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This study evaluated the effects of Sweet Bran (SB) and wet distillers grains with solubles (WDGS) in the diet alone or in combination on physically effective neutral detergent fiber (peNDF), ruminal pH, and rumination behavior of finishing beef cattle. For this study, 455 steers (373 ± 15.5 kg) were allocated to 48 pens in a randomized complete block design. Treatments ( n = 12 pens per treatment) were one of four steam-flaked corn-based diets containing no corn-milling products (CON), 20% WDGS (WDGS20), 20% SB (SB20), or 20% SB and 10% WDGS (COMBO). Within each pen, two steers were randomly selected to receive an indwelling ruminal pH bolus to quantify ruminal pH and a 3-axis accelerometer tag to measure rumination for the first 92 d of the study. Diet samples were collected weekly to determine particle size, neutral detergent fiber (NDF) concentration, and peNDF. Physically effective NDF was calculated using both the proportion of particles > 4.0 mm (peNDF 4 .0 ) and the proportion of particles > 8.0 mm (peNDF 8.0 ). The percentage of particles > 4.0 mm was greatest ( P < 0.01) for CON, intermediate for SB20, and least for WDGS20 and COMBO. Both NDF ( P < 0.01) and peNDF 4.0 ( P < 0.01) were greatest for COMBO, intermediate for WDGS20 and SB20, and least for CON. The percentage of particles > 8.0 was greatest ( P < 0.01) for CON, intermediate for WDGS20 and SB20, and least for COMBO, but peNDF 8.0 did not differ ( P = 0.40). A diet × day interaction ( P < 0.01) was observed for daily rumination minutes per kg of DMI, NDF, peNDF 4.0 , and peNDF 8.0 . A diet × hour interaction ( P < 0.01) was observed where CON cattle spent less time ruminating at 0800 and 1000 h in a 24 h period. Daily ruminal pH was greatest ( P < 0.01) for COMBO, intermediate for SB20 and WDGS20, and least for CON. A diet × hour interaction ( P < 0.01) was also observed for circadian ruminal pH, where pH was least for CON from 0800 to 1800 h. Relationships between peNDF, rumination behavior, and ruminal pH observed in this study suggest that SB and WDGS similarly enhance rumen buffering capacity when steam-flaked corn is replaced in the diet., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science.)

The study objective was to determine the effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on serum chemistry, complete blood count, and fecal Salmonella spp. count in high-risk beef cattle during a 56-d feedlot receiving period and the subsequent finishing period. Four truckload blocks of crossbred beef bulls ( n = 300) and steers [ n = 84; total n = 384; average initial body weight (BW) = 220 ± 16.2 kg] were sourced from regional auction markets and assigned randomly to treatments arranged in a 2 × 2 factorial. Blood samples were collected from two bulls nearest to the median BW on arrival in each pen ( n = 96) and fecal samples were collected from cattle in block 3 ( n = 96). The generalized complete block design consisted of 12 pen replications per treatment with pen as the experimental unit. Treatments were: 1) negative control (CON); 2) 13 g per animal daily of prepared B. subtilis PB6 product (CST); 3) 450 ppb dry matter (DM) chromium propionate (CHR); and 4) 13 g per animal daily of prepared B. subtilis PB6 product and 450 ppb DM chromium propionate (CST + CHR). Treatments were top dressed in feed bunks daily using 0.45 kg per animal ground corn carrier immediately following feed delivery. Data were analyzed using mixed models with repeated measures. Day affected all serum chemistry variables ( P ≤ 0.03) except total CO 2 ( P = 0.34) and all complete blood count variables during receiving ( P ≤ 0.02) except percentage basophils ( P ≥ 0.12). During the overall receiving period, serum calcium was decreased ( P = 0.02) by CHR. Cattle fed CHR had greater total leukocyte count ( P = 0.04) and neutrophil count ( P = 0.02) during the overall receiving period. Fecal Salmonella spp. count was markedly reduced in cattle fed CST on day 28 ( P = 0.01) and overall ( P = 0.07). Overall, these data provide metabolic and hematologic insight into the unique challenges presented by lightweight, high-risk feeder cattle. Notably, CST was found to be effective in mitigating fecal enumeration and presumably replication of Salmonella spp. in the gastrointestinal tract., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

The study objective was to determine the effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on health, growth performance, and carcass characteristics of high-risk beef cattle during a 56-d feedlot receiving period and the subsequent finishing period. Four truckload blocks of crossbred beef bulls ( n = 300) and steers [ n = 84; body weight (BW) = 220 ± 16.2 kg] were sourced from regional auction markets and assigned randomly to treatments arranged in a 2 × 2 factorial. The generalized complete block design consisted of 12 pen replications per treatment with pen as the experimental unit. Treatments were: 1) placebo control (CON); 2) 13 g per animal daily of B. subtilis PB6 (CST); 3) 450 ppb dry matter (DM) chromium propionate (CHR); and 4) 13 g per animal daily of B. subtilis PB6 and 450 ppb DM chromium propionate (CST + CHR). Treatments were top dressed in feed bunks daily using 0.45 kg per animal ground corn carrier immediately following feed delivery. Data were analyzed using mixed models. During the receiving period, dry matter intake (DMI) increased ( P ≤ 0.03) for CST during each interim period. Overall receiving period daily DMI was 0.35 kg per animal greater for CST ( P = 0.01). Cattle fed CST had greater ( P ≤ 0.06) BW on days 14, 28, and 56. Likewise, average daily gain (ADG) was improved for CST from day 0 to 14 ( P = 0.04) and for the overall receiving period (days 0-56; P = 0.04). From days 0 to 14, CST tended ( P = 0.08) to increase gain:feed. During the finishing period, CHR reduced ( P = 0.02) final BW and ADG (day 56 to final; P = 0.01) and ADG was less for CHR over the entire feeding period (day 0 to final; P = 0.03). The main effect of both CST ( P = 0.02) and CHR ( P = 0.03) decreased the overall treatment rate for bovine respiratory disease (BRD), and CST reduced overall antimicrobial treatment cost by $3.50 per animal compared to CON ( P = 0.03). Hot carcass weight (HCW) decreased ( P = 0.01) in cattle fed CHR. The percentage of edible livers tended to increase (CST × CHR; P = 0.08) in the CST treatment. Feed intake and growth performance outcomes during the receiving period were improved by CST but not CHR supplementation. However, both CST and CHR supplementation decreased the BRD morbidity rate. During the finishing period, performance and HCW were reduced in cattle supplemented with CHR., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Available energy plays a critical role in the initiation and maintenance of an immune response to a pathogen, a process that is further altered by activation of the stress system. This study was designed to determine the effect of an acute vs chronic stress model on the metabolic response to vaccination in naïve beef steers. Steers ( n = 32; 209 ± 8 kg) were blocked by body weight (BW) and randomly assigned to one of three treatments: 1) Chronic stress (CHR), 0.5 mg/kg BW dexamethasone (DEX) administered i.v. at 1000 h on day 3 to day 0; 2) Acute stress (ACU), 0.5 mg/kg BW DEX administered i.v. at 1000 h on day 0 only; or 3) Control (CON), no DEX. On day -4, steers were fitted with jugular vein catheters and moved into individual bleeding stalls in an environmentally-controlled facility. Blood samples were collected at -74, -50, and -26 h, at 0.5-h intervals from -4 to 6 h, and at 12, 24, 36, 48, and 72 h relative to vaccination with a combination vaccine (Pyramid 5 + Presponse SQ, Boehringer Ingelheim Animal Health USA, Duluth, GA) at 1200 h on day 0. Data were analyzed by the MIXED procedure of SAS specific for repeated measures. There was a treatment × time interaction ( P < 0.001) for serum glucose concentrations. Specifically, glucose concentrations increased at -50 h in CHR steers and at 1200 h in ACU steers and remained elevated through 72 h postvaccination period in these two treatments compared to CON steers. The change in nonesterified fatty acid ( NEFA ) concentrations relative to baseline values was affected by treatment and time ( P < 0.001) such that the change in NEFA was greater in CHR (0.06 ± 0.01 mmol/L), followed by CON (-0.01 ± 0.01 mmol/L) and ACU steers (-0.04 ± 0.01 mmol/L). There was a tendency ( P = 0.08) for a treatment × time interaction for change in serum NEFA concentrations. Serum urea nitrogen (SUN) was affected by treatment and time ( P < 0.001) such that SUN concentrations were greatest in CHR (12.0 ± 0.1 mg/dL) followed by ACU (10.4 ± 0.1 mg/dL) and CON steers (9.6 ± 0.1 mg/dL); however, the treatment × time interaction was not significant ( P = 0.12). These data demonstrate that activation of the stress and immune axes using an acute or chronic stress model can increase energy mobilization prior to and following vaccination in naïve steers, potentially affecting available energy needed to mount an adequate antibody response to vaccination., (Published by Oxford University Press on behalf of the American Society of Animal Science 2019.)

Two treatments were evaluated in heifers to determine the effects of a yeast supplement on immune and metabolic responses to a combined (tandem viral-bacterial) respiratory disease challenge. Thirty-two beef heifers (325 ± 20.1 kg BW) were selected from a larger population previously assigned to one of two treatments: Control (CON), receiving no yeast supplement in the diet, or yeast (YST), CON diet plus a combination live yeast (2.5 g·heifer -1 ·d -1 ) and yeast cell wall (2.5 g·heifer -1 ·d -1 ) supplement (Phileo Lesaffre Animal Care, Milwaukee, WI). Heifers were maintained on treatments for 31 d prior to the challenge. On day -3 all heifers were fitted with an indwelling vaginal temperature recording device, received an intranasal challenge with 2 × 10 8 plaque-forming units of bovine herpesvirus-1 (BHV-1), and placed in outdoor pens. On day 0, all heifers were fitted with an indwelling jugular catheter, challenged intratracheally with an average dose of 3.0 × 10 7 colony-forming units (cfu) of Mannheimia haemolytica in 100 mL media, and were transferred into individual stanchions in an enclosed, environmentally controlled barn. Whole blood samples were collected at -72 h and at 0, 2, 4, 6, 8, 12, 24, 36, 48, 60, and 72 h (hematology) and at 0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 24, 36, 48, 60, and 72 h (serum isolation) relative to M. haemolytica challenge (0 h). Data were analyzed using the MIXED procedure of SAS specific for repeated measures with fixed effects of treatment, time, and the treatment × time interaction. Vaginal temperature and cortisol concentrations were similar between treatments ( P ≥ 0.39). Although total leukocyte count following BHV-1 challenge was similar between treatments ( P = 0.21), there was a tendency ( P = 0.07) for CON heifers to have greater neutrophil counts than YST heifers. Serum haptoglobin concentration was similar between treatments ( P = 0.13). Heifers in the YST treatment had similar serum glucose concentrations ( P = 0.25) and decreased serum concentrations of urea nitrogen compared to CON ( P = 0.03). Dietary treatment did not affect serum nonesterified fatty acid concentrations ( P = 0.37). Nasal lesion score severity (0-4) tended ( P = 0.07) to be decreased in YST compared to CON (2.5 vs. 3.19 ± 0.26), while water intake tended to be increased in YST ( P = 0.06). Feeding a yeast supplement had little effect on the acute-phase response but improved metabolic outcomes in heifers during a respiratory disease challenge., (Published by Oxford University Press on behalf of the American Society of Animal Science 2018.)

One hundred and eighty beef bulls (BW = 337 ± 10.9 kg) were blocked by BW (6 blocks) and assigned randomly to one of three treatments on day 0: 1) INJ; received 1 mL (100 mg Zn) of a Zn solution in each testis, 2) BAN; received blood-restrictive rubber band placed upon the dorsal aspect of the scrotum, and 3) BUL; bulls with testicles remaining intact. Cattle were grouped by weight block in a randomized complete block design (three treatment pens/block and 10 cattle/pen) and harvested by block on three separate dates when blocks reached similar BW and visual subcutaneous fat thickness depth. Striploins were removed from the left carcass sides, vacuum packaged and aged for 14 d, and then frozen at -20 °C. Frozen striploins were sliced into 2.54-cm-thick steaks and remained frozen until analyses. Steaks ( n = 3/animal) were used to assess consumer acceptability via consumer taste panel ( n = 152 panelists), Warner-Bratzler shear force, percentage cook loss, and cooked color values. Data were analyzed using mixed model procedures; pen was the experimental unit for all dependent variables. Hot carcass weights and LM area were greater ( P < 0.01) for the INJ and BUL treatments compared with BAN. Mean yield grade did not differ between treatments ( P = 0.12), although BAN carcasses had smaller LM area ( P < 0.01) than BUL or INJ carcasses. Percentage of USDA Choice or better carcasses was greater ( P < 0.01) for BAN than INJ and BUL treatments. Consumer panelists detected a difference in perceived tenderness; BAN steaks had greater ( P = 0.02) tenderness scores than BUL steaks, whereas INJ steaks were intermediate. Panelists rated juiciness of BAN steaks greater ( P < 0.01) than either BUL or INJ steaks. Panelists rated beef flavor greater ( P = 0.01) for BAN and BUL steaks than INJ steaks. Overall acceptability was greater ( P < 0.01) for BAN compared with INJ steaks, whereas BUL steaks were intermediate. Percentage cook loss of striploin steaks ( P = 0.47) and Warner-Bratzler shear force values ( P = 0.11) did not differ. Cooked color lightness ( L *) and redness ( a *) values were not affected ( P ≥ 0.23) by treatment. Striploin steaks from BAN and BUL treatments had greater ( P = 0.02) yellowness values ( b *) than INJ steaks. The ratio of red-to-brown (630:580 nm) of cooked striploin steaks was greater ( P = 0.05) for INJ than either BAN or BUL treatments. Carcass and palatability outcomes of INJ were more similar to BUL than BAN, suggesting limited efficacy of INJ in mature beef bulls at feedlot entry., (© The Author(s) 2018. Published by Oxford University Press on behalf of the American Society of Animal Science.)

For decades, we have relied upon visual observation of animal behavior to define clinical disease, assist in breeding selection, and predict growth performance. Limitations of visual monitoring of cattle behavior include training of personnel, subjectivity, and brevity. In addition, extensive time and labor is required to visually monitor behavior in large numbers of animals, and the prey instinct of cattle to disguise abnormal behaviors in the presence of a human evaluator is problematic. More recently, cattle behavior has been quantified objectively and continuously using advanced technologies to assess animal welfare, indicate lameness or disease, and detect estrus in both production and research settings. The current review will summarize three methodologies for quantification of cattle behavior with focus on U.S. beef production systems; 1) three-axis accelerometers that quantify physical behavior, 2) systems that document feeding and watering behavior via radio frequency, and 3) triangulation or global positioning systems to determine location and movement of cattle within a pen or pasture. Furthermore, advances in Wi-Fi and radio frequency technology have allowed many of these systems to operate remotely and in real-time and efforts are underway to develop commercial applications that may allow early detection of respiratory or other cattle diseases in the production environment. Current challenges with commercial application of technology for early disease detection include establishment of an appropriate algorithm to ensure maximum sensitivity and specificity, reliable and repeatable data collection in harsh environments, cost:benefit, and integration with traditional methodology for clinical diagnosis. Advanced technologies have also allowed cattle researchers to determine temporal variance in behavior or variability between experimental treatments. However, these data sets are typically very large and challenges exist regarding statistical analysis and reporting., (© The Author(s) 2018. Published by Oxford University Press on behalf of the American Society of Animal Science.)