Abstract
Various clinical and blood biochemical parameters were examined during the transition period in multiparous Holstein cows to evaluate the relationship between nutritional conditions and the reproductive efficiency. Cows with delayed postpartum estrus (determined by the number of days before the first artificial insemination) had elevated prepartum urinary ketone body level, lower ruminal ingesta volume (RV) at 3 weeks postpartum and lower body condition scores (BCS) at 2 and 3 months postpartum. Blood biochemistry profiles of these cows showed elevated prepartum serum BUN, elevated postpartum NEFA and lower postpartum Ca and iP. In cows with longer open periods, BCS was higher prepartum but lower at 3 months postpartum. These cows had lower RV at 3 weeks postpartum. The blood biochemistry of these cows revealed lower prepartum glucose, higher postpartum NEFA and lower postpartum T-CHO levels. These results suggested that food intake and the nutrient status during the transition period play an important role for the reproductive efficiency of cows.
