by Lowell Ackerman, DVM, Ph.D 

In this exclusive excerpt from his new book CANINE NUTRITION, author Lowell Ackerman, DVM, Ph.D, examines the nutritional needs of dogs throughout their various life stages and activities.

Dogs are very versatile when it comes to meeting their dietary needs. They are not strict carnivores by nature. They do have teeth for tearing flesh and their digestive tracts are short and simple, but they do not have a strict requirement for meat in their diet. Meat protein is easier for dogs to digest and contains more optimal blends of amino acids from which proteins are made. In the 20,000 or so years that dogs have been man's companion, however, they have gradually become accustomed to the foods we eat, and have lost their need to be strict carnivores. By comparison, the cat is still a strict carnivore and must receive animal protein in its diet.

Nutritional needs for a dog change during his lifetime. Nutrients that are critical when he is a pup are less important when he reaches adulthood. A bitch has different needs when she is pregnant or lactating than when she is spayed or not used for breeding. Finally, as your dog ages, his nutritional needs also change. Superimposed on this is the realization that other factors such as sporting competition, the show circuit and disease have an impact on nutrition.

Feeding the Newborn Puppy
Soon after pups are born, they should begin nursing their mother. Their level of nutrition will parallel that of the dam. Pups must nurse extensively during the first 24 hours because that is when they receive the antibody-rich colostrum from their mother. Colostrum helps protect them from infection for the first two to three months of life. Pups should be allowed to nurse for at least six weeks before they are completely weaned from their mother. Supplemental feeding may be started by as early as 3 weeks of age.

It is critical that puppies nurse effectively. The energy needs of growing pups are nearly three times what they are for an adult when compared on the basis of metabolic body size. Small or weak pups must be closely supervised because they may appear to nurse yet can eventually weaken and die. If they nurse ineffectively, they may ingest only air, not milk. If the bitch has limited milk supplies, it is best to let the smallest pups drink their fill and supplement the larger ones with milk replacer. Weak puppies that do not improve within a few hours must be tube fed or given some other method of supportive therapy.

Feeding the Growing Puppy
By 2 months of age, pups should be fed puppy food. They are in an important phase of life-growth! Skeletal development is at its peak for the first six months of life. Nutritional deficiencies and/or imbalances during this period are more devastating than at any other time. During this phase, your dog develops a functioning immune system, dramatically adds bone and muscle mass, and he learns all about his new environment, developing proper socialization behaviors all the while. There is no more critical time to ensure proper nutrition.

This is not the time to scrimp on nutrition. Puppies in their active growth phase should be fed a high-quality diet that meets their specific nutritional needs. Purchase a food specially designed for this growth period, and be certain that feeding trials have been conducted by the manufacturer. Keep pups on this diet until 12 to 18 months of age, depending on the breed. Many large breeds do not mature until 18 months of age and so benefit from a longer period on these rations.

When it comes to feeding schedules, most puppies do best being fed at specific times throughout the day rather than having food available at all times. Put the food down for 20 to 30 minutes, then remove it until the next feeding. Pups initially need to be fed two to three meals daily until they are 3 to 4 months old. By 3 or 4 months of age, many puppies can be fed three meals daily. Continue this schedule until they are 12 to 15 months old, then feed twice daily when they are converted to adult food.

It is important for pups to receive regular feedings, but it is just as important that they not be overfed. Puppies that are overfed, especially the large breeds, are more prone to bone diseases when they grow too fast or become overweight. Keep pups lean and healthy during their growth phase, and disorders such as hip dysplasia and osteochondrosis are less likely to occur.

It should come as no surprise that the nutritional needs of pups are different from those of adults. Even the amino acids needed are different, and pups require much more arginine than adults. They also require many more calories. Vitamin and mineral imbalances can be disastrous for a puppy. Vitamin E deficiency can cause muscle degeneration in pups, while choline deficiency can interfere with liver function. Pantothenic acid deficiency impairs the growth rate, and fewer antibodies are produced when pups are exposed to viruses. Vitamin D deficiency can result in osteoporosis, while vitamin A deficiency can cause abnormal bone development, eye and skin problems and a greater susceptibility to infection. All of these can be prevented by providing a high-quality diet designed specifically for this important growth phase.

One pitfall to be avoided is supplementing pups with protein, vitamins or minerals. It is easy to become overzealous with supplements, but this is not wise. Most of the mistakes are made with supplements containing calcium, phosphorus and/or vitamin D. You may think that these supplements will help your growing puppy by adding to his calcium resources. After all, children are encouraged to drink milk to build strong bones and teeth. Why not pups? The reason is because growth rations have been formulated with an ideal ratio of calcium to phosphorus, usually around 1.3 parts calcium to every 1 part phosphorus. This is the optimal ratio for healthy bone growth. This can be quickly unbalanced by providing calcium, phosphorus, vitamin D, or combinations. 

There is more than adequate proof that these supplements are responsible for many bone deformities seen in growing dogs. Avoid the temptation to supplement. If you really must supplement, select moderate amounts of the water-soluble vitamins (vitamin C and the B vitamins) instead of the minerals or fat-soluble vitamins. If you must select a fat-soluble vitamin for supplementation, use vitamin E rather than vitamins A, D or K.

Now is the time to ensure optimal nutrition and create proper eating habits that will last a lifetime. Learn how to feed pups amounts that won't make them fat, but don't deprive them either. And, don't try to second-guess nature by supplementing the diet with potentially dangerous nutrients, even if it appears to make sense on the surface. This is definitely not the time to make mistakes with your dog's nutrition.

Feeding the Adult Dog
When pups become adults, they enter a new nutritional phase - maintenance. Once they've finished growing, the "growth" diets provide more calories and protein than they really need. If they continue on the growth diets, they may become obese. The goal is to switch them to a maintenance ration that is balanced correctly for this phase of life.

The term "maintenance" is used loosely, but it is important to understand what is really meant by it. Dogs require maintenance rations when they are living a comfortable and relatively stress-free existence as a housepet. A dog staked by a four-foot-long chain in the backyard is not being "maintained." A dog tossed outside at night in the cold to patrol a lot is also not being "maintained." The maintenance energy requirements can be calculated with a mathematical formula for dogs that are not kept as housepets. This book is dedicated to the caring dog owner, however, and these exceptions will not be discussed.

There are many choices when it comes to selecting a maintenance diet. Most commercially available foods are combinations of animal-based and plant-based ingredients. The animal-based ingredients are tastier for dogs and easier for them to digest, but the plant-based ingredients are cheaper. To be cost-effective, most commercial dog foods blend ingredients from both plant and animal sources.

In general, dogs can do well on maintenance rations containing predominantly plant- or animal-based ingredients as long as that ration is specifically formulated to meet maintenance-level requirements. This contention should be supported by studies performed by the manufacturer in accordance with American Association of Feed Control Officials (AAFCO). In Canada, these products should be certified by the Canadian Veterinary Medical Association (CVMA) to meet maintenance requirements.

There are many criteria by which you might select a dog food for maintenance purposes. A dog that is fairly sedentary, has finished growing, is not in competition, and is not being used for breeding can accommodate varying amounts of dietary fat, protein, and carbohydrate. They are the classic lowess dogs for which the maintenance requirements were designed. These dogs do well on most commercial or homemade diets. In fact, it is probably a mistake to feed these animals super-premium dog foods because they tend to become obese.

Many manufacturers of premium dog foods market their products on the basis of ingredients. Most of the super-premium diets have a higher content of meat and meat byproducts. Most of the cheaper brands of dog food have a higher content of cereal. It is not always easy, however, to tell the difference by looking at the pet-food label. For instance, the label may read "chicken, corn-gluten meal, ground corn, ..." and so on, leading you to believe that chicken is the main ingredient. In fact, by dividing corn into individual ingredients such as ground corn, corn-gluten meal, corn flour, and corn bran, the total cereal content of the diet may be camouflaged. You think you're feeding a predominantly chicken-based diet when cereal is actually the primary ingredient. Canned pet foods contain more than 75 percent water, yet this can also be confusing when you examine the label. It may list chicken or beef as the main ingredient but when you examine the analysis, it lists "moisture" at about 78 percent.

There's nothing wrong with feeding a cereal-based diet to dogs on maintenance rations, and this is the most economical diet. Unfortunately, corn is low in certain essential amino acids, and this must be remedied by complementation, a process combining different protein sources to provide a suitable blend that does meet requirements. In the least expensive brands, this can often be done by selecting soy as a vegetable protein source. Most dogs tolerate soy well, but some dogs are soy intolerant and do not do well on these rations. Certain breeds, such as the Irish Setter, the Siberian Husky and the Chinese Shar-Pei have a higher incidence of soy intolerance, although any breed is susceptible. Soy also contains some sugars (e.g., raffinose, stachyose) that are not digestible by dogs but that are digestible by bacteria. As a result, the sugars may get digested by microbes in the colon, producing gas. This may contribute to flatulence or "windiness" in a dog. Other ingredients in soy can also be problematic if the food is not processed adequately.

Keep in mind that maintenance rations meet only the minimum requirements for stress-free house pets. There are many stressful situations that can change a dog's nutrient requirements from maintenance levels to above-maintenance levels. Dogs housed outside in cold weather, dogs that are exercised extensively, dogs that are used for breeding, and dogs that are ill often will benefit from eating foods that provide more than just minimum requirements. Also, most of the dogs that are first switched from puppy foods to maintenance foods still have some growing to do. It is therefore recommended that you feed your dog a diet that contains easily digested ingredients that provide nutrients at least slightly above minimum requirements. Typically, these foods will be intermediate in price between the most expensive, super-premium diets and the cheapest generic diets. Select diets that have been substantiated by feeding trials to meet maintenance requirements, that contain wholesome ingredients, and that are recommended by your veterinarian. Don't select a food based on price alone, on company advertising, or on total protein content.

Feeding the Aging Dog
Dogs are considered elderly when they have achieved 75 percent of their anticipated life span. This obviously differs for each breed. A Great Dane may be considered old at 6 years of age, while a Poodle may not be seen as elderly until 10 years of age. And, there is so much variability between individual dogs that even breed generalizations are merely guidelines. It is important to recognize the needs of these "senior" pets before the onset of age-related problems, while nutrition can still provide the best preventive medicine. 

As a dog ages, his metabolism slows. There is a decreased sense of thirst that can result in dehydration if not detected. At the same time, if maintenance rations are fed in the same amounts and metabolism is slowing, weight gain is common. Obesity is the last thing you want to contend with in an elderly pet, because it increases the risk of other health-related problems. On the other hand, an elderly dog may lose weight, and this is not good either. The older dog doesn't have as acute a sense of smell as he had when he was younger. Dental problems also plague him. Approximately 85 percent of dogs over 4 years have periodontal disease. This can result in painful chewing, infection and tooth loss. All of these conditions can contribute to undesirable weight loss as your dog ages. Dental health care is an important part of overall wellness. Don't wait until your dog is old to consider the impact of routine dental care.

As dogs age, most of their organs do not function as well as they did in youth. In the digestive system, the liver, pancreas and gallbladder do not work at peak capacity. The intestines have more difficulty extracting all the nutrients from the food consumed. The colon doesn't have the motility that it used to have, and constipation becomes more common. In the cardiovascular system, the heart has been beating relentlessly for years and is more likely to show the effects of overwork. The blood vessels aren't as flexible anymore, and the heart valves are not as efficient. The kidneys contain a finite number of filtering units that are not replaced as they succumb. A gradual decline in kidney function is considered a normal part of aging.

A responsible approach to geriatric nutrition is to realize that degenerative changes are a normal part of aging. The goal is to minimize the potential damage by taking appropriate measures while your dog is still well. If you wait until your elderly dog is ill before you change his diet, the job will be much harder.

A geriatric diet often provides fewer calories per serving than the growth or maintenance rations to accommodate a slower metabolism. If the energy content of the diet is not restricted, but a dog exercises less, then he will become obese. Of course, this is not true for all senior dogs. If your dog loses weight with age, you may need to increase the calorie content of his diet. If your dog tends toward obesity, however, you will need to reduce the fat and protein contents of the diet and provide more calories in the form of easily digestible carbohydrates. Older dogs benefit from essential fatty acids like linoleic acid but have little need for saturated fats or other oils. If you provide high-quality vegetable oils (safflower oil, flaxseed oil), you will meet the essential fatty acid requirements. These oils also allow for the absorption of the important fat-soluble vitamins.

Most elderly dogs do better on diets that are easily digested. Geriatric diets are typically low in fiber because dogs have a difficult time absorbing fiber. There are some medical conditions that benefit from fiber, including diabetes mellitus, colitis and constipation, and a geriatric diet can be augmented with psyllium (Metamucil) or pectin if your dog requires a higher fiber content. Because the digestive system becomes less efficient as a dog ages, a diet that is more digestible is also more likely to provide needed vitamins, minerals, amino acids and essential fatty acids.

Older dogs don't need more protein in their diet, but they do benefit from better-quality protein. The protein content of the diet is only a source of essential amino acids. Protein is typically hard to digest and requires metabolism in the liver and filtering by the kidneys. All of these functions can be impaired in the older dog. Your goal is to provide lower levels of total protein (typically 14 to 21 percent of dry matter) but higher levels of the essential amino acids. You need to provide your aging dog with the proteins that do the most good. If you severely limit protein in your elderly dog's diet, especially if he is losing weight, you can induce protein deficiency and adversely affect immune function and enzyme activity.

It is very important to understand the dynamics of vitamin and mineral nutrition in the older dog. Older dogs need higher levels of vitamins A, B1, B6, B12 and E than they did when they were younger. Zinc is also needed to help with body repairs and to bolster the immune system. Most maintenance diets are much too high in sodium (salt) for the geriatric dog and the levels are restricted in the "senior" diets. These diets also take into account the changing dynamics of calcium and phosphorus metabolism and slightly reduce the phosphorus content to lessen the workload of the kidneys.

There are many options for feeding your senior dog. Ideally, you should change his diet when he is still healthy and has not slowed down too much or become ill. Switch him to a senior diet when he has achieved about 75 percent of his expected life span, or when recommended by your veterinarian. This may stall the onset of heart, kidney and digestive disorders by being more "user-friendly" and not overtaxing his system. For example, a low-protein diet may not prevent kidney disease, but it certainly is easier to handle for a dog experiencing any impairment of kidney function. The diet should contain ample amounts of the amino acids that dogs require and lesser amounts of the ones deemed dispensable. A low-salt diet won't necessarily prevent heart disease, but it is certainly helpful in dogs with impaired cardiac efficiency. 

Elderly dogs need to be treated as individuals. While some dogs benefit from the nutrition found in "senior" diets, others might do better on the highly digestible puppy and super-premium diets, which provide an excellent blend of digestibility and amino acid content. Unfortunately, many are higher in salt and phosphorus than the older dog really needs. It is not advisable to continue to feed your elderly dog maintenance rations even if you cut down the amount you feed to limit calories. Maintenance rations were formulated to meet minimum requirements for stress-free housepets. Advancing age is a definite stress on the system, and maintenance rations do not optimally meet the protein, fat, vitamin and mineral requirements of an aging dog. If you must feed this diet for economic reasons, give your dog a daily vitamin-mineral supplement designed for "seniors." These supplements are typically rich in the B vitamins and the antioxidant nutrients vitamin A, vitamin C, vitamin E, and selenium, as well as zinc. There is also a good argument for providing high-quality table scraps to the very senior dog that tends to lose weight. Freshly prepared chicken, beef, organ meats and cooked grains and vegetables can provide a tasty and nutritious treat for dogs that may not be eating enough of their own food. At this time of life, there is no point in being hard-nosed about the evils of table scraps unless there is a medical reason for doing so.

Feeding the Pregnant or Nursing Bitch
Care of the pregnant or nursing bitch presents certain nutritional challenges which must be considered and met. Prior to being bred, the bitch should be in good body condition, not too thin and definitely not obese. She should be in excellent dietary status to enhance the chances of conception and then maintained on an increasing nutritional plane as her body strives to meet the needs of pregnancy and then lactation (milk production). It is important to understand that the nutrient requirements may increase as much as four times over usual adult maintenance levels. Providing proper nutrition to the reproducing dam directly influences the quality of the milk she produces, the survival of the pups, and their birth weight.

Usual maintenance diets are not suitable for the pregnant or lactating bitch. They do not provide enough energy to meet her needs on a daily basis. The diet must be complete and balanced for this stage of life and provide at least 1,600 digestible calories for every pound of food fed. This type of diet should be introduced before the fourth week of pregnancy when nutritional demands begin to skyrocket. Acceptable diets usually contain more meat than do regular diets, and only certain super-premium and canned dog foods actually meet these criteria. Many commercial canned cat foods also meet the criteria and are useful in toy and miniature breeds of dogs. These claims should be supported by actual feeding trials, not just lab analysis. With regular maintenance diets, the bitch is unlikely to consume enough food to meet her actual needs. It is also difficult to "supplement" regular maintenance diets to be suitable for pregnancy and lactation. If this option is an economic necessity, it will be necessary to add eggs, meat (with fat) or small amounts of super-premium canned dog foods or cat foods to the ration.

Most bitches do not show appreciable weight gain until into their fourth week of pregnancy (gestation). Over the final month of pregnancy, it is not unusual for food consumption to increase by 40 percent. As the pups occupy more and more area in the abdomen, the bitch will appreciate being fed several small meals throughout the day rather than one or two large ones. During the final two weeks of pregnancy the pups, placenta, fluids and developing mammary glands all contribute to additional weight gain. Within a day or two of littering, however, it is not unusual for the bitch to lose her appetite. It normally is recovered within a day after whelping. It is important that the bitch not be underweight or overweight at this time. Underweight bitches may have difficulty meeting the nutritional needs of the pups after whelping. Overweight bitches have more trouble with delivery, have less efficient lactation and increased risk of complications for the puppies and themselves.

After whelping, the dam has an additional nutritional drain. She now has attentive pups hungering for her milk and the challenge of meeting her own needs in the process. She may not have time or inclination to leave the pups so care must be taken to make her food and water accessible, palatable and laden with energy (calories). As the pups grow so does her need to provide for their nutritional needs. This reaches a zenith when they are about 3 to 4 weeks of age, at which time she may be consuming two to four times the amount of calories she did when she wasn't pregnant. After this time the pups start to take more of an interest in solid food and demand for milk then diminishes. When the pups are fully weaned at 6 weeks of age, the food consumption of the dam is down to about 50 percent above non-pregnant levels and continues to diminish.

Nutritional supplementation can be helpful during pregnancy within very strict guidelines. It is much better to provide a wholesome, well-balanced diet than to predict the benefits of nutritional supplements. A good choice would be a "senior" vitamin-mineral supplement that includes the B vitamins, vitamin E and zinc. Supplements containing significant amounts of calcium, phosphorus or vitamin D should only be given under the direction of a veterinarian.

Feeding the Stud Dog
With so much attention focused on the brood bitch, sometimes the stud dog gets short-changed. Males need proper nutrition too if they are going to perform reproductively at their best. Dogs shouldn't be too thin, or too fat, but being normal to slightly overweight is best. Dogs that are too thin or too fat often have medical problems that could affect their ability to properly mate and impregnate a bitch. The amount and type of food fed should be adjusted, before breeding, to bring the male in optimal body condition.

Most stud dogs can be maintained on moderately priced dog foods and do not require the energy-dense foods fed to the brood bitch. However, check the label and make sure the ration has been assessed by feeding trials (AAFCO or CVMA). The diet should be fed so that the dog maintains optimal body condition, not necessarily the recommended level on the label. Stud dogs are individuals and some may require more or less than recommended to maintain optimal body condition.

Currently, research is underway to examine in more detail the role of specific nutrients in sperm development. For example, deficiencies of beta-carotene and vitamin A have resulted in testicular degeneration in other species; ascorbic acid may be involved in normal sperm production; pyridoxine is involved in the release of pituitary hormones; chromium is important in maintaining the integrity of nucleic acids; and zinc has been reported as a cause of testicular degeneration in some species. However, there is not enough research done in the dog to make any specific recommendations. 

Avoid the temptation to supplement the stud's diet, although some healthful meat and vegetables isn't a bad idea. Most vitamin-mineral supplements will not perk up the sperm, and some have definite adverse effects. A standard one-a-day vitamin is fine, but high doses of specific nutrients are not recommended. 

Feeding the Show Dog
The requirements for feeding a show dog are significantly different from those for a field trial dog and also different from the typical maintenance ration for a sedentary house pet. The goal of feeding the show dog is to optimize the physical characteristics of the dog, not meet its minimum dietary requirements. Most breeders are adamant about the foods they will and won't feed their dogs. When they sell puppies, they often provide dietary recommendations for "what works for them." Whether there is any scientific rationale for the choice often takes a back seat to personal experience. Even poorly balanced diets may produce a champion and this attests more to the resiliency of dogs than to the intuitiveness of breeders.

Most show dogs benefit from a blend of protein, fat and carbohydrate and do not need the energy-dense format found in performance diets. These performance diets often provide too much fat, and the wrong kind of fats to promote good skin and haircoat. A maintenance ration containing "wholesome ingredients" should be provided and it needn't be high in protein, fat or carbohydrate. These dogs truly benefit from a "balanced" ration, not one of extremes.

Most dog foods intended for show dogs are primarily meat-based. Soy protein contains much indigestible fiber and some highly-bred canines do not tolerate soy as well as meat. Chicken, beef, pork and lamb are all well digested by dogs. If these ingredients make up the protein basis of the dog food, a high-protein ration is not needed. Meat protein provides ample amounts of the essential amino acids that are required. If there is too much meat in the diet, the content of saturated fat will also increase and this is counterproductive to enhancing the skin and hair coat. By incorporating easily digestible carbohydrates into the diet, such as rice, potatoes or corn starch, calories can be provided without relying on high levels of fat or protein.

Supplementation of foods intended for show dogs is commonplace and so there is no point in recommending against it. It is better to discuss options for sensible supplementation that does not "unbalance" a balanced ration. If the starting point is a good-quality "maintenance" ration rather than a performance ration, better results will be seen with or without supplementation.

Fat and oil supplements are commonly given to dogs, and the show dog is no exception. Unfortunately, these fats and oils are often poorly formulated and provide more calories than essential nutrients. The purpose of supplementing with fats is to provide the essential linoleic acid to the diet. The best source of this fatty acid is safflower oil or flaxseed oil. Corn oil is only about 50 percent linoleic acid, and the other vegetable oils contain even less. It is cheaper and more effective to purchase safflower or flaxseed oil directly rather than the vegetable-oil mixtures found in pet-supply outlets. Don't overdo it - add no more than a tablespoon per day to the food. Another fatty acid that might be helpful to skin and hair coat is gamma-linoleic acid, found in evening primrose oil or borage oil. These can be found in health food stores or may be purchased from your veterinarian. Veterinary products often combine the plant oil with marine oil for added benefit; the combination product is not currently available from health food stores.

Protein supplements are not needed for the show dog and can be harmful. The real need is for essential amino acids, which are present in the protein source itself. All protein ingested is "broken down" first to individual amino acids. The most important amino acids for skin, hair coat and claws (nails) are the sulfur-containing methionine, cysteine and cystine. Additional protein in the diet cannot be stored and will be converted to fat or excreted by the kidneys.

Vitamins and minerals are important to healthy skin and fur, but indiscriminate supplementation is unlikely to be beneficial. A general "stress" vitamin-mineral supplement is helpful, as it provides a broad spectrum of important B vitamins and antioxidants such as vitamin A (or beta-carotene), vitamin C, vitamin E and selenium. It is unwise to supplement with additional calcium and phosphorus, because this frequently results in bone deformities in growing dogs. 

Many other supplements that have no scientific rationale are used by breeders. Some of the most common are brewer's yeast and kelp. Brewer's yeast is a good source of B vitamins, but it also lacks the much-needed vitamins A, C and E. Despite the contentions of many to the contrary, scientific studies of brewer's yeast have not found it to repel fleas. 

Kelp is a type of seaweed and is indeed a rich source of vitamins and minerals. It is not nutritionally complete on its own but does provide several useful amino acids in addition to the vitamins and minerals. In most cases, if a dog improves on brewer's yeast of kelp, it indicates that the food being fed previously was not properly fortified. In this instance, it is usually more cost-effective to switch to a better diet than to continue supplementing with these products.

* Lowell Ackerman is a veterinarian and nutritional consultant. The past editor of Advances in Nutrition, he has authored 66 books and more than 150 articles, and lectures extensively on the subject of nutrition across the United States, Canada and Europe.

Lowell Ackerman, DVM, Ph.D
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