Wet pet food: when is it indicated?
Semi-dry and kibble-based diets have gained in popularity in recent years, but wet pet foods have some unique features and may offer distinct advantages in certain situations. Megan Shepherd and Jess Benson take a brief look at some of the facts behind these diets and discuss why they may be the food of choice for some cats and dogs.
Wet pet foods may offer some advantages over semi-moist and dry pet foods in certain situations.
Consider feeding wet pet food after evaluating the pet’s health, diet history and the owner’s resources, and always purchase pet food from reputable manufacturers.
Most pets are fed a commercially produced pet food. Few pets consume commercially produced wet pet food (wet food) as their primary food 1, although cats appear to consume more wet food than dogs 2. Owners will often seek veterinary advice as to the best food to offer their pet, and this brief article reviews some of the salient points for wet foods.
Some important facts
Wet food (i.e., moist, canned) contains 60-80% moisture, which is in contrast to semi-moist food, at around 25-35% moisture, and kibble (i.e., dry food), which is around 10% moisture 3. Wet foods include gelling ingredients, such as soluble fibers 4, starch, wheat gluten and spray-dried animal plasma 5, for texture. The gelling agents do not appear to impact macronutrient digestibility 5, 6. However, micronutrients such as selenium 7, sodium and potassium 8 appear to be less bioavailable in wet food, possibly due to the gelling agents 5. Furthermore, thiamine is a heat-labile essential nutrient reported to be deficient in some pâté-style wet foods, and in wet food produced by some small petfood companies 9. Additionally, wet food should contain a higher taurine content (as compared to dry food) to balance the enhanced bile acid excretion and subsequent microbial degradation of taurine seen with wet vs. dry food 10.
What are the advantages of wet foods?
Wet food is often reported to be more palatable than dry foods 11,12. This may partly be because wet foods are typically higher in protein when compared to dry foods 13, which cats in particular find palatable 14. Furthermore, wet food is often higher in fat, which generally enhances palatability ( Figure 1 ). Wet food may also be more aromatic and is available in different forms (textures), such as pâté or morsels and gravy 15. While some pets may show a preference to wet food, some pets express a strong desire for dry food rather than wet food 16.
The high-moisture content of wet food may reduce the total calories consumed at a meal 17, and may also decrease the risk of obesity in cats 18. However, pets have successfully lost weight on dry food with enhanced insoluble fiber. Cost (price per calorie) and the perishable nature of wet food may reduce the incidence of overfeeding, as compared to dry food. However, wet food has a higher fat content than dry food and thus a higher calorie content on a dry matter basis.
Wet food increases total daily water intake 19, 20 despite negatively influencing drinking water intake 21. The strongest indication for wet food is for the patient with urinary disease in general, where urine dilution is required ( Figure 2 ). Feeding a wet diet can be indicated for management of feline idiopathic cystitis (FIC) 22. Urine specific gravity (USG) and the relative supersaturation (RSS) of calcium oxalate is reduced when cats 19 and at-risk dog breeds 20 are fed a diet with 73% moisture, as compared to a diet with 7% moisture. Feeding dry food can be one of many other dietary risk factors for calcium oxalate urolithiasis in dogs 23.
Wet foods are generally lower in digestible carbohydrates and thus may be a good option for the patient with diabetes. Furthermore, the perishable nature of wet food promotes meal feeding (as opposed to ad-lib feeding), which is likely ideal for the diabetic patient. Wet foods may also be helpful for patients with oral pain due to the softer texture. However, wet foods do not serve a role in preventing dental disease due to the lack of gingival stimulation, as provided by dental-specific dry food and/or brushing.
There are many factors to be considered when selecting an appropriate diet for a pet. In some situations, wet food may be helpful. Wet food is more expensive (price/kcal) and more perishable than dry food. Therefore, a pet’s health and diet history, as well as the caregiver’s resources should be considered when selecting a diet. Importantly, whatever diet is endorsed, the clinician should emphasize that all pet foods should be sourced from reputable manufacturers that employ scientists trained in pet nutrition, food science and engineering, to ensure the food is both nutritious and safe.
- Laflamme DP, Abood SK, Fascetti AJ, et al. Pet feeding practices of dog and cat owners in the United States and Australia. J Am Vet Med Assoc 2008;232(5):687-694.
- Vandendriessche VL, Picavet P, Hesta M. First detailed nutritional survey in a referral companion animal population. J Anim Physiol Anim Nutr (Berl) 2017;101Suppl 1:4-14.
- Zicker SC. Evaluating pet foods: How confident are you when you recommend a commercial pet food? Top Companion Anim Med 2008;23(3):121-126.
- Farcas AK, Larsen JA, Fascetti AJ. Evaluation of fiber concentration in dry and canned commercial diets formulated for adult maintenance or all life stages of dogs by use of crude fiber and total dietary fiber methods. J Am Vet Med Assoc 2013;242(7):936-940.
- Rodríguez C, Saborido N, Ródenas J, et al. Effects of spray-dried animal plasma on food intake and apparent nutrient digestibility by cats when added to a wet pet food recipe. Anim Feed Sci Technol 2016;216:243-250.
- Karr-Lilienthal LK, Merchen NR, Grieshop CM, et al. Selected gelling agents in canned dog food affect nutrient digestibilities and fecal characteristics of ileal cannulated dogs. J Nutr 2002;132(6 Suppl 2):1714S-1716S.
- van Zelst M, Hesta M, Alexander LG, et al. In vitro selenium accessibility in pet foods is affected by diet composition and type. Br J Nutr 2015;113(12):1888-1894.
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- Markovich JE, Freeman LM, Heinze CR. Analysis of thiamine concentrations in commercial canned foods formulated for cats. J Am Vet Med Assoc 2014;244(2):175-179.
- Anantharaman-Barr G, Ballèvre O, Gicquello P, et al. Fecal bile acid excretion and taurine status in cats fed canned and dry diets. J Nutr. 1994;124(12 Suppl):2546S2551S.
- Hewson-Hughes AK, Hewson-Hughes VL, Colyer A, et al. Consistent proportional macronutrient intake selected by adult domestic cats (Felis catus) despite variations in macronutrient and moisture content of foods offered. J Comp Physiol B. 2013;183(4):525-536.
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- Salaun F, Blanchard G, Le Paih L, et al. Impact of macronutrient composition and palatability in wet diets on food selection in cats. J Anim Physiol Anim Nutr (Berl) 2017;101(2):320-328.
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- Rowe E, Browne W, Casey R, et al. Risk factors identified for owner-reported feline obesity at around one year of age: dry diet and indoor lifestyle. Prev Vet Med 2015;121(3-4):273-281.
- Buckley CMF, Hawthorne A, Colyer A, et al. Effect of dietary water intake on urinary output, specific gravity and relative supersaturation for calcium oxalate and struvite in the cat. Br J Nutr 2011;106 Suppl 1:S128-130.
- Stevenson AE, Hynds WK, Markwell PJ. The relative effects of supplemental dietary calcium and oxalate on urine composition and calcium oxalate relative supersaturation in healthy adult dogs. Res Vet Sci 2003;75(1):33-41.
- Thomas DG, Post M, Bosch G. The effect of changing the moisture levels of dry extruded and wet canned diets on physical activity in cats. J Nutr Sci 2017;6:e9.
- Forrester S, Roudebush P. Evidence-based management of feline lower urinary tract disease. Vet Clin North Am Small Anim Pract 2007;37(3):533-558.
- Lulich JP, Osborne CA, Thumchai R, et al. Epidemiology of canine calcium oxalate uroliths; identifying risk factors. Vet Clin North Am Small Anim Pract 1999;29(1):113-122, xi.
Jess L. P. Benson
Dr. Benson received her DVM from Virginia Maryl and College of Veterinary Medicine (VMCVM) in 2018. She has a particular interest in nutrition Read more
Megan L. Shepherd
Dr. Shepherd received her DVM from VMCVM in2006 and spent two years in general equine practice before returning to VMCVM Read more