Effects of Pyrantel HCl and Dietary Protein on Growing Pigs Infected in Different Sequences with Strongyloides Ransomi, Ascaris Suum and Oesophagostomum Spp.

Abstract

Forty-eight crossbred barrow pigs naturally exposed to Strongyloides ransomi and Ascaris suum were used in a 23 factorial experiment to study; (1) the effects of pyrantel HCl (0 and 0.0715 g/kg of feed fed continuously for 42 days); (2) levels of dietary crude protein (higher, 18-16-14%; and lower, 15-13-11%); and (3) sequence of experimental exposure to 3 parasite genera (S. ransomi, A. suum, Oesophagostomum spp.; and A. suum, S. ransomi, Oesophagostomum spp.) on performance of pigs weaned and placed on experiment at 8.9 kg average weight. After 42 days, rates of gain of pigs on the lower protein diet with and without pyrantel HCl were not different; however, pigs fed pyrantel HCl in the higher protein diet gained 20% faster (P.10), but pigs which had received pyrantel HCl had gained 8% faster (P.10). The S. ransomi EPG counts had no bearing on feed efficiency at 42 or 77 days, but Ascaris and Oesophagostomum EPG counts had a negative correlation (P.10). Pyrantel HCl effectively reduced the average numbers of S. ransomi and A. suum up through 77 days; however, such apparent differences did not exist at market weight. Exposure to S. ransomi first was associated with greater daily feed intake (P<.10); a decreased rate of efficiency (P<.05); and a greater number of S. ransomi and Oesophagostomum spp. worms (P<.10) at market weight.