Performance, Water Use and Effluent Output of Weaner Pigs Fed ad libitumwith Either Dry Pellets or Liquid Feed and the Role of Microbial Activity in the Liquid Feed

Abstract

Forty eight and ninety six pigs weaned at 22·6±2·6 days, were allocated to two trials to study the effect of feeding post-weaning diets ad libitum, either as dry pellets (DF) or as meal mixed with water in the ratio 2·5:1 (LF). The trials, lasting 28 days, differed only in the type of trough used to present the liquid feed to the pigs. In both trials the daily gain of LF pigs over the 4 weeks of the trial was significantly (P<0·001) better than that of the DF pigs. Daily gains for the two treatment groups were respectively 428 and 343±15 g day−1 in Trial 1 and 454 and 397±10 g day−1 in Trial 2. The feed conversion ratio (FCR) (corrected to fresh weight of dry feed) of LF pigs was significantly poorer (P<0·01) than that of DF pigs in both trials primarily as a result of feed wastage by the LF pigs. FCR for the DF and LF pigs was, respectively, 1·31 and 1·89±0·05 in Trial 1. In Trial 2 improvements in the trough design reduced the difference in FCR. FCR for the DF and LF treatments was 1·37 and 1·44±0·02 respectively. In Trials 1 and 2 LF pigs used on average 76% and 35% more water than DF pigs. LF pig produced 12% (Trial 1) and 5·7% (Trial 2) more effluent per unit of liveweight gain than DF pigs. Microbiological examination of the liquid feed system demonstrated that the system acted as a fermenter.Lactobacillusspp proliferated rapidly and became the dominant organism within 5 days and the populations remained relatively constant thereafter. The proliferation of lactobacilli reduced the pH of the liquid feed from approximately 6·0 to between 3·5 and 4·0. At the lower levels of pH the number of coliforms in the feed was significantly reduced.