The article describes helminthological experiments  of the hoofed mammals on 6 maral farms and 1 hunting farm located in different regions of the Russian Federation, exactly in the Altai Territory and, Kaluga and Tver regions. The researchers investigated 773 samples of coprological material and highlighted the main pathogens of parasitic diseases: they are elaphostrongyls, intestinal strongylitis, eimerias, trichocephalans, scabies and nematodes. The researchers identified 12 types of pathogens. The authors observed highest rates of invasiveness caused by elaphostrongillosis, gastrointestinal strongylitis, trichocephalosis, and nematodeirozis in marals inhabiting in the Altai Territory. Their degree of  invasion extensity  was 100, 90, 87.5 and 25%, whereas  invasion intensity was 9842, 147, 19 and 2 samples. The extensive invasion when experiencing eimeriosis reaches maximum parameters in mouflons at 100% when intensive invasion is 45 oocysts per gram of material. Scallop mites are widely spread in Tver region among the European deer population when extensive invasion is 85.7% and intensive invasion is 2 samples. The common causative agents of invasive diseases among the animals are gastrointestinal strongylitis, eumeria, elaphostrongyls, trichocephaly, scabies and nematodes. They are observed in three regions of Russia.  The difference in the extensive and intensive rates of invasion depends on the geographical, climatic and anthropogenic factors that comprehensively influence their changes to a certain extent.

Altai Region has always been and remains a region of developed animal husbandry. Velvet antler industry is an integral part of it. It specializes in the breeding of marals and sika deer. One of the main problems encountered in maral breeding is the infection of animals with helminths. The resistance of helminths to various environmental conditions without loss of invasiveness, as well as anthelmintic treatments is carried out, as a rule, with the same drugs from the group of macrocyclic lactones. They do not have a sufficient destructive effect on the causative agents of parasitic diseases (in particular, on trematodes) and promote helminths circulation and their distribution. In this regard, we set a goal: to analyze the epizootic situation in terms of trematodes of marals in the farms of the Altai Region and to study the effectiveness of the antiparasitic action of the drug Santel 10%. In the course of clarifying the epizootic situation on trematodosis of marals in the main maral breeding areas of the Altai Region, it was established that this group is currently represented by the causative agent of dicroceliosis. In general, over the period of research, the invasion of marals by the causative agent of dicroceliosis tended to slightly decrease in terms of the extent of invasion - by 20%. An experiment in the study of the anti-trematode efficacy of the drug Santel 10% by OOO VIK-Animal Health (Russia), was carried out on stag beetles in the Altai Territory of the Altai Region. As a result of production experience on the use of the drug Santel 10% on spontaneously infested marals, it was revealed that the drug is effective against dicrocelia, in particular, in terms of intensity efficiency, which was 84.5% with an intensity efficiency of 40%.