The effects of mineral supplementation to ewes in late pregnancy on colostrum yield and immunoglobulin G absorption in their lambs

One hundred and eight ewes were allocated to nine treatments (n = 12) to determine the effects of various mineral/vitamin supplements during the final 6 weeks of pregnancy on colostrum production and quality, lamb serum immunoglobulin G (IgG) concentration and IgG absorption efficiency. Ewes were offered grass silage ad libitum supplemented with 400 g/ewe/day of concentrate from days 98 to 133 of gestation and thereafter with 600 g/ewe/day until parturition. Ewes received one of the following supplements: C, no supplement; M, mineral/vitamin supplement (Ca, P, Mg, Na, Zn, Se, I, Mn, Co and vitamin E (Vit. E)); Zn, mineral/vitamin supplement excluding zinc; P, excluding phosphorous; Se, excluding selenium; I, excluding iodine; Mg, excluding magnesium, Mn, excluding manganese; Co, excluding cobalt. The ewes were milked at 1, 10 and 18 h post partum and the colostrum was fed back to the lambs. The progeny of ewes receiving supplementary iodine (M, Zn, P, Se, Mg, Mn, Mg and Co) had lower serum IgG concentrations and IgG absorption efficiencies at 24 h than the progeny of ewes not receiving iodine supplementation (C and I; P < 0.001). We conclude that high level dietary inclusion of iodine results in a reduced lamb serum IgG concentration and efficiency of colostral IgG absorption.