Nutrient requirements for dog include proteins, fats, minerals, vitamins and water. They can also utilise carbohydrate although it cannot strictly be described as essential.
Most foods contain a mixture of some or all of these nutrient Classes and therefore careful combination of different foodstuffs will result in a suitable diet.
Significance Of Nutrient Requirements For Dog
Nutrients are required in the diet in different quantities.
Even so, if any essential nutrient is missing or present in insufficient quantity, the whole diet will be inadequate.
Nutrients Provide Energy
In addition to providing specific nutrients, food also provides energy or calories. Energy is needed not just for muscular activity or exercise, but also for maintenance of body temperature and for processes necessary for life such as breathing and heart function. Even a sleeping dog uses energy.
Factors Affecting Energy Requirements
There are many factors which affect energy requirements. Puppy growth, Pregnancy and lactation increase the requirement, but for normal adult dogs the most important factor is body weight. Although larger dogs have a greater requirement, this is not strictly in proportion to their bodyweight.
A range in energy requirement is shown to allow for other influences such as age, sex, level of activity and environmental temperature.
The energy requirements of every dog will change through its lifetime. While many dogs will not experience such large fluctuations, it is important that owners recognise that needs may vary through the dog’s life cycle and that food intake Will need to be adjusted accordingly.
Sources Of Energy In Food
The energy in food comes from protein, fat and carbohydrate which are oxidized, or burned, in working tissues to release energy. Each gram of protein and carbohydrate provides about 4 kcal while fat supplies double that amount.
Excessive intake of any of these nutrients will lead to the accumulation of energy as body fat, inadequate energy intake will result in poor growth (in puppies) and weight loss (in adult dogs).
It is therefore important to provide the corect number of calories for the particular dog at a specific stages in its life cycle, taking into consideration it’s lifestyle and it’s environment in which it lives.
#1 Nutrient Requirements For Dog
Proteins are very long molecules made up of chains of many small unit called acids- rather like a string of beads. There are about 20 different amino acids’ but since each combination produces a protein with specific characteristics, there is an almost infinite variety of proteins.
Proteins are essential constituents of the cells which make up the body tissues, having several irnportant functions in the regulation of metabolism (as enzymes and some hormones); in a structural role in cell walls and musle fibers, in transport of essential materials, and in the body’s defence against disease.
The protein requirements of growing puppies, pregnant and lactation bitches are greater, weight for weight than normal adult dogs. This is because protein is necessary for the synthesis of new tissue, and for the production of milk However, even adult dogs need to replace protein broken down and lost from the body every day, mostly at the urine but also in faeces and in hair growth.
Protein quality is an important consideration in the selection of foodstuffs and is governed by two factors digestibility and the amino acid profile.
Digestible protein is that part which is absorbed through the gut wall into the body and not lost in the faeces, The digestibility of protein in the dog can vary from as low as 50 per cent in some cereals up to 95 per cent for milk or egg protein.
The amino acid profile reflects which of the 20 amino acids are present in the protein. This is particularly important as 10 of these are essential to the dog. Essential amino acids cannot be synthesised in sufficient quantity by the body and must, therefore, be provided in the diet.
Non-essential amino acids are equally necessary, but can be synthesised if sufficient raw materials are present (in the form of excess amounts of other amino acids and non-protein nitrogen). Milk and eggs contain the greatest proportions of essential amino acnds; cereals the least.
This does not mean, however, that dogs should be fed entirely on meat, milk and eggs but that judicious mixing may be necessary if cereals form a large part of the diet.
Protein deficiency can result from either insufficient dietary protein or from a shortage of particular amino acids. The observable signs are largely non-specific poor growth or weight loss, loss of appetite, rough and dull hair coat and increased susceptibility to disease.
It is known that the recommended protein allowance is 22 per cent of the dry matter of the food. This is an extremely generous allowance and covers all stages of the life cycle including puppy growth and breeding.
In fact, assuming a good quality protein is fed, 10 per cent would probably be quite adequate for non-breeding adult dogs.
Protein which is surplus to the body’s requirements is not laid down as additional muscle but is converted to fat and stored as adipose tissue. Feeding extra protein to produce ’body’ will only produce fat.
#2 Nutrient Requirements For Dog
Fat has several roles in the nutrition of the dog: it is a very concentrated source of energy, It enhances the palatability of many foods and it serves as a carrier for the vitamins that are soluble such as A, D, E and K.
Its most important function, however, is as a source of the essential fatty acids, particularly linoleic acid, which are used to form part of the cell walls and which are necessary for the synthesis of prostaglandins.
Linoleic acid deficiency results in a coarse dry coat, thick dandruff, skin lesions and in reproductive failure. Dogs with this deficiency usually respond quickly to dietary supplementation with sunflower oil which is a rich of linoleic acid.
Fat is well digested by healthy dogs e Alaskan Husky’s traditional diet as seal meat Which is two thirds fat and these dogs thrive despite adverse environmental conditions and hard work.
However, any diet withavery high fat content may need supplementation with other nutrients such diets will be eaten in smaller quantities, therefore other nutrients should be present in higher proportions to ensure that daily requirements are met.
It is important to note that diets containing very high levels of polyunsaturated fat may become rancid with the destruction of nutrients, particularly vitamin E.
#3 Nutrient Requirements For Dog
lt has been assumed for many years that while dogs are good at utilising carbohydrate as an energy source, it is not an essential dietary requirement.
This is because dogs are able to synthesise their glucose requirement from dietary fat and protein if these Present in sufficient quantity. However, recent work in the USA has indicated that pregnant bitches need a dietary source of carbohydrate in order to produce healthy puppies.
It is difficult to reconcile this with what we know of the dog’s evolutionary history, as the prey which formed the diet would contain vely little carbohydrate, Whether this finding is confirmed or not is largely academic, as the majority of dogs are traditionally fed diets which contain large proportions of carbohydrates as biscuit or meal.
There are three major groups of carbohydrates in foods: sugars, starches and the indigestible polysaccharides like cellulose.
Sugars are easily digestible and are palatable to dogs which tend to have a ’sweet tooth’t Starches are long chains of the simple sugar units.
They are easily digested by enzymes (amylases) in the digestive tract after the starch is degraded by cooking or crushing. Untreated starch is much more difficult to digest and dogs fed on raw potatoes or uncrushed cereal are likely to suffer from diarrhoea and flatulence as the starch passes undigested to the large intestine where it is fermented by bacteria.
The indigestible polysaccharides can be collectively grouped under the title of ’dietary fibre’ or ’roughage’. This passes through the digestive tract relatively unchanged, adding bulk. Because it acts like a sponge retaining water, it tends to reduce the incidence of constipation (by keeping stools soft) and diarrhoea (by mopping up surplus fluid vitamins though many benefits associated with the intake of high levels of dietary fibre have been described in man, these are mostly associated with diseases not commonly seen in dogs.
The action of fibre in the human gut is through a reduction of transit time (the time taken for food to pass through the digestive system) and the dog already has a much shorter transit time than man. It seems likely therefore that if there are any uses for dietary fibre in dog nutrition, these are limited to the management of constipation, diarrhoea and diabetes and possibly obesity.
The incorporation of high levels of fibre in the diet of normal dogs may decrease the availability of absorption of other nutrients, especially minerals. It will also markedly increase faecal volume; consequently not more than 10 per cent of the dry matter of the food should be made up of dietary fibre (less than this for puppies).
#4 Nutrient Requirements For Dog
Although required in very small amounts,vitamins are necessary for normal health and function. A vitamin is an organic compound which plays an essential part in the regulation of various metabolic pathways and is broken down in the process.
Vitamins are distinguished from other compounds with similar functions in that the animal is unable to synthesise replacements and must obtain a dietary source.
It is usual to describe the different vitamins by the major specific sign of deficiency. Thus vitamin A is popularly associated with sight, since deficiencies lead to an impairment of vision; Vitamin E with reproduction; and so on.
This is an over simplification since deficiencies of all the vitamins have signs in common, particularly ‘poor appetite, general loss of condition and poor growth.
Vitamins are classified according to their solubility in either water or fat. This apparently arbitrary division has practical nutritional consequences. The wa ter-soluble vitamins are not retained in the body when given in excess and are lost in the urine.
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Since they are not stored, regular intake is necessary. Conversely, the fat-soluble vitamins A, D, E and K are retained when fed in excess of requirements.
While daily intake of these vitamins is necessary, there is a danger of accumulation following prolonged overfeeding. Vitamins E and K are unlikely to be toxic, but overfeeding of vitamins A and D has been shown to have serious results, principally malforma tion of the bones (vitamin A) and calcification of the soft tissues (vitamin D).
It is understandable that owners who want to do the best for their dog are tempted to give generous supplements ‘just to make sure’ but the outcome may be tragic.
Most diets need no supplementation, but where this is necessary great care should be taken to ensure that the manufacturer’s instructions are followed closely and that the same vitamin is not being given several times under different proprietary names.
#5 Nutrient Requirements For Dog
Dogs require about 20 minerals, but some are needed in such small quantities that the absolute requirements have not been established. These trace elements are present in most common foodstuffs and deficiencies are most unlikely.
Important functions Of Minerals
•As structural components of bones and teeth (calcium, phosphorus and magnesium);
•As soluble salts which control fluid balance (sodium chloride in blood and extracellular fluid; potassium, magnesium and phosphorus inside body cells);
•In enzymes and other proteins (such as iron in haemoglobin).
Again, many are toxic if given in repeated overdoses and indiscriminate supplementation should be avoided. Some breeders believe that the larger breeds have special requirements for calcium and phosphorus as these are the principal mineral constituents of bone.
However, the greater total food requirement of these dogs will ensure appropriate calcium intake. provided the diet is balanced.
#6 Nutrient Requirements For Dog
Water should be considered in conjunction with feeding. A shortage of water leads to illness and death more quickly than that of any other nutrient and a fresh supply of drinking water is an essential part of a dog’s diet.
Water is necessary for many different functions in the body. It is used as a transport medium (blood), the route for elimination of toxic wastes (urine), for heat lost (evaporation), to allow the chemical reactions necessary for life (in digestion and withil‘ the body cells) and many other functions. Water balance is controlled within quite narrow limits, and since some water from the body is obligatory, daily intake is essential.
Water is taken into the body in several forms: in fluid drunk, as a part of food and in the water released when protein, fat and carbohydrate are broken down. It is lost in the faeces, urine, by evaporation (mainly from the lungs), and in the milk of lactating bitches. The precise daily requirement of each dog will depend on its particular situated and therefore a plentiful supply of clean drinking water should always be available.
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Choice of foods And Advantages
There are many different ways of satisfying the need for nutrients. For dogs these falls broadly into two categories the use of prepared pet foods and of homemade Made diet. Neither of these methods is frankly right or wrong, each having different advantages.
Prepared petfoods from reputable companies provide a correctly balanced diet- Guaranteed nutrition, good palatability and digestibility, suitable energy density and safety, in addition to convenience. They also offer variety without loss of consistency.
Most of the dogs in the population are normal adult dogs and the majority of foods are intended to meet the needs of this group. More specialised foods are readily available to meet the requirements of other lifecycles stages, such as puppy growth
Foods for adult dogs can be divided into complete and complementary (those intended to be mixed with other foods, eg canned food with biscuit.
This diversification is not as complicated as it may seem at first sight; the label should specify the intended role, give a guide to quantity and may also state how the food has been developed and tested.
Complete diets are carefully balanced to provide for all a dog needs, and do not need supplementation. Dog owners should be careful when choosing products to make sure that they are comparing like with like.
The contents are often expressed in different ways. To avoid confusion, the current tendency is to express the amounts of nutrients present in the food in relation to the kcal provided (usually the amount per 400 or 1000 kcal)
Although not necessary, complete prepared petfoods can be supplemented with fresh foods in the firm or left-overs of food prepared for the family, or table scraps.
If this IS done the amount of prepared petfood could be reduced proportionally; this extra source of nutrients should not make up more than 15-20 per cent of the daily intake.
Considerable skill is necessary to put together a satisfactory diet from fresh raw materials. It is not enough simply to buy ‘meat’, whether best steak or pet mince, on the assumption that this is the na tural diet of a dog.
As a hunter the dog did not restrict itself to the muscle meat of its prey, but in the whole body, so obtaining minerals, vitamins and even roughage from the bones, brains, skin, gut and gut contents.
Muscle meat alone cannot form a balanced diet as it contains inadequate amounts of calcium, iodine, copper and the fat-soluble vitamins.
It is possible to calculate that to meet its calcium requirement, a half-grown Labrador Retriever would need to eat seven times its own bodyweight in lean meat every day! Nevertheless, meat (including offals and tripe) is an excellent source of protein and, with careful supplementation, can form the basis of a reasonable diet.
Other raw materials have different problems. For example, cow’s milk contains the milk sugar lactose in substantial quantities, bitchs’ milk contains little and many puppies lose the ability to digest lactose after weaning.
When fed cows’ milk, such puppies (and adult dogs) develop severe diarrhoea as a result of lactose intolerance Eggs, when fed raw in substantial quantities, may cause a vitamin deficiency; this is because raw egg white contains a substance called avidin which binds biotin (a water soluble vitamin) and makes it unavailable.
Heating destroys avidin and therefore eggs should be fed cooked. Mineral availability can be a problem when some cereals are fed, as one of their constituents binds to certain minerals, limiting their availability.
Although there are some materials which can be fed raw, cooking is advisable by most foods, particularly meats. Cooking will kill most bacteria and parasites and Will improve the digestibility of some materials.
However, over-cooking should be avoided as this will reduce the food value of proteins and destroy vitamins. Minerals and vitamins may be lost if the cooking water is discarded.
The same principles of hygiene should be employed in the preparation of food for pets as for the family.
As mentioned earlier, most prepared petfoods, when fed as directed, require no additional supplementation. The larger manufacturers have large analytical laboratories which run continuous checks on the mineral and vitamin contents of their foods, and also conduct long-term feeding trials.
Nutrient requirements for dog also include Home-made diets which are based on offal and fresh meats usually do require some supplementation, even when a good quality biscuit or meal is fed. The dangers of excessive supplementation have already been outlined, these are real dangers and should not be ignored.