Abstract #T155

# T155
Supplementation of dairy cows with a blend of direct-fed microbes: Performance and digestion.
L. N. Resende1, R. B. Silva2, R. A. N. Pereira3,2, M. N. Pereira*1,2, 1Universidade Federal de Lavras, Lavras, MG, Brazil, 2Better Nature Research Center, Ijaci, MG, Brazil, 3Empresa de Pesquisa Agropecuaria de Minas Gerais, Lavras, MG, Brazil.

Probiotics (PBT) may improve diet digestibility and lactation performance of dairy cows. This experiment evaluated the effect of a liquid supplement containing a blend of viable lactic acid bacteria, spore forming bacteria, and yeast (S. cerevisiae) cultured in consortium (Global Saúde, Brazil/SCD Probiotics, USA) on digestion, intake, and lactation performance of dairy cows. Twenty-six Holstein cows (185 ± 141 DIM) were individually fed a standard TMR for 14 d and treatments control or PBT (3.5 mL/kg of TMR DM) for 56 d, in a covariate adjusted randomized block design with repeated measures over time. The PBT increased DMI (23.5 vs 22.5 kg/d. P < 0.01, SEM 0.37) and tended to increase the yields of milk (30.0 vs 29.4 kg/d. P = 0.06, SEM 0.50) and lactose (+ 60 g/d. P = 0.09). Energy-corrected milk to DMI ratio was reduced by PBT (1.25 vs 1.31. P = 0.02, SEM 0.033). Milk solids concentration and yield did not differ (P ≥ 0.28). Cows fed PBT tended to have higher BCS (3.02 vs 2.91. P = 0.08, SEM 0.039), but BW did not differ (641 kg. P = 0.27). The PBT tended to reduce the total-tract digestibility of the non-fibrous OM (81.2 vs 84.1%. P = 0.08, SEM 1.11) whereas starch (90.7%) and NDF (48.4%) digestibilities did not differ (P ≥ 0.20). Molar proportion of butyrate in ruminal fluid tended to be reduced by PBT (9.4 vs 10.4%, P = 0.06, SEM 0.40) as well as total protozoa concentration (P = 0.10). The acetate to propionate ratio (3.1. P = 0.89) and the ruminal microbial yield estimated by the daily urinary allantoin excretion (P = 0.21) did not differ. The PBT reduced the proportion of daily intake in the morning (35.1 vs 40.4%. P = 0.02, SEM 1.52) and increased the proportion in the afternoon (45.9 vs 41.9%. P = 0.03, 1.23). Rumination and ingestion behaviors did not differ (P ≥ 0.16). The PBT reduced blood urea-N at 0900 h (P = 0.01) and tended to reduce at 1630 h (P = 0.06) and 2300 h (P = 0.09), but did not affect milk urea-N (18.6 mg/dL, P = 0.47, SEM 0.44). The PBT induced a greater increase in DMI than in milk yield, decreasing feed efficiency, and had effects on digestibility and ruminal fermentation profile.

Key Words: probiotic, direct-fed microbes, yeast