Information is provided on the causative agents of fasciolosis and the developmental biology of Fasciola hepatica. Fasciolosis of cattle is widespread in the conditions of the Kaluga Region and the Central Federal District on farms of different forms of ownership. The greatest number of F. hepatica eggs in 1 g of feces in cattle is established in JSC "Iskra" - 175,4 specimens, the lowest - in the samples from cows from private farms - 87,6 sp. At the opening slaughter of cattle at meat processing plants region and slaughterhouses invasion of their fasciolae was 34.8%. The average number fascial one infected animal was 32.1 specimens, including adult - and larval specimens of 25.2 and 6.9 copies At veterinary-sanitary expertise and helminthological autopsy of the liver, gallbladder and bile ducts installed year-round invasion fasciolae mainly in the adult stage. Young animals of the current year are infected with fasciola in the pasture massly in August-September, and the extent of invasion in November was 4.3%, for winter-stabling months an average of 12.6%, in March - 17.9% and in April after de-worming - 5.9%.The data obtained in the study of the distribution of the small pond has shown that in the Kaluga region these mollusks are widespread. In this case, the invasion of the small pond snail by larval forms of fasciolae in different years has its own peculiarities, which are influenced by climatic factors.The different dosage forms of clozantel - Rolenol and Santel and Genamectin with mixed fascioliasis and hypodermatosis of bovine in the recommended dose against subcutaneous gadfly larvae - provided 100% efficacy. The tested dosage forms of clozantel are similar in effectiveness against subcutaneous gadfly larvae (EE-100%) and fasciol (EE-95 and 90%, IE-97.4 and 96.3%).The therapeutic and economic effectiveness of complex domestic preparations of Helmicide and Fascocida in spontaneous fascioliasis of cattle is studied.
