Document Type : Research Paper
Author
Assistant Professor, Animal Sciences, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran
Abstract
Objective: The objective of this study was to evaluate the effect of feeding a close-up premix on the incidence of retained placenta and other metabolic disorders, milk yield, and reproductive performance of Holstein dairy cows.
Methods: A total of 190 multiparous Holstein cows (Farm 1 = 94 cows, Farm 2 = 96 cows) with similar parity, body condition score, and previous lactation milk yield were enrolled in the study 21 days before the expected calving date. The cows were randomly assigned to one of two dietary treatments: cows fed the herd’s close-up diet (control group) and cows received a premix, which replaced 7.5% DM of the basal diet (Power Close). The premix contained protein supplements, macro and micro minerals, vitamins, and additives. The sex and weight of calves were determined immediately after calving, and the amount of colostrum produced at the first milking was recorded. Milk yield and composition were recorded monthly at each milking within 150 DIM, and milk samples were collected monthly to measure milk composition. The incidence of metabolic disorders including dystocia, retained placenta, milk fever, ketosis, displaced abomasum, metritis, clinical endometritis, and culling were recorded within 60 DIM. Reproductive factors such as calving interval to first insemination, pregnancy rates at first and second insemination, pregnancy rate, number of inseminations per pregnancy, and open days were recorded.
Results: The results of this study indicated that feeding Power Close during the close-up period significantly reduced the incidence of retained placenta (P < 0.05) and ketosis (P 0.05). Additionally, the incidence of metritis and culling tended to decrease in cows fed Power Close compared to the control group. However, the incidence of other metabolic disorders, including dystocia, milk fever, displaced abomasum, and endometritis was not significantly affected. Colostrum yield during the first milking (P 0.05), milk yield (P < 0.05), and 4% fat-corrected milk yield (P 0.05) were higher in cows fed Power Close compared to the control group. However, milk fat content was lower in the Power Close group than in the control group (P < 0.05). Calf birth weight and reproductive parameters, including the number of inseminations per conception, conception rate in the first and second inseminations, and pregnancy rate up to 150 days in milk were not affected by Power Close supplementation. However, the interval to first insemination and days open were reduced in cows fed Power Close compared to those fed the control diet (P < 0.05).
Conclusion: The findings of this study indicate that feeding Power Close during the transition period can effectively reduce the incidence of retained placenta, metritis, and culling within the first 60 days of lactation, while also increasing colostrum and milk production. However, despite its positive effect on the average days open, it did not significantly impact pregnancy rate.
Keywords
)