[Dysfunction of the esophageal groove ("ruminal drinking") as a complication of neonatal diarrhea in the calf].

It is well documented that the induction of the oesophageal groove reflex in the milk fed calf depends on certain prerequisites: The fluid drunk by the calf must come into contact with the receptors located in the pharynx, it must be consumed voluntarily by the animal without undue disturbances, it should have no offensive smell or taste and the general status of the calf should not be disturbed. When those conditions are not met the oesophageal groove closes incompletely or not at all and the milk flows into the reticulo-rumen. If the milk or any other nutrient solution remains there for a sufficient period of time, the nutrients it contains are subjected to bacterial breakdown. In a study including 249 calves (age less than 14 days) suffering from enteritis catarrhalis acuta it could be demonstrated that no closure of the oesophageal groove occurred in 11.2% of the patients; 11 calves of that group died. The same was probably true for a further 11.8% of the diarrheic calves; 12 of them died. In 37 ruminal drinkers, suffering from neonatal diarrhea (n = 30) or another primary disease (n = 7) the acid status of the rumen fluid could be examined several times. According to the analyses the following types of fermentation could be distinguished: --predominant butyric acid fermentation; --predominant lactic acid fermentation; --"biphasic type": predominant lactic acid fermentation changes to predominant butyric acid fermentation or vice versa. In the milk fed calf suffering from neonatal diarrhea, dysfunction of the oesophageal groove reflex (ruminal drinking) with its consequences (rumen acidosis, dyskeratosis of the ruminal mucosa) can result in a fatal outcome.