The rate of passage of food through the alimentary tract of pigs

Abstract

A method for measuring the rate of passage of meal through the alimentary tract of pigs by feeding a stained marker is described. The results are given of sixty-four experiments made under standardized conditions on four fattening pigs with live weights ranging from 49·9 to 185·5 lb. and six experiments on a sow weighing 500 lb.Results were expressed by means of excretion curves. These were sigmoid in shape and from them a value termed R, the mean retention time (hr.) of all the stained particles in the alimentary tract, directly proportional to the area to the left of the curve, was calculated.In the fattening piga the first appearance of the marker in the faeces occurred 10–24 hr. after feeding, and the mean 5 and 95% excretion times were 21 and 53 hr. respectively. The marker was completely excreted after approximately 80–90 hr. The R value averaged 34·2 hr.A marker fed at the morning feed (9 a.m.) had earlier 5 and 95% excretion times and the R value was significantly smaller.There was no statistically significant relationship between the R values and live weight, digestibility of the dry matter of the ration or the dry-matter content of the faeces.In the sow the 5 and 95% excretion times were 38 and 68 hr. respectively, and the R value averaged 51·1 hr.Counts of stained particles in the intestines of two of the pigs after slaughter showed that food was delayed mainly in the large intestine.