Colostrum Quality as an Indicator of the Immune Status of Cows and Its Association with Peripartum Disease Risk in a Grazing Dairy Herd

This study aimed to evaluate the association between colostrum quality, as indicative of the immune status of the cows, and peripartum disease risk occurrence in a herd of grazing dairy cows. A prospective cohort study was conducted on a grazing dairy farm with 3000 Holstein milking cows from 15 March 2022 to 15 March 2023. Multivariable binary logistic models evaluated the association between colostrum quality (expressed in Brix grades as a continuous predictor) and the risk of peripartum diseases (including dystocia, stillbirth, retention of fetal membranes, metritis, and clinical endometritis). We found that colostrum quality was negatively associated with the risk of dystocia (<i>p</i> = 0.02), stillbirth (<i>p</i> < 0.01), clinical endometritis (<i>p</i> = 0.02), and total peripartum diseases (<i>p</i> < 0.01). Conversely, colostrum quality was not related to the risk of retention of the placenta (<i>p</i> = 0.25) or metritis (<i>p</i> = 0.76). Additionally, we found that the calving season affected colostrum quality (<i>p</i> < 0.01). Conversely, parity number, dry period length, and milk yield in previous lactation did not affect it (<i>p</i> > 0.10). We concluded that colostrum quality, expressed in Brix grades, is negatively associated with peripartum disease risk in dairy cows and could be a useful indicator of the immune status of the cow.