Slow Release Rbst Administration During the Transition Period on Performance and Blood Cell Counts of Dairy Cows

Abstract

This study aimed to evaluate recombinant bovine somatotropin (rbST) supply on feed intake, performance, serum metabolites, and blood cells count of transition cows. Thirty pregnant Holstein cows (607 ± 28.6 kg of body weight) were randomly allocated to one of the following treatments: 1) Control (CON), without rbST supply; and 2) rbST: 250 mg of slow release rbST (Lactotropin, Elanco Animal Health, USA) supplied every 14 d from 28 d of the expected calving date until 28 d of lactation. rbST group had increased dry matter intake during the post partum period and higher body condition score in both pre- and post-partum periods compared to CON. rbST treatment increased milk yield and milk fat content. Although no effects were observed on serum metabolites before parturition, rbST increased post-partum serum concentrations of glucose, cholesterol, and ionized calcium, and decreased serum concentration of triacyglyceride. rbST had minor effects on complete blood cell count, which included reduced neutrophil counts. In conclusion, this study supports that rbST supply during transition period improves performance of dairy cows that is partially related to improvements in metabolism.