Things to Consider Before Spaying or Neutering Your Pet Early
Despite previous practice, there now exists evidence that spaying or neutering your pet before the age of 12 months can be detrimental to the health of your pet. For the reasons stated below based on recent studies performed, Dr. Judy Jasek now recommends waiting until around 12 months of age to spay or neuter your pet.
ORTHOPEDIC CONSIDERATIONS
Evidence shows that spaying or neutering your dog before a year of age allows the growth plates to remain open, resulting in your pet becoming taller than he or she normally would. This occurs because the sex hormones communicate with other growth-related hormones that promote the closure of the growth plates at puberty. Hence, the bones of dogs altered before puberty continue to grow. Furthermore, sex hormones are also important for achieving peak bone density. (1)
One study showed that spayed and neutered dogs had a higher incidence of cranial cruciate ligament (CCL) rupture. (2)
Another recent study showed dogs neutered before 5 ½ months of age had a significantly higher incidence of hip dysplasia than those spayed or neutered after 5 ½ months of age. (3)
CANCER CONSIDERATIONS
One study shows that spayed females have a 5 times greater risk and neutered males a 2.4 times greater risk of hemangiosarcoma of the heart, one of the three most common cancers in dogs. (4)
A study of over 3,200 dogs showed that dogs neutered before a year of age had a significantly increased chance of developing bone cancers, such as osteosarcoma. (5)
Despite previous thought, one study suggests that neutering does not decrease the rates of prostate cancer in dogs. (6)
Although the risk of mammary cancer in female dogs is increased after one heat cycle, and more so for each subsequent heat cycle, only about 30% of mammary cancers are malignant. With regular exams by your vet, early detection and removal of such tumors leads to a very good prognosis. (7)
OTHER HEALTH CONSIDERATIONS
The same study that identified a higher risk of hip dysplasia also noted increased frequency of noise phobias and undesirable sexual behaviors in spayed and neutered dogs. (3)
Multiple studies have shown increased risk of female urinary incontinence of dogs spayed early and urethral sphincter incontinence in neutered males. (8, 9)
One study of several thousand Golden Retrievers showed that altered dogs were more likely to develop hypothyroidism. (10)
References:
1. Salmeri KR, Bloomberg MS, Scruggs SL, Shille V.. Gonadectomy in immature dogs: effects on skeletal, physical, and behavioral development. JAVMA 1991;198:1193-1203
2. Slauterbeck JR, Pankratz K, Xu KT, Bozeman SC, Hardy DM. Canine ovariohysterectomy and orchiectomy increases the prevalence of ACL injury. Clin Orthop Relat Res. 2004 Dec;(429):301-5.
3. Spain CV, Scarlett JM, Houpt KA. Long-term risks and benefits of early-age gonadectomy in dogs. JAVMA 2004;224:380-387.
4. Ware WA, Hopper DL. Cardiac tumors in dogs: 1982-1995. J Vet Intern Med 1999 Mar-Apr;13(2):95-103
5. Cooley DM, Beranek BC, Schlittler DL, Glickman NW, Glickman LT, Waters D, Cancer Epidemiol Biomarkers Prev. 2002 Nov;11(11):1434-40
6. Obradovich J, Walshaw R, Goullaud E. The influence of castration on the development of prostatic carcinoma in the dog. 43 cases (1978-1985). J Vet Intern Med 1987 Oct-Dec;1(4):183-7
7. Meuten DJ. Tumors in Domestic Animals. 4th Edn. Iowa State Press, Blackwell Publishing Company, Ames, Iowa, p. 575
8. Stocklin-Gautschi NM, Hassig M, Reichler IM, Hubler M, Arnold S. The relationship of urinary incontinence to early spaying in bitches. J. Reprod. Fertil. Suppl. 57:233-6, 2001
9. Aaron A, Eggleton K, Power C, Holt PE. Urethral sphincter mechanism incompetence in male dogs: a retrospective analysis of 54 cases. Vet Rec. 139:542-6, 1996
10. http://www.grca.org/healthsurvey.pdf
