In its natural state, your body, my body, an animal's body tends toward homeostasis - balance.
In a healthy body, all organs and tissues function in order to maintain a condition of equilibrium - balance. Blood flows through the body at rest about once a minute, carrying oxygen and nutrients to some 70 to 100 trillion cells. Plus this circulation animates seven to 10 million new cells that are born every second of every moment of every day the body is alive.
If nothing intervenes, the body works perfectly on its on to maintain homeostasis. For every action in the body, there's an equal and opposite reaction. Muscles strengthen or weaken depending on use or inactivity. Hormones speed up or slow down metabolism. Heart rate speeds or slows circulation. Moment by moment, day in and day out, the body adjusts to compensate for what we ingest, inhale, absorb, inject or do, be it energetic or supine.
It's all autonomic and reflexive - unconscious and automatic.
Of course, the statistics vary for smaller bodies like dogs and cats, but they function the same. So what is the picture of health (homeostasis) in a dog? According to the American Kennel Club, a dog in top condition looks like this:
Skin - Healthy skin is flexible and smooth. Color ranges from pale pink to brown or black depending on the breed. Freckled skin is normal, whether the dog has a spotted or solid coat. Healthy skin is free of redness (inflammation,) malodorous eruptions, scabs, growths, white flakes and parasites such as fleas and ticks.
Coat – A healthy dog coat comprises three types of hair – guard hairs, fine hairs and tactile hairs otherwise known as whiskers. The preponderance of either guard hairs or fine hairs varies depending on breed. For example, the boxer has a coat of fine, short hair. Most terriers have a coarse coat of relatively stiff, short guard hairs. Some shedding is normal; dogs replace their coat continuously. Breeds with a long, woolly coat of extremely modified fine hairs such as the poodle, Bichon Frise and Maltese do not shed and must be groomed regularly to maintain a coat health. Long or short, fine or coarse, a healthy coat is glossy and pliable, without dandruff, bald spots, or excessive oiliness.
Eyes – Healthy eyes are bright and shiny. Mucus and watery tears are normal but should be minimal and clear. Eyelids (conjunctiva) should be free of inflammation, swelling or excessive discharge. The whites of your dog’s eyes should not be yellowish. Eyelashes should not rub the eyeball. It is common to see a dog’s third eyelid, a light membrane, at the inside corner of an eye. It may slowly come up to cover his eye as he goes to sleep.
Ears – The skin inside a healthy ear and on the external pinna is light pink and clean. The ear canal and flap is free of redness, swelling or odor. Some discharge of yellow or brownish wax is normal; however, a heavy extrusion of wax or crust signals an underlying imbalance. By virtue of conformation, i.e., a deep, dark, narrow ear canal, poodles, spaniels, retrievers and other breeds with floppy ears are predisposed to ear problems; it takes extra attention to keep the ears dry and clean inside and out.
Nose – A dog’s nose is usually cool and moist. Depending on the breed, it can be black, pink or the same color as the coat. Healthy nasal discharge is clear, never yellowish, thick, bubbly or foul smelling. A cool, wet nose does not necessarily mean the dog is healthy, and a dry, warm nose doesn’t necessarily mean he’s sick. Taking his temperature is a better indication of illness.
Mouth, Teeth and Gums – Healthy gums are firm and pink, so close to the teeth that they look attached. Freckles and pigment consistent with the dog’s skin are normal. Gums are free of plaque. Teeth are free of calculus. Breath is sweet and unoffensive.
Temperature – A dog’s normal temperature is 101 to 102.5 degrees Fahrenheit (38.3 to 39.2 degrees Celcius). You need an ear or rectal thermometer to check your dog’s temperature. If your dog pulls away from an ear thermometer, you can’t get an accurate reading. In this case, use a rectal thermometer just like you do with an infant.
Heartbeat and Pulse –A healthy heart beats from 50 to 130 times a minute in a resting dog. It’s faster in puppies and small dogs, slower in large dogs in top condition. To check your dog’s heartbeat, place your fingers over the left side of the chest, where you can feel the strongest beat. It’s always good to establish a baseline – the normal pulse for your dog at rest. Any extreme deviation faster or slower signals distress or illness.
Elimination – The character and frequency of urine and feces are excellent indicators of a dog’s health. Healthy urine is clear or slightly yellow without traces of mucus or blood. A dog evacuates his bowels once or twice a day depending on what and how often he eats. Stools should be firm and well-formed. Dark, smelly urine with too often or little elimination; runny, watery or bloody stools, straining to evacuate the bowel, too often or too seldom evacuation are all symptoms of an underlying imbalance.
Anal sacs – Anal sacs (scent glands) normally secrete a thin, watery fluid that is yellow to tan in color. These glands empty normally when your dog defecates thus leaving his scent marker wherever he eliminates.
Claws (toenails) – A healthy dog uses claws for both traction and digging. The outer layer may be pigmented or not. The inner layer – or quick – contains blood vessels and tissue connecting to your dog’s circulatory system. Normal claws barely brush the ground, permitting your dog to stand compactly.
Weight – Every dog breed has a healthy weight range which is available from the breeder or online. A healthy balance between diet and exercise maintains this weight. At a healthy weight, you should be able to feel the ribs below the surface of the skin without much padding.
By this standard, my dog's immune system was already talking soon after he was weaned to dry dog food and following his puppy shots. By the time I got the message, it was too later to turn it around.
~Courtesy of the American Kennel Club