480 The effect of parity on the quality of colostrum, internal parasite load, and postnatal development of Holstein calves

Abstract This research aimed to associate the effect of the parity number of the mother on the transfer of immunity, internal parasite load, and weaning weight of the female progeny. Calves that receive sufficient and good quality colostrum shortly after birth present improved passive immunity, vital for optimum calf health and future production. Management practices and the parity of the dam can influence colostrum composition, leading to an unsuccessful transfer of passive immunity and an increased incidence of infectious agents, which increases diarrhea and, thus, morbidity or mortality in newborn calves. The study included 90 animals, Holstein cows and their female progeny that were distributed into three groups according to the dam parity: first (n = 15 + 15), second (n = 15 + 15), and third (n = 15 + 15) parity. Immediately after birth, birth weight was recorded, and colostrum immunoglobulins (IgG) were determined by colostrometer and refractometry. The chemical composition (fat, protein, and non-fat solids) of the colostrum was determined using a milk analyzer (Ekomilk, Milkana KAM 98-2A, Satara Maharashtra) according to the manufacturer for cow milk. The calves consumed 10% of their birth weight of colostrum from their respective mother. Fecal samples were collected at 0 and 30 d of age and assessed for internal parasites (coccidia). Our preliminary results indicate that calves from dams from third parity were heavier at birth (P 0.001; Table 1). The specific gravity of the bovine colostrum was similar among groups (P 0.05). IgG concentration in colostrum tended to differ among groups by the refractometry (P = 0.08; Table 1), but not by colostrometer (P 0.05; Table 1). The density and protein content in colostrum differed among groups, favoring dams from third parity (P 0.05; Table 1). Fat content in colostrum was greater in dams from first parity (P 0.01; Table 1); but not non-fat solids (P 0.05; Table 1). The internal parasite load and incidence of coccidia at 30 d of age did not differ among groups (P 0.05). Our preliminary conclusions indicate that the fat content in colostrum was greater in first-parity dams than in third-parity dams, perhaps due to a dilution effect. The difference in birth weight is possibly due to maternal body weight. The greater weight at birth, IgG content in colostrum and the better colostrum quality from third-parity dams led to healthier calves at 30 d of age. More research is needed to elucidate if these conditions remain up to weaning and in their first insemination.