Constipation is not a disease, but it is a condition that can be caused by many diseases. It represents a dysfunction in the normal process of defecation. A constipated dog or cat exhibits infrequent or difficult evacuation of the feces or stool. The feces is usually hard and dry which increases straining and reduces stool volume.

Many things may cause constipation, but the most common are dietary and environmental factors. Dietary factors include insufficient fiber in the diet, insufficient supply of water, and ingestion of substances such as hair, bones, or foreign materials that can form hard masses when mixed with feces. Environmental factors include changes which affect an animal's daily routine such as removal of the litter box, a dirty litter box, a hospital stay, or lack of exercise.

There may be many other causes of constipation. They include aging, fractures of the pelvis or pelvic limbs, lesions around the rectum, prostate disease, spinal cord or disc disease, large bowel nervous disorders, tumors, metabolic or endocrine disorders, debilitation, and dehydration.

As you can see, there are many reasons your pet can become constipated. Some are not serious while others may be life-threatening. For this reason, your pet should be brought to your veterinarian if showing signs of being constipated. Your veterinarian will perform a physical examination of your pet and will ask you about your pet's medical history, its diet and its daily routine. Blood tests, X-rays or other tests may also be necessary and will be explained to you prior to testing.

If it is determined that the underlying cause is due to disease or trauma, medical treatment may be necessary to correct the problem. If the cause is dietary or environmental, the appropriate recommendations will be made. The important step is to recognize that there is a problem and act accordingly.

The writers are Dr. Steven B. Holzman, Dr. William R. Haagenson and Dr. Kathleen Tapley. They are associated with the Nassau-Suffolk Veterinary Hospital of Farmingdale.