Colonisation and degradation of dung pats after subcutaneous treatment of cattle with ivermectin or levamisole.
The fauna and degradation of dung pats from cattle treated with ivermectin or levamisole were examined in a field study conducted in southern Germany. Four groups of seven cattle each grazed on four paddocks. The cattle were treated subcutaneously with ivermectin (0.2 mg/kg) or levamisole (5 mg/kg) 3, 8 and 13 weeks after turnout. A total of 300 pats voided naturally before the first and third treatment and 3, 7, 14 and 28 days after treatment were evaluated. Half of them were used as sampling pats, in which adult and immature Coleoptera, larvae of Diptera and soil and dung nematodes were counted. Earthworms were weighed in samples taken on 8 occasions within 63 days after pat deposition. Dung degradation was investigated using 150 observation pats by measuring surface area, weight and organic matter content on six occasions within 63 days from deposition. A photographic record was also maintained. There was no difference between treatment groups as to the range of Coleoptera, nematodes and earthworms collected from the pats. No quantitative differences between groups were seen regarding the total number of adult and immature dung beetles, soil nematodes and earthworms isolated within 63 days after deposition. Populations of Diptera larvae in pats voided up to 28 days after treatment were reduced for the ivermectin treated group relative to the levamisole group. There were reductions in numbers of dung specific nematodes in pats from both groups and some species were reduced in pats deposited 3, 7, and to a lesser extent, 14 days after treatment for the ivermectin group compared with pats from the levamisole group. These effects on dung fauna had no impact on dung degradation. The results of serial measurement of pat area, photographic evaluation, and determination of remaining dung weight and organic matter showed no difference between treatment group.
Barth
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Merck Research Laboratories, Kathrinenhof, Rohrdorf, Germany.
Heinze-Mutz
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Langholff
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Roncalli
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Schlüter
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D000818:Animals; D002417:Cattle / Q000469:parasitology*; D001517:Coleoptera; D004175:Diptera; D005243:Feces / Q000469:parasitology*; D007279:Injections, Subcutaneous; D007559:Ivermectin; D007814:Larva; D007978:Levamisole; D009348:Nematoda
D007978:Levamisole; D007559:Ivermectin