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To evaluate the prophylactic and therapeutic effects of an ivermectin controlled-release capsule (IVM-CRC) on the productivity of growing sheep infested with Psoroptes ovis 24 male and 24 female Merino landrace lambs, 5-6 months old and weighing 21.2-35.0 kg, were used. Sixteen replicates of three animals were formed based on sex and Day 0 body weight. Within each replicate animals were randomly allocated to one of three groups: untreated control; IVM-CRC on Day 0; IVM-CRC on Day 84. For treatment an IVM-CRC for sheep weighing 20-45 kg was used which is designed to deliver ivermectin at a minimum dose of 20 microg/kg/day for 100 days. The lambs were infested with 50-60 P. ovis mites each on days 14 and 21. The animals were shorn on Day 126. After slaughter on Day 127 the quality of the leather produced from their skins was evaluated. The IVM-CRC treatment on Day 0 prevented the establishment of P. ovis. All untreated lambs became infested. The lambs treated with an IVM-CRC on Day 84 became mite-free from Day 112 onwards. The lambs which were treated on Day 0 had significantly (p<0.05) greater clean fleece weight (1.5 kg) and fleece yield (52.1%) than the untreated controls (0.9 kg and 34.1%, respectively) or than lambs treated on Day 84 (1.0 kg and 47.8%, respectively). Clean fleece weight and fleece yield were in the tendency (p=0.055) or significantly (p<0. 001) greater, respectively, for lambs treated on Day 84 than for the untreated controls. The chrome tanned dried crust leather of all untreated controls and six of the 16 lambs treated on Day 84 showed grain surface defects such as discolourations, indurations and coarse, pitted grain. The useful (defect-free) leather size was significantly (p<0.01) higher for the lambs treated on Day 0 (100%) than for the lambs treated on Day 84 (82.7%) and the untreated controls (7.8%). The physical testing revealed that the leather of sheep treated on Day 0 had significantly (p<0.05) higher thickness, elongation break and tear resistance than the leather of both untreated controls and sheep treated on Day 84. There were no significant differences in the physical characteristics of the leather of the untreated controls and the sheep treated on Day 84.

Reports on the effects of mange on the production performance of pigs are conflicting. So far, studies have used experimental infections, by depositing encrusted lesions from chronically infected pigs into the ears of experimental pigs. However, this is a poor representation of what happens under natural field conditions. The purpose of our study was to quantify the effects of sarcoptic mange on production performance and pruritus in pigs that were infected by contact with S. scabiei var. suis-infected pigs. A total of 80 piglets were matched by sex and weight and randomly divided between experimental and control compartments. In the experimental compartment, each of three naturally S. scabiei var. suis-infested pigs were randomly allocated to three pens with 13 susceptible pigs each. From day 0 to 35, the growth performance of pigs in the experimental compartment was significantly (P=0.04) worse (35 g/d) than of pigs in the control compartment. From day 35 to 112, there was a statistical trend (P=0.10) that the growth performance of pigs in the experimental compartment was lower (50 g/d) than that of pigs in the control compartment. For the complete fattening period (0-112 or more days), the growth performance of pigs in the experimental compartment was significantly (P=0.05) worse (41 g/d) than that of pigs in the control compartment. Mean feed conversion ratio (kg feed per kg gain) was 2% higher in the experimental compartment compared with the control compartment. Pigs in the experimental compartment had a nine times (95% CI: 2 - 44) higher chance of showing pruritic behaviour than pigs in the control compartment.