Abstract
Crossbred beef calves [n = 240, body weight (BW) = 257 ± 3.5 kg] were obtained on 3 dates (block, 8 pens/block) and were assigned randomly to 1 of 2 treatments: 1) CON = top-dress supplement (0.11 kg/d) with no direct-fed microbial, 2) BOV = top dress supplement (0.11 kg/d) that provided 113.5 mg/d of a direct-fed microbial (BOVAMINE DEFEND®, 2 g/d, Lactobacillus animalis, Propionibacterium freudenreichii, 1 × 109 CFU2/g). Study objective was to determine the effect of BOV on growth performance and health when included in the diet. From d 0 to 14, ADG was improved (P = 0.05) for BOV compared to CON as ADG were 0.89 and 0.74 kg, respectively. Overall ADG over the 43-d receiving period was not different (P = 0.65); numerically there was a 0.03 kg improvement in BOV (0.90) compared to CON (0.87 kg). The percentage of calves treated for clinical BRD with the first treatment antibiotic (florfenicol) was not affected (P = 0.40); however, was numerically reduced by 6.8% for BOV (61.2% morbidity) compared to CON (68.0% morbidity). There was a trend for the percentage of calves treated with a second antibiotic (enrofloxacin) to be reduced (P = 0.17) for calves supplemented with BOV (9.1%) compared to CON (15.2%). There was also a trend for the mean total number of antibiotics used to be reduced (P = 0.16) in BOV compared to CON. Overall antibiotic cost, was not affected (P = 0.23) by BOV supplementation; however, numerically there was a $3.27 reduction in antibiotic cost for BOV compared to CON. The supplementation of BOV in high-risk calves may improve growth performance and health, reduce clinical BRD in calves after first treatment and could potentially reduce the use of antibiotics in calves at a high risk for BRD during the receiving period.
PSXIV-35 Evaluation of a direct fed microbial in newly received, high-risk beef calves and the subsequent impact on performance and health