INFECTION OF WEANLING PIGS WITH KNOWN NUMBERS OF ASCARIS-SUUM FOURTH STAGE LARVAE

Abstract

Nineteen weanling pigs were each infected orally with 200 fourth stage A. suum larvae and were fed either a low protein or a high protein diet for 8 wk. Worms expelled during the 8 wk were recovered and all worms remaining in the gastrointestinal tract at slaughter were collected. Of these worms, 54% were recovered at slaughter. Of the 19 animals, 10 maintained an infection for 8 wk; the other 9 showed no signs of A. suum infection. A total of 377 worms were recovered. Average worm burdens were 37.7 worms/pig, 50.8 worms/low protein pig, and 30.8 worms/high protein pig. Times of and possible causes for expulsion are discussed. Procedure for infection of pigs is discussed in detail and possible improvements in technique suggested.