Energy Requirements in Dogs

Energy Requirements in Dogs

Formulating an exact equation to estimate the energy requirements in dogs is a difficult task because of the wide variety of body sizes and weights in this species.

The amount of energy that is used by the body is correlated with total body surface area. Body surface area per unit of weight decreases as animals increase in size.

Energy Requirements in Dogs is correlated to Feeding Management of Dogs.

As a result, the energy requirements of animals with widely differing weights are not well correlated with body weight; they are more closely related to body weight raised to a specified power.

This unit of body weight is called metabolic body weight. Representing weight as metabolic body weight helps to account for differences in body surface area between animals of varying sizes.

Energy Requirements Calculation in Dogs
Energy Requirements Calculation in Dogs

Energy Requirements for Dogs at Different Stage of Life

Energy Requirements for Dogs at Different Stage of Life
Energy Requirements for Dogs at Different Stage of Life

Protein Requirements for Dog

The current National Research Council (NRC) recommends a minimum protein requirement of 80g of crude protein per kg diet in foods with an energy density of 4.0 kilo calories (kcal) ME/g, when proteins that are of high quality (both bio available and with the correct amounts of the essential amino acids) are fed.

This is equivalent to just 7 % of the diet‘s ME. The NRC‘s recommended allowance is slightly higher (8.75 % of ME), presumably to account for lower digestibility coefficients of protein sources used in practical diets.

It is important to consider that when lower-quality protein sources are fed, protein requirement estimates will increase significantly, typically as high as 20% of the ME calories.

For this reason, the current American Association of Feed Control Officials‘ (AAFCO‘s) Nutrient Profiles for dogs recommends that adult maintenance dog foods contain at least 18 % of ME calories as protein.

The protein requirement of growing puppies is significantly higher than that of adult dogs. Early studies using mixed protein sources reported minimum protein requirements of between 17 % and 22 % of ME for growing dogs.

These experiments used maximum weight gain as an indicator of minimum protein needs. More recent studies, which also used weight gain as the major response criterion, reported minimum requirement estimates for recently weaned puppies of approximately 180 g crude protein/kg diet in a food containing 4.0 kcal/g. This is equivalent to just 16% of ME.

However, the protein sources used in all of these studies were either highly digestible protein or supplied as free amino acids. Interestingly, weight gain in growing dogs is maximized at lower protein intakes than is nitrogen retention.

The current NRC recommends that a minimum of 16 % of a diet‘s calories should be supplied as high-quality protein to maximize nitrogen retention in newly weaned puppies between the ages of 8 and 14 weeks. After 14 weeks, the minimum requirement decreases to about 12.25 % of ME.

However, just as with adult maintenance diets, these estimates increase substantially when feeding practical diets that contain less available protein sources. The NRC recognizes this and recommends minimum levels of 21 % (250 grams/kilogram [g/kg]) for puppies less than 14 weeks of age and 17.5 % for puppies over 14 weeks of age when fed practical diets.

The current AAFCO Nutrient Profiles recommend a minimum level of 22 % protein ME for growth and reproduction and do not distinguish between newly weaned and adolescent puppies.

Fat Requirements in Dog Diet

Although there is not an absolute requirement for dietary fat per se, fat is needed in the diet to provide EFAs and energy and to enhance diet palatability.

A minimum amount of dietary fat is also needed as a carrier for the fat-soluble vitamins.

Most dry dog foods that are marketed for adult maintenance contain between 5 % and 13 % fat (DM basis).

In comparison, the fat content of dry dog foods that are formulated for gestation, lactation, or performance may be 20 % or greater.

The current Association of American Feed Control Officials‘ (AAFCO‘s) Nutrient Profiles minimum fat recommendations are 5 % for adult maintenance and 8 % for growth and reproduction (DM basis) provided in a food containing 3500 kcal/kg.

An adult dog maintenance food should also provide a minimum of 1 % of the food‘s dry weight as linoleic acid.

Although a requirement for alpha-linolenic acid has not been established for dogs, a minimum requirement (NRC) recommends that aratio of linoleic acid to alpha-linolenic acid of between 2.6 and 26 should be maintained in all foods.

Although EPA and DHA are considered to be conditionally essential during certain stages of life for dogs, a minimum dietary requirement for these LCPUFAs has not been established for dogs.

The current NRC provides an adequate intake (AI) estimate of 0.11 g of EPA and DHA combined per 1000 kcal of diet of approximately 0.044 % DM (or 0.09 % ME) in foods containing approximately 1% linoleic acid is suggested.

Because the n-3 and n-6 fatty acids compete for metabolic pathways, the amount of alpha-linolenic acid in the food must always be determined relative to the level of linoleic acid.

If the linoleic acid content of the food is higher than 1%, alpha-linolenic acid should also be increased to maintain an appropriate balance between the two families of fatty acids.

The current National Research Council (NRC) recommends that a ratio of linoleic acid to alpha-linolenic acid of between 2.6 and 26 should be maintained in all foods. Although EPA and DHA are considered to be conditionally essential during certain stages of life for dogs, a minimum dietary requirement for these LCPUFAs has not been established for dogs.

The current NRC provides an adequate intake (AI) estimate of 0.11g of EPA and DHA combined per 1000 kcal of diet.

Requirement of Essential Nutritive Ingredients in the Feed of a Dog

Requirement of Essential Nutritive Ingredients in the Feed of a Dog
Requirement of Essential Nutritive Ingredients in the Feed of a Dog
Recommended Nutrient Composition in Adult Pet Dog Food
Recommended Nutrient Composition in Adult Pet Dog Food

Nutritional Management of Newborn Puppies

The neonatal period in puppies and kittens is considered to be the first 2 weeks after birth. The offspring of dogs and cats are altricial, which means that puppies and kittens are born in a relatively immature state and are completely dependent upon their mother‘s care.

Because of this immature state, preweaning mortality estimates for puppies and kittens are estimated to be as high as 40 %, and the vast majority of deaths occur during the neonatal period.

The first 36 hours of a puppy‘s or kitten‘s life are a critical time because the process of birth and the sudden environmental changes that newborns experience are physiologically stressful. Therefore every effort should be made during this time to minimize stress and variations in the environment.

A quiet, warm whelping area should be provided, and human visitors outside of the immediate family should be prevented from disturbing the litter during the first few days.

Colostrum Feeding

The dog and cat have an endotheliochorial placenta consisting of four layers. This type of placenta allows only about 10 % to 20 % of passive immunity to be transferred in utero. Therefore, for puppies and kittens, the major proportion of passive immunity is acquired after birth via the colostrum.

This emphasises the importance of immediate nursing and the provision of colostral antibodies and bioactive factors to puppies and kittens immediately after birth.

The intestinal mucosa of newborn dogs is capable of absorbing intact immunoglobulins provided by colostrum. The time during which the newborn‘s gastrointestinal tract is permeable to the intact immunoglobulins in colostrum is very short.

The term closure refers to the change in the gastrointestinal tract‘s absorptive capacity that precludes further absorption of large, intact proteins.

The mechanisms behind closure are not fully understood, but they appear to be hormonally mediated, possibly related to increased circulating insulin that appears after the initiation of suckling. This limits the ability of the neonatal intestine to absorb intact proteins to about the first 48 hours of life. Therefore it is vitally important that newborn puppies and kittens receive adequate colostrum as soon as possible during the first day after birth.

Dog Milk

The nutrient pattern of dog‘s milk is somewhat different. The most recent study reported that while milk protein is very high on the first day of lactation (>10%), it decreases gradually for the following 3 weeks and then, after day 21, increases slightly until weaning.

The lipid content of dog‘s milk is higher than that reported for cat‘s milk and does not show the dramatic decrease early in lactation that is reported for cat mammary secretions.

Because of this higher fat content and possibly due to its slightly higher protein concentration, dog‘s milk is higher in energy than cat‘s milk.

In both species the total energy content of the milk decreases gradually from colostrum to the milk that is produced during mid lactation. Energy concentration then increases until weaning in both species. Lactose concentration in dog‘s milk is lowest in colostrum and increases gradually until mid lactation.

Nutrient Composition of Dog Milk

Nutrient Composition of Dog Milk
Nutrient Composition of Dog Milk

The gastrointestinal tracts of newborn puppies are uniquely suited to digest and absorb the milk produced by the mother. Immediately after birth, the ingestion of milk is a potent stimulator for enteric growth and for the development of the intestinal mucosal cells.

Fat and lactose are the primary sources of energy in milk; puppies have high intestinal lactase activity and are capable of digesting milk fat very early in life.

Similarly, both the type and amount of protein found in the milk are intricately matched to the developmental state of life. Gastric acid production is low in puppies and kittens until they are about 3 weeks of age. However, this does not appear to inhibit their ability to digest milk proteins. The renal capacity of neonates is also not fully developed and is sensitive to excessive or poor quality protein intake.

Milk protein is of high quality and at a concentration that is closely matched to the metabolic capabilities of the developing young.

Lastly, at birth, the gastrointestinal tract of puppies and kittens is sterile. Microbial colonization begins within the first day of life as the newborns ingest milk.

This continues to evolve when solid food is introduced at 3 to 4 weeks of age and as the young attain adulthood. Volume of milk intake is affected by age, rate of growth, and for dogs, breed size.

Breed Variation in Milk Production

Naturally, puppies of larger breeds are expected to consume a greater volume of milk, with smaller breeds and kittens consuming less volume. Similarly, the volume of milk that a female dog produces varies with her size.

German Shepherds produce about 900 g (32 oz) of milk per day in early lactation, with increases of up to 1700 g (60 oz) per day during peak lactation.29 In contrast, a much smaller breed.

The Dachshund, produces between 100 and 180 g (3 to 6 oz) of milk per day in early lactation. Other influences upon the volume of milk produced are litter size, the age at which supplemental food is introduced, and age of weaning. In healthy puppies and kittens, the dam‘s milk supports normal growth until the young are 3 to 4 weeks old.

Supplemental feeding with commercial milk replacer is usually not necessary, with the exception of unusually large litters. Even in those cases, dividing the litter into two groups and allowing each group to feed every 3 to 4 hours can often allow adequate intake for all of the puppies or kittens.

After 4 weeks, milk alone no longer provides adequate calories or nutrients for normal development. At approximately the same time, puppies become increasingly interested in their environment and begin to spend more time awake and playing with each other. The time at which the dam‘s milk is no longer solely able to meet the nutrient needs of the offspring corresponds to the time at which the young are becoming interested in trying new foods and when they are developmentally capable of handling the introduction of semisolid food.

Introduction of Solid food

Supplemental food should be introduced to puppies and kittens when they are 3 to 4 weeks of age. A commercial food made specifically for weaning puppies or kittens can be used, or a thick gruel can be made by mixing a small amount of warm water with the mother‘s food.

Cow‘s milk should not be used to make the gruel because it is higher in lactose than bitch‘s and queen‘s milk and may cause diarrhea.

Puppies and kittens should also not be fed a homemade “weaning formula”. Although the foods that are used to make these formulas are usually of high nutrient value, many homemade formulas are not nutritionally balanced or complete. The use of this type of formula should be avoided unless its exact nutrient composition is known.

The semisolid food should be provided in a shallow dish, and puppies can be allowed access to fresh food several times per day. The bowl should be removed after 20 to 30 minutes. At first, little of the semisolid gruel will be consumed, and the litter‘s major food source will continue to be the dam‘s milk. However, by 5 weeks of age, puppies and kittens are readily consuming semisolid food.

The deciduous teeth erupt between 21 and 35 days after birth. By 5 to 6 weeks of age, puppies and kittens are able to chew and consume dry food. Nutritional weaning is usually complete by 6 weeks of age, although some bitches continue to allow their young to nurse for 8 weeks of age or longer.

Puppies will suckle occasionally and will continue to interact with the mother dog at 7 weeks of age even when offered free access to solid food.

It is believed that the psychological and emotional benefits of suckling may be as important as the nutritional benefits in puppies that are older than 5 weeks of age. For this reason, complete weaning (behavioral weaning) should not be instituted until puppies and kittens are at least 7 to 8 weeks of age.

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