Long-chain polyunsaturated fatty acids (PUFAs) are essential components of cellular membranes and are associated with prostaglandin synthesis. Supplementing ewes with long-chain PUFAs during gestation has been demonstrated to increase gestation length and improve lamb vigour (Capper et al., 2002). Furthermore, increasing the dietary vitamin E supplied to pregnant ewes is reported to increase lamb growth rate (Gentry et al., 1992). However, fish oil supplementation during lactation may reduce milk component yield and lamb growth rate (Capper et al., 2002). The objective of this experiment was to investigate the effects of dietary long-chain PUFA and vitamin E supplementation of pregnant ewes on lamb performance.