Desexing dogs

There’s now another option when desexing dogs

Surgical castration used to be the only option when desexing dogs but now a non-surgical implant offers an alternative to dog owners unsure if a permanent reduction of testosterone is best for their pet. By Sarah Thomas 

Desexing is one of the core elements of preventive treatment procedures within any practice. Reasons to opt for surgical castration include population control, medical considerations such as reducing the risk of testicular cancer or prostate problems, and behavioural issues such as aggression, roaming and urine marking. 

However, not all pet owners feel good about the procedure, citing changes to their dog’s physical appearance and potential health risks as cause for concern. Fortunately, there are alternatives available that don’t have to mean an irreversible procedure. 

Suprelorin is a reversible non-surgical castration method developed and launched in Australia in 2007 by Peptech Animal Tech, which was taken over by global animal health pharmaceutical company Virbac in 2011. 

It’s an implant containing deslorelin, a slow-release gonadotropin-releasing hormone agonist which suppresses testosterone. It comes in two formats: a 4.7mg implant which lasts six months and a 9.4mg implant which lasts 12 months. It’s inserted under the skin between the dog’s shoulder blades, without the need for anaesthetic or surgery, and eventually disintegrates over time so it doesn’t need to be removed. 

Virbac’s senior technical product manager Dr Michelle Murdoch says it’s a quick and simple procedure vets can offer to pet owners, and it doesn’t involve pets being left at the clinic for the day. 

“It’s also useful for dogs where owners or the vet are concerned that castration may not be best for that particular animal,” she says. “They can use it for a trial to see if reducing testosterone will improve the situation or not, and if it does, they can go on to have surgical castration at a later point.”

“We can say, ‘Look, it doesn’t have to be surgical; there is another option which doesn’t involve removing testicles’. You can then open up a discussion with people who may have been completely against desexing.”—Dr Jenni Green, vet, Uni Vets Camden

Dr Jenni Green, a small animal veterinarian from Uni Vets Camden in south-west Sydney, says that it’s an option she discusses with pet owners from time to time when dogs are in a controlled home environment. “It would usually be for breeders that might have a young bitch coming on but be holding the stud dog and we don’t want accidental mating. We would be able to temporarily castrate him for that,” she says. 

“It also allows vets to provide an alternative to owners who really don’t like the idea of their dog not having testicles. We can say, ‘Look, it doesn’t have to be surgical; there is another option which doesn’t involve removing testicles’. You can then open up a discussion with people who may have been completely against desexing.

“It just brings to the table another method for desexing if that’s something we need to do,” says Dr Green.

Implant use on an ongoing basis has potential benefits for businesses in ensuring pet owners have to keep coming back for top-ups, but Dr Green says it’s not particularly feasible as cost is almost always the dominating factor in any preventative or health treatment for dogs. 

“In my experience, we’re trying to get owners to think about desexing their pet permanently,” she says. “There doesn’t seem to be a lot of sense in paying [more]; you’d be talking about doing it 10 times in the life of a dog and it’s virtually 10 times more expensive than desexing it surgically. But it gives a bit more control around the situation without making that fairly dramatic decision.” 

Dr Green says another factor is that the duration is quite variable for each animal. 

“It’s a little bit more vague in terms of when fertility ends and begins, if you need these dogs to be absolutely not breedable. I think for working dogs and for show dogs, there is a place for them to have this opportunity. But relying on this as a general desexing option…I’m not sure what I would do. I like it as another opportunity for people who, for whatever reason, are concerned about a more permanent desexing.”

“There are lots of potential uses for the product in lots of different species, from wildlife through to other domestic species.”—Dr Michelle Murdoch, senior technical product manager, Virbac

Small animal veterinarian and animal behaviour specialist Dr Paul McCarthy from the Brunker Road Veterinary Centre in Newcastle, NSW, agrees that cost and duration are restrictive factors in implant use. He says the clinic treats about two or three dogs a year with the implant on a case-by-case basis, such as for breeder work or for behavioural issues where owners want to see if it will make a difference before committing to full surgery. 

“Generally, the problem is that it’s expensive compared to a normal sterilisation—no-one has done this because it was cheaper. People have used it for a particular purpose,” says Dr McCarthy.

“Also, breeders have been a little nervous about the fact that there’s been so much unpredictability as to how long the dog will be unable to breed. I think that’s played a role in its popularity with breeders. I think breeders are more or less now keeping their male dogs separate, rather than looking at using anything that might hamper the dog’s fertility for a time period.”

There are wider uses on the horizon for Suprelorin, however. Research has been done into population control for brumbies, grey kangaroos, tammar wallabies, koalas and brushtail possums, although Dr Murdoch says this isn’t an area Virbac is actively pursuing. 

“There will always be lots of interest in those off-label usages because of the nature of the way it works,” she says. “There are lots of potential uses for the product in lots of different species, from wildlife through to other domestic species, but there’s not an active area to develop a market or to look at increasing registrations in some of those other species at this point in time.”

For vet clinics, however, it remains an option that’s out there. “Generally, on the topic of desexing, I think it’s hard to be cut and dried about whether you should or you shouldn’t,” explains Dr Green. “The nice thing about this is it does give you a little bit more opportunity. So, I wouldn’t necessarily say this is the answer but it does enable a conversation to be had.” 



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