by Dr Chris Piper BVSc MRCVS
"They are sick that surfeit with too much as they that starve with none." - Shakespeare
This is essentially a discussion on canine dietary requirements although most of it will apply to the cat as well. These two domesticated animals do have very different dietary requirements.
The dog is essentially a carnivore although his association with man over thousands of years has required adaptation to a more omnivorous diet. For a moment consider the diet of the wild African dog. He hunts in a pack and preys on grazing animals - herbivores. The pack competes to eat the most accessible organs - the abdominal contents first, including the stomach and its large quantities of partially digested vegetable matter, then the muscle tissue, and finally the skeleton. They eat the whole animal, which includes a reasonably large proportion of grasses and herbs.
From a holistic perspective it is important that we mimic the "wild" diet using whole foods, unprocessed and unrefined. Organically grown foods are preferable - "Demeter" and "biogro" are symbols of quality certified organic food. Raw fresh food is best, although it is impractical to offer it in quite the same way as in the wild. Prolonged storage, including freezing and refrigeration, will reduce the nutritive value of the food.
If we extend this concept of the "wild" diet it is obvious that cooking is unneccesary. Unfortunately, the idea that cooking is necessary is a myth that persists, encouraged by conflicting opinion amongst veterinarians. However, it is well known that cooking decreases the digestibility (i.e. utilisation) of food by denaturing protein, destroying vitamins, and inactivating enzymes. It is also a major cause of halitosis (bad breath) and flatulence (farting). However, cooking has the advantage of reducing spoilage and therefore extending storage life, and it often improves palatability.
Palatability is the degree of acceptance of a food by the animal, and is improved by the following:
Manufacturers of commercial foods go to great lengths to provide "mouth feel", which can only be described as the sensation which enhances taste and appetite.
It should be clear by now that commercially prepared foods do not meet the requirements of the "wild" diet. Before moving away from cooking, there are two occasions when cooking is useful. It is preferable to cook vegetables and grains as this renders them digestible and mimics the fermentation process which occurs in the multiple stomachs of the herbivore. Alternatively, grains and legumes can be sprouted and fed raw.
As we become more discerning about the food we eat, we should give thought to the food that we provide for our pets. Let's consider the forms of contamination that may affect the food we provide. Generally it is safer to use foods from sources low down in the food chain. Small animals are prey to larger animals. Small animals are lower in the food chain. Large animals will eat large numbers of small animals, thereby concentrating any contaminants in their prey. Concentration of pollutants such as lead, mercury, hormones and antibiotics can occur. Special mention should be made of chlorine and fluorine which are intentional additives to our water supply. I doubt that any consideration was given to our pets when they considered adding these chemicals, especially fluorine. Dogs use panting as a means of heat regulation, and during the hot summer will lose a lot of water from the body through panting. On a comparative body weight basis they drink a lot more water than humans. I am sure this high intake of fluorine affects the health of our animals. By collecting rainwater, allowing animals to drink from natural waterways (preferably running water), and filtering water through reverse osmosis or ion exchange machines, we can help overcome this pollution. Incidentally, the use of aluminium bowls for water or food may lead to excessive intake of aluminium. Stainless steel bowls are recommended.
Commercial foods may contain all or some of the following additives: preservatives, emulsifiers, stabilizers, extenders, humectants, and colourings. How the body battles with this onslaught of chemicals and still remains reasonably healthy is surprising!
Another rule of thumb to remember is that dogs eat to meet their energy needs. If you were to feed a food high in fat, which is a very dense energy food, you would find the animal may not eat very much. In fact, if it is also low in protein your animal may not be ingesting sufficient protein to meet its needs - especially in a growing puppy. Therefore it is important to ensure the balance of protein to energy (fat and carbohydrates) is suited to the particular needs of the animal. A similar problem can arise with bulky foods. Some of these foods which contain a lot of vegetable fibre (which is not very digestible anyway) have a low protein-energy density. The physical size of the dog's stomach is insufficient for the animal to eat enough food to meet its requirements. This arises particularly in the lactating bitch whose demand for food can increase by 300%. During lactation high quality protein, energy dense foods are needed. There are other circumstances when a different balance of protein and energy is required. For growth and late pregnancy a higher proportion of protein is required. The convalescing animal also needs quality protein and readily digestible foods to aid healing. The working dog has obvious needs for extra energy, water and B vitamins.
Sometimes we provide what we think is a very appetizing meal and our pet refuses to eat. Often appetite can be affected by a variety of factors: the surroundings, light, noise, presence or absence of people, or other animals, and the type and cleanliness of food bowls. He may have just returned from scavenging next door and just is not hungry. Hunger is the best stimulant of appetite. Fasting one day each week enables the intestinal tract to rest (and heal) and allows the body to eliminate accumulated wastes/toxins from the body.
Feeding too little will cause a loss of weight but feeding too much will not only cause obesity but may contribute to serious developmental problems as well as diarrhoea. A sudden change in diet may also cause diarrhoea.
Developmental problems in the growing animal are commonly associated with feeding too much protein and mineral/vitamin supplements. The giant breeds are especially vulnerable. Trials using two groups of pups, one group allowed unrestricted food and the other group three quarters of the amount eaten by the first group, showed some interesting differences. The unrestricted group all had bone and joint problems while only 10% of the other group had similar problems. My advice is to keep puppies "lean and hungry looking".
You can also feed too much mineral supplement, or too little depending on the balance of the ingredients of the food used. Perhaps the most important mineral is calcium which is vital for the developments of the skeleton. When the dog eats the whole animal in the wild, the correct balance of bone to meats to organs is achieved. If we feed a high meat diet (which is very common) we need to balance it with additional calcium. There are many calcium supplements on the market to choose from the but the richest source (and cheapest) is calcium carbonate. The best source of course is raw bones. If you are feeding brisket, which includes the bone, it is unnecessary to add extra calcium. There are two occasions when extra calcium is required: firstly, with the all meat diets, and secondly, when you feed cereals and grains, which are high in phytates. Phytates interfere with the uptake of calcium by the body.
Too much calcium will interfere with the absorption of other minerals - iron, copper, zinc and iodine. People who tend to give additional calcium in pregnancy may precipitate birthing problems by inducing a zinc deficiency. Uterine inertia, retained foetus and toxic milk syndrome are thought to be due to zinc deficiency.To confuse things even more, a high protein diet (i.e. all meat) causes a calcium loss through the kidneys. It is important to emphasize again the need for balance, not too little nor too much.
A few comments now on some of the ingredients we consider feeding dogs. Eggs, raw and whole are an excellent source of high quality protein. There is no need to discard or cook the white of egg. There is sufficient biotin in the yolk to saturate the avidin in the white. Some fish contain an enzyme thiaminase which will destroy vitamin B1. Gentle cooking will destroy this enzyme thiaminase. You would need to feed almost exclusively raw fish to induce a B1 deficiency. Milk is considered food for the young although it can remain a valuable supplement for all ages if given in moderate amounts. Too much milk may cause diarrhoea. Some animals are unable to digest lactose in milk, and this may ferment in the lower bowel causing diarrhoea. Watering the milk down 50:50 is often helpful. Too much liver may also lead to diarrhoea. Liver is very "rich" and best given in small amounts.
Although we are almost entirely responsible for providing the food our pets eat I think it is important not to discourage them from foraging for some things themselves. If they chew grass/herbs, let them, providing they are not poisonous. Often they chew grass when unwell. It induces vomiting and helps empty the stomach. If they are garbage gobblers, stealing from neighbours and rubbish bags, they are predisposed to gastrointestinal problems.
If they eat the droppings of other animals (sheep and cattle) it is probably a worthwhile supplement to their diets. When they eat their own it may reflect a behavioural or digestive problem. Incompletely digested food in the droppings may still be palatable.
I can hear you say "yuk!" I think it is important not to be anthropomorphic - not to attribute human qualities and tastes to animals. They are "happy" to accept routine feeding and variety is not as important to their appetite as it is to ours. Variety provides the opportunity to provide a wide range of nutrients and reduces the risk of any deficiency. The body is very adaptable and will preferentially absorb nutrients that it is short of.
Somewhere I have mentioned feeding raw bones. Cooked bones are less digestible and often more brittle. Brittle bones may splinters and cause penetration of the bowel. Chop bones and vertebrae are most likely to cause problems. Chicken bones, however, are not the problem they used to be. Today the meat chickens are slaughtered at the tender age of 9 weeks when their bones are still very soft. Old broilers and layers have brittle bones and should be avoided. Bones are not only an excellent source of minerals but they also provide cleaning of the teeth and hours of enjoyable distraction. Cooking fish will cause the flesh to flake from the bones unveiling a sharp and often dangerous weapon.
Unless you have the time and motivation to prepare your own balanced diets you could be better off to use commercial foods and supplement these with raw brisket and household scraps.
You can economise by using household scraps (vegetable peelings, cores and left overs) and purchasing ingredients unsuitable for human consumption (bug-infested grain, damaged packets and butcher scraps). Don't use mouldy foods. Buying in bulk is often cheaper although consider the shelf life and possible deterioration of the quality over a long period of time. You can also save time by preparing large quantities which can be stored for a few days in the fridge. Using a pressure cooker (stainless steel) will reduce the cooking time and minimise the damage to the quality of the food.
The protein to energy ration should match the special requirements already mentioned. (growth, lactation, etc.).
Protein : energy (by volume)
75% : 25% - growth, late pregnancy, convalescence
50% : 50% - maintenance
40% : 60% - working
This is a simple guide only and should be discussed with your veterinarian. For simplicity I recommend rotation of the following menu, changing to the next when you have finished your store.
Vegs - cereals - brown rice (best), oats, bulgur, millet, potatoes, wholemeal bread or macaroni;
Pumpkin, carrot, peas, beans, garlic and onion as condiments, raw grated carrot and alfalfa sprouts.
Because of the meat (without bone) and cereal content, and additional supplement of calcium is required. The following supplements can be used in this recipe.
For giant breeds these quantities should be reduced by 30-50%.
Clearly, more effort and resources are required to prepare food for your pets. However, this is offset by improved economy, a healthier dog, and the feeling of satisfaction that you have cared for and contributed to the well-being of your pet.