Evaluation of an improved oesophageal cannula in dairy cows

Dairy cows with an oesophageal fistula are used to study herbage intake, diet composition and grazing behaviour. Experimental oesophageal fistulation was carried out on 10 adult dairy cattle. Critical factors in the success of this procedure included preoperative halter-training, secure intra-operative physical restraint, use of a probang to identify the oesophagus, modification of the oesophageal plug to reduce the risk of fibre entrapment and regular postoperative inspections to detect and correct complications. Complications recorded included wound soiling, oesophageal occlusion, aspiration pneumonia, shock, leakage of saliva and digesta, and loss of the oesophageal plug. Three out of the six cows surgically modified in 1986 are still in use on experiment 10 years later in 1995.