TASTE-AVERSION LEARNING IN 3 SPECIES OF RUMINANTS

Taste-aversion learning was investigated in cattle, sheep and goats. Three types of taste-aversion tasks were investigated in sheep and goats: (1) learning to avoid a food associated immediately with apomorphine injection; (2) learning to avoid a food associated with apomorphine injection 30 min after ingestion of the feed; (3) learning to avoid one of three feeds when only that food is associated with apomorphine injection. Cattle and sheep were able to learn to avoid alfalfa pellets and cracked corn, i.e. they decreased their intake on subsequent exposures. Goats learned to avoid alfalfa pellets, but not cracked corn. Neither sheep nor goats could learn to avoid alfalfa pellets that were associated with apomorphine injection 30 min after ingestion. When offered oats and soybean meal for several days and then both those feeds and corn, sheep and goats learned to avoid the corn. Goats, but not sheep, learned to avoid alfalfa pellets when they were presented with soybeans and oats. This series of experiments confirms that ruminants can form aversions to food associated with illness, but there are constraints on the learning in that the illness must occur shortly after feeding in order for the ruminant to learn to avoid it. Apomorphine is a practical substance to use in teaching animals to avoid potentially dangerous plants before exposure to the plants in a pasture or range situation. © 1990.