Influence of BOVAMINE DEFEND Plus on growth performance, carcass characteristics, estimated dry matter digestibility, rumen fermentation characteristics, and immune function in finishing beef steers.

One hundred and eighty crossbred beef steers (406.0 ±â€…2.2 kg) were used to determine the impact of a novel direct-fed microbial (DFM) on growth performance, carcass characteristics, rumen fermentation characteristics, and immune response in finishing beef cattle. Steers were blocked by body weight (BW) and randomly assigned, within block, to 1 of 2 treatments (3 replicates/treatment: 30 steers/replicate). Treatments included: (1) no DFM (control) and (2) DFM supplementation at 50 mg ∙ animal-1 ∙ d-1 (BOVAMINE DEFEND Plus). All steers were fed a high-concentrate finishing diet and individual feed intake was recorded daily via the GrowSafe system. BWs were collected every 28 d. On day 55, 10 steers per pen were injected with ovalbumin (OVA). Jugular blood samples were collected from each steer on days 0, 7, 14, and 21 post injection. On day 112, the same steers were injected again with OVA and intramuscularly with a pig red blood cell solution. Jugular blood samples were collected from each steer on days 0, 7, 14, and 21 post injection. On day 124, rumen fluid was collected from 3 steers per treatment and used to estimate in vitro rumen fermentation characteristics. Equal numbers of steers per treatment were transported to a commercial abattoir on days 145, 167, and 185 of the experiment, harvested, and carcass data were collected. Initial BW was similar across treatments. On days 28 and 55, steers receiving DFM had heavier BW (P < 0.01) compared to controls. The average daily gain was greater in DFM-supplemented steers from days 0 to 28 (P < 0.01) and days 0 to 55 (P < 0.01) of the experiment compared to controls. Overall dry matter intake (DMI) was greater (P < 0.04) and overall feed efficiency was similar in DFM-supplemented steers compared to controls. Dressing percentage (P < 0.02) was greater in steers receiving DFM compared to controls. Antibody titers to injected antigens were similar across treatments. However, red blood cell superoxide dismutase activity was greater (P < 0.05) in DFM-supplemented steers compared to controls. In vitro molar proportions of isobutyric and butyric acid were greater (P < 0.01) and dry matter (DM) digestibility tended (P < 0.07) to be greater in rumen fluid obtained from steers supplemented with DFM. These data suggest that BOVAMINE DEFEND Plus supplementation improves growth performance during the initial period of the finishing phase, increases overall DMI and dressing percentage, and may impact antioxidant status in beef cattle.

The effect of breed, sex, and oral meloxicam administration on pain biomarkers following hot-iron branding in Hereford and Angus calves.

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.

Trace mineral source impacts rumen trace mineral metabolism and fiber digestion in steers fed a medium-quality grass hay diet.

Twelve Angus steers (BW 452.8 ± 6.1 kg) fitted with ruminal cannulae were used to determine the impact of trace mineral (TM) source on digestibility, ruminal volatile fatty acid (VFA) composition, ruminal soluble concentrations of Cu, Zn, and Mn, and relative binding strength of trace minerals located in the rumen insoluble digesta fraction. Steers were fed a medium-quality grass hay diet (DM basis: 10.8% CP, 63.1% neutral detergent fiber [NDF], 6.9 mg Cu/kg, 65.5 mg Mn/kg, and 39.4 mg Zn/kg) supplemented with protein for 21 d. Treatments consisted of either sulfate (STM) or hydroxy (HTM) sources (n = 6 steers/treatment) to provide 20, 40, and 60 mg supplemental Cu, Mn, and Zn/kg DM, respectively. Following a 21-d adaptation period, total fecal output was collected for 5 d. Dry matter (P < 0.07) and CP (P < 0.06) digestibility tended to be reduced, and NDF (P < 0.04) and acid detergent fiber (ADF) (P < 0.05) digestibility were reduced in STM- vs. HTM-supplemented steers. On day 6, ruminal fluid was collected at 0, 2, and 4 h post-feeding and analyzed for VFA. There were no treatment x time interactions for VFA. Steers receiving HTM had less (P < 0.02) molar proportions of butyric acid and greater (P < 0.05) total VFA concentrations than STM-supplemented steers. Steers were then fed the same diet without supplemental Cu, Zn, or Mn for 14 d. On day 15 steers received a pulse dose of 20 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either STM or HTM (n = 6 steers/treatment). Ruminal samples were obtained at 2-h intervals starting at -4 and ending at 24 h relative to dosing. There was a treatment x time interaction (P < 0.03) for ruminal soluble Cu, Mn, and Zn concentrations. Ruminal soluble mineral concentrations were greater (P < 0.05) for Cu at 4, 6, 8, 10, 12, and 14 h; for Mn at 4 and 6 h; and for Zn at 4, 6, and 8 h post-dosing in STM compared with HTM-supplemented steers. Copper concentrations were greater (P < 0.05) at 12 and 24 h and Zn concentrations in ruminal solid digesta were greater at 24 h in HTM-supplemented steers. Upon dialysis against Tris-EDTA, the percent Zn released from digesta was greater (P < 0.05) at 12 h (P < 0.03) and 24 h (P < 0.05), and the percent Cu released was greater (P < 0.02) at 24 h post-dosing in HTM steers when compared with STM-supplemented steers. Results indicate that Cu and Zn from HTM have low solubility in the rumen and appear to be less tightly bound to ruminal solid digesta than Cu and Zn from STM. The lower ruminal soluble concentrations of Cu and Zn in steers given HTM were associated with greater fiber digestibility.

Influence of Molybdenum in Drinking Water or Feed on Copper Metabolism in Cattle-A Review.

The majority of Mo research has focused on the antagonist effect of Mo, alone or in combination with elevated dietary S, on Cu absorption and metabolism in ruminants. Diets containing both >5.0 mg of Mo/kg DM and >0.33% S have been reported to reduce the Cu status in cattle and sheep. Therefore, due to the potential for inducing Cu deficiency, Mo and S concentrations in the diet should be monitored and kept within appropriate values. Elevated sulfate concentrations in drinking water can also be detrimental to livestock production, especially in ruminants. High concentrations of sulfate in water have been extensively studied in cattle because high-sulfate water induces polioencephalomalacia in ruminants. However, little research has been conducted investigating the impact of Mo in water on Cu metabolism in ruminants. Based on the limited number of published experiments, it appears that Mo in drinking water may have a lower antagonistic impact on the Cu status in cattle when compared to Mo consumed in the diet. This response may be due to a certain percentage of water bypassing the rumen when consumed by ruminants. Therefore, the objective of this review was to examine the impact of Mo in drinking water on cattle performance and Mo and Cu metabolism.