Canine Female Contraceptives in Remote Communities

There are many different forms of contraception for our canine companions that are effective in population control for remote community animals. Some are more effective than others, some have dangers attached and some contraceptives are prohibitively expensive. In this article, we will explore some of the main drugs that are used in remote community work.

So what are they and what do they actually do?

There are 2 main types of contraceptives that are used in remote community work, one family is called progestagens, and the other main family is GNRH antagonists.
- The progestagens (MPA® or Covinan®) mimic female hormones that make the dog think it is pregnant  By doing this, it stops the body’s production of eggs and hence acts as a contraceptive.
- GNRH antagonists (Suprelorin®) work in a different way by stopping the flow of oestrogen which will stop the dog becoming fertile.
Both of these types of drugs can be used successfully to reduce breeding of dogs in remote communities, but there can be side effects, so caution must be used.

Administering the Contraceptive

What should we be looking for when trying to work out the best contraceptives for our community's dogs?

Well, we have to work out how frequently we have to use them. With the progestagen Covinan®, this drug needs to be used every 3 months. With the progestagen MPA, studies have shown that this is 98% effective if used every 5 months, and reduces to 90% if used every 6 months. With the GnRH antagonist, Suprelorin®, it is highly effective if used every 12 months, but it should be noted that a bitch will actually become more fertile for the first month.

So why don't we jump straight for the GnRH antagonist (Suprelorin®)?

The problem is that it is exceedingly expensive. The price of Suprelorin® is between 10 to 30 times more expensive than progestagens. In fact it is almost more expensive or equates to the cost of desexing a dog in some programs.
This means that for every Suprelorin® injection, 15 dogs could have had their 2 contraceptives each year.
The second problem is there is a very high risk of side effects. Some studies indicate that they can be as high as 60%.
So, it is our belief that it is better to use a progestagen for population control.

So when should we use them?

Female canine contraception can be incorporated into any effective dog program to help control dog numbers. It is important when organising a service provider that you direct them to the combination of drugs that you want for the animals in your community. In making this decision, it is vital to work out the timing of the visits in relation to the drugs being used. Please note, it is important to always incorporate desexing into any dog program as this will give permanent contraception. Contraceptives should only be used on undesexed animals.
The contraceptive type ultimately depends on how frequent the programs are to be run:
One Visit per Year: If only one visit a year is available, then Suprelorin® can be used. One visit still misses any dogs that were born and reached a breeding age, so it is never ideal to have just one visit. Additionally, other contraceptives will not act for a long enough period. Using Suprelorin® can become a very expensive exercise and can often cost more than having another two to three visits each year.
2+ Visits per Year: If two or more visits a year are available, then it is better to go with the drug MPA.  This is a cheaper option and is extremely effective.  Another added advantage is that more regular visits allow more desexings to be performed, and ultimately provide longer lasting population control results in the community’s dogs.

Can anyone give this drug?

Unfortunately no, and generally there are good reasons. These drugs are what's known as prescription drugs and must be either administered or dispensed by a veterinarian. Overdosage can lead to health problems in the animal that may not be reversible. Also these drugs can be dangerous to people, so caution must be used. A skilled veterinary operator is well versed in administering these drugs.

If you would like further information, please contact us on info@ntvet.com.au or call 08 89723599.

Dr Alexander Burleigh BSc(Vet) BVSc

Dr Alex Burleigh is based in Katherine, NT at Katherine Veterinary Clinic, part of Northern Territory Veterinary Services. He is a part owner and one of the senior veterinarians at both Katherine Veterinary Clinic and Alice Veterinary Centre. Dr Alex Burleigh is a published author with works appearing in veterinary texts, scientific journals and online websites. He consults regularly at both practices.