The effects of iodine supplementation to the pregnant ewe on immunoglobulin G, vitamin E, T3 and T4 levels in the newborn lamb

Abstract

Lambs are born hypoimmunocompetent and are dependent on the absorption of immunoglobulin G (IgG) from colostrum for immunity in early life, similar to the situation with vitamin E (vit. E), which is also involved in maximising immunocompetence (Puls, 1994). High-level iodine supplementation during late gestation period of the ewe results in the production of progeny with an impaired ability to absorb colostral IgG and vit. E post partum (Boland et al., 2006). Iodine is essential in the synthesis of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3; McDonald et al., 2002) that regulate the metabolic pattern of most cells and play a vital role in the process of cellular differentiation, growth and development in the foetus and neonate (Stanbury, 1996). The objectives of this experiment were to determine the effects of offering supplementary iodine for the final three weeks of pregnancy on serum vit. E, IgG, T3 and T4 concentrations at 1h, 24h and 72h post partum.