The Effect of Including a Yeast Culture Containing Essential Oils in Receiving Cattle Diets on Growth Performance and Health

Due to the increased risk of bacterial resistance to antibiotics and the endemic incidence of bovine respiratory disease (BRD) among growing and finishing cattle, alternative strategies must be developed to improve the health of cattle. The objective of this study was to evaluate the use of a supplement containing a yeast culture and an essential oils blend (YEO) on the health and growth performance of stocker calves at high risk for BRD. Crossbred male beef calves (n = 185) received on two separate dates were used in a 42-d study. Within each truckload, calves were stratified by body weight and arrival castration status (steer or bull) and assigned to 1 of 8 pens (10 to 12 calves/pen). Pens were assigned randomly to either 1) a corn-distillers’ grain-soybean meal-based supplement with no YEO (CON) or 2) the CON supplement with the addition of YEO with a target intake of 2.5 g/calf daily. Calves were observed daily for signs of clinical BRD and deemed morbid if presenting symptoms and a rectal temperature of ≥40°C. Body weights were recorded. Supplementing YEO for the duration of the 42-day trial did not affect body weights (P = 0.98). Morbidity rates (P ≥ 0.1752; CON = 45%, YEO = 46%) and day of antibiotic administration (P ≥ 0.2186) were also not significant. Overall, the inclusion of this YEO did not improve overall growth performance or incidence of BRD in high-risk beef calves within this 42-day receiving period; however, further investigation is needed for future product formulations.