Formation and transfer of passive immunity in Santa Ines sheep: effect of feeding and the number of lactations

Abstract

The supply of colostrum with high quality immune to the newborn animals is essential to ensure the healthiness, reducing mortality and morbidity in the herd, ensuring thus greater productive efficiency. However, the formation of colostrum can be influenced by conditions associated with the mother. The colostrum of the first milking and feeding of antinutritional factors, such as gossypol present in cottonseed, for example, may interfere with the protection potential and antioxidant status of mammary secretions. Thus, this project aims to evaluate the training and transfer of passive immunity in primiparous and multiparous Santa Inês sheep fed cottonseed, as well as the antioxidant potential of the blood and mammary secretions. Santa Ines sheep will be separated into two groups: 16 primiparous and 16 multiparous and then randomly assigned to two treatments: CO - concentrated without cottonseed; CA - concentrate with cottonseed. The diets will be provided at 15 hours and the hay in the morning and afternoon, promoting leftover 10% of roughage. The trial period will be divided into adaptation (15 days), pre-breeding season (1 month), breeding season (two months), pregnancy (five months) and breastfeeding / weaning (2 months). Blood samples will be collected from the jugular vein of the sheep and lambs once a month during the trial, being conducted additional sampling in sheep and lambs during the peripartum and postpartum, respectively. Colostrum samples will be collected immediately after birth, as well as samples of subsequent mammary secretions up to 15 days after delivery. The immune potential in the blood of sheep and lambs will be analyzed by the concentration of immunoglobulins and serum proteins, including lysozyme, transferrin, and C-reactive protein, while the antioxidant potential by superoxide dismutase, glutathione peroxidase and catalase activity and the by the oxygen radical absorption capacity. In addition to the concentration of immunoglobulins, total protein, activity of antioxidant enzymes and ORAC value, the concentration of lactoperoxidase, lactoferrin and vitamin C will be determined in the mammary secretions of sheep. The variables will be analyzed as repeated measurements over time, the effects of number of lactations (primiparous or multiparous) and feeding regimen (with and without cottonseed) will be applied to plots and repeated measures over time to subplots. (AU)