36 Impact of feeding different selenium (Se) sources to pregnant and lactating ewes on lamb Se enrichment and serum biochemistry profiles

Abstract Abstract: Introduction Global pre-weaning lamb mortalities have remained above 10%, a detriment to farm profits. Selenium (Se) is a trace mineral vital to several functions in sheep. Se supplementation during late pregnancy and lactation, particularly organic Se supplementation, may produce more robust lambs. Objective To determine how differences in maternal Se supplementation impact lamb health within 10 days postpartum (ppd 10). Methods Ewes (n = 110) were enrolled in a feeding trial from gestation day (gd) 110 to ppd 10, and supplemented with either no Se, 0.3 mg/day inorganic Se, or 0.3 or 0.6 mg/day organic Se. Lambs only received Se via maternal nursing. Lamb serum was collected on ppd 0, 2, and 10 to assess maternal transfer of Se, and muscle samples were collected on ppd 10 to assess lamb Se stores. Serum glutathione peroxidase (GPx) levels, thyroid hormone triiodothyronine (T3) levels, and a complete ovine 23-parameter biochemistry panel were assessed on ppds 0 and 10. Results Maternal organic Se supplementation significantly increased Se levels in lamb serum (P < 0.0001) and muscle (P < 0.0001) as compared to other treatments. Organic Se supplementation significantly increased GPx activity at birth (P > 0.001), but T3 levels were not affected. From the biochemical panel, serum levels of non-esterified fatty acid, potassium, chloride, albumin, total bilirubin, creatine kinase, aspartate aminotransferase, and glutamate dehydrogenase showed significant treatment differences. Conclusions Organic Se supplementation to ewes during late gestation and lactation improved lamb Se status and antioxidant capacity at birth. Other serum biochemistry parameters were only marginally affected by Se treatment. (Supported by NSERC 401814)