Effect of Oral Calcium Supplementation in Second Parity Lactating Dairy Cows: Animal Health,Performance and Reproduction

The present study was conducted to evaluate the effect of oral calcium supplementation in the postpartum period on milk production and composition, animal health  and reproduvtive performance. For this purpose, forty-two Holstein lactating cows were selected and divided into two groups: control (twenty-one cows, without any calcium bolus) and treatment group (twenty-one cows,43 g oral bolus immediately after calving). The results showed milk yield and composition (fat and protein), and milk somatic cell count were not affected by oral calcium bolus. The incidence of impending diseases in this group of cows such as metritis, mating and abomasum reversal in the experimental group was lower than animals that did not consume calcium bolus (odds ratio (OR) = 0.13). It is also worth noting that in the case of reproductive indices, the mean of open days in the treatment group decreased compared to the control treatment but was not statistically significant. There was no difference in body condition score at the time of insemination in the control and treatment groups (P <0.05) and the mean number of inseminations per pregnancy in the treatment group was not significant compared to the control treatment (P <0.05). In general, with proper nutrition management during the close up with diet DCAD controling, it is possible to pass the transfer cows without consuming calcium bolus, and also to avoid increasing costs.