ORPHANS
Support of orphaned puppies and kittens involves maintenance of adequate environmental temperature, feeding a well balanced milk-based diet for the first three weeks of life, and stimulation of urination and defecation. Pediatric animals do not have well developed thermoregulatory systems and rely on an external heat source, ideally the dam, for maintenance of normal body temperature. Orphans should be maintained in an environment at about 85F (29.5C) for the first two weeks of life, and about 80F (26.5C) for the subsequent two weeks. Warmed and cooler areas should be available, so the puppies and kittens can crawl to an area appropriate in temperature. Among surface sources of heat, circulating hot water blankets are best. Hot water bottles should be wrapped in towels and frequently changed. Regular heating pads may heat unevenly and more easily burn the fragile skin of neonates. Heat lamps are an excellent, safe way to provide radiant heat.
Ascertain, if possible, whether the puppy or kitten has ingested colostrum (see previous notes). The puppy or kitten should have been weighed at birth, and should be weighed daily thereafter. Slight weight loss may occur in the first 24 hours of life. After that, the puppy or kitten should gain weight daily, doubling their birth weight by 7 to 10 days of age (see previous notes).
Milk is the primary diet of puppies and kittens up to three weeks of age. Besides providing passive immunity and nutrients, milk, composed of about 85% water, is the primary source of fluid for neonates and is vital for maintenance of normal hydration and fluid volume and provision of non-nutritive bioactive agents, such as enzymes, hormones and growth factors.
An effort should always be made to find another lactating bitch or queen to support orphan animals. No commercial or home-made milk replacer contains all the components of bitch's or queen's milk. The protein content and percent of calories from protein in milk are positively correlated with growth rate in animals. Cow's milk is lower in protein than is either bitch's or queen's milk. Goat's milk, a commonly described supplement for orphans, also is a poor substitute for bitch's and queen's milk.
Commercial milk replacers are recommended over home-made diets. Commercial formulas are balanced, of high nutrient density, low in fiber, and contain protein of high biologic value. Feline milk replacers must contain a source of taurine for optimal growth to occur. Home-made diets are best used in emergency situations only.
Problems reported with feeding of either commercial or home-made milk replacers to puppies and kittens include small, focal cataracts due to deficiencies in vitamins or amino acids that resolve after weaning, and slower growth rate due to lack of enzymes necessary for fat digestion. Bitch's milk varies in composition over lactation and cannot be mimicked by milk replacers, which provide constant levels of protein and other nutrients. Hand-raised puppies and kittens achieve the same size as littermates allowed to nurse by several months of age. The high lactose content of cow's milk and decreased caloric density of formulas make it difficult to provide orphans with an adequate number of calories without inducing diarrhea. If feeding induces diarrhea, the formula can be diluted 1:2 with electrolyte solution until the neonate can tolerate it.
Amount to be fed varies with caloric density of the formula, and age and weight of the animal. Kittens should receive 100 to 175 kcal per pound (220 to 380 kcal/kg) daily, split into 4 to 6 feedings. Puppies should receive 105 to 120 kcal per pound (230 to 260 kcal/kg) daily, split into 4 feedings. Feeding frequency can be decreased to 3 times daily after the orphan reaches 2 weeks of age. For example, kitten home-made diet number 1 above contains 237 kcal/cup, which equals 30 kcal/fl oz (3 kcal/ml). Kittens require 100 to 175 kcal/pound daily; a 4 oz (1/4 pound = 113 gm) kitten requires 25 to 44 kcal daily. The amount to be fed daily is 0.8 to 1.5 fl oz (8 to 15 ml). This yields, for 4 daily feedings, a per feeding volume of 0.2 to 0.4 oz (2 to 4 ml). Similarly, puppy home-made diet number 3 above contains 208 kcal/cup. Calculation determines a per feeding volume for a 1 pound puppy of 1 to 1.3 fl oz (10 to 12 ml). Commercial milk replacers often bypass discussion of calories, providing volume instructions only. Examples are the puppy milk replacer, Esbilac and kitten milk replacer, KMR (Pet-Ag, Elgin IL; 2 T / 4 oz (10 ml / 125 gm) daily).
The formula should be warmed to 95 to 100F (35 to 38C) when feeding 1 to 2 week old animals. If the animal has been inappetant, it may be beneficial to feed half the calculated dose for 1 to 2 days. Equipment for feeding of pediatric animals includes spoons, droppers, bottles, or tubes. Spoon- and dropper-feeding are dangerous since the limited gag reflex of puppies and kittens easily permits aspiration of formula into the lungs. Bottle-feeding poses less risk of aspiration and more readily satisfies the neonate's need to suckle. Small bottles marketed for animals or bottles intended for premature human infants may be used. The hole in the nipple should allow milk to ooze slowly. The bottle should never be squeezed to force expulsion of milk while the animal is nursing.
Tube-feeding is quick. Caution must be used to ensure proper placement of the tube into the gastrointestinal tract and to prevent overflowing and regurgitation. The animal should be held horizontally on its ventrum. The feeding tube varies in diameter and length with age. A #5 French feeding tube should be used in animals weighing less than 300 gm and a #8 to #10 French feeding tube used in animals weighing more than 300 gm. Measure the length of the feeding tube by marking off 75% of the distance from the animal's last rib to the tip of its nose. This length ensures placement in the stomach without kinking of the tube within the gastrointestinal tract. Length should be rechecked and adjusted weekly. The warmed formula is gently expelled through the tube with a syringe. Monitor gastric distension; average stomach capacity in neonates is about 0.7 fl oz (4 tsp) per pound (40 ml/kg). The genital area should be massaged with a cotton ball or soft cloth moistened with warm water after feeding to promote urination and defecation.
WEANLINGS
Weaning, introduction of solid food, begins at 3 weeks of age in puppies and at 3-4 weeks in kittens. By three weeks of age, the muscularis layer of the intestinal tract has doubled in size, promoting passage of bulky foodstuffs, and pancreatic enzyme secretion is increased. A growth food appropriate for the species, not human baby food, should be introduced. Young animals need more nutrients to allow for normal growth and development but take longer to ingest food and have a smaller digestive capacity, necessitating feeding of an energy dense, highly digestible food. Food should be offered as a gruel initially, formed by thoroughly blending 1 part dry food to 3 parts water or 2 parts canned food to 1 part water for puppies, and 1 part dry food to 3 parts formula or 2 parts canned food to 1 part formula for kittens. Fewer problems with post-prandial gastric distension occur if the food is thoroughly soaked. Fresh water always should be provided as well. Gradually mix less water or formula with the food until the puppy or kitten is eating dry food exclusively. Weaning usually is complete by 6 to 8 weeks of age. By the time the animal is weaned, it should have a body weight roughly 6 to 10 times its birth weight.
ADOLESCENTS
Once weaned, kittens can be fed ad-libitum. They should be maintained on a growth diet until they achieve adult size. The average kitten consumes about 1 oz (28 gm) of dry food at 5 weeks of age, 2 oz (56 gm) at 10 weeks of age, and 2.5 to 3 oz (70 to 84 gm) by 20 weeks of age.
Puppies should not be fed for maximal growth rate. Excess energy intake is associated with obesity and skeletal problems. Excessive caloric intake during adolescence promotes increase in size and number of adipocytes, predisposing the animal to obesity throughout its life. Skeletal problems reported in dogs provided with excess energy in adolescence include hip dysplasia, osteochondosis (OCD), angular limb deformities, and cervical spondylopathy (Wobbler's). Calories should be limited to permit a moderate growth rate, especially in puppies of large and giant breeds that are genetically programmed to grow quickly. As a general rule, puppies require twice the adult energy requirement by body weight when half-grown. Age at attainment of adult size and body conformation varies by breed.
Puppies should be meal-fed, with the food made available for 10 to 20 minutes twice daily, until the puppy reaches 80 to 90% of adult weight. Puppies receiving up to 25% less food than littermates while growing achieve the same height at the shoulder and body weight after 1 year of age.