Effect of vanadium as vanadyl sulfate on milk yield, follicular dynamic, and some blood metabolites of Holstein dairy cows during late gestation throughout early lactation

The objective of this study was to investigate theeffect of supplemental vanadium (V) as vanadyl sulfate on milk yield, performance responses, nutrients total tract digestibility, follicular dynamics and some blood metabolites in late gestation and earlylactation of dairy cows. Thirty-two multiparous Holstein dairycows according to the expected calving date were randomly assigned to one of thefour groups. Treatments were supplementation of 0, 0.04, 0.08, and 0.12 mg of V as vanadyl sulfate/kg of BW0.75. Cows ovarian were synchronized on d 28-30 with Targeted Breeding. Vanadium supplement increased milk yield (P = 0.05). Vanadium supplementation could not affect dry matter intake, body weight, nutrients total tract digestibilities and BCS both before and after calving. Serum progesterone concentration decreased by increasing V supplementation (P = 0.001). Serum insulin and glucose concentrations for cows receiving 0.04, 0.08 mg of V as vanadyl sulfate/kg of BW0.75 were higher than those receiving 0.12 mg of V as vanadyl sulfate/kg of BW0.75 and control group (P = 0.01). The number of small and large follicles for cows receiving 0.04, 0.08 mg of V as vanadyl sulfate/kg of BW0.75 were higher than those receiving 0.12 mg of V as vanadyl sulfate/kg of BW0.75 and control group (P = 0.02 and P = 0.05 respectively). The numbers of total follicles were higher for cows receiving 0.04 mg of V as vanadyl sulfate/kg of BW0.75 than the others (P = 0.03). Overall, we concluded that vanadium could improve production, blood metabolites, and developmental dynamics of follicles in dairy cows.