The relationship between colostrum quality, passive transfer of immunity and birth and weaning weight in neonatal calves

Calves are born almost agammaglobulinemic and thus need an adequate amount of good quality colostrum to avoid failure of transfer of passive immunity. The quality of colostrum is influenced by several factors such as the volume of colostrum produced, collection time, the concentration of immunoglobulins, breed, the age of dam, and mastitis events in the previous lactation. In this study, we evaluated the relationship between colostrum quality, serum total protein (TP), birth, and weaning weight of the calf. Seventy-three calves born in the same farm were included in the study. Three liters of colostrum were administered to the calves as soon as the calf could drink while the other 3 L was administered 8 h later. Immediately after birth, and at 60 days of age, each calf was weighed. Colostrum was evaluated after calving by a qualified operator using an optical Brix refractometer. Twenty-four hours after birth, 10 mL of blood was collected from each calf in order to evaluate the serum TP using a digital refractometer. The relationship between colostrum quality, serum TP, birth and weaning weight was analyzed using a mixed linear model. Colostrum quality increased with parity; serum TP increased in association with an increase in the Brix percentage of the colostrum administered to the calves. Data indicated that heavier calves had a lower TP at 24 h of age than lighter calves under the same colostrum transfer protocol of 6 L of quality colostrum in 12 h. Serum TP (g/dL) decreased continuously in all calves from 8.267 by 0.032 x kg of birth weight. The birth weight of the calves could influence the quantity of colostrum necessary to achieve the same level of TP, so heavy calves should be fed more. Further studies would be necessary in order to evaluate the mechanism of IgG absorption in the gut of calves with different body weight