Incorporating nutritional assessment into patient care is critical for maintaining pets’ health and their response to disease and injury. WSAVA lists nutritional assessment as the 5th vital assessment (after temperature, pulse, respiration and pain assessment). The American Animal Hospital Association (AAHA) guidelines for nutritional assessment are explained in the WSAVA Global Nutrition Committee toolkit (https://www.wsava.org/nutrition-toolkit). Nutritional assessment includes consideration of animal-specific factors, diet specific factors, feeding management, and environmental factors. Animal specific factors include age, life stage, activity, and nutrient sensitive disorders requiring specific dietary management (e.g., chronic kidney disease, obesity). Diet specific factors include the safety and appropriateness of the diet and include nutrient imbalances, spoilage, and contamination. The feeding of an unbalanced homemade diet or a poor-quality commercial diet would be noted under this part of the assessment.
Feeding and management factors include the frequency, timing, location and method of feeding. Feeding management includes over- or under-feeding, feeding of treats, scavenging and hunting. Environmental factors include the pet’s housing, presence of other animals, access to the outdoors, and environmental enrichment.
The nutritional assessment has two parts: a screening evaluation and when needed, an extended evaluation. The screening evaluation should be performed for every pet at every visit as part of routine history taking and physical examination. It includes a diet history, body weight, body condition score, muscle condition score, and evaluation of the coat and teeth.
Body condition scores (BCS) using a 9-point scale show relatively good repeatability. Lower numbers indicate cachexia and higher numbers indicate obesity. For dogs 4 to 5/9 is ideal; 4/9 would be appropriate for leaner breeds (e.g., Greyhounds) or working dogs. For cats 5/9 is ideal. Body condition charts include profile and “top-down” pictures and verbal descriptions. Body condition is determined using a combination of visual appearance of the cat or dog, e.g., is a waist apparent, and palpation, e.g., the amount of fat over the ribs.
The BCS evaluates body fat; however, it is possible for a pet to be overweight but still have muscle loss. This is particularly seen in diabetic and other ill pets. Diseases can cause loss of muscle mass disproportionate to the loss of fat due to the cytokine and neurohormonal effects on metabolism. Muscle mass scoring systems are based on palpation of skeletal muscle over the skull, scapulae, spine and pelvis. Animals with no muscle wasting are scored as a 3, those with mild wasting are scored as 2, moderate wasting is a 1, and a 0 represents severe wasting.
Every pet should leave the hospital or appointment with a dietary recommendation, which should be written on a discharge sheet along with other instructions, e.g., for medications. If no change is recommended, the owners should be advised that the current diet is adequate and appropriate.
An extended evaluation should be performed if nutrition-related risk factors are found or suspected based on the screening evaluation or medical assessment. Additional animal factors in an extended evaluation include changes in food intake or behaviour such as problems with prehension or swallowing, changes in the amount of food eaten, and changes in the coat or skin e.g., dryness or alopecia. The diagnostic work up would usually include a minimum data base (haematology, serum chemistry, urinalysis and blood pressure) as well as other tests as indicated, e.g., serum folate, cobalamin, iron, taurine, T4, or feline/canine specific pancreatic lipase. The effect of nutrient wasting diseases such as diabetes mellitus or protein losing enteropathies should be considered, as well as medications that may affect serum electrolyte concentrations or appetite.
Diet factors in an extended evaluation include the food’s caloric density. The provision of additional foods, e.g., treats, table food, food given to administer medications, and successful hunting or scavenging, should be evaluated for their effect on the diet balance and the caloric intake. If disease conditions exist which may be due to contamination of the food, testing should be performed.
The diet should be assessed to determine if it is complete and balanced. Some commercial diets are meant to be treats; they should be labelled a “complementary” food and not be fed as the sole diet. Foods which are complete and balanced should have this stated on the label.
Therapeutic diets may be indicated, and the use of the correct diet should be checked. Not all patients with a disease, e.g., hepatic, renal, or cardiac disease, need to be on a commercial therapeutic diet labelled for that disease. A concurrent disease may take precedence for diet choice or the diet may not be appropriate for that individual pet, e.g., some diets for liver disease are protein restricted, which is only appropriate when hepatic encephalopathy is present. In early (IRIS stage 1) chronic kidney disease, an early renal diet or senior diet may be more appropriate than a severely protein restricted diet.
Diets should be appropriate for the life stage of the pet. There is no life stage dietary profile for geriatric cats or dogs, and they should be fed as individuals as no single type of diet is suitable for all older pets.
Diets should be formulated to meet European Petfood Industry Federation (FEDIAF), Association of American Feed Control Officials (AAFCO), or National Research Council (NRC) nutrient requirements. Generally commercial foods use FEDIAF or AAFCO requirements. Ideally, appropriate feeding trials of commercial diets have been performed. The reputation and research of the company are also important. If the owner is feeding a homemade diet it should be evaluated to see if it is complete and balanced.
Feeding management factors in an extended evaluation include: who feeds the pet, are there multiple pets resulting in either competition or pets getting a diet which is only appropriate for one of the pets (e.g., everybody fed a renal diet). Environmental factors include the activity of the pet, whether it lives indoors, outdoors or both, availability of water (e.g., can an arthritic dog get upstairs to the bowl?), and access to the litter box (e.g., is one cat guarding the box, can the arthritic cat get into the box?). Stress due to other cats within the household or cats outside the house looking in a window, negative interactions with family members, especially children, or being left alone for long periods of time have an impact on the health of cats. Dogs may show competitive eating, coprophagy or obesity due to environmental factors.
An example of the effects of environmental factors has on feline health is that indoor confinement and inactivity are risk factors for overweight and the development of diabetes in cats, whereas feeding dry food is not a proven risk factor. Another example of feeding management is feeding cats with feeding balls increases activity and decreases food intake.
Feeding Management Plan
Following the assessment, a written dietary and feeding management plan should be developed and provided to the owner. The plan depends upon whether the animal is healthy or ill and if it is to be hospitalized. Some factors that need to be considered include the animal’s energy needs, protein requirements, special dietary needs for disease (e.g., kidney disease, diabetes mellitus, dietary sensitivity), nutrient losses via diarrhoea, urine (proteinuria, glucosuria) and chest or abdominal drains.
The owner should be taught to monitor the pet’s weight and BCS, and adjust food intake appropriately. These factors should be considered at every veterinary appointment, and the type and amount of food changed as needed. It is usually recommended that diet changes take place over 5 to 10 days.
The owner’s needs should be considered, e.g., if they work full time, feeding multiple times per day may not be feasible. Where treats and snacks are part of the owner’s relationship with the pet, advice should be given for appropriate treats and the amount should not exceed 10% of the calorie intake. Asking an owner to completely stop feeding treats may result in poor compliance; better to accept that treat giving will occur and give advice that will work for the owner and pet.
Feeding management may include weighing or, less ideally, measuring the amount of food. Many cats do well on free choice feeding, which mimics their natural frequent feeding pattern of 10 to 12 mice a day. Overweight cats may require meal feeding as they may over-eat even a low-calorie food with free choice feeding. Most dogs are fed meals once to several times per day. Other factors include the location of feeding, and how other pets and humans influence eating, such as conflict with another cat or toddlers dropping food. Environmental enrichment may also include increasing the predictability of the animal’s life or increased opportunities for play or exercise.
When the pet comes into the clinic, all the veterinary healthcare and reception team are important for promoting the importance of nutrition. As noted by the American Animal Hospital Association, “Best results are achieved when every member of the pet’s health care team—from practice owner to pet owner—pulls together to provide the best health care for the pet.”