In the United States, >60% of colostrum does not meet the industry standards of ≥50 g of IgG/L. Ingestion of high quality colostrum is imperative for survival of the newborn calf, as it has little to no circulating immunoglobulins (Ig) at birth. Calves that do not absorb enough Ig to obtain successful passive transfer have an increased risk of morbidity and mortality, decreased average daily gains, and produce less milk in the first and second lactations. Previously, supplementing 48 g/d of nicotinic acid (NA) to prepartum dairy cows 4 wk before expected calving date increased Ig concentration of colostrum by 18%. The objective of this study was to determine the effects of incremental levels of NA (0, 16, 32 or 48 g/d) on Ig concentration in colostrum and subsequent effects on the pre-weaned calf. Thirty-six multiparous Holstein dairy cows were blocked by expected calving date and randomly assigned to 1 of 4 treatments 4 wk prepartum. The NA was mixed with 40 g of corn meal and top dressed onto the total mixed ration (TMR), fed once daily. Within 90 min of parturition, the calf was removed, colostrum was harvested and weighed and an aliquot was taken for IgG determination via radial immunodiffusion (RID) assay. Calves were weighed and fed 8 pints of maternal colostrum. Blood samples were collected from calves via jugular vein at 0 and 24 h of age for analysis of IgG concentration via RID. Calves remained on study until weaning at 6 w old. Results are shown in Table 1. These results indicated that supplementing NA to prepartum dairy cows improves the overall quality of colostrum. Table 1. Effects of supplementing incremental levels (0, 16, 32 or 48 g/d) of nicotinic acid to prepartum dairy cows

Item	Treatment (g/d)				SEM	P-value
0	16	32	48	Linear	Quad
IgG, g/L	72.7	87.4	81.1	94.7	5.7	0.02	0.91
Colostrum yield, L	11.4	11.6	12.3	7.7	1.5	0.13	0.11
IgG yield, g	822.1	919.1	1004.2	676.7	127.2	0.54	0.1
Protein, %	13.5	15.1	14.8	15.8	0.9	0.11	0.76
Fat, %	4.5	7.3	6.9	5.7	0.95	0.47	0.03
Solids, %	22.5	26.4	25.8	26.1	1.2	0.05	0.12
Ash, %	1.03	1.15	1.22	1.24	0.04	<0.01	0.25
Lactose, %	3.3	2.9	3	3.3	0.3	0.94	0.13
24-h calf serum IgG, g/L	24.9	27.4	28.3	27.7	2.6	0.42	0.53
Apparent efficiency of absorption	37.5	35.6	38.2	32.3	3.2	0.33	0.51