Research suggests broader strategies addressing abandonment, migration
Abdul Wahab Khan
Panaji : A study conducted across multiple sites in Goa has challenged the conventional wisdom that surgical sterilisation is effective in controlling stray dog population.
According to the study, intensive sterilisation campaigns achieving 58-66% female coverage have failed to reduce the adult dog numbers over a two-year period. However, the campaigns did have a positive outcome in the form of reduced barking of dogs, one of the most frequently cited problems related to the strays.
A team of 21 researchers, led by Dr Helen Fielding from the University of Edinburgh’s Roslin Institute, carried out the first randomised controlled trial of dog sterilisation programmes worldwide.
The study, published in Scientific Reports in April 2025, involved collaboration between UK institutions and local partners, including Worldwide Veterinary Service in Ooty, Government of Goa’s Department of Animal Husbandry and Veterinary Services and the Goa Veterinary Association.
The researchers implemented a sophisticated Before After Control Intervention (BACI) framework across ten paired study sites in Goa, with five receiving intensive sterilisation treatment and five serving as controls. Over 3,200 dogs were surgically sterilised during the campaigns lasting an average of 119 days per site, with trained surveyors conducting 3,617 systematic surveys along designated routes using motorcycles.
“We conducted single intensive sterilisation campaigns in five areas, achieving female sterilisation coverages of 58-66%,” the study states. The research team monitored dog populations for 26 months following intervention.
Despite achieving substantial sterilisation rates, the study found no significant differences in adult dog counts between the intervention and control sites.
However, researchers observed encouraging signs in other areas. “We observed a decrease in puppies and lactating females and a reduction in the residents’ reports of barking, a common problem associated with free-roaming dogs,” according to the study.
Community perception surveys revealed interesting findings with residents in the intervention areas reporting significantly less barking. Additionally, fewer survey participants in treated areas reported seeing increased number of puppies compared to the control sites.
The research identified a crucial limitation affecting programme effectiveness: dog migration. “Post intervention, there was an increase in unsterilised adult male free-roaming dogs in intervention sites compared to the control sites,” suggesting that unsterilised dogs from surrounding areas moved into the treated zones, potentially attracted by the reduced territorial competition from the sterilised animals.
As per the research team, sterilised dogs exhibited less territorial behaviour, creating space for immigrant dogs. This finding aligned with the residents’ reports of reduced barking, typically associated with territorial defence.
The study also noted that 88% of the observed dogs showed ideal body condition and reduced numbers of underweight animals in intervention sites. “Unsterilised and lactating dogs were more prone to being underweight,” the researchers noted, suggesting that sterilisation contributes to improved individual animal welfare even without population reduction.
The findings support the World Organisation for Animal Health’s recommendation for comprehensive approaches to dog population management. The research suggests that dog population control requires broader strategies addressing abandonment, migration, resource availability and responsible ownership practices.
