Parasite Worry and Restlessness caused by Sarcoptic Mange in Swine

Abstract

Thirty-two crossbred pigs, weighing 13 to 28 kg each at the start, were used to study the effects of sarcoptic mange infestations and subsequent treatment with ivermectin on metabolic rate, protein gain and energy requirements of pigs. Pigs were paired by body weight and allocated to two identical environmentally controlled respiration chambers, where they were penned in groups of eight. Amounts of feed provided were measured and adjusted periodically according to weights of the pigs. Treatment with ivermectin (300 mcg/kg) was administered to all pigs in one chamber (selected as the one with pigs exhibiting more severe clinical signs of mange) on day 21. Pigs in the second chamber served as infested-nontreated controls. Weight gains, activity levels, energy metabolism, parasitological data and leukocyte differentials were monitored throughout the trial.

Mange mites were not identified in skin scrapings during the trial, but clinical evidence of sarcoptic mange hypersensitivity was evident (thickened and encrusted skin and restlessness) for these pigs. Skin biopsies also revealed cell proliferation and hyperaemia, typically seen with mange hypersensitivity. Mean weight gains were slightly greater for controls at each sampling time, except at the final posttreatment evaluation. Similar trends were observed for feed conversion. In general, pigs with heavy mange infestations did not eat well and had increased activity levels, resulting in greater maintenance requirements and reduced efficiency in energy utilization. Substantial improvements were noted following treatment with ivermectin. The trial provided useful data for examination of trends of effect of sarcoptic mange infestations in pigs.