Reproductive performance and milk production of grazing cows parenterally supplemented with minerals and vitamins in the transition phase

The aim of this study was to evaluate the effects of injectable mineral and vitamin supplementation on reproductive and productive performance in grazing cows. Seventytwo cows were assigned to the following groups: (1) control (CON, n=18); (2) injectable mineral supplementation (SIM, n=18); (3) injectable vitamin supplementation (SIV, n=18); and (4) SIMV (SIM + SIV) (n=18). IM supplementation was done 20 days before calving, on the day of calving and 30 days after delivery. SIM, SIV and SIMV treatments resulted in a decreased calving interval to first artificial insemination and improved milk production. The injection of vitamins or minerals did not differ from the control group in number of assisted calving, retained placenta, interval from calving to conception and pregnancy rate according to the number of inseminations.