by Barry B. Burtis D.V.M.
Aging in Cats
When does my kitten become an adult and no longer require kitten food? How old, in human years, is my cat? At what age is my cat considered a senior? How long do cats live? These questions are ones that veterinarians are frequently asked by cat owners. They all relate to aging, a normal life process. A cat goes through a number of life stages. Cats are first kittens or juveniles progressing to adulthood, then maturity and finally become an aged or senior cat. There are a number of physiological or normal body functioning changes that occur as cats go through these stages. Many of these changes have important implications for pet owners and veterinarians interested in providing optimal health care for cats.
Adulthood begins following sexual maturity at approximately one year of age and extends until the cat is approximately 6.5 to 7 years of age. This is normal breeding period for cats. Cats in this stage of their life should be very active, very muscular, having a high percentage of lean tissue mass and high bone density. It is usually a period in the cat's life when they generally are healthy and free from disease.
After adulthood cats enter their stage of maturity that extends from approximately 7 years to 11 years of age. During this time period activity is only moderate and dietary energy intake decreases. There is often an increase in body weight and a progressive increase in total body fat. Obesity becomes more of a clinical problem during this life stage and there is an increased incidence of disease observed. Many veterinarians believe this is a time in a cat's life when wellness health laboratory screening should begin on a routine basis.
A cat is considered to be a senior when they are approximately 11 years old. For more and more cats, these days, this may actually be the longest stage of their life. It is not unusual to find cats living into their late teens or early twenties. A few years ago I had a client who had two cats, Tiger, who was 22 years old and his mother, Isobel, who was 23 years of age. They were both in remarkably good health. However, the senior life stage is the period of highest disease incidence and acquired disease plays the primary role in influencing longevity. Some changes that occur during this time of a cat's life include a progressive loss in body weight with a decrease in both fat and lean (muscle) tissue. Also, at this stage food consumption decreases and in some cats there is a decrease in the digestibility of nutrients in their diets. The aged cat also will demonstrate reduced general activity with an increase in the amount of sleep cycles. They become more sedentary sleeping more throughout the day. As the aging process continues, cats will show obvious changes in physical characteristics as well as changes in laboratory values when blood and urine samples are used to monitor their health status.
It is important for both veterinarians and pet owners to remember that age, itself, is not a disease process. One should not be reluctant to diagnose or treat a pet simply because it is "too old". Cat owners sometimes will make comments like, "I know she really needs some dental care but she's too old for the anesthesia." In a properly evaluated senior patient, found free of serious disease, veterinarians should be able to develop a low risk anesthesia protocol based on the life stage of the patient. Our pets are now living longer due to the improved nutrition they receive throughout their life, advances in veterinary medicine and the ability for early detection of disease. I believe it is wrong to deny them the improved quality of life that they can be given, at a time in their life when we should be celebrating their longevity.
How long will my cat live? It's still a question we cannot answer, when a client asks us. The answer is unknown and primarily dependent upon the development of acquired disease. However, we can remember these normal aging changes that occur during a feline's life. Based on these observations we can make some generalizations concerning the diet we should be feeding a cat, the activity levels we should be encouraging and the health care they should receive during their various life stages.