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No silver bullet: Animal Birth Control for India’s dogs is ridden with challenges

Read time: 5 mins
No silver bullet: Animal Birth Control for India’s dogs is ridden with challenges

Image Credits: Pixabay

One of the most common animals we encounter each day are dogs (Canis lupus familiaris), either as our pets or in India, on the streets of our cities and villages. Free-ranging dogs, which aren’t owned by anyone and roam around human settlements, make up over 70% of the dogs in the world. As most of them are unvaccinated, they pose a risk of transmitting rabies to humans, a fatal disease that claims around 60,000 lives per year around the world. In India, 20 million dog bites and 20,000 rabies deaths are recorded annually. Since dogs come in contact with wild animals, especially around protected areas, they could be potential carriers of other animal-mediated diseases. Hence, it is necessary to regulate the numbers of free-ranging dogs and vaccinate them to keep diseases like rabies at bay.

In India, before the adoption of Animal Birth Control (ABC), many town municipalities indulged in culling street dogs to bring down their numbers. However, it is now illegal to do so. Instead, the recommended approach is to capture these dogs, neuter or sterilize them so they can't reproduce, vaccinate them against rabies and release them back to areas where they were captured. Studies show that if implemented right, this approach can reduce dog numbers by about 70% in about two decades. However, with ABC focused on cities and mismanaged with lack of monitoring, this effort has been largely unsuccessful.

In a recent study, two Indian researchers have developed a mathematical model to guide the authorities to better understand the challenges of ABC and effectively manage dog populations. Based on the intensity of ABC in a region, it calculates the total number of dogs, the number of reproducing adults that add to number per year and the coverage of anti-rabies vaccination. The study, published in the journal Scientific Reports, was funded by the DBT/Wellcome Trust India Alliance Grant, NSF Award, and U.S. Fish and Wildlife Service.

“As scientists studying dog ecology, we have been alarmed at the way the ABC program is mooted as a silver bullet to solve the problem of India’s dog population management,” says Abi Tamim Vanak, the corresponding author of the study. He is an animal ecologist and conservation biologist at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bangalore. “Instead of only critiquing it, we thought that the best way would be to enable managers and others to simulate the consequences of their actions with an easy to use, scientifically robust tool,” he adds about the motivation behind the study.

The researchers ran their model with different intensities of ABC, defined by the number of sterilisation surgeries. A low-intensity ABC considered sterilising about half the number of dogs, medium-intensity had about eight in ten neutered and a high-intensity covered almost all the dogs. One set of simulations included differences in real-world factors like the age, sex, reproductive status, geographical accessibility, catchability and mortality of the dogs, all of which influence the ABC program. The other set of simulations assumed an ideal case where there were no such differences. Each of these tracked the changes in the dog numbers over 30 years.

The results showed that in both simulations, modelled at various ABC intensities, the dog numbers reduced initially, but bounced back or even surpassed the levels prior to the start of ABC. Besides, even with the highest intensity of ABC, only 35% of dogs can be vaccinated against rabies, says the study. It is because practically, not all dogs in a population can be captured and neutered. While it is easy to catch some, others require tedious efforts. The number of dogs caught also depends on how accessible a particular area is for the catchers. The current ABC program does not take into account these practical challenges and differences in the dog population in its planning and implementation process. 

The study also found that a high-intensity ABC program, with approximately 42,600 surgeries per year, would require close to half a million dollars, forcing the government agencies to rethink spending such a huge sum of money on ABC programs.

The researchers argue that unplanned, short-bursts of ABC interventions are not sustainable in the long run. Instead, we need consistent interventions and monitoring of ABC programs to effectively regulate dog numbers and mitigate rabies. “We hope that managers will not frivolously waste money chasing pipe dreams of ‘dog-free’ cities by intermittently neutering a few thousand dogs,” says Abi. “Instead, we hope they will set reasonable target reductions in dog populations with adequate budgetary allocations or advocate for alternate methods for dog removal from the cities.”

If poorly-implemented ABCs do not work, what could be the alternatives to keep a check on free-ranging populations? “First and foremost, we need to promote responsible dog ownership wherein the dogs are not left unsupervised on the streets and we need to stop irresponsible feeding of un-owned free-ranging dogs, as that tends to increase carrying capacity,” says Abi. Making changes to the currently-implemented unscientific ABC programs, and designing policies where unowned dogs could be sheltered could also help. “We also need to have a zero-tolerance policy for free-ranging dogs in ecologically sensitive areas,” points out Abi, as dogs prey on endangered wildlife in such areas.

As a next step, the researchers plan to use their model to show how and why current management plans to control dogs have failed, with city-specific examples.

“We also plan to develop this model further to simulate alternative scenarios of anti-rabies vaccination campaigns and test which method is likely to deliver the best target coverage, within a reasonable time-frame and budgetary allocations,” signs off Abi.


This article has been run past the researchers, whose work is covered, to ensure accuracy.