This is a report on a study looking at a durable contraceptive for female feral cats to try and control numbers in the US. We constantly read about feral cats decimating wildlife although, if we are honest, we don’t know accurately the impact feral cats have on the population numbers of the feral cats’ prey animals such as birds and more commonly rodents. There is a large element of speciesism in attempts to protect wildlife in the US. Birds need protection. Rodents don’t as they are pests. That’s speciesism but I understand where it comes from.
More: Non-chemical method of female cat contraception
Using a contraception to manage feral cat populations is not new. It was discussed decades ago. This study is perhaps one of the latest (published: 06 June 2023) to find an alternative to spaying and neutering which is resource intensive. The study is not actually that recent but it’s importance allows me to look at it again.
In 1986 one of the best books ever on domestic cat behaviour was published: CatWatching by Dr. Desmond Morris. In it under “How fast do cats breed?” he writes:
“In some areas there are fairly ruthless extermination programmes for feral and stray cats, and in certain countries there have been oral contraceptive projects with the stray cat population given food laced with ‘the pill’. Israel for example claims to prevent about 20,000 kittens a year by using this technique.”
I don’t think the technique was successful in the long terms as feral cats are common in Israel to this day. See base of page for a lot more on Israel’s use of contraception to control feral cats.
Certainly in Australia an effective contraceptive that could reduce the feral cat population to near zero in a reasonable time would be much more humane than the cruel methods currently employed, which are wholly unacceptable to cat and animal advocates.
The study on a durable contraception
The study titled “Durable contraception in the female domestic cat using viral-vectored delivery of a feline anti-Müllerian hormone transgene” explores a novel approach to controlling feral cat populations through a long-lasting, non-surgical contraception method. This research, led by William Swanson and collaborators, offers a potentially humane and practical alternative to traditional spay-and-neuter programs. The team focuses on using a viral vector to deliver a gene coding for the feline anti-Müllerian hormone (AMH), which regulates ovarian function and fertility in cats.
Key Points of the Research
- Anti-Müllerian Hormone and Fertility Control: AMH is a naturally occurring hormone involved in reproductive system development and maintenance. By increasing AMH levels in female cats, researchers aim to inhibit ovarian follicle development, thereby reducing or eliminating fertility. The team hypothesized that sustained high levels of AMH could prevent ovulation without requiring surgery.
- Viral Vector Delivery System: The study utilizes an adeno-associated virus (AAV) as a vector to deliver the AMH gene directly to the target cats’ cells. This vector is chosen because it is non-replicative and has shown effectiveness in delivering genes for long-lasting expression in other medical applications. Once inside the cells, the vector promotes ongoing production of AMH, leading to contraceptive effects.
- Experiment Design and Results: Researchers administered the AMH gene via AAV to female cats and monitored them for signs of estrus (heat) and pregnancy. Over time, the treated cats showed a significant reduction in estrus behaviors, indicating a suppression of ovarian activity. Additionally, these cats did not become pregnant, even when exposed to male cats. The duration of effectiveness varied slightly but was generally long-term, offering a practical contraceptive solution for feral and outdoor cats.
- Advantages and Potential Applications: This gene therapy-based contraception method offers several benefits over traditional spaying. For one, it is minimally invasive and avoids the risks associated with surgical procedures. Furthermore, it could be applied to large populations of feral cats, where individual surgical spaying/neutering is logistically challenging and costly. By reducing the breeding potential of feral cats, this approach could help manage and reduce feral cat populations in urban and rural areas.
- Future Prospects and Challenges: While promising, the study acknowledges that further research is needed to assess the long-term safety and potential side effects of AAV-based AMH contraception. Additionally, regulatory hurdles and potential public acceptance issues must be addressed before widespread adoption. There is also interest in exploring if similar methods could apply to other wild or stray animal populations to manage ecological impacts.
Summary
This study presents a significant step forward in wildlife contraception, using gene therapy to achieve long-term reproductive control in female cats through sustained AMH production. This viral vector-based contraception could provide a humane and effective solution to the challenges of feral cat overpopulation, reducing the need for surgical spay and neuter programs and offering a practical approach to animal population control.
Israel’s use of contraception to control feral cats
Yes, Israel has used contraception as part of efforts to control feral cat populations, although the country primarily relies on a combination of methods, including trap-neuter-return (TNR) programs and non-surgical contraceptive initiatives.
Background of Feral Cat Control in Israel
Israel, like many countries, has struggled with a large and growing population of feral cats, particularly in urban areas. This overpopulation has led to concerns about public health, animal welfare, and the ecological impacts of feral cats on wildlife. To address these issues, the Israeli government and animal welfare organizations have implemented various measures.
Contraceptive Efforts in Israel
Israel has experimented with both surgical and non-surgical methods to manage the feral cat population. While TNR programs (where cats are trapped, sterilized, and then returned to their environment) have been widely used, there has also been exploration of non-surgical contraceptive methods.
- Non-surgical Contraceptives: In recent years, some Israeli municipalities and organizations have tested non-invasive contraception methods, such as hormone-based injections, to control fertility in feral cats. These efforts aim to reduce the need for surgical sterilization, which can be costly, time-consuming, and difficult to implement for large feral cat populations. However, the widespread use of non-surgical contraception has not yet replaced TNR as the dominant method.
- Government Initiatives: In 2018, the Israeli government allocated funding to control the feral cat population. Some of the funding was earmarked for research into alternative methods of population control, including non-surgical contraceptives. The use of such contraceptives is seen as a potential way to manage the problem more effectively, but so far, it has not become the primary strategy.
Effectiveness and Challenges
While non-surgical contraceptive methods, like hormone injections or viral-vectored gene therapies, hold promise for population control, their effectiveness on a large scale is still under study. Some of the challenges include the need for repeated treatments (in cases of hormone injections), logistical difficulties in capturing and treating feral cats, and public acceptance of these methods.
Conclusion
Israel has indeed explored contraception, both surgical (TNR) and non-surgical (hormonal or gene-based), to manage its feral cat population. Although contraceptive efforts are a part of the broader strategy, TNR remains the most commonly used approach. Ongoing research into non-surgical methods, such as those involving contraception via gene therapy, may offer new solutions in the future, but these are still in the experimental stage.
