The Inf luence of Subc linical Hypocalcemia on Production and Reproduction Parameters in Israeli Dairy Herds

A large percentage of mature dairy cows experience some degree of hypocalcemia during the first days post-calving. In some cases calcium concentrations decline to levels that disrupt neuromuscular function, resulting in the clinical syndrome known as parturient paresis or milk fever. Post-parturient hypocalcemia is divided into clinical and subclinical forms. It has been established that cows suffering from clinical milk fever are susceptible to a variety of secondary conditions, however to the best of the authors’ knowledge there has been no evaluation of the impact of the subclinical form on production and reproductive parameters. The objective of this study was to investigate the association between subclinical hypocalcemia and postparturient disorders, production and reproductive parameters in Israeli dairy herds. Blood results for corrected calcium concentrations were analyzed from 634 mature cows from 5 farms. The subclinical hypocalcemic cows produced 3.2, 2.7 and 1.9 kg more milk in the first three milk recordings than the normocalcemic cows. Subclinical hypocalcmic cows did not show an increased risk for post-parturient diseases nor compromised reproduction parameters in comparison to normocalcemic cows. It was concluded that there was no negative impact of subclinical hypocalcemia on production and reproductive parameters in Israeli dairy cows after parturition.