EN
The development and prevalence of gastro-intestinal larvae of sheep in the Lublin region have been studied for 3 years. Feces of sheep containing numerous eggs of trichostrongyloides were laid out on grass plots from April until December. Every three days the grass was cut and examined by Baerman’s method for the presence of larvae. Results of the experiment revealed that the development of larvae in spring was extended to 9 weeks. In summer (July and August), when temperatures did not show day and night fluctuations, the period of larvae development was reduced to 3 weeks. Prevalence of larvae on grass was 35 days in spring and 30 days in summer.