Supplementation of nicotinic acid to prepartum Holstein cows increases colostral immunoglobulin G, excretion of urinary purine derivatives, and feed efficiency in calves

We evaluated the effects of incremental levels of unprotected nicotinic acid (NA) supplementation prepartum (0, 16, 32, or 48 g/d; CON, 16NA, 32NA, and 48NA, respectively) on colostrum yield and composition and cow and calf performance. Previous research indicated that 48 g/d of NA prepartum increased colostrum IgG concentration. Exact mechanisms for this increase are not clear. The effects of NA supplementation to prepartum cows on growth and performance of their calves have not been studied. Thirty-six multiparous Holstein cows housed in a tie-stall barn were blocked by expected calving date and randomly assigned to treatments at 4 wk prepartum. Blood samples were collected 3 times weekly for analysis of nonesterified fatty acids, ketones, and IgG. Urine samples were also collected 3 times weekly for analysis of creatinine and purine derivatives. Colostrum was collected within 90 min after parturition. Calves were removed from their dams before suckling, weighed within 30 min of birth, and received 4 L of maternal colostrum. The 38 calves born were blocked based on treatments of dams. All calves were fed 449 g dry matter (DM) of milk replacer (19.3% crude protein, 19.5% fat, DM basis) and a textured starter (41% starch, DM basis) at 2 d of age until weaning at 42 d, with water available ad libitum. Feeding NA resulted in linear decreases in DM intake in cows, but colostrum yield was not affected. Yield of metabolizable energy (ME) tended to change cubically, decreasing from control (CON) to 16NA, increasing from 16NA to 32NA, and decreasing from 32NA to 48NA. Concentration of IgG, protein, ash, and solids increased linearly with NA. Concentration of ME showed a tendency to increase quadratically with NA. Yield of IgG, fat, protein, and solids content increased quadratically with NA, while allantoin and total purine derivatives increased linearly. Calf 24-h IgG and apparent efficiency of absorption were not affected by NA. Calf ME intake from colostrum tended to increase quadratically with NA, but calf starter intake was not affected. Feed efficiency of calves increased quadratically with NA. Calf average daily gain changed cubically with NA, decreasing from CON to 16NA, increasing from 16NA to 32NA, and decreasing from 32NA to 48NA. Hip width gain, body length gain, and final body length changed cubically with NA, decreasing from CON to 16NA, increasing from 16NA to 32NA, and decreasing from 32NA to 48NA. Calf blood concentrations of ketones increased qu