Nicotinic acid (NA) has been shown to reduce lipolysis, alter milk components and the ruminal environment, and increase blood flow. Increased blood flow to the mammary gland during colostrogenesis might increase nutrients and immunoglobulin concentration of colostrum. Twenty-six multiparous Holstein cows were housed in a tiestall barn. Cows were blocked by expected calving date and randomly assigned to 1 of 2 treatments 4 wk prepartum: (1) 0g/d of NA (control, CON) or (2) 48g/d of NA (NA). Total mixed ration amounts fed and refused were measured daily to determine dry matter intake. Blood samples were collected from dams every Monday, Wednesday, and Friday from the coccygeal vein or artery and were analyzed for glucose, nonesterified fatty acids (NEFA), and β-hydroxybutyrate (BHB). Colostrum was collected and weighed within 90 min of parturition. Colostral immunoglobulin G (IgG) concentration was analyzed using radial immunodiffusion assay. Calves were removed from their dams before suckling and weighed within 30 min after birth. Calves received 3 L of a lacteal-based colostrum replacer that provided a total of 225.8g of IgG within 2h of birth. Calf blood samples were collected via jugular venipuncture at 0 and 24h of age and analyzed for IgG concentration and determination of apparent efficiency of absorption. Colostrum yield, dry matter intake, IgG yield, and fat and solids percentage of colostrum did not differ between treatments. Serum concentrations of glucose and BHB were not affected by treatment. We detected an effect of week on serum glucose concentrations at calving and on serum BHB concentrations at 1 wk postpartum. There was a treatment by week effect for serum NEFA concentrations at 1 wk postpartum, where cows that received NA prepartum had higher serum NEFA concentration than CON cows, indicating that a NEFA rebound occurred. No differences were observed for calf body weight, 0- or 24-h serum IgG concentration, or apparent efficiency of absorption. Supplementation of NA increased IgG concentration in colostrum from 73.8 to 86.8g/L. Results indicate that 48g/d of supplemental NA during the prepartum period improved colostrum quality.
