Megasphaera elsdenii dosed orally at processing to reduce BRD and improve gain in high-risk calves during the receiving period

Abstract

Two experiments were conducted to determine the effect of oral administration of a Megasphaera elsdenii -containing product at initial processing on health and performance of high-risk calves during the receiving period. In Exp. 1, 1294 crossbred steers (BW=262±1.3 lb; 119±0.59 kg) were assigned to a control (CON) group (no M. elsdenii [ME]) or a ME treatment group (100-mL oral dose of M. elsdenii) at arrival processing. All steers were fed a 55% concentrate receiving diet ad libitum, and observed daily for signs of bovine respiratory disease (BRD). There were no differences in dry matter intake, average daily gain, feed efficiency, morbidity, or mortality (P≥0.34). There were significantly fewer first-time relapses in the ME group (P=0.02); however, second-time relapses were similar between treatment groups (P≥0.14). In Exp. 2, crossbred calves (504 bulls, 141 steers; BW=443±10.8 lb or 201±4.9 kg) were allocated to treatment using the same procedures as Exp. 1. Calves in Exp. 2 were fed the same diet as in Exp. 1, and observed daily for clinical signs of BRD. Calves dosed with M. elsdenii had greater dry matter intake, average daily gain, and feed efficiency (P≤0.05) than CON calves. Morbidity due to BRD was 31% less for calves administered M. elsdenii compared to the CON group (P=0.02). First- and second-relapses were not different between treatments (P>0.70), but BRD therapeutic treatment cost/calf was decreased (P<0.05) from $19.70 to $17.06 for calves in the ME treatment compared to CON steers. While there were no relevant clinical or economic differences between treatment groups in Exp. 1, dosing calves in Exp. 2 with M. elsdenii at processing improved performance and decreased the incidence of BRD.