The Impact of Season, Parity, and Volume of Colostrum on Holstein Dairy Cows Colostrum Composition

The objectives of the study were to assess colostrum quality and nutrients in dairy cows in Isfahan, Iran, and to determine the effects of calving season, parity, and volume of first colostrum on colostrum quality. Colostrum samples were collected over the period January-December, from 365 Holstein dairy cows from 12 dairy farms and analyzed for their IgG, IgM, total solids, fat, protein, lactose, Ca, and P concentrations. The IgG and IgM contents were measured to be 35.8 ± 17.6 and 5.8 ± 3.8 mg/mL, respectively. Mean percentages of total solids, fat, protein, and lactose in the samples were 27.2 ± 5.8, 4.6 ± 3.4, 18.5 ± 4.9, and 2.0 ± 0.9, respectively while calcium and P concentrations were 2.69 ± 0.9 and 2.02 ± 0.88 g/kg. Colostral IgG and IgM concentrations were found to be higher during the winter months. Calving season affected lactose, Ca, and P concentrations as evidenced by the higher colostral lactose percentages in cows calved in the fall but higher calcium and P concentrations in those calved in the summer. Parity had no significant effects on IgG and IgM concentrations. However, a decreasing trend was observed in Ca and P concentrations with increasing parity. Volume of first milking colostrum did not have any effect on colostral composition. The findings of this study indicate that colostrum quality may be affected by calving season.