Lactose utilisation by the growing pig

Abstract

Twenty-eight weaning pigs were used in a feeding experiment to determine the effect of different levels of lactose in the diet on growth performance and carcass characteristics. Seven pigs weighing initially 50 lb and penned individually were allocated to each of four treatment diets in which lactose was substituted for wheat starch at levels of 0%, 15%, 30%, or 45% of the diet. The meal mixtures were fed as a gruel using three parts water : one part meal (w/w). Over a period of 56 days pigs receiving diets containing 30% or 45% lactose grew 10% and 39% slower respectively than the controls (P < 0.01). The pigs on the 45% lactose diet also grew significantly slower (P < 0.05) than those fed diets containing either 15% or 30% of lactose. Reduced food consumption was a major factor contributing to the poor and very variable performance of the group fed the 45% lactose diet. Similar treatment differences were evident for food conversion efficiency but there was little treatment effect on carcass fatness. The incidence and duration of diarrhoea increased with increasing levels of dietary lactose. Diets containing up to 30% lactose caused a transient diarrhoea, but some of the animals on 45% lactose continued to scour until the termination of the experiment.