 1) and digestive function (Exp. 2), and related responses on liver abscess incidence and AA supply to the small intestine of feedlot steers. In Exp. 1, a total of 200 calves were used in a 321-d experiment. Four strategies for liver abscess control using virginiamycin (VM; 16 mg of VM/kg of diet DM, Phibro Animal Health) were used: (1) 0% VM; (2) VM supplementation during the initial 168 d; (3) VM supplementation during the final 153 d; and (4) VM supplemented continuously for 321 d. During the initial 168-d feeding period, 2 levels of rumen-protected Met and Lys (Smartamine ML: SML; 0 vs. 0.6% DM basis, Adisseo) were supplemented across VM treatments in a 2 × 4 factorial arrangement. In Exp. 2, 4 Holstein steers (382 ± 23 kg) with cannulas in the rumen and proximal duodenum were used in a 4 × 4 Latin square design to evaluate treatment effects on digestion. Cattle growth performance was not affected ( P ≥ 0.18) by VM supplementation strategy. Moreover, VM supplementation did not affect ( P ≥ 0.10) carcass characteristics. Liver abscess incidence was low (4%) and not affected ( P ≥ 0.62) by supplementation strategy. Supplemental VM did not affect characteristics of ruminal and total-tract digestion ( P ≥ 0.27). Supplementation of SML during the first 168 d decreased ( P = 0.02) DMI during the last 153 d of the experiment, and tended to decrease ( P = 0.07) overall (321-d) DMI. Smartamine ML supplementation did not affect ( P ≥ 0.11) ADG, G:F, carcass characteristics, percentage of abscessed liver, or characteristics of ruminal and total-tract digestion. Timing of VM supplementation did not influence cattle growth performance or incidence of liver abscess, which was low (4%) regardless of VM treatment. Protected Met and Lys supplementation increased Met or Lys supply to the small intestine. However, MP and AA supplies of the basal diet, alone, were apparently adequate to achieve expected growth performance.