Hot-iron branding uses thermal injury to permanently identify cattle causing painful tissue damage. The primary objective was to examine the physiological and behavioral effects of oral meloxicam (MEL), compared to a control, administered at the time of hot-iron branding in Angus and Hereford steers and heifers. The secondary objectives were to investigate breed and sex effects on pain biomarkers. A total of 70 yearlings, consisting of 35 heifers and 35 steers (Angus, Hereford, or Angus × Hereford), were enrolled in the study. Animals were blocked by sex, randomized across weight, and assigned to receive MEL (1 mg/kg) or a placebo (CON). Biomarkers were assessed for 48 h after branding and included infrared thermography (IRT), mechanical nociceptive threshold (MNT), accelerometry and a visual analog scale (VAS), and serum cortisol and prostaglandin E₂ metabolites (PGEM). Wound healing was assessed for 12 wk. Hair samples to quantify cortisol levels were taken prior to and 30 d post-branding. Responses were analyzed using repeated measures with calf nested in treatment as a random effect, and treatment, time, treatment by time interaction, breed, and sex as fixed effects. There was a treatment by time interaction for PGEM (P < 0.01) with MEL having lower values than CON at 6, 24, and 48 h (MEL: 18.34 ± 3.52, 19.61 ± 3.48, and 22.24 ± 3.48 pg/mL, respectively; CON: 32.57 ± 3.58, 37.00 ± 3.52, and 33.07 ± 3.48 pg/mL; P < 0.01). MEL showed less of a difference in maximum IRT values between the branded (2.27 ± 0.29 °C) and control site (3.15 ± 0.29 °C; P < 0.01). MEL took fewer lying bouts at 0–12 h (4.91 bouts ± 0.56) compared with CON (6.87 bouts ± 0.55; P < 0.01). Compared with Hereford calves, Angus calves exhibited greater serum but lower hair cortisol, greater PGEM, more lying bouts, and less healed wound scores at 3, 4, and 5 wk. Compared with heifers, steers exhibited lower PGEM, lower branding site and ocular IRT, higher MNT, and lower plasma meloxicam levels. Steers spent more time lying, took more lying bouts and had greater VAS pain, and more healed wound scores at 5 wk than heifers. Meloxicam administration at branding reduced branding and control site temperature differences and reduced lying bouts for the first 12 h. Breed and sex effects were observed across many biomarkers. Changes from baseline values for IRT, MNT, lying time, step count, VAS pain, and wound scoring all support that branding cattle is painful. Hot-iron branding uses thermal injury to permanently identify cattle causing painful tissue damage. The primary objective was to examine the effects of oral meloxicam (MEL), compared with a control, administered at the time of hot-iron branding in Angus and Hereford steers and heifers. The secondary objectives were to investigate breed and sex effects on pain biomarkers. A total of 70 yearlings, consisting of 35 heifers and 35 steers (Angus, Hereford, or Angus × Hereford), were enrolled. Animals were assigned to receive MEL or a placebo. Changes from baseline values for infrared thermography (IRT), mechanical nociceptive threshold, lying time, step count, visual analog scale score, and wound scoring all support that hot-iron branding cattle is painful and investigation into analgesic strategies is needed. MEL administration reduced IRT differences from the branding and control site and reduced lying bouts. Breed and sex effects were observed across a wide range of biomarkers and should be considered in future pain studies. The practicality of administering a nonsteroidal anti-inflammatory drug once at the time of branding is attractive. However, a multimodal approach using a combination of analgesics or longer acting analgesic option warrants further investigation to alleviate pain and discomfort caused by hot-iron branding.

Two experiments were conducted to examine the impact of trace mineral (TM) source on in vitro and in vivo solubility characteristics. Experiment 1: Hydroxy TM (HTM) and sulfate TM (STM) sources of Cu, Mn, and Zn were incubated separately in water for 24 h. Immediately after mixing, initial pH of each solution was greater (P < 0.03) for HTM compared to STM for all elements. Final pH tended to be greater for Cu (P = 0.09) and Zn (P = 0.07) from HTM compared to STM. Water solubility of Cu, Mn, and Zn from STM was greater (P < 0.01) than HTM sources. Experiment 2: Eight steers fitted with rumen cannula were blocked by body weight and randomly assigned to treatments. Treatments consisted of 10 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either STM or HTM sources. Steers were individually fed a cracked corn-corn silage-based diet. Treatments were top-dressed daily. Rumen contents were collected at 0, 2, and 4 h post-feeding on d 1 and 14. On d 15, strained ruminal fluid and particle-associated microorganisms were obtained. Zinc was more tightly bound (P = 0.01) to the digesta in HTM-supplemented steers compared to STM on d 14. These data indicate that TM source influences pH and solubility of Cu, Mn, and Zn in water and may affect rumen soluble Cu concentrations and binding strength of Zn to solid digesta.

Non-hormone-treated beef steers (n = 1625; 371 ± 8.4 kg) were used to determine the impact of a direct-fed microbial (DFM) on growth performance, carcass characteristics, health parameters, and economic outcomes in finishing beef cattle. Steers were blocked based on initial BW, sorted into three optimal marketing groups for each day of enrollment, randomly assigned to one of two treatments (12 replicates per treatment), and fed for an average of 133 days before harvest. Treatments included the following: (1) control (CON) and (2) 50 mg/head per day of a DFM (BDP) containing Lactobacillus animalis 506, Propionibacterium freudenreichii 507, Bacillus licheniformis 809, and Bacillus subtilis 597 (BOVAMINE DEFEND^® Plus). Steers were weighed in drafts by pen on a certified scale at closeout, and both pens within a block were harvested on the same day. Carcass characteristics and liver scores were collected upon slaughter. Data were analyzed as part of a completely randomized block design with the pen as the experimental unit. There was no difference in dry matter intake and final body weight between treatments. The BDP steers exhibited a lower number of total outs (deads and removed) throughout the experiment (p < 0.01). Average daily gain (ADG) tended to be greater (p < 0.06), and feed efficiency (p < 0.01) was greater, for steers receiving BDP. Although there were no statistical differences in hot carcass weight and quality grade between treatments, there was a lower incidence of liver abscess scores (p < 0.01) in the BDP steers. These data suggest that BOVAMINE DEFEND^® Plus supplementation improves growth performance during the finishing phase, reduces overall mortality, and improves feed to gain efficiency.

Two experiments were conducted to evaluate the effects of trace mineral (TM) source on: (1) nutrient digestibility and rumen fermentation characteristics, (2) rumen TM solubility, and (3) TM binding strength on ruminal digesta. In experiment 1, twelve cannulated Angus steers were adapted to a high-concentrate diet, blocked by body weight, and randomly assigned to dietary treatments consisting of 18, 40, or 90 mg of supplemental Cu, Mn, and Zn/kg DM, respectively, from either sulfate (STM) or hydroxy (HTM) sources. Following diet adaptation, total fecal and rumen fluid were collected over a 5 d period. Nutrient digestibility was not affected (p > 0.15) by TM source. Steers supplemented with HTM had greater (p < 0.05) ruminal molar proportions of propionate and lower (p < 0.05) molar proportions of butyrate compared to STM-supplemented steers. In experiment 2, steers received a single pulse dose of their respective TM treatments via the cannula. Ruminal samples were obtained at 2 h intervals from −4 to 24 h post-dosing. Ruminal-soluble Cu concentrations were greater (p < 0.05) for STM-dosed steers. Steers receiving HTM had greater (p < 0.01) Cu and Zn and lower (p < 0.01) Mn released from digesta compared to those receiving STM.

Six steers fitted with ruminal cannulae were used in a crossover design to examine the impact of direct fed microbial (DFM) supplementation on in vivo rumen fermentation characteristics and in vitro lactic acid clearance. Steers were fed a moderately high concentrate ^-1∙day^-1 of 4.45x 10¹⁰ CFU/g of Propionibacteria acidipropionici). Treatments were administered daily, directly into the rumen via the cannula as a single bolus dose at the time of feeding. Rumen contents were sampled two h post-feeding daily and analyzed for short chain fatty acids (SCFA). On d 7 and 14, rumen fluid was collected from all steers and subjected to an in vitro lactic acid clearance challenge. Lactic acid and SCFA concentrations were determined at 3, 6 and 9 h post incubation. After d 14, all cattle received the basal diet for 21 d. On d 22, treatment crossover was implemented and the experiment repeated. Animal was considered the experimental unit and data were analyzed as a crossover design using Proc Mixed in SAS. In vivo propionic acid concentrations were greater (P < 0.05) and total SCFA tended (P < 0.06) to be greater in rumen fluid from steers receiving DFM. D- and total lactic acid concentrations were lesser (P < 0.05) at 3 h post in vitro incubation for steers receiving DFM. D-, L+, and total lactic acid concentrations were similar between treatments at all other timepoints. In vitro propionic acid and total SCFA concentrations were greater (P < 0.05) and acetic acid concentrations lesser (P < 0.05) in steers receiving DFM. These data indicate that the DFM Propionibacteria acidipropionici, alters in vivo and in vitro rumen fermentation characteristics.

Eight individually fed fistulated steers (410 ± 10 kg) were used to investigate the impact of trace mineral source on rumen trace mineral solubility and in vitro fermentation characteristics. Steers were sorted by body weight, into two trace mineral (TM) treatment groups (n = 4/treatment). Treatments consisted of TM supplementation at 10 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either sulfate TM (STM) or hydroxy TM (HTM) sources. Steers were fed a diet balanced to meet the nutrient requirements (TMR) for lactation dairy cow. Dietary TM treatments were mixed with dried distillers grains and top dressed daily. Rumen contents were collected at 0, 2, and 4 h post feeding on d 1 and 14 of the experiment. Rumen samples were centrifuged at 1,500 × g for 15 min. The supernatant and the digesta pellet were frozen, separately, at −20°C for TM analysis. On d 15 of the experiment, approximately 500 g (wet weight) of rumen contents were collected from each steer 2 hours post-feeding. Strained ruminal fluid (SRF) was obtained by squeezing the rumen contents through 2 layers of cheese cloth. The retained digesta (150 g wet weight) was washed with 2.2 L pre-warmed McDougall’s buffer to remove particle associated microorganism (PAO). The SRF and the PAO were then filtered through 8 layers of cheesecloth, separately, and mixed at a ratio of 1:2 (SRF:PAO). The SRF:PAO mixture for each steer was incubated with the TMR containing HTM and a separate incubation with the TMR containing STM for 0, 12, and 24 h (3 replicate in vitro tubes/animal/TMR treatment) at 39°C under anaerobic conditions. After each incubation time, samples were centrifuged at 1,500 x g. The supernatant was removed and frozen at -20°C for VFA analysis. The digesta pellet was dried at 60°C and DM, NDF, and ADF digestibility determined. Data were analyzed as a completely randomized block design with individual animal as the experimental unit. There was a treatment x day x sample type interaction for rumen Zn (P < 0.04) and Mn (P < 0.03) concentrations. Zinc and Mn concentrations were greater in digesta and lesser in supernatant in STM compared with HTM supplemented animals. Rumen distribution of Cu was not impacted by TM source. In vitro molar proportions isobutyric acid were greater (P < 0.01) in HTM compared with STM supplemented animals, while the molar proportion of propionic acid were greater (P < 0.01) in STM supplemented animals. Total VFA concentration, molar proportions of acetic and propionic acid, and DM, NDF, and ADF digestibility were not impacted by dietary trace mineral source or rumen fluid source. These data may indicate that the source of trace mineral can influence trace mineral solubility in the rumen.