Protein metabolism and the resumption of ovarian cyclicity post partum in high yielding dairy cows

The influence of the energy and protein metabolism on early post-partal ova rian function was studied under fietd conditions. In total, 138 high yieldi ng dairy cows from three well-managed herds in Belgium were involved. Durin g the first 75 days after calving, energy and protein metabolism was follow ed by repeated measurements of metabolites in the blood plasma. Ovarian fun ction was monitored by a combination ofhvice weekly progesterons determinat ion in milkfat, rectal palpation, and heat detection. Metabolic profiles we re described for cows with different postpartal ovarian function to analyze the impact of both the energy and protein metabolism on the occurrence of ovarian dysfunctions during the preservice postpartum period. Cows that res umed ovarian activity after 50 days post partum had significantly lower ure a and albumin plasma levels during the immediate postpartum period than cow s cycling before 50 days post partum. A significant role of the energy or p rotein metabolism on the occurrence of another important ovarian dysfunctio n, a prolonged luteal phase, could not be demonstrated. A prolonged luteal phase is mainly caused by puerperal problems and not by metabolic influence s.