PSVIII-26 - Utilizing Megasphaera elsdenii probiotic to improve the performance of crossbred Holstein x Angus calves

This study evaluated the effect of an oral probiotic bolus (Megasphaera elsdenii NCIMB 41125; Lactipro Advance®, MS Biotec, Wamego, KS) on the performance of crossbred Holstein x Angus calves. Thirty-one calves (45.3 ± 7.1 kg; 8.2 ± 2.0 d old) were enrolled in a 76-day randomized block trial in two blocks. This study was conducted at the University of Kentucky Large Animal Unit between August, 2020 and April, 2021. Calves were assigned to one of three probiotic treatments: no probiotic (ME₀), single dose of probiotic on day 15 (ME₁₅), or probiotic administration on day 15 and 39 (ME₁₅₊₃₉). Calves were individually housed and had ad libitum access to water and a pelletized calf starter (18% CP, 2.5% fat). Calves were fed 7 L/d of milk replacer (Cows Match Warm Front, Land O Lakes, MN; 1L, 150 g/L) divided into two equal meals until day 41. On day 42, milk allowance was reduced in half and then weaned on day 56. Grain orts were weighed daily and grain intake was calculated for each calf. Individual body weights were measured weekly. A mixed linear model determined the effect of treatment on total grain dry matter intake (total DMI), total weight gain (TWG), average daily gain (ADG), and feed conversion ratio (FCR). Manual stepwise backward elimination retained predictors with a P-value < 0.30 of the factors block, treatment, age and weight at enrollment, and if treated with antibiotics. Calves receiving the M. elsdenii bolus had greater TWG (ME₀=53.57±5.83, ME₁₅=72.52±6.71, ME₁₅₊₃₉=77.51±5.00 kg; P = 0.01), greater ADG (ME₀=0.73±0.08, ME₁₅=0.99±0.09, ME₁₅₊₃₉=1.05±0.07 kg/d; P = 0.01), and tended to have greater total DMI (ME₀=72.24±10.49, ME₁₅=95.20±12.07, ME₁₅₊₃₉=105.36±9.01 kg; P = 0.06) throughout the study. FCR did not differ between treatments (ME₀=0.79±0.04, ME₁₅=0.78±0.04, ME₁₅₊₃₉=0.76±0.03 kg; P = 0.84). Overall, strategic pre-weaning intervention of a M. elsdenii bolus improved the performance of crossbred Holstein x Angus calves.