The effects of oral nicotinic acid to prepartum of late lactation dairy cow

Nicotinic acid (NA) has reduced lipolysis, altered milk components, and ruminai environment. Experiment 1 used 3 farms, and 300 cows to investigate effects of NA fed prepartum on postpartum blood metabolites and milk components. Nicotinic acid increased milk protein (P=0,07) and fat percent (P=0.02) of multiparous cows at the first test day postpartum for farm 1. Direct comparisons could not be made at farms 2 and 3. This study indicates that effects of NA on milk components are not maintained once supplementation ceases. Experiment 2, utilizing 4 late lactation Holstein cows in a 2x2 Latin square design, investigated the effects of NA on ruminal protozoa, and production parameters. Nicotinic acid tended to reduce non-esterified fatty acids (NEFA) (P=0.07). Diplodiniinae increased when NA was added to a grass silage diet (GS), but decreased with a corn silage diet (CS). This study indicates that NA affects the ruminai environment, and depresses lipolysis.