No abstract

No abstract

No abstract

Young Hereford s t e e r s of even body weights were grazed on pasture a t 2 levels of stocking rate a n d artificially infected with 0, 600 or 1,200 metacercariae of Fasciola hepatica. In addition all g r o u p s obtained a low g r a d e natural infection.S t e e r s w e r e s l a u g h t e r e d a t intervals throughout t h e 32-week trial period a n d total fluke c o u n t s obtained. Fluke c o u n t s were significantly higher in all artificially infected g r o u p s when compared to t h e natural infection alone g r o u p s with t h e exception of t h e 600 metacercariae group during t h e 12 to 32-week analysis period. T h e r e w e r e no significant d i f f e r e n c e s between c o u n t s in s t e e r s in t h e 2 nutritional regimes.Rates of growth were significantly r e d u c e d by 14.7% a n d 14.1% in s t e e r s receiving a s u p e r i m p o s e d artificial infection rate of 1200 metacercariae a n d grazed a t 3.54 b e a s t s / hectare and 4.39 b e a s t s / h e c t a r e respectively. Similarly g r o u p body weights w e r e d e p r e s s e d 3% and 20% in s t e e r s receiving 600 rnetacercariae a n d grazed a t 3.54 b e a s t s l h e c t a r e a n d 4.39 b e a s t s / h e c t a r e respectively. T h e r e was a significant interaction between level of nutrition and size of artificial infection on body weight c h a n g e s in t h e first 12-week period.