Seasonal Aspect of the Larval Inhibition of Ostertagia Circumcincta

摘要

The seasonal dynamic of permanent parasitism of Ostertagia circumcincta in young ovine/ewe generation was studied. Spontaneously infected animals were slaughtered in December and March for examination of the content and scrape of abomasum mucosa by traditional methods. The numerical abundance of evolutionary forms of O. circumcincta varies depending on gender, physiological status, and seasonal dynamics. In female lambs of imaginal parasitism constitutes 41,73,48 [ex/animal] in winter and 336,638,1 [ex/animal] in spring, but in males it was 61,93,93 [ex/animal] and 634,257,47 [ex/animal] respectively. The level of larval parasitism during the winter constituted 479,339,94 [ex/animal] in female lamb, and [716,530,11 ex/animal] in male. During the spring, larval forms were not found in scrape of abomasum, both in females and males. In the structure of O. circumcincta population the numerical dominance of larval forms in winter season and the index of larval inhibition constituted 92.8% for both genders. The inhibition of larval evolution represents survival reaction to environments factors. This phenomenon with a seasonal character represents a mechanism for regulating the density of parasitic population determining functional stability of the biological system Ostertagia circucincta Ovis aries in time and space.