A fat based rumen protection technology post-ruminally delivers a B vitamin complex to impact performance of multiparous Holstein cows

Our previous research demonstrated that milk production of early lactation dairy cows benefits from postruminally delivered B vitamins in addition to those supplied in rumen microbes. In this study, our objective was to determine effects of supplementation of a complex of ruminally protected B vitamins (BV), using a fat based rumen protection technology, of biotin, pantothenic acid, folic acid, cyanocobalamin and pyridoxine, to dairy cows through 200 days in milk (DIM) on reproductive performance through 200 DIM, as well as milk production and composition through 180 DIM. Multiparous Holstein cows calving between November 2007 and April 2008 were assigned to one of two treatments as they moved from a common fresh pen to one of four early lactation pens at 22 ± 2.1 DIM. Two pens were fed the early lactation control diet (C) and two were fed the same diet with BV supplementation. Cows were observed for heat daily at the morning ‘lock’ and bred each morning by artificial insemination. Pregnancy was diagnosed by rectal palpation and yields of milk and milk composition were measured monthly. A total of 949 cows, 448 C and 501 BV, provided data for statistical analyses of reproduction and production response parameters. Body condition score (BCS) was determined in a subgroup of 200 cows (i.e., 50/pen) at 40 and 100 DIM. Dry matter (DM) intake was calculated on a pen basis in four discrete time blocks of 21 d each. First service conception rate was higher with BV supplementation 42 d after insemination (358 cows/1000 cows versus 406 cows/1000 cows; P=0.03), which was maintained at 150 (334 cows/1000 cows versus 381 cows/1000 cows; P=0.04) and 200 DIM (334 cows/1000 cows versus 381 cows/1000 cows; P=0.06). However because cumulative pregnancy rate at 150 and 200 DIM was not impacted by BV feeding, it is clear that cows became pregnant sooner, but that more cows did not become pregnant, through 200 DIM with BV supplementation. Cows in the BV group were 20% less likely (P=0.046) to be culled through 200 DIM, but the incidence of mastitis was not influenced by treatment. Supplementation with BV tended to reduce (P=0.058) DM intake (26.0 kg/d versus 25.6 kg/d) but had no impact on milk (44.5 kg/d versus 45.0 kg/d) or milk component production through 180 DIM. There were no treatment differences in BCS change between 40 and 100 DIM. Supplementation of this novel ruminally protected BV complex positively effected aspects of reproductive performance, while reducing culling in these early lactation high producing multiparous dairy cows.