Nicotinic Acid and Serum Metabolite Concentrations of Lactating Dairy Cows Fed Supplemental Niacin

The effect of supplemental niacin on production and metabolite changes associated with early lactation were measured. Differences of milk production between treatments were not apparent, but serum nicotinic acid concentrations remained higher for those cows fed niacin (12 g/day). Changes of serum metabolites did occur when cows received a single oral dose of 12 or 120 g niacin. Significant alterations of nicotinic acid, free fatty acids, beta-hydroxybutyrate, blood urea nitrogen, serum glutamic-oxalacetic-transaminase, sodium, and chloride occurred within 24 h after initiation of treatment. These metabolites returned to basal concentrations within 60 h after administration.