Feed aversion learning in cattle with delayed negative consequences.

Two experiments were conducted to study the ingestive behavior of cattle when given a delayed dose of the aversive agent lithium chloride (LiCl) after eating a novel feed. In the first experiment, 20 calves were randomly divided into four groups (n = 5). The control group (G1) received 80 mg/kg BW of sodium chloride (NaCl) 4 h after eating a novel feed. Groups 2 (G2), 3 (G3), and 4 (G4) received 80 mg/kg of LiCl at 4, 8, and 12 h, respectively, after eating the novel feed. When calves were offered the novel feed on subsequent days, G2 and G3 ate less (P < .05) than G1. There was no difference (P > .05) in intakes between G1 and G4. In the second experiment, 15 calves were randomly divided into three groups (n = 5). The control group (G1) received 80 mg/kg BW of NaCl 12 h after eating a novel feed, whereas G2 and G3 received 80 and 160 mg/kg BW, respectively, of LiCl 12 h after eating the novel feed. When calves were offered the novel feed on subsequent days, G1 and G2 ate similar (P > .05) amounts, whereas G3 ate much less (P < .05) of it than the other groups. Cattle learned to avoid novel feeds even when they experienced negative postingestive consequences up to 12 h after they ate the feeds. The capacity for long-delay learning seems to be related to the severity of negative consequences experienced.