Dr. Pitcairn's Complete Guide to Natural Health for Dogs and Cats (29 page)

Foxtails, or plant awns, are those stickery little things that attach to your socks when you walk across a field. They latch onto dogs, too. And because of their pointed ends, these burrs work their way not only into the coat but sometimes right through the skin, burrowing also into the eyes, ears, nose, mouth, vagina, rectum, and between the toes.

Because our patient was so badly affected, we had to give him a general anesthetic before beginning the long process of removing the stickers. First we pulled and clipped the burrs out of his coat, then we worked them from between his toes. While my assistant, Dottie, attended to the feet, I found and removed two or three foxtails from deep in the ear canal. Careful examination revealed another lodged in the eye—the cause of the inflammation and discharge.

As we worked, Dottie and I began talking about how pets get into such a state after even a short trek in the fields.

“Here is the cause of the problem,” I said, holding up some of the matted hair we had clipped off. “An animal with this kind of curly coat is like walking Velcro. Once the stickers brush against it, there’s almost no place else for them to go but deeper in.”

I pondered the matter for a moment. “You know,” I went on, “people have unwittingly created this type of problem by deliberately breeding dogs to have such hair, as well as floppy ears like these. Both are perfect traps for foxtails. Wild animals don’t have anywhere near this difficulty with stickers.”

Situations like this have led me to reflect on the many ways we have interfered with the natural reproductive patterns of domestic animals. In the process of selective breeding, we have created a host of abnormal body structures that increase the likelihood of health problems. In addition, drugs, synthetic chemicals, radiation, and certain infectious diseases can damage a fetus and further increase the incidence of birth defects.

Animals born with defects can face lifelong health troubles despite excellent care and feeding. That’s why it’s so important to understand how these malformations are caused and what can be done to prevent or minimize them. First let’s look at problems that have developed because of inbreeding and unwise selection.

THE EFFECTS OF BREEDING

When we humans began to domesticate animals, we took over many of nature’s decisions about which animals were best suited to carry on the line. No doubt we made many good choices, often picking the strongest and the healthiest. But often animals were chosen for a unique appearance or some unusual behavior that pleased us or suited a particular need—horses with thick, beefy legs for pulling heavy loads; toy versions of dogs for lap companions; no-tail novelty cats. The inbreeding created new lines that had never before existed.

Consider the dog. As the first animal to be domesticated (some 10,000 to 20,000 years ago from wolves that began to associate with humans), the dog has probably been bred more than any other animal. Over thousands of generations, we developed dogs of every size and purpose. With a social structure and instinct similar to our own, they have served us well as hunters, herders, sled dogs, watch dogs, guide dogs, religious symbols, personal companions, and even as a source of food.

Cats, by contrast, were the last animal to share the home life of humans. They were lured by the many mice in the granaries of ancient Egypt and stayed to become a religious symbol of that culture. Not easily trained, the cat was not bred for any further duties except companionship. Their natural talent as mousers made cats welcome in households all over the world.

Just page through a picture book on breeds and you’ll see the different breeding histories of dogs and cats. Dogs show much more variety in size, shape, and hair texture than cats. The difference in appearance between certain modern breeds of dogs and their wild ancestors is particularly striking in comparison with the relatively minor changes in cats.

Surely this greater interference with natural selection explains why a clinical study of birth defects in cats, cows, dogs, and horses showed that dogs had the most congenital malformations at birth and cats the fewest, despite the fact that cats are generally more sensitive to chemicals and other agents known to cause birth defects.

How does selective breeding lead to defects and malfunctions? An important factor in the creation of many breeds is
neoteny
, or a return to more primitive or undeveloped characteristics—either those that occurred early in the species’ existence or those common to immature puppies or kittens: short legs and muzzles, silky hair, floppy ears, and the tendency to bark (adult wolves rarely bark).

So, many of the features we find appealing in purebred animals are actually the products of arrested development—either physical or psychological. A desired trait is often a trade-off for a defect or loss of function. For instance, breeding dogs for a short
muzzle (upper jaw) has spelled trouble for breeds like bulldogs, boxers, and terriers. That’s because separate genes determine other features that are closely related, such as the teeth and the soft palate (which separates the mouth and throat), and the genes continue to size them for a normal muzzle. So the crowded teeth are forced to grow in crooked and sideways, and the soft palate hangs so far back into the animal’s throat that the threat of suffocation is ever present.

Inbreeding adds to the problem. To fix a given characteristic into a breed (so that it will breed
true
, that is, reappear consistently), selected brothers and sisters must be mated, or a parent crossed with its offspring. Such intensive inbreeding might ensure the desired trait, but it might also perpetuate basic weaknesses in the line, such as poor resistance to disease, low stamina, low intelligence, birth defects, and inherited diseases that include hemophilia or deafness.

Breeding to meet market demand can also lead to disaster. During the 1920s, for example, the recently imported Siamese cat became so popular that breeders mated siblings as well as parents and offspring to meet the demand. The kittens born of these matings so weakened the breed that it almost died out entirely. Sobered by this experience, breeders began to make wiser selections. Many breeds of dogs—such as the collie, the cocker spaniel, the beagle, and the German shepherd—have also suffered as a result of surges in popularity.

The problem of genetic disease is particularly sad. Animals undergo much unnecessary suffering because they’re often bred for financial gain or for some trait considered “cute,” unusual (such as squat faces, long faces, curly or silky hair, hairlessness, wrinkly skin, floppy ears, or missing tails), or useful (such as short legs for access to dens in hunting or massive size for fighting or guarding). The question of whether the animal will have a comfortable, well-adapted, potentially healthy body rarely comes up. And we don’t seem troubled by the high rate of defective pets. People rightly get alarmed at a human birth defect rate of one in a thousand, but many pet breeders simply accept statistics that predict 10 to 25 percent of their litters may be born defective. Generally, the largest and smallest breeds tend to suffer the most from genetic weaknesses.

Some other examples of problems created in breeding “un-wolfly” shapes and sizes of dogs include the bulldog, Chihuahua, and others bred to have a small pelvis. Many of these animals require cesarean deliveries. Giant breeds such as Saint Bernards and Great Danes are known for their bone problems and their short lives. Breeds that have abnormally short noses and jaws (bulldogs, Pekinese, boxers, and Boston terriers) generally suffer from breathing problems. As might be expected, dogs bred to have short legs (dachshunds and basset hounds) also tend to have deformed spines. Among cats, breeding for
tailless cats (the Manx breed) has also led to litters with severe malformation of the urinary tract and genitals.

Another ethical issue involves producing countless litters to satisfy the demands of people who insist on purebreds. At the same time, millions of mixed-breed animals that would make equally good pets go begging. Up to 75 percent of the dogs and cats born each year face death by accidents, starvation, or euthanasia because they can’t find permanent homes. Selecting a mongrel from the local animal shelter, however, won’t necessarily reduce the risk of acquiring a pet with congenital problems. Often an adopter chooses an animal that especially arouses pity, perhaps one with strangely colored eyes, or drooping ears and eyes that look sad, or a short, pushed-in, childlike face.

Sometimes pets just find their way into our homes and hearts (such as the deaf white cat that came to us as a stray), and we accept them as is. But at least we can decide not to breed an unhealthy animal or one with characteristics that interfere with normal functioning.

ENVIRONMENTAL INFLUENCES ON BIRTH DEFECTS

Environmental poisons and stresses also contribute to congenital problems. Some of these hazards (mutagens) can cause a change in one or more genes that can be passed on to future generations. The result could be a sad legacy of genetic defects and diseases, as well as spontaneous abortion, lowered disease resistance, decreased life span, infertility, or unnatural behavior. Add unwise breeding practices to the mix, such as mating affected parents and their offspring, and the effects can be even worse.

Other hazards (teratogens) attack the embryo but are not passed on. Depending on the timing and the amount of exposure during pregnancy, such factors can cause deformed bodies, miscarriages, retarded growth, congenital tumors, and various disabilities or abnormalities that surface.

If you are planning to breed an animal, it is very wise to take special care to minimize certain risk factors suspected of damaging genes and/or fetuses. The following are the most important to avoid because they can pose a threat both before and during pregnancy.

• Radiation (the worst threat; use filtered water and avoid unnecessary diagnostic x-rays and radioisotopes)
  
• Lead, mercury, and cadmium (see chapter 8)
  
• Chlorpromazine, phenobarbital and urethane (veterinary sedatives and anes thetics)
  
• The insecticides carbaryl, dichlorvos, dieldrin, fipronil, Imidacloprid, Permethrin, Pyriproxyfen, and lindane (some are banned, yet they persist in the environment and accumulate in animal fat, so emphasize diets with lean meats; also minimize use of any chemical insecticides)
  
• Aflaxtoxin (may be in moldy or spoiled foods)
  
• Fungicides (especially captan and griseofulvin)
  
• Anti-cancer drugs (not a good idea to breed an animal that has had cancer anyway)
  

In addition, do your best to protect your pet from the following:

Before breeding:
the antibiotics Actinomycin D, erythromycin, and streptomycin; the antiseptics hexachlorophene, mercury chloride, and hydrogen peroxide; the drugs Butazolidin (phenylbutazone), EDTA, methylene blue, and ethidium bromide; canine distemper (or the live vaccine); the herbicides 2,4-D and 2,4,5-T; chemical soil sterilants; formaldehyde (see chapter 8); and benzene (found in cigarette smoke and car exhaust; don’t keep your pet in a garage).

During pregnancy:
overheating (from being in a hot car or exercising in hot weather); lack of oxygen (from anesthesia, high altitude, anemia, air pollution, or chemical exposure); traumatic injury; most veterinary antibiotics, corticosteroids and sedatives; aspirin; feline leukemia virus (or vaccine); microwave ovens; herbicides, especially paraquat and MCPA; many chemicals, especially complex organic hydrocarbons (follow advice in chapter 8); general underfeeding and malnourishment; insufficient levels of vitamins A, D, or B complex, iron, magnesium, zinc, copper, iodine, or manganese; excessive amounts of calcium, vitamin A, iodine, or salt; certain poisonous plants (jimsonweed, locoweed, skunk cabbage, and wild pea).

Some of these factors are known to cause reproductive problems only when given in high doses to experimental animals. For that reason they may not be an issue under ordinary exposures. Their safety, however, is questionable, and it is best to err on the side of caution.

The harm caused by these agents can show up in everyday veterinary practice, not only in laboratory experiments. For instance, pups born of a mother given corticosteroid therapy during pregnancy have been born grossly swollen with fluid. Also, extreme leg and leg joint deformities occurred in an entire litter of cocker spaniel puppies born to a mother treated with the corticosteroid dexamethasone during the second half of pregnancy.

COMMON CONGENITAL PROBLEMS IN DOGS

The parts of the dog’s body most frequently affected by birth defects are the central nervous system, eyes, muscles and bones. For example, the German shepherd, collie, beagle, miniature poodle, and Keeshond can inherit epilepsy. A variety of other nervous system disorders are sometimes passed on within certain breeds. These include paralysis of the
front and back legs (Irish setter), a failure of muscle coordination (fox terrier), idiocy (German shorthaired pointer and English setter), and abnormal swelling of the brain (Chihuahua, cocker spaniel, and English bulldog).

Congenital eye abnormalities, including cataracts, glaucoma, and blindness, are found in
most
of the common breeds.

Hernia is a typical muscular problem. The basset hound, basenji, cairn terrier, Pekinese and Lhasa apso all have a high risk for inguinal hernias (the gut protrudes into the groin). Umbilical hernias (gut protrudes through the navel) are inherited defects in the cocker spaniel, bull terrier, collie, basenji, Airedale terrier, Pekinese, pointer, and Weimaraner.

Besides bone-related problems like those mentioned in very small, large or short-legged dogs, many canines suffer lameness from abnormal hip formation (dysplasia), probably the most common inherited defect among dogs (see
Hip Dysplasia
). It is seen in most purebreds, particularly cocker spaniels, Shetland sheep dogs, German shepherds, and many large breeds.

For more specific information on particular breeds, see
Behavioral Patterns and Congenital Defects in Dogs
.