Features of seasonal dynamics of sheep Haemonchosis in the territory of Zaporizhzhya region

The article presents the results of studies on the indicators of invasiveness of domestic sheep Ovis aries (Linnaeus, 1758), the causative agent of Haemonchus contortus (Rudolphi 1803; Cobb 1898) and its characteristics depending on the season in the climatic and geographical conditions of the Zaporizhzhya region. The research was conducted during 2015–2019 on the basis of laboratories of the departments of parasitology and ichthyopathology of the Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv and Parasitology and Veterinary-Sanitary Examination of the Poltava State Agrarian Academy. Helminths were isolated by the results of complete helminthological sections of the digestive organs of the dead or slaughtered sheep, and the indicators of the extent and intensity of the invasion were established. Specific identification of the identified nematodes was performed taking into account the morphological features of mature males and females. It is proved that H. contortus is a fairly widespread species of nematodes in the population of domestic sheep in the territory of the studied region. The magnitude of the invasion of animals reached 66.36 %, the intensity of the invasion – 25.56 ± 1.51 samples/animal (for fluctuations from 1 to 79 sp./an.). It is noted that the causative agent of Haemonchosis is registered during the year. At the same time, the degree of sheep infection depends on the season of the year and is characterized by certain patterns in the extent and intensity of H. contortus invasion of sheep. The peak of the animals with the nematodes was detected in the autumn-winter period of the year, EI ranged from 73.23 to 78.57 %. The decline in invasion magnitude was observed in spring (52.63 %) and summer (59.68 %). Seasonal fluctuations in the infestation rates had some differences and were characterized by maximum values in the summer and autumn seasons ranging from 27.49 ± 2.52 to 37.35 ± 2.36 samples/animal. During the winter, the intensity of H. contortus infestation in sheep gradually decreased (13.73 ± 2.12 sp/an) and gained minimum values in the spring of the year (10.85 ± 1.78 sp./an). The conducted researches illuminate the current epizootic condition of sheep haemorrhage in the territory of Zaporizhzhya region, expand and supplement the already existing data that will allow to increase the effectiveness of the use of therapeutic and preventive measures in this invasion