Animals should be offered the option to eat before each feeding. If oral intake is not possible or if an animal will not voluntarily
consume enough calories of a complete and balanced diet to meet its energy and nutrient requirements, assisted nutritional
support is indicated.
Planning for the feeding route before other procedures are performed is strongly recommended. If an animal with confirmed
or anticipated anorexia is to be sedated or anesthetized for a diagnostic or therapeutic procedure, consider placing a feeding
tube at that time. Prophylactic placement of a feeding tube can provide a safety net when it is unclear whether an animal
will begin eating on its own. In cases in which an animal has intractable vomiting, severe malabsorption, or neurologic disorders
in which a gag response is compromised, parenteral nutrition is the preferred route of nutritional support. Information on
parenteral nutrition is available from other resources.14,15
Depending on how long the animal was anorectic, feedings should provide 25% to 50% of RER on the first day, divided into four
to six feedings (although most animals can tolerate four feedings a day), with each feeding administered over at least 10
to 15 minutes. As long as the animal tolerates the feedings, the amount fed can be gradually increased to achieve 100% RER
over two to four days. In our clinical experience, most animals tolerate volumes between 5 to 20 ml/kg per feeding. When sending
the animal home, it is best to adjust to three feedings a day, if possible, to aid in owner compliance.
Feeding hospitalized animals by continuous-rate infusion is appropriate for those that do not tolerate bolus feeding (e.g. delayed gastric emptying, ileus).
All enteral diets should be refrigerated after opening and should be discarded after 48 hours since contamination can occur.
Enteral diets should then be warmed to room temperature before administration to the patient. Choosing the most appropriate
diet depends on several factors, including the animal's medical condition and nonpatient factors such as the tube type, diet
availability, and cost.
For patients with small-bore tubes (NE, NG, J tubes), a liquid enteral diet must be given. One liquid enteral diet that meets
nutritional requirements for dogs and cats is CliniCare Canine/Feline Liquid Diet (Abbott Laboratories). For cats with underlying
renal disease that require decreased protein and phosphorus or for dogs requiring phosphorus restriction but minimal protein
restriction, CliniCare RF Feline Liquid Diet (Abbott Laboratories) is a better choice; however, this product provides too
much protein for a dog that requires significant protein restriction.
Not all enteral diets marketed for dogs and cats are nutritionally complete and balanced, so they should be evaluated carefully
to ensure that they meet the Association of American Feed Control Officials minimums for all nutrients before use.
Some liquid enteral diets for people (e.g. Ensure—Abbott Nutrition, Peptamen—Nestlé HealthCare Nutrition) can be used short term in dogs, but these diets do not provide
complete and balanced nutrition and modifications are necessary if they are to be given for more than a week. When human enteral
products are given to dogs and cats in the short term, additional protein, B vitamins, arginine, and taurine is almost always
required, and calcium, zinc, iron, and choline supplementation is almost always required for long-term administration of these
products. However, the specific nutrients and amounts that need to be supplemented vary with each product. A board-certified
veterinary nutritionist can assist you in selecting (and modifying, if necessary) the most appropriate enteral product for
Some veterinary enteral critical care diets are formulated to meet canine and feline nutritional requirements, have a consistency
amenable to tube feeding, and are relatively caloric-dense. When mixed with a small amount of water (25 ml per 5.5- to 6-oz
can), these diets provide 1 to 1.8 kcal/ml (Table 2). Each diet has a different nutrient profile that can be used to determine the diet most appropriate for an individual animal
(e.g. avoiding diets high in sodium for a cat with cardiac disease or selecting a diet higher in protein for a dog with hypoalbuminemia).
Table 2: Nutritional Assessment of Available Veterinary Critical Care Diets
When these critical care diets are contraindicated for an individual animal (e.g. a dog with advanced kidney disease or a cat requiring a novel ingredient diet), commercial canned veterinary diets may be
given for enteral feeding if liquified by adding water and using a high-speed blender for two or three minutes. The amount
of water added to each diet varies based on the individual diet, but the resulting caloric density is typically well below
that of critical care diets (e.g. 0.5 to 1.2 kcal/ml). Additionally, these diets require careful flushing to avoid tube clogging.