In general, acceptance of a diet by dogs and cats provokes a lot of problems for the animal and the pet owner. It starts to be even a bigger problem when cats or dogs need to be treated by the vet through a therapeutic diet, mainly linked to liver, heart, renal or kidney problems.
Difficulty substituting a restricted therapeutic diet for regular commercial pet food diets is commonplace in small animal practice and can create significant medical problems. In a 1984 study, Finco and Barsanti comparing protein-restricted commercial diets in renal patients found “partial anorexia occurred due to the diet’s poor palatability” in referring to a markedly restricted protein diet.(1) In a 1991 study of the effect of undigestible components used to lower calorie density in cat food, a generalized decrease in acceptance took place with increasing percentages of the indigestible component.(2)

  1. Barsanti, J.A.; Finco, D.R. Dietary Management of Chronic Renal Failure in Dogs. J.A.A.H.A., May/June 1985, Volume 21, pp 371-375.
  2. Kienzle, Ellen; Meyer, Helmut; Schnieder, Roland. Investigations on Palatability, Digestibility and Tolerance of Low Digestible Food Components in Cats. Journal of Nutrition, 1991, 121:S56-S57.

This advent of dietary management of disease in dogs and cats has highlighted the importance of pet food palatability. Nutrient components that correlate positively with palatability (fat, protein, sodium) are often decreased in special diets in order to achieve therapeutic objectives. Substitution of crude fiber and carbohydrates for fat and protein causes a decrease in palatability.

What is Palatability?

The palatability of food is its degree of acceptability to an animal, as determined by the sensory response to specific chemical and physical characteristics – namely smell, taste and texture. The combination of smell and taste is referred to as ‘flavor’.1

The relative importance of these sensory qualities that determine food preference differs slightly in dogs and cats. In dogs, the ranking is smell, taste and texture; in cats, smell, texture and taste. Both species are particularly sensitive to odors and tastes associated with meat,2 but the appearance of the food is of little importance. Dogs have taste bud receptors for sweet, bitter and salty. Cats have no preference for sweet (sucrose) as do most mammals, but this is not unexpected in a strict carnivore. Dogs prefer (most to least) beef, pork, lamb, chicken, horsemeat and prefer a meat diet to a high-protein non-meat diet.7 Cats prefer fish to meat and are extremely sensitive to small differences in diets.

Faced with a choice of foods, dogs will smell them and almost immediately decide which one they want to eat. However, they will periodically sample the others, even when one food is strongly preferred. If the food originally chosen is more palatable, they will quickly return to eating it.3 In general, dogs will pick up the food with their teeth.
On the other hand, cats will not only smell all the foods that are available, but also taste each one before they decide which to eat, unless the odor of one is significantly more attractive.4

Cats will then pick up the food with their tongue, not their teeth. While eating, cats may change their minds several times. Both dogs and cats sniff unfamiliar foods extensively before eating,5 which greatly increases the air flow across the olfactory mucosa.6

Often called “mouth feel” by industry experts, it relates to the friction, viscosity and smoothness of the food as it contacts the surfaces of the mouth. Fat and moisture positively impact the mouth feel aspect of palatability. As a rule canned food (75% moisture) is more palatable than soft-moist food (30% moisture) which is generally more palatable than dry dog food (10% moisture).7 Fat also contributes to a positive mouth feel in food, and palatability of fat-restricted diets suffer accordingly. A fat-free diet prepared as a gel with 50-60% water proved acceptable to cats.8 It seems that fat can be reduced in a diet as long as the texture is maintained.

  1. Thomson DMH. The meaning of flavour. In GG Birch, MG Lindley (Eds) Developments in Food Flavours, pp. 1-21. London, Elsevier Applied Science, 1986.
  2. Stein LJ. Chemosensory insights. Petfood Industry, September 2001, 4-6.
  3. Smith JC et al. Fine-grained measures of dogs’ eating behavior in single-pan and two-pan tests. In LM Beidler et al (Eds) Neuroscience and Biobehavioral Reviews, Vol 8 (2), pp. 243-251. Fayetteville, New York, ANKHO International, 1984.
  4. Hullar I et al. Factors influencing the food preferences of cats. J. Anim. Physiol. Anim. Nutr. (Berl) 85: 205-211, 2001.
  5. Bradshaw J, Thorne C. Feeding behaviour. In C Thorne (Ed) Waltham Book of Dog and Cat Behaviour, pp.115-129. Oxford, Pergamon Press, 1992.
  6. Vadurel A, Gogny M. L’odorat du chien: aspects physiologiques et facteurs de variation. (Sense of smell in dogs: physiological aspects and factors of variation.) Point Vét. 28 (181):1037-1044, 1997.
  7. Houpt, K.A. Domestic Animal Behavior, Iowa University press, Ames, Iowa. 1991 p 290.
  8. McDonald, M.L., Rogers, Q.R., and Morris, S.G. Role of Linoleate as an essential fatty acid for the cat independent of arachidonate synthesis. Journal of Nutrition, 1983, Volume 113, pp 1422-1433.