Yeast supplementation alters the performance and health status of receiving cattle123

The objective of this experiment was to determine the effect of yeast supplementation on the performance and health of newly weaned receiving cattle. Weaned crossbred steers (n = 184; initial BW = 203 ± 1 kg) were blocked by BW and randomly assigned to pen (4 pens/block; 5 to 6 animal/pen). Pens within a block were assigned randomly to 1 of 4 treatments (9 pens/treatment): 1) control (CON; no yeast); 2) live yeast (LY; 5 g/d per animal live yeast), 3) yeast cell wall (YCW; 5 g/d per animal yeast cell wall); 4) LY + YCW (5 g/d per animal LY and 5 g/d per animal YCW). Daily DMI was recorded and individual BW was collected every 14 d for 56 d. Data were analyzed using a randomized complete block design with the fixed effect of treatment and random effect of block. A subset of 24 steers (n = 6/treatment) was used on d 38 for a lipopolysaccharide challenge. Calves were fitted with jugular catheters and indwelling rectal-temperature measuring devices that measured rectal temperature. Cumulative DMI increased (P = 0.05) for the LY, YCW, and LY + YCW treatments compared with CON (6.02, 5.96, 5.89, and 5.47, kg/d, respectively). Before lipopolysaccharide challenge, CON calves had higher rectal temperature compared with LY + YCW (P ≤ 0.01) and LY (P ≤ 0.04) calves. Peak cortisol concentrations after lipopolysaccharide challenge were 26.5 ng/mL greater (P ≤ 0.04) in CON calves compared with LY + YCW calves. Results indicate that yeast supplements increased DMI and could improve cattle health during the receiving period.