In adolescent sheep, high nutrient intakes to promote rapid maternal growth during pregnancy results in a major restriction in placental growth which leads to a significant reduction in lamb birthweight relative to moderate intake adolescents of equivalent gynaecological age (Wallace et al 1996). Placental hormones play a crucial role in the development, differentiation and function of the mammary gland and we have previously reported that maternal concentrations of progesterone, growth hormone and pregnancy-specific protein B are significantly reduced in high intake dams with growth restricted placentae (Wallace et al 1997 a,b). For newborn lambs, the ingestion of adequate quantities of nutrient dense colostrum is essential to provide fuel for heat production and to ensure absorption of maternal antibodies to give immunological protection against infection. The objective of the present study was to examine the effect of nutritionally-mediated placental growth restriction on colostrum yield, nutrient composition and immunoglobulin content.