Use of a commercial probiotic supplement in meat goats1

Sixty-three Boer crossbred goats were used in 5 separate experiments (Exp. 1 to 5) to evaluate the effects of a commercial probiotic supplement on growth performance (Exp. 1 to 4), diet digestibility (Exp. 5), carcass traits (Exp. 3), and fecal bacterial populations (Exp. 4). Goats were either fed a commercially pelleted concentrate diet and supplemented with a commercial probiotic (PRO) that had shown anecdotal positive effects on goat growth and performance according to local goat producers, or they remained as controls. The dose of PRO used was within the labeled dose for sheep for all studies. For Exp. 1, goat BW and feed intake were measured and G:F was calculated every 7 d for 56 d. For Exp. 2 to 4, BW and feed intake were measured and G:F was calculated every 14 d. The first day of supplementation was considered d 0. Carcass traits were also collected at slaughter on d 57 for Exp. 3, and fecal samples were collected every 14 d for microbial culture for Exp. 4. For Exp. 5, which was a digestibility trial that lasted for 10 d, animals were placed in metabolic pens for collection of feces and orts. Growth performance of goats was not affected by probiotic supplementation, with the exception of performance in Exp. 2, in which ADG and G:F were improved (P < 0.03) in PRO goats compared with control goats on d 56 only (treatment x clay interaction; P < 0.05), averaging 0.21 + 0.02 kg/d for PRO goats and 0.11 + 0.02 kg/d for control goats for ADG and 0.17 ± 0.02 for PRO goats and 0.10 + 0.02 for control goats for G:F. Carcass weights and weights of fabricated cuts (shoulder, loin, leg, rack, shank, and total parts) as well as carcass length, leg circumference, loin eye area, and hackfat were not influenced by PRO supplementation. Apparent digestibilities of OM, DM, NDF, ADF, CP, and GE (on a DM basis) were similar for the PRO and control treatments. Fecal culture analysis of Escherichia coli and coliforms, Lactobacillus, and Bifidobacterium populations were not influenced by the PRO treatment. Overall, although the PRO treatment affected goat ADG and G:F in Exp. 2, no PRO treatment effects were noted on growth performance for Exp. 1, 3, arid 4. Furthermore, the PRO treatment did not affect diet digestibility, carcass traits, or fecal microbial populations in goats. In conclusion, no consistent benefits were noted from supplementing healthy, growing meat goats with PRO. [PUBLICATION ABSTRACT]