The effect of vitamin and mineral complex used as bolus in pre and postpartum period on fertility parameters in cows

In this study, the effects of vitamin mineral bolus supplement applied to cows in the transition period and early postpartum period on reproductive performance were evaluated. Postpartum uterine involution, endometritis, ovarian functions and pregnancy rates after the first three inseminations were evaluated. The animal material used in the study consisted of 200 healthy Holstein cows with a lactation between 1- 3, with approximately 14 days remaining to the estimated birth date in the dry period. Cows were randomly divided into two equal groups with mean BCS of 3 and lactation mean of 1.5. In addition to the standard ration, the cows in the treatment group were given boluses containing vitamins and minerals 14 days before the expected delivery date and bolus administration was repeated 60 days later. Only standard ration was given to the cows in the control group. Cows in the treatment and control groups were controlled by rectal examination, endometritis and ovarian examination on the postpartum 30th day. Insemination was applied to the cows that showed heat and were suitable for insemination. On the 7th, 14th, 21st and 28th days after insemination, blood was drawn to measure the progesterone value. Ovarian examination was performed with USG on the 21st and 28th days of inseminated cows, and the presence of CL was evaluated and pregnancy examination was performed on the 30th day. No significant difference was found between the mean BCS at the time of birth and the postpartum 30th day (P>0.05). When the vaginal discharge was scored, it was seen that the presence of endometritis in the control group was higher than in the treatment group (P<0.05). As a result of rectal examinations performed on the postpartum 30th day, no significant difference was found between the administration and control groups in terms of uterine involution (P>0.05). When cows with active CL in their ovaries (P>0.05) and cows with cystic ovarian degeneration (P>0.05) were compared, no statistical difference was found. On the 21st and 28th days after insemination, the presence of active CL was found to be statistically significantly higher than the control group (P<0.05). Progesterone levels were higher in the control group than in the treatment group, but it was not statistically significant (P>0.05). In the pregnancy examinations performed by USG on the 30th day after insemination, it was determined as 32% vs 13% after the first insemination, 45% vs 16% after the second insemination, and 54% and 20% after the third insemination in the treatment and control groups, respectively. In conclusion, although a positive effect of boluses containing vitamins and minerals, used orally in the transition period and early postpartum period, on uterine involution on the postpartum 30th day could not be determined, it was determined that it decreased the incidence of endometritis and significantly increased the pregnancy rates after the first three inseminations.