Your dog started bringing back undigested food that had formed a sausage shape. You thought he was vomiting, but when you showed the video to the vet, she disagreed and said the dog was regurgitating. Now you understand that regurgitation is a passive process, a bit like a car with the handbrake off, rolling downhill.
Your dog is old but otherwise in good health, and it transpires his gullet has become weak and baggy. Instead of food passing cleanly down into his stomach, his meal is stagnating in the gullet in his throat and so when he lowers his head the food tumbles out of his mouth.
The answer, you learn, is to feed the dog with his head well above his heart, so that gravity assists the food down. Indeed, further investigation leads you to the Bailey chair. The latter is a large box-like structure with a door. The dog enters and sits upright in a begging position, while he eats and for 15 - 30 minutes afterward, to aid digestion.
The Bailey chair is an ingenious way of helping these dogs, by supporting them in an upright position while eating. This means gravity assists the food down into the stomach, which means less risk of regurgitation and choking.
Ideally, the dog should sit calmly in the chair for at least 15 minutes after eating, to wait for the food to go down. Thus, it's important the dog is relaxed and comfortable in the Bailey chair so that he sits calmly for the duration of this time and doesn't feel trapped.
Be prepared to take your time training an older dog. In addition to coming to terms with this new apparatus, he may be suffering from arthritis or a lack of agility which make it more awkward for him to sit in the upright posture. If this is the case, be sure to work with your vet to provide adequate pain relief for the older dog.
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