Control of nutritional muscular dystrophy in lambs by selenium implantation

Abstract

SUMMARYAn implantation technique utilizing slow-release selenium pellets was evaluated as a means of controlling nutritional muscular dystrophy (NMD) in sheep. Sixty ewes were fed a dystrophy-producing hay and implantations were made at mid-pregnancy (14 animals) and in late pregnancy (15 animals); the remainder were kept as controls. Selenium was determined at intervals on milk and blood samples from the ewes and on blood samples from the lambs. Various muscles were examined histologically for NMD lesions.Selenium levels in the milk of implanted ewes were higher than controls up to the 60th day of lactation and levels in the blood of both ewes and lambs were higher than controls during nursing. Selenium implantation at mid-pregnancy resulted in higher selenium concentrations in lamb's blood at birth than implantation in late pregnancy. However, by 30 days of age and thereafter, this difference was reversed. Large variability was encountered in the blood values for implanted ewes and their lambs. While complete protection against NMD was not achieved, implantation reduced the incidence and severity of the disease. The earlier implantation gave slightly fewer deaths from NMD, but the numbers were too small to make critical comparisons.