Factors Affecting the Passage of Liquids into the Rumen of the Dairy Calf. II. Elevation of the Head as Milk is Consumed

Summary 1.Anatomical studies suggested that the elevation and the mechanical manipulation of the head and neck of calves, within limits that may be employed in practical feeding, are not primary factors affecting the functioning of the esophageal groove. 2.This suggestion was substantiated from observations of rumen-fistula calves fed milk either through a rubber nipple at different levels, floor and elevated, or from open pails at these levels. 3.Though the elevation of the head and neck was not an important factor affecting the extent of milk passage into the rumenoreticular cavity, the type of feeder, nipple or open, was very significant. 4.Irrespective of feeder level, milk rarely entered the rumen when consumed via nipple but frequently entered when drunk from an open pail. 5.The vagi are paths over which certain stimuli may be transmitted to the esophageal groove, but the transmission and resulting esophageal groove reaction are unaffected by positions of the head and neck.