The importance of sufficient vitamin A in the diet of cattle has been adequately substantiated (Rosenberger, 1970; Bauernfeind & Marusich, 1971; Thompson 1975; Lotthammer, 1978). It has been claimed that under semi-arid conditions (winter range) where no green pasture is available, it is important for animals to store sufficient vitamin A so as to carry them through to the summer when adequate intakes of carotene again become possible. In South Africa vitamin A supplementation is recommended widely and used extensively in practice, both by farmers and by the feed industry. This situation prevails despite the fact that in this country there appears to be no conclusive evidence indicating that such supplements hold any benefit in terms of animal performance.