Sick Dogs Need to Eat Sooner Rather than Later

Published Oct. 23, 2015

I recently wrote a post over on Daily Vet about sickness behaviors in animals. These are “a classic array of behavioral and physiological signs associated with illness, including loss of appetite and reduced feed intake, reduced activity, and attempts to withdraw from social contact.” The gist of the article was that sick animals act in this way because it helps them recover from illness, and we should support these behaviors rather than try to override them.

While sickness behaviors are generally beneficial, like most things in life, if taken too far they can be detrimental. This is especially true when it comes to a dog’s unwillingness to eat.

I don’t worry when a sick dog doesn’t feel like eating for a couple of days. If the gastrointestinal tract is involved in the dog’s illness a few days “off” can give it a chance to recuperate. Even if the GI tract isn’t the source of the problem, a few days without food will generally not do much in the way of harm.

But new research presented at the 2015 American Academy of Veterinary Nutrition meeting shows that taken too far, a lack of adequate nutrition is certainly detrimental to a sick dog’s welfare.

Scientists evaluated 490 dogs who were hospitalized for a day or more at the Veterinary Teaching Hospital of the Universitat Autonoma de Barcelona. They looked at many parameters, including body weight, body condition score, muscle condition score, laboratory data, diagnostic tests, reason for hospitalization, length of hospitalization, resting energy requirement, food intake, clinical signs, nutritional intervention, severity of disease, and outcome (discharged, died, or euthanized).

Dogs had a better chance of being discharged alive when they ate (or were fed) enough to meet their resting energy requirements. Other factors that improved outcomes were a higher initial body condition score and nutritional intervention. Worse outcomes were seen in dogs who were not eating on their own when they arrived at the hospital and/or were hospitalized for long period of times. A previous study by the same authors showed that length of hospitalization, age, body condition score, and vomiting at admission were all associated with a reduction in a dog’s body condition score during hospitalization.

For veterinarians, this research brings home the importance of calculating a dog’s resting energy requirement, updating it regularly (it changes with weight gain/loss), monitoring how much food a dog is taking in, and instituting appropriate interventions (e.g., anti-nausea medications and/or a feeding tube) in a timely manner.

For owners, the take home message is even simpler: If your dog is not eating well, don’t wait more than a few days to seek veterinary care (sooner if symptoms like vomiting, diarrhea, or discomfort are also present). The faster treatment is started the better the chances of a successful outcome for your dog.

Dr. Jennifer Coates


Using Behavior to Assess Animal Welfare Module. National Veterinary Accreditation Program. USDA.

Nutrition related risk factors for malnutrition and negative outcome in hospitalized dogs. Molina, J. et al. 15th Annual AAVN Clinical Nutrition and Research Symposium Proceedings. 2015.

Jennifer Coates, DVM


Jennifer Coates, DVM


Dr. Jennifer Coates is an accomplished veterinarian, writer, editor, and consultant with years of experience in the fields of veterinary...

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