PASSAGE OF FEED THROUGH THE ADULT ROOSTER

Five experiments were made to measure the time required for feed residues to clear the alimentary canal. The cumulative production of excreta dry matter was the primary criterion of measurement although attempts were made to adopt a stained particle technique. The latter was confounded by the production of metabolic and endogenous wastes. When full-fed adult roosters were taken off feed the residues within their alimentary canals were voided within 24 hr. Subsequent experiments involved placing known quantities of feed in the crops of starved roosters and measuring excreta production. Finely ground corn, wheat, oats, and barley (30 g) cleared the alimentary canal in 24 hr. The amount of wheat or wheat bran (10, 20, 30 g) placed in the crop affected the rate of passage but clearance was completed within 24 hr. A confounding factor was that the production of metabolic and endogenous waste decreased with the degree of starvation which was a function of feed input. Corrections based on the excreta production of negative control birds were not wholly satisfactory. The rate of excreta production was affected by the duration of starvation prior to the feeding of coarsely ground corn, soybean meal, and meat meal. The time of feeding also had a small effect. However, neither variable was of practical importance. It was found that while corn and soybean meal resideus cleared the alimentary canal in 24 hr meat meal required about 30 hr. Alfalfa, fish meal, and wheat fed as pellets produced more excreta than when fed as meals. Pellets appeared to have the faster rate of passage through the alimentary canal. Both alfalfa and fish meal required more than 24 hr to pass through the birds.