Life-stage Nutrition for Small Animals
The average mature ideal body weight of domestic cats is 3.2 kg (7 lb) for toms and 2.8 kg (6 lb) for queens. Normal birth weight of kittens is 90–100 g. The growth rate is exceptionally rapid for the first 3–4 months, and kittens gain 50–100 g/week. The growth rate begins to plateau at 150–160 days old, and growth is usually completed within 200–220 days. Kittens are generally transitioned to an adult diet sometime between 8 months and 12 months.
Growth rates of puppies are rapid for the first 5 months; in this period, pups gain an average of 2–4 g/day/kg of their anticipated adult weight. The growth rate begins to plateau after 6 months, and growth and skeletal maturity may be completed by 8–12 months in small and medium breeds. However, growth and skeletal maturity may not be completed until 10–16 months in large and giant breeds.
Growth rate charts are available for plotting growth rates for individual puppies, and just like growth rate charts for humans, they can indicate whether a puppy is following a healthy growth pattern.
It is important to continue to feed a puppy a complete and balanced diet meant for growth until it reaches skeletal maturity, not only until obvious growth has stopped. If the breed of puppy is a large or giant breed, it is important to feed a growth diet specifically formulated for large or giant breeds.
Feeding Practices in Maintenance of Small Animals
After a dog has reached ~90% of its expected adult weight, a diet less nutrient dense than the growth diet is generally recommended. The dietary goal is to maintain optimal body weight and condition for that particular dog. Some adult dogs can be fed free choice, but most cannot without becoming obese.
The best feeding regimen to use in most adult dogs to prevent obesity is portion-controlled feeding, eg, feeding two premeasured meals at regular times each day. Most dogs will eat all their food immediately; however, some dogs will graze throughout the day.
Many owners feed treats and snacks, which are often an important aspect of the human-animal bond. Complete and balanced treat products that use low-fat, high-fiber ingredients are available. However, most treats are not complete and balanced; therefore, to prevent nutrient deficiencies, the total daily amount of treats should be < 10% of the total caloric intake.
Nutritional supplements are not required and, in fact, may be harmful in some cases. In an animal prone to obesity, the caloric content of all treats fed should be considered in an effort to match energy intake to expenditure. Regular assessment of the animal’s body condition helps ensure minimal weight gain beyond optimal adult values throughout life.
Some inactive, neutered adult cats can be fed a reduced-fat diet (9% dry-matter basis) ad lib; however, this may not work well in other cats. Cats exposed to variations in temperature (eg, cats that remain outdoors year-round or at night) may eat more during the winter.
The need for a different nutritional profile in older cats versus middle-aged cats may be necessary. Middle-aged cats are at increased risk of developing obesity, whereas older cats often have a difficult time keeping weight on.
The ability of older cats to digest protein and especially fat is often less than that of younger and middle-aged cats. Therefore, it is important to feed a diet with highly digestible protein and fat sources. The quantity of these nutrients in the diet may also have to be modified (usually increased) to compensate for impaired protein and fat digestion. However, depending on activity level, feeding a food with a different fat and fiber content (increased or decreased as needed) may be required to maintain optimal body weight and condition.
Feeding Practices in Growth and Reproduction in Dogs
Growth, pregnancy, and lactation greatly increase nutrient demands over those of maintenance. Growth diets have increased nutrient density, digestibility, and bioavailability to provide nutrients necessary in a smaller volume of food. Supplementation of calcium, phosphorus, and vitamin D beyond amounts present in complete and balanced diets designed for growth and reproduction is rarely necessary and may be contraindicated.
Growth
Overfeeding during growth increases growth rate. This is not desirable, because it is incompatible with proper skeletal development and also contributes to obesity later in life. Feeding methods for growing puppies should be individualized for the puppy and owner.
General recommendations are that puppies between weaning and 6 months old should be fed three times a day; puppies 6–12 months old should be fed twice daily. Large- and giant-breed puppies should be fed complete and balanced growth diets that display the Association of American Feed Control Officials (AAFCO) statement indicating they are formulated for large-breed puppies (eg, "including growth of large size dogs [32 kg or more as an adult]").
Small-breed puppies may have to be fed more than three times a day, and small- and medium-breed puppies can be fed a growth or all-life-stage diet that does not meet the criteria for growth of large-size dogs.
Only limited data have been published with respect to breed growth curves. Nonetheless, a slow growth rate is preferable to a fast growth rate. Weight gains should be closely monitored (weekly), and feeding recommendations adjusted such that the puppy gains a small amount of weight each week.
When growing large-breed puppies were fed 50%–70% of their littermates' ad lib intake, adult height, length, and bone or muscle mass were not stunted; only total body fat was affected. It is difficult to stunt the growth of a puppy being fed a complete and balanced growth diet that has passed an approved AAFCO feeding trial using meal feeding of an appropriate amount 2–3 times/day.
Gestation
Bitches should be transitioned to a complete and balanced growth diet at the beginning of gestation. Growth diets provide the nutrient requirements for the bitch but also help support the nutritional requirements for the growing fetuses. The average length of gestation in the bitch is 63 days. In pregnant bitches, very little growth of fetuses occurs during the first two trimesters, but substantial growth of fetuses occurs starting at the end of the second trimester or beginning of the third trimester. Energy requirements for pregnant bitches through the first two-thirds of gestation are generally the same as those for maintenance provided the bitch was not underweight at the beginning of gestation.
A common mistake is to overfeed during early gestation and to underfeed during lactation. In the last third of gestation, the total amount of food offered should be increased at least 20–30% over the amount for maintenance, depending on the size of the litter and the body condition of the bitch at the time of pregnancy.
Lactation
Depending on litter size, lactating bitches often require energy levels 2–4 times those of maintenance to avoid excessive loss of body condition. Ad lib feeding using a complete and balanced growth diet containing 10%–20% fat (dry-matter basis) is recommended to maintain lactation and to achieve optimal body weight and condition of the litter prior to weaning.
If a bitch loses appreciable body condition during lactation, the fat content of the diet should be increased to 20%–30% fat (dry-matter basis), and she should be fed ad lib. Growth diets not formulated for large- and giant-breed puppies are also recommended even if the bitch is a large or giant breed.
Feeding Practices in Growth and Reproduction in Cats
One of the most important differences between queens and bitches is that pregnant queens exhibit a linear increase in weight (fetal growth) throughout pregnancy. As a result, pregnant queens need to consume more calories almost immediately after becoming pregnant. In contrast, fetal growth is minimal during the first two trimesters of pregnancy in the bitch, and caloric intake does not generally have to be increased until sometime between the end of the second trimester and the beginning of the third trimester.
Because queens tend to lose weight during lactation regardless of diet fed, it has been assumed that net tissue reserves should increase somewhat in preparation for lactation. A growth diet for kittens that contains 10%–35% fat, 30%–40% protein, and low (< 5%) fiber (dry-matter basis) should be fed. Growing kittens and pregnant and lactating queens can be fed ad lib or several times a day to meet their daily needs.
During the latter third of gestation, the amount of food and level of nutrient intake normally increases an average of 25%, although energy intakes for cats during pregnancy have been estimated to be as much as 40% greater than for maintenance. Early in gestation and immediately before parturition, some queens may eat less; such changes are of concern only if prolonged.
Queens require 2–3 times the normal food intake during lactation, depending on litter size. Supplementing an already balanced diet is not necessary and should be discouraged.
Feeding Practices in Geriatric Dogs and Cats
Older dogs may not be as efficient in metabolizing dietary protein as younger dogs. As a result, older dogs may actually require more dietary protein than their younger counterparts to maintain protein reserves and maximize protein turnover rates. In addition, decreased fat digestion occurs with age in cats, so geriatric cats may actually require a higher-fat diet than their younger counterparts. In contrast, some dogs and cats begin old age considerably overweight, whereas others may show some loss of condition.
Feeding an appropriate food with a different nutrient profile with respect to energy, fat, or fiber content (increased or decreased) may be needed to maintain optimal body weight and condition.
Geriatric dogs and cats should be monitored in a preventive health program that includes periodic assessments of body weight and condition as well as organ function and cognitive function (dogs). The incidence of chronic degenerative organ disease increases with age, and early diagnosis fosters earlier treatment and more effective nutritional management.
Work or Stress in Feeding Practices in Small Animals
The caloric needs of working or stressed dogs may exceed the levels of a maintenance diet, depending on the animal and the extent of work performed. Most diets designed for work or stress have increased levels of animal fats, with the other nutrients appropriately balanced to the increased energy density. At extreme levels of stress (eg, an Alaskan sled dog requiring 10,000 kcal/day), many recommend not only increasing the percentage of metabolizable energy (ME) from fat but also from protein, while minimizing the contribution of carbohydrate.
Any daily feeding recommendation should be considered an estimate or starting point and should be modified based on continual evaluation of the dog’s weight and condition, skin and coat, performance, and general attitude. Feeding a smaller amount of the daily ration (eg, one-third of the daily amount) before beginning a work shift is recommended with the remainder being fed thereafter. Plenty of fresh water should be available, and opportunities to stop work for a water break should be scheduled in any daily work routine for these dogs.
