Physical Changes in Aging Pets

We’ve been discussing changes that occur in senior pets and have covered behavorial changes. Now, let’s look at physical changes

Brain & Senses
Size and weight of brain decreases with aging. The fluid-filled ventricles can increase in size. Neurotransmitters change. Senses diminish and pets don’t see, hear or smell well. The lenses of the eyes become cloudy. The eyes become red and dry (keratoconjunctivitis sicca or dry eye) as tears lose their lubricating ability and thick discharge appears in the corners.

Bones & Muscles
Older pets lose muscle mass; the spine becomes more prominent. Seniors have weak and stiffened ligaments & tendons, and thin, ineffective joint fluid. Joint fluid cannot nourish the cartilage in their joints so that it dries and becomes brittle. Bones demineralize and soften. These bone & muscle changes make it difficult for seniors to take long walks, climb steps, jump into the car or onto the counter. Senior pets are stiff & wobbly; they fall over easily.

Mouth
Almost all aging pets have dental disease with inflammation of gums (gingivitis). Dental calculus (tartar) builds up. While some believe kibble and dry food causes less tarter than canned or soft food, this is not necessarily true. It is true that accumulated calculus leads to gum disease, pain, infection, and loss of teeth. The speed and severity of these problems is influenced by genetics, nutrition, infections such as Feline Leukemia, and feeding habits.

Stomach, Intestines & Digestion
Older dogs and cats may lose weight and become cachectic or gain weight and become obese. If they lose weight, it is because they don’t digest their food as well as a younger pet or have disease process such as cancer that demands more nutrient than they consume. Seniors are inclined to problems with constipation and diarrhea. They have fickle appetites and like a food one day, but not the next so that variety becomes important. Enzymes, probiotics, and B Vitamin injections are helpful.

Kidneys
Aging kidneys lose their ability to hold water so that pets drink more and urinate more (polyuria polydipsia or PUPD). In addition, several diseases (diabetes, Cushing’s disease, kidney disease, hyperthyroidism) cause pets to have PUPD. The large volume of urine in the bladder can cause house-trained pets to urinate in the house. With the loss of large volumes of water into the urine, the body dehydrates, stools become dry and are more difficult to pass so pets develop chronic constipation secondary to kidney disease.

Bladder
Aging kidney cells produce urine so dilute that it cannot prevent bacteria from growing within the bladder. Bladder infections (cystitis) cause frequent, painful voiding of small amounts. Pets with cystitis often urinate in the house or outside the litter box.

Skin
Pets have thinner drier skin and coats as they age. The skin loses its elasticity because vitamin C-dependent collagen doesn’t form. Cysts, warts, and tumors form. There’s an increase in chronic Staph and yeast infections. The coat becomes unkempt. Dogs will grey; cats maintain their coat color, although usually it is less vibrant than when young. Nails grow thicker and longer as the result of liver disease.

Weight
Aging pets increase total fat and decrease total muscle. To prevent obesity, they need joint medications and frequent, mild exercise. For most aging pets, senior diets are not as helpful as a good regular diet with herbs.

We've covered lots of material on senior pets. These are wonderful years that you can look forward to enjoying. If you prepare to spend a little more in veterinary care & supplements than you've spent for your young robust cats & dogs, then the days ahead will still be good.