Abortion Effects on Production, Reproductive Performance, and Health of Dairy Cattle

In order to investigate the consequences of abortions on dairy cattle performance, records from the software of seven dairy farms in Argentina were studied between February 2015 and June 2019. Two randomly chosen groups were compared in terms of aborted cows ( n = 264) and normal calving cows without abortion ( n = 245). Milk liters at 305 days (L/305), total milk production, days in milk, open days, insemination number, calving intervals, number of postabortion reproductive health disorders, and number of cows that continued in the farm, culled, died, or were slaughtered were recorded. The parameters were taken in the lactation in which the abortion occurred in aborted cows and in that with the same characteristics (lactation number and date) in the normal calving cow animals and in their corresponding subsequent lactations of the 2 groups. As a result, higher L/305 production in normal calving cows was found in the first lactation ( p = .013) and last lactation ( p = .003) than that of aborted cows. In first lactation, the aborted cow group showed longer ( p = .001) days in milk, more ( p = .0001) open days, higher ( p = .0001) insemination, and longer calving interval ( p = .0001) than those of the normal calving cows. In first lactation, aborted cows had a higher ( p = .0001) probability of suffering from, respectively, reproductive health disorders (OR = 5.7, 95% CI, 4.07-8.06) and culls plus deaths/slaughters for reproductive reasons (OR = 27.5, 95% CI, 11.7-64.5) than normal calving cows. In last lactation, aborted cows suffer more ( p < .05) infertility, mastitis, and abortion problems than normal calving cows. Only, 59.4% of the aborted cows finished their last lactation and calved, while 85.1% of the normal calving cows cows did. These results show the serious negative effects of abortions on milk production, reproductive performance, and the health of dairy cows.