337 Supplementation of a Kaolin and Yeast-Based Feed Additive on Performance of Feedlot Cattle

Abstract

Abstract The objective of this project was to examine the effectiveness of feeding a kaolin and yeast-based feed additive on the performance of feedlot cattle. Seventy-five steers (initial BW; 545 ± 42.4 kg) were blocked by BW and randomly allocated into 25 blocks of 3 steers (n = 25 per treatment) in a randomized complete block design with 3 treatments including control, low (10 g/day) and high (15 g/day) kaolin and yeast-based feed additive (FA) supplementation. The steers were fed a finishing diet consisting of 7% corn silage, 1% straw, and 92% corn-based concentrate (DM basis). The duration of the feeding period was 120 days. Supplementation of high grain finishing diet with FA did not affect feed intake (average, 12.4 kg/d), final BW (average, 768 kg), averaged daily gain (average, 1.77 kg/d), carcass traits, and abscessed livers. However, increasing the feeding of FA (0, 10, 15 g/d) to finishing steers linearly (P = 0.05) improved feed efficiency from 0.139 to 0.143 and 0.148 kg gain/kg feed and linearly (P = 0.06) improved net energy for maintenance from 2.05 to 2.10 and 2.15 Mcal/kg and net energy for growth from1.39 to 1.43 and 1.47 Mcal/kg, respectively. Fecal IgA concentration linearly (P = 0.06) increased from 15.0 to 22.7 and 30.1 µg/g with increasing FA addition, suggesting an improvement in nutrient absorption, and potentially better gut health. The increasing addition of FA also linearly (P = 0.03) increased plasma lipopolysaccharide binding protein (LBP) concentration from 46.3 to 56.2 and 64.7 µg/mL but decreased blood total antioxidants from 0.282 to 0.251 and 0.204 mM. These results suggest that the addition of FA may support gut health.