Effects of challenge with trichostrongylid nematode larvae on immunologically resistant grazing yearling sheep in South Australia.
Paddocks near Gawler, South Australia, were grazed by newly weaned sheep which received either no anthelmintic treatment, regular 3-weekly treatment or a single treatment in February. A decline in the faecal egg count of untreated sheep in autumn associated with the ingestion of infective larvae indicated that the sheep had developed a resistance to reinfection. At the end of the experiment, 10 sheep were experimentally infected with Trichostrongylus vitrinus larvae to demonstrate this resistance. Untreated sheep grew less wool and had lower body weights when compared with treated animals and were extremely 'daggy'. A single treatment in February did not prevent production losses or scouring.
Pullman
A L
AL
South Australian Department of Agriculture, Turretfield Research Centre, Rosedale.
Beveridge
I
I
Martin
R R
RR
D000367:Age Factors; D000818:Animals; D007113:Immunity, Innate / Q000276:immunology; D007814:Larva / Q000302:isolation & purification; D010270:Parasite Egg Count / Q000662:veterinary; D012756:Sheep / Q000276:immunology / Q000469:parasitology* / Q000502:physiology; D013021:South Australia; D014254:Trichostrongylus / Q000276:immunology* / Q000469:parasitology; D015430:Weight Gain