Evaluating the impact of Bovamine® on performance, nutrient digestibility, and digestive function in lactating dairy cows
Date
2018
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Delaware
Abstract
Two experiments evaluated the effect of a direct fed microbial (DFM) (Bovamine®®, Chr. Hansen, Hørsholm, Denmark) on performance and digestion of dairy cows. In Experiment 1 (Exp1), 30 multiparous cows (75 + 32 DIM) were assigned to one of two treatments fed for 10 weeks, BOV (3 x 109 CFU/d Bovamine ®) or CON (control, no Bovamine®). In Experiment 2 (Exp2), 6 ruminally cannulated cows (123 + 129 DIM) were assigned to a crossover design with two 6 week periods with the same treatments as Exp1 except that cows were fed a 23.8% starch diet during weeks 1–5 of each period then abruptly switched to a 31.1% starch diet for week 6. For both experiments, intake and milk yield were measured daily and milk samples were collected weekly. In Exp1, fecal grab samples were collected every 6 h on d 7 of week—1, 1, 2, 4, 6, 8, and 10, fecal consistency was scored, and fecal starch measured in composited daily samples. Composites from a subset of 7 cows per treatment were used to measure apparent total tract nutrient digestibility. In Exp2, rumen pH was continuously recorded during weeks 5–6. Rumen in situ digestibility was measured on week 5 day 7, week 6 day 1, and week 6 day 7. On those dates, rumen fluid and feces were collected every 6 h for rumen VFA, fecal pH, and fecal starch (composited by cow within day). Rumen and fecal microbiome samples were collected at one time point on these days. In Exp1, treatment did not affect intake, milk yield or composition, fecal score or fecal starch. BOV tended to increase starch digestibility compared to CON (98.74 vs. 98.46%, P = 0.051), but digestibility of other nutrients was unaffected. In Exp2, intake, milk yield, and milk composition were unaffected when evaluated over the entire study. However, during the abrupt switch to the high starch diet, milk fat yield was increased for BOV compared to CON (1.39 vs. 1.28 kg/d, P = 0.002) and milk fat percentage tended to increase (3.59 vs. 3.42%, P = 0.09). Treatment did not impact rumen pH, rumen VFA, in situ digestibility or the rumen and fecal microbiomes. Contrary to Exp1, BOV increased fecal starch compared to CON (2.49 vs. 2.03%, P = 0.02), and this was most evident during the high starch feeding. Overall, Bovamine®? modestly improved starch digestibility in Exp1 and increased milk fat during the high starch challenge in Exp2.