Effects of Monensin on Dry Matter Intake, Milk Production and Healthy of Transition Holstein Dairy Cows

Effects of the Monensin (Monensin sodium 10%, 350 mg/cow daily) on dry matter intake, milk production and healthy during the transition period and early lactation were determined in 360 Holstein cows. Cows were divided into groups of 2 depending on calving date. A total of 100 Holstein cows and heifers were assigned to a control group (n = 50) and administered 350 mg/cow daily of Monensin (n= 50). Cows had unlimited access to fresh water. However, no differences in dry matter intake between treatment groups were noted. Monensin significantly affected daily milk yield (p< 0.05). Significant effects of Monensin supplementation were observed on disease incidence. The open days of Monensin group had a significant difference with the control group (p= 0.0211). The Monensin group, on average, was 16 days in open days less than the control group. The conception rate in the control and Monensin groups was 43.2% and 81.5% respectively (p= 0.0113). The pregnancy rate of Monensin group (34.6%) was significantly higher than the control group (28.4%) (p= 0.0100). Also on the calving to first insemination distance was higher in the control group compared with Monensin (p= 0.0317). Monensin supplementation decreased postpartum BHBA concentration. Results suggest that prepartum and postpartum administration of Monensin increase milk production and healthy and can have beneficial effects on reproductive performance during early lactation.