Epidemiology of gastrointestinal nematode parasitism in Suffolk and Gulf Coast Native sheep with special emphasis on relative susceptibility to Haemonchus contortus infection.

摘要: An eight-year study was conducted to define the epidemiology of gastrointestinal nematode infection in Suffolk and Gulf Coast Native (Native) breeds sheep, determine if sheep is more resistant infection. For initial three years, each breed grazed separate pastures where anthelmintic treatments were administered individual animals on a salvage basis. last five both concurrently; basis for first all animals, when treatment criteria met, two years. The fecal egg count (FEC) blood packed cell volume (PCV) monitored, tracer lamb burdens determined. Overall, FEC increased spring (periparturient rise) most years summer Under grazing conditions, ewes lambs had consistently lower levels than lambs. During haemonchosis season (June-September) year, ewe PCV decreased, remained relatively stable. protocol resulted 27 one ewes; similarly lambs, 13 zero Native. Tracer with their respective breed, mean total burden corresponded pattern breed. predominant nematodes found Haemonchus contortus Trichostrongylus spp., respectively. concurrent same seasonal repeatable present exhibited by breeds, being significantly (p < or = 0.05) higher PCV. 57 ewes, respectively; 46 11. again infection, H. spp. Data from showed low level hypobiosis (H. only), and, although there no consistent season, tendency occur fall. These results that classic occurred (specifically contortus) sheep.