Influence of an experimental infection of swine kidneyworm (Stephanurus dentatus) on performance of pigs.

Forty pigs (average 25.2 kg live weight) were individually housed and fed to study the effect of a single infection of Stephanurus dentatus (either 0, 72, 457 or 842 S. dentatus larvae/kg body weight) on performance of growing-finishing pigs. Final weight and average daily gain were depressed (P less than .05) by increasing levels of kidneyworm infections. Average daily gain of pigs not infected was 69% greater (P less than .05) than that of pigs given 842 S. dentatus larvae/kg body weight. Feed to gain ratios of pigs were increased linearly (P less than .05) with increasing levels of kidneyworm larvae. Feed to gain ratio for pigs not infected was 24% less (P less than .05) than that for pigs given 842 kidneyworm larvae/kg body weight. In each of two trials, eight crossbred barrows (average 26.0 kg in trial 1 and 22.6 kg body weight in trial 2) were examined for the effects of two levels of kidneyworm infections (0 and 457 larvae/kg body weight) on digestion and absorption of nutrients and on N balance. Digestion coefficients for dry matter, crude protein and energy for pigs not infected and for those experimentally infected were similar (P greater than .05). Pigs not infected had higher (P less than .01) N intakes, excreted more (P less than .05) N in feces and urine and had a higher (P less than .01) N balance than pigs infected with kidneyworms, due largely to difference in feed intake.