Doramectin causes significantly less discomfort during injection than Ivermectin.

T. Grandin, K. MaxweII, and J. Lanier
Colorado State University, Fort Collins and
Pfizer Animal Health, Lee's Summit, MO.

Journal of Animal Science 1998 (Abstract)(Supplement1) 76:102

This study was conducted to determine if there was a difference in the behavioral reaction of cattle during an injection of either doramectin 1% injectable solution or ivermectin 1% injectable solution. Sixty-one red Angus-cross, two year old heifers were used. Each animal was held in a squeeze chute and given a 9 ml subcutaneous injection of either doramectin, ivermectin or sterile saline. Two observers, who were blind to the treatment, rated the behavioral reactions to the injections. Each animal was scored on a four number rating scale, 1 = no reaction stood still, 2 = slight movement, 3 = shaking and 4 = vigorous shaking. The cattle were also scored for willingness to re-enter the squeeze chute. Animals in the doramectin group reacted significantly less to the injection compared to cattle injected with ivermectin. The results for observer 1 with a score of 1 were, doramectin 17 animals, ivermectin 6 animals, saline 14 animals. The results for observer 2 with a score of 1 were, doramectin 14 animals, ivermectin 4 animals, saline 12 animals. Differences between doramectin and ivermectin (p=.OO1) and ivermectin and saline (p=.002) were found. Re-entry scores into the chute were significantly different for one observer and not significantly different for the other observer. Doramectin caused significantly less discomfort during injection than ivermectin. Use of a product, which causes less discomfort during injection, may improve ease of handling in the future and reduce animal discomfort. From a behavioral standpoint, this experiment is of interest because it showed that small differences in animal discomfort can be detected with a simple technique.

Key Words: Anthelmintic, Cattle, Stress

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