Evaluation of the efficacy of macrocyclic lactones with different routes of administration in reindeer edemagenosis

The article presents the results of a study conducted to evaluate the larvocidal effectiveness of macrocyclic lactones containing avermectins against reindeer edemagenosis. The spread of edemagenosis and the degree of infestation of reindeer by subcutaneous botfly larvae were studied by examining animals during the period of clinical manifestations of the disease (January-February), as well as by examining skins during the planned slaughter of deer. The extent of infestation by subcutaneous gadfly larvae was 6.9% for mature male, 16.4% for first time pregnant female, and 29.9% for mature female. The drug "Novomek 1%", containing ivermectin as an active ingredient, was used intramuscularly; “Aversect-2” containing aversectin C – subcutaneously; “Hypodectin N” (DV ivermectin) was applied along the back in a thin stream, spreading from the withers to the sacrum. Taking into account the timing of the summer of the imaginal stages of gadflies, the animals were treated once in the third ten days of September. It has been established that the parental route of administration of macrocyclic lactones for edemagenosis is preferable. After using a drug containing ivermectin intramuscularly, larvae were found in one choir, 2 heifers and 5 heifers. After subcutaneous injections of the drug containing aversectin, edemagen larvae were not found in the choirs, but were detected in one heifer and 3 heifers. In animals treated with a drug containing ivermectin by applying it to the skin along the back, larvae were found in 2 mature males, 4 first time pregnant female and 6 mature females. When examining the skins of all deer in the control group, O. tarandi larvae were detected. A drug containing ivermectin as an active ingredient, used intramuscularly, has a more pronounced larvocidal effect compared to a drug used externally. After subcutaneous application of a drug containing aversectin C, edemagen larvae were not detected in choruses, and in heifers and important heifers, the extent of invasion did not exceed 30%. Preparations from the group of macrocyclic lactones, regardless of the route of administration, did not have a 100% larvocidal effect on the larvae of the subcutaneous botfly O. tarandi when used once.