PSIV-15 Effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on health, performance, and blood parameters of high-risk cattle during the feedlot receiving period. (5th December 2019) - Smock, Taylor M
Abstract: The objective was to determine the effects of Bacillus subtilis PB6 and/or chromium propionate supplementation on health, performance, and blood parameters in high-risk beef calves during a 56-day receiving period. Four truckload blocks of crossbred beef calves (n = 384; BW=220±16.2 kg) were 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/animal/d Bacillus subtilis PB6 (CLOSTAT®, Kemin Industries; CST); 3) 1 g/animal/d Cr propionate (KemTRACE® Chromium, Kemin Industries; CHR); and 4) CST+CHR. Treatments were top dressed in feed bunks daily using 0.45 kg/animal/d ground corn carrier. Blood samples were collected on days 0, 14, 28, and 56 for analysis of serum chemistry and complete blood count variables from a pen subset (n = 2/pen). Data were analyzed using MIXED and GLIMMIX procedures of SAS. The DMI was increased for CST during each interim period (P ≤ 0.03) and overall DMI was increased by 0.78 lb/animal/d for CST (P = 0.01). The CST supplemented cattle had greater BW on days 14, 28, and 56 (P ≤ 0.06). Likewise, ADG was improved for CST from day 0 to 14 (P = 0.04) and for the overall receiving period (P = 0.04). Main effects of CST (P = 0.02) and CHR (P = 0.03) decreased the percentage of calves treated for bovine respiratory disease (BRD). Morbidity was 28.0 and 39.9% for cattle with and without CST supplementation and 28.6 and 39.3% for cattle with and without CHR supplementation, respectively. Cattle fed CHR had increased (P ≤ 0.04) total leukocytes, neutrophils, serum aspartate aminotransferase and less (P = 0.02) serum calcium. Performance was improved by CST and BRD morbidity was less for CST and CHR.