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.

Performance and plasma concentration of metabolites in transition dairy cows supplemented with vitamin E and fat

The objective of this study was to evaluate the effects of vitamin E（VE; 1 500 or 3 000 international units（IU） d^（-1）） and fat（2% of dry matter calcium salt of soybean oil） supplementation during the transition period on feed intake, milk yield and composition and blood metabolites of dairy cows. 48 multiparous Holstein cows were randomly assigned into one of four treatments in a 2×2 factorial arrangement of vitamin E and supplemental dietary fat during the transition period. Treatments were： 1） 1 500 IU d^（-1） vitamin E without fat supplementation（1 500VE-F）; 2） 1 500 IU d^（-1） vitamin E with fat supplement（1 500VE＋F）; 3） 3 000 IU d^（-1） vitamin E without fat supplementation（3 000VE-F）; and 4） 3 000 IU d^（-1） vitamin E with fat supplement（3 000VE＋F）. Dietary treatments were initiated at approximately 28 d before expected calving dates and continued through 28 d postpartum. Dry matter intake（DMI） was unaffected（P〉0.05） by prepartum treatment. Regardless of vitamin E supplementation, DMI was greater（P〈0.01） in fat-supplemented cows compared with un-supplemented cows（19.60 vs. 18.45 kg d^（-1）; SEM=0.42） during the postpartum period. Energy balance and body weight were not affected（P〉0.05） by treatments. Postpartum diets had no significant effect on milk yield or milk composition. Plasma concentrations of non-esterified fatty acids, glucose, and insulin were not affected（P〉0.05） by treatments. Regardless of vitamin E supplementation, plasma β-hydroxybutyrate concentration was greater（P〈0.05） in fat-supplemented cows compared with un-supplemented cows during the postpartum period. These results showed no indication of positive effects on lactation performance associated with vitamin E and dietary fat supplement in transition cows.