Studies on the alimentary tract of the Merino sheep in South Africa. I. Investigations into the physiology of deglutition

Abstract

The possibility of dosing into the abomasum by administering various materials, especially inert powders, after stimulating the oesophageal groove to close, was investigated and the results obtained with 264 sheep are recorded. The work of Wester was taken as a basis and numerous variations were made in the preparation of the animals, the method of administration and the materials administered. The results are of such a nature that practically no conclusions can be drawn. It is possible that soluble sodium salts stimulates the vagus endings in the pharynx and may thus cause reflex closure of the oesophageal groove, but other important factors, which have not been elucidated, frequently counteract such stimulation or the reflex. It is possible that semi-solid nature of the ruminal contents and the presence of gas in the rumen and reticulum are such adverse factors. On the whole, the age and the condition of the sheep did not appear to affect the results.