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Pet food for thought

Written by  Dr Joan Kleynhans-Jordaan
| in Veearts
| June 26, 2014

Pet owners are often confused by the array of Pet Foods out there. Some people prefer to prepare their pet’s food themselves.

As a vet, I see more and more pets living into advanced age as people feed better foods.
Nutrition is an exact science. It takes specialist veterinary nutritionists to really know what nutrients should be included in a pet’s food and in which quantities and relative balance, how age, disease and activity levels influence those needs, and what ingre-dients will deliver enough of the right nutrients. Digestibility of the ingredients also needs to be considered.
        Although preparing one’s own pet food is possible, I would not advise it unless a specialist nutritionist has worked out a recipe for your pet and the recipe is revised for advancing life stages. It is definitely much easier to leave the preparation of pet food to the experts and purchase a good quality commercial diet.
The reality is that premium pet foods cost more per kg than other brands. The price difference is less significant if one compares the actual amount the dog needs. A great advantage of good quality food is the fact that one has a lot less dog poop to scoop!
        But if you are not an expert, how do you compare foods? All pet foods have to be labeled. Better brands will list all ingredients in detail. Ingredients are the vehicles that provide nutrients e.g., meat provides nutrients such as protein, fatty acids, and vitamins. Ingredients will be listed in descending order by weight. Because chicken, beef and lamb have a high water content, they will weigh more than dry ingredients such as grains, meals and vitamins. They are generally listed first for this reason.
        The next part of the label should indicate a guaranteed analysis. This indicates the minimum or maximum levels of nutrients such as protein, fat, fiber and moisture. It does not indicate the exact levels of nutrients and is not a guarantee of quality. Varying moisture levels in pet foods make comparisons difficult. Premium brands will usually list ingredients in more detail than cheap brands and will not generally change the ingredients. Cheaper brands often only list the guaranteed analysis and not all the ingredients. This may be because they vary the recipe according to which ingredients are least expensive at the time. No one food can support all life stages adequately. The higher levels of protein required for puppies and kittens may be harmful for adult or senior pets. Excesses can be as harmful as deficiencies. Especially in the case of dogs, “ one size fits all” is not suitable for different breeds. Incorrect feeding may lead to obesity, skeletal problems, too rapid growth, poor muscle and bone development, and a poor immune response at an age it is most needed.
        Puppies and kittens need more protein, energy and calcium than adult pets. A large breed puppy needs a food carefully formulated to ensure proper bone and muscle development. Calcium: phosphorus ratio also needs to be considered.
A dog is regarded as an adult between the ages of 1 and 6 years. They require nutrition with controlled levels of phosphorus, sodium, protein and energy. Their activity level influences an individual dog’s needs. Certain breeds, e.g., Labrador retrievers, dachshunds and cocker spaniels are prone to obesity, and allowing them to be overweight has health consequences such as arthritis.
        Maintaining kidney health is very important in dogs and cats. Dietary phosphorus, protein and salt excesses may speed the  progression of kidney damage that leads to kidney failure and death. Unbalanced high amounts of phosphorus, protein and salt are significant risk factors, as they have to be excreted by the kidneys. Some commercial pet foods do contain excess protein, phosphorus, calcium and salt.
        Senior dogs older than 7, (or 5 in the case of giant breeds) need less energy and protein than younger dogs and kidney health becomes even more critical. Prescription diets for many disease conditions are also available, but should initially be prescribed by your vet.

        The following nutrients need to be considered in the formulation of pet food:

         Water: A loss of 15% of the body’s water will lead to death. Generally speaking a healthy dog or cat needs about 50 ml of water per bodyweight per day. This will be influenced by ambient temperature and activity level. As a general rule all animals should have free access to clean water all the time.
        Carbohydrates and starches in foods are used as a source of glucose. They provide energy, produce heat and can be used as building blocks for other nutrients such as certain amino acids and lactose. Energy from these sources can be stored as glycogen or fat.
Although there are hundreds of different amino acids, only 21 are used in animal proteins. Proteins have a structural role in all cell walls and are required for all tissue growth and repair. They are essential to muscles, connective tissue, skin, hair and nails, blood proteins, enzymes, hormones and antibodies. Excess protein may also be used as a source of dietary energy.
        Dietary fats are required for energy, and to aid in absorption of fat-soluble vitamins (A, D, E and K).
Dogs and cats need at least 1 to 2% fat in their food to absorb fat-soluble vitamins. Fats also supply essential fatty acids, Omega-3 and Omega-6.
        The essential fatty acids are required constituents of cell membranes. They are also needed in the synthesis of active substances required by the body, such as prostaglandins. They control water loss through the skin.
        More than 18 mineral elements are believed to be essential for mammals. Seven macro minerals, namely sodium, phosphorus, calcium, chloride, magnesium, potassium and sulphur are required by the animal in the diet in larger amounts and 11 micro minerals or trace elements in much smaller amounts. The major micro minerals are iron, zinc, copper, and selenium. Others are iodine, chromium, fluorine, cobalt, molybdenum, boron, and manganese. Minerals are required for maintenance of skeletal structure, acid-base balance, fluid balance, cellular function, nerve conduction and muscle contraction. Many cat foods sold in grocery stores have a very high salt content.
        Other constituents of a balanced dog food are antioxidants in a specific combination, as well as fat-soluble vitamins (4), water-soluble vitamins (11) and vitamin-like substances (3).
        Ultimately it comes down to the difference between survival and optimum nutrition.  If you want the best for your pet, my advice is to feed the best quality pet food you can afford.