THE FLOW OF DIGESTA INTO THE DUODENUM OF SHEEP

Abstract

A method is described to determine the volume of flow of digesta into the duodenum of sheep. A solution of polyethylene glycol 4000 was continuously infused into the abomasum via a cannula. The volume of digesta flowing was calculated from the dilution of polyethylene glycol in samples of digesta obtained from a duodenal cannula.Mature wethers were fed rations containing different amounts of straw and urea to give two levels of readily fermentable carbohydrate and two levels of nitrogen in a factorial arrangement. The sheep were fed once daily and there was a monophasic diurnal flow pattern with the highest rates occurring just prior to and during feeding and the lowest rates 6–12 hours after feeding. Both the composition of the ration and the quantity eaten affected the volume of flow which averaged 0.9 ml and 0.6 ml per hour per gram of organic matter consumed per day for the high straw and low straw rations respectively. Additional urea had no effect on flow volume.The average net disappearance, from the stomachs, of organic matter was 24.5 and 50.0% for the high straw and low straw rations, respectively. This difference was reflected in the overall digestibilities which were 57.2 and 78.5% for the high straw and low straw rations, respectively. Additional urea caused slight but not significant increases in digestibility.