Epsilon Archive for Student Projects

Abstract

Working as a veterinary nurse includes advising animal owners, helping them to make discisions through well-based facts and experience. Preemptive spaying of the healthy bitch brings many advantages and disadvantages. It leads to cessation of gonadal hormone production, and how the exact extent the surgery affects the dog is not yet fully understood. The sex hormones mainly control the reproductive system, but receptors of these hormones are found in many tissues of the body, and have complex relationships with other hormone systems. Spaying decreases the metabolism although the bitch gets an increased appetite, which enhance the risk of obesity, unless the owner restricts food intake. Urinary incontinence is rarely seen in intact bitches but is estimated to affect between 5 to 20 % of females who are spayed. Mainly larger dogs are affected, and tail docking seems to increase the risk further. Although several studies are contradictory, there seems to be a correlation between the age when the bitch is spayed and the risk of developing of urinary incontinence. The age when surgery is performed is an important factor for the development of mammary tumours. This type of tumour is very common in intact females, and about half of the neoplasms are malignant. The risk decreases significantly if the bitch is spayed early, preferably before the first estrous. However, early spaying is widely discussed, and linked to an increased risk of obesity and urinary incontinence, delayed physeal closure of the growth plate, and changes in behaviour and immune system.

Estrogen has a preserving effect on bone mass and osteoporosis is a major problem for women in menopause. The cessation of gonadal hormone production causes a loss of bone mass in dogs as well, but not to the extent that it shows clinical significance. Osteosarcoma is a severe type of cancer that is not entirely uncommon in larger breeds. Spaying induced the risk for larger dogs to be affected. Studies have also demonstrated the link between spaying and increased risk for developing hip dysplasia, cranial cruciate ligament rupture, patellar luxation and osteoarthritis. The author of this report concluded that excessed weight after spaying increases the risk further. Studies in the hind limb muscles have shown that the operation may result in a reduction of the muscle mass, and that it may contribute to diseases in the musculoskeletal system. As for the prevention of pyometra, the only efficiant way to prevent the disease is through neutering. When the uterus is removed, the condition can not occur. The veterinarian and veterinary nurse should inform the owner that the bitch can become more reactive to stimulus after the precedure. They should also provide information about that the cessation of gonadal hormone production may lead to changes of the fur, and that it may become more like the fur seen on puppies, though not all females are affected.

The aim of this review is to serve as a compilation of available research in the field, presented in a comprehensible manner. The author hopes that it can be helpful to veterinary nurses supporting pet owners in the decision on preemptive spaying of the healthy bitch.