Post-lambing maternal effects in hair ewes fed omega-6 polyunsaturated fatty acids in the late gestation

Abstract

Soybean oil (SBO) is rich in omega-6 polyunsaturated fatty acids and its dietary supplementation during late gestation to ewes improves colostrum production and lamb pre-weaning growth; however, little is known about the long-term maternal effects after lambing. So, aim was to determine the effects of dietary inclusion level of SBO (0 [control], 30 and 60 g kg-1 dry matter) during late pregnancy on udder size, milk secretion, and dam metabolism during the first 60 d post-lambing. Thirty Katahdin x Pelibuey multiparous ewes (100 d of gestation) were blocked and randomly assigned within each block to three treatments. After lambing, ewes were fed the same lactation diet until 60 d post-lambing and study variables were measured on this period every 10 d. Solids non-fat in milk from control ewes were lower at day 10 and greater at day 20 compared to milk from SBO-fed ewes, although opposite effects were observed for lactose content on those days. Udder volume, depth and width increased linearly as the SBO level increased. Body status, physiological variables, milk production and serum analyte concentrations were unaffected by SBO. It was concluded that feeding hair ewes in late gestation with diets including SBO improves udder size, and solids non-fat and lactose content in milk, without affecting dam metabolism, during the post-lambing period.