by Lexie Hunter & Dr Prue Honson
What is desexing?
The decision to desex is an important decision for every pet owner. The term ‘desexing’ can be misleading as your pet will not lose their gender! Desexing is a sterilisation surgical procedure that involves the removal of reproductive organs. In a female, desexing is referred to as ‘speying’ and involves the complete or partial removal of the uterus, uterine horns and ovaries. In the male, testicles are removed in a process called ‘castration’. After the surgery your pet will no longer be able breed, and therefore this procedure is the most widely available, effective and permanent method for pregnancy prevention.
Why is desexing done?
- Increases lifespan
- Council registration significantly lower
- Behavioural issues e.g. less likely to roam or exhibit aggression to other dogs/cats
- Reduces the risk of mammary and ovarian cancer, uterine infections and pyometra
- Eliminates the issue of dealing with a queen or bitch on heat including bleeding, vocalising and confinement.
- Reduces the numbers of unwanted pregnancies and therefore the number of animals entering shelters/pounds
- Reduces the risk of many prostate, testicular and peri-anal diseases
- Reduces the risk of urine spraying in cats
When is desexing done?
Veterinarians vary in their recommendations on when to desex as there is a lack of clear evidence to support desexing at any particular age. Many shelters desex puppies and kittens as young as 8 weeks of age to eliminate the risk of breeding more shelter animals. However most private practice vets will suggest waiting until the animal is slightly larger and more robust to withstand the anaesthetic and to reduce the risk of low blood sugar.
For cats we recommend desexing at 4-6 months old.
For dogs we recommend desexing females before their second cycle so this is usually between 6 and 12 months old. For male dogs we recommend desexing them once they have reached skeletal maturity which depends on breed and size. For example, a Jack Russell may have reached skeletal maturity by 6 months old but a Great Dane does not reach skeletal maturity until 2 years old. For more information on when to desex large to giant breed dogs check out this article.
How is desexing done?
Laparotomy is the conventional method for desexing females and males and is performed through a moderate-sized mid-line incision to the abdomen. The exploratory surgery involves the removal of the entire reproductive system through exteriorising the ovaries/testes and associated vessels. This routine procedure is like second-nature for general practitioners and is quick, simple and has minimal complications. One study indicated 0.01% chance of intra-operative complications (e.g. haemorrhage) and a 0.06% chance of post-operative complications (e.g. wound healing complications, urinary incontinence or ovarian remnant syndrome). Risk of complications does increase slightly with larger dogs.
Laparoscopic or ‘keyhole’ desexing is a method limited to female cats and dogs or males with retained intra-abdominal testicles. The endoscopic examination involves small incisions into the abdominal cavity to introduce a camera for removing ovaries. Procedural time is based on operator capabilities and recovery time is also varied. The specialised equipment and expertise required for this procedure means it is more expensive than standard desexing.
Whilst this procedure is considered to be less invasive, humans report it is quite painful due to the gas used to inflate the abdomen for visualisation and unlike standard desexing incisions it involves cutting through muscle which can be more painful than the standard midline incision. Other complications noted include vulval discharge, transient anorexia or inadvertent splenic laceration mammary congestion.
It’s important to note laparoscopic desexing removes only the ovaries (not the uterus or uterine horns) so the rest of the reproductive tract is still prone to disease however removal of the ovaries reduces hormonal output decreasing the risk of uterine disease.
Laparoscopic desexing is an option to consider particularly in dogs that are prone to bloat and would benefit from a prophylactic gastropexy at the same time. We recommend seeking out a skilled surgeon who is well versed in handling laparoscopic surgeries and thus can complete them rapidly and smoothly with low risk of complications.
These procedures are partial methods of desexing. In males the ductus deferens is ligated and in females the communication between the ovaries and uterus are ligated. This stops the animal from being able to breed but they are still at risk of all the reproductive diseases associated with a retained reproductive tract. Some breeders will recommend this procedure at only a few months of age so the pet can be purchased with assurance it will not be bred with the view to desexing it once it’s reach skeletal maturity. On the assumption an owner can manage their undesexed pet until the time of desex we do not recommend this unnecessary procedure.
Are there any risks to surgical desexing?
As with any surgical procedure, there is a small risk of complications during and after desexing. These can include your pet pulling their sutures out, swelling and/or infection at the site of incision. There is also an inherent risk, however minimal, with general anaesthesia (<0.04% morbidity).
Medical castration is a temporary non-surgical method for desexing. The resorbable contraceptive implant is inserted similarly to a microchip, between your pet’s shoulders, without the need for general anaesthesia, surgery or testes removal. However, this method offers a short-term solution to desexing as your pet’s fertility will gradually return as the effects of the implant wear off. It is recommended that the implants are repeated every 6 or 12 months, which can be costly and inconvenient for owners.
Chemical castration agents, such as calcium chloride, can also be used to dampen the reproductive hormones required for an animal to fall pregnant. This method offers an inexpensive alternative to surgical castration. However, it is not currently available in Australia with little research to support the long-term effects on sterilization permanency, drug safety, animal welfare and consistent effects on testosterone reduction and sterilization efficacy.
With consideration of the pros & cons, our recommendation for the vast majority of pets is desexing via the conventional method of laparotomy. Please discuss any concerns you may have with our vets.
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A literature review on the welfare implications of gonaectomy of dogs. J Am Vet Med Assoc. May 2017; 250 (10): 1155-1166.
J Norris & M Awad. Early-Age Desexing. Aust Vet Ass Proceedings 2012, RSPCA Australia.
L Muraro & RS White. Complications of ovariohysterectomy procedures performed in 1880 dogs. Tierarztl Prax Ausg K Klientiere Jeimtiere Jan 2014; 42 (5): 297-302.