An important question regarding supplementation of grazing beef cattle is how frequently this should be done. Responses of cattle to supplementation weekly with cereal grains are not as well documented as daily, probably because of the high risk of acidosis in cattle fed rapidly fermentable sources of starch. Successful weekly supplementation of cattle with barley containing virginiamycin to reduce the risk of acidosis has been reported by Zorrilla—Rios et al. (1994). It is possible that feeding whole maize grain to cattle can reduce rate of ingestion, stimulate mastication and saliva secretion compared to ground grain and thereby reduce the risk of acidosis. It is also likely that the amount of forage available (FA) can affect animal response in relation to weekly or daily supplementation.