Abstract
Seventy-two crossbred pigs were weaned at 3 wk of age and fed either a simple or semicomplex diet. Each diet was fed at three levels of feed intake: ad libitum, restricted intake by limiting time exposed to the feeder and restricted feed intake by regulating the amount of feed per day. The effects of diet and feeding system were assessed by monitoring piglet performance and incidence and severity of diarrhea. Diet complexity did not significantly affect pig performance. Restriction of feed intake significantly reduced performance compared to that of pigs fed ad libitum. There was no significant difference in performance between pigs fed by either of the two methods of feed restriction. The diarrhea which occurred with pigs fed the semicomplex diet was significantly more severe (P < 0.01) than that which occurred with those fed the simple diet. Restriction of feed intake by weight of food fed significantly reduced the incidence and severity of postweaning diarrhea. Limiting time exposed to the feeder was not a satisfactory method of reducing diarrhea as it resulted in greater incidence of diarrhea than did ad libitum feeding. Diarrhea significantly reduced performance. Restricting feed intake by the methods used in this experiment reduced performance more than did the diarrhea. The number of days taken to reach 90-kg liveweight was not affected by diet complexity, feeding method or diarrhea in the immediate postweaning period. Key words: Diet complexity, feed restriction, pig diarrhea