At the Australian Veterinary Association Conference in Perth (2015) evidence was presented linking early prepubertal desexing in medium to large breed dogs of either sex to a higher incidence of cruciate ligament rupture and clinical evidence of hip dysplasia.
At EHVH we feel it is important to provide our clients with current & well researched peer reviewed information. This may cause an ‘about-turn’ on long held policy; but ultimately it is for you as owner to be provided with facts enabling you to make your own decision based on personal circumstances.
For example – letting a medium to large breed bitch endure its first heat without adequate yard security or supervision may be a poor option. Temporarily suppressing the production of sex steroids with drugs as an alternative to early desexing is not an option if the full benefit to bone development is wanted from natural pubertal hormone flow.
We have long known that the lack of circulating sex steroids (oestrogen & testosterone) as in the prepubertally desexed dog caused delayed growth plate closure in the long bones but the slight increase in length of the bones was not thought to be of any consequence. Recent studies, however, have shown that as different bones have different growth plate closure times, there may be problems with the differential growths of these separate bones (and even within sections of bones as in the tibia).
For most medium or large breeds desexing after the first heat is ideal – usually 9-12 months in medium breeds and later for large and giant breeds. Eg, a great dane may be left until 18 months of age.
Other possible advantages of later vs early desexing:
1. Less chance of developing urinary incontinence later in life.
2. Lower disposition to obesity.
3. The external genitalia of the bitch is sometimes underdeveloped (inverted or hidden vulva) and if left for 1-2 heat cycles this will often self correct.
4. Certain types of tumours (haemangiosarcoma, osteosarcoma & bladder cancer) are of lower incidence in non-desexed or later desexed dogs.
5. However, there is a higher incidence of testicular,. ovarian, uterine & mammary tumours in non-desexed dogs.
6. Even post pubertally desexed females can develop mammary cancer later in life.