Milk Yield and Blood Metabolite Profile in Late Pregnancy in Lori Ewes Receiving Diets Containing Undegradable Protein Sources

An experiment was conducted to investigate the effects of supplementing Lori ewes with rumen-undegradable protein (RUP) in late pregnancy on their performance and that of their lambs. Milk yield and blood metabolite profile were measured. Forty pregnant ewes were used in a completely randomized design trial with four treatments: 1) a basal diet (control); 2) with a supplement of 5% fishmeal; 3) with a supplement of 5% extruded soybean and 4) with a supplement combining both sources. Supplementation started 30-days before the estimated parturition date. Dietary inclusion of fish meal significantly improved body weight at lambing compared to the other groups (P<0.05). Lambs of ewes fed diets supplemented with rumen undegradable protein (RUP) were heavier at birth and weaning compared to other groups (P<0.05). Soybeans, of the combined supplement improved the colostrum concentration of IgG in postpartum ewes (P<0.05). Diets containing extruded soybeans resulted in milk with higher milk urea nitrogen content than the control diet (P<0.05). Serum concentration of glucose was significantly decreased in ewes fed diets containing RUP pre-partum (P<0.05), while post-partum glucose concentration was only decreased in ewes fed diets containing fish meal without or with extruded soybeans (P<0.05). Plasma concentration of beta-hydroxybutyric acid (BHBA) and non-esterified fatty acid (NEFA) were significantly decreased in the treated groups compared to the control group in post-partum ewes (P<0.05).