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Researchers set to tackle the growing wild boar problem with oral contraception in innovative wildlife fertility programme

Posted on 8 March 2024

Wild boar are to be given oral contraception in a pioneering programme to control the numbers of an animal that is becoming an increasing problem around parts of Europe.

Numbers of wild boar have increased dramatically in recent years

Numbers of wild boar have increased dramatically in recent years and if left unchecked can cause enormous economic and environmental impact. The animals are destroying crops, causing traffic accidents and are involved in transmission of diseases to both people and livestock. 

Global collaboration

A University of York academic is collaborating with global specialists in wildlife control who are delivering a new and humane way to control the numbers of wild boar and will soon be using a high-tech species-specific delivery system to ensure only targeted wild boars consume the contraceptive.

The pilot programme is now underway and is being led by the Latium and Tuscany Institute for Animal Health in Italy, in collaboration with the Istituto Zooprofilattico Sperimentale del Lazio e Toscana (IZSLT) in Rome, the University of York, the University of Milan, the University of Pisa and the National Wildlife Research Institute in Colorado. 

Exponential growth

Dr Giovanna Massei, a Senior Research Fellow in the Department of Environment and Geography at The University of York, said: “The population of wild boar is growing incredibly quickly worldwide. This is largely due to the declining numbers of hunters. This means an exponential growth in wild boar and an ever increasing impact on agriculture and other human activities.” 

Examples of human wild boar conflicts include the animals rooting up turf, munching through bags of rubbish, attacking dogs, causing traffic accidents and transmitting diseases such as African Swine Fever which have severe consequences for farmers. More and more, wild boar are being drawn to urban areas thanks to an easy and ready supply of food.

Carefully controlling

Dr Massei explained that animal health emergencies and pandemic concerns about diseases such as swine fever has made wild boar control more pressing: “Wild boar can carry a host of diseases, including tuberculosis toxoplasmosis that can be transmitted to humans. The wild boar is native in Europe, so we are not looking to eliminate this animal but the numbers need to be urgently controlled if we want to co-exist with this intelligent and adaptable species.”

If the pilot project is successful then scientists will start using a high-tech species-specific delivery system called BOS (Boar Operated System) which means the baits are hidden in a device that can only be accessed by wild boars - ensuring no other mammals access the contraceptive. 

Rapid growth

According to the Coldiretti farmers association in Italy, wild boar populations in Italy doubled from 500,000 in 2010 to one million 10 years later. The environmental agency in Italy claims there are an estimated 2.3 million of them in the country today and these numbers are rapidly growing. 

Wild boar feed on acorns, cereals, most types of crops and will eat almost anything humans consume. Females can produce as many as two litters per year, averaging five or six piglets per litter. When food is abundant more females in the wild boar population can reproduce. The animal becomes sexually mature when they reach about 35kg, sometimes before their first birthday.

Better targeting

The pilot project is taking place in Italy where researchers are testing different formulations of the oral contraceptive and assessing potential side effects. 

Contraceptives have already been tested to reduce wild boar numbers and currently these have been delivered by manual injection, which involves the capture of the animals and requires significant effort and resources. However, research shows that if an oral contraceptive was widely available it would be possible to target the majority of wild boars with much lower costs. 

Urgent action

Dr Massei added: “This is a complicated topic, but most people simply don’t want to hunt animals any more so we are forced to find a new solutions to control their numbers. Unchecked there will be ever more damage to nature, to agriculture and escalating human conflicts in busy urban areas.”

Closer to home, the current UK boar population is derived from captive animals that either escaped or were illegally released. Around  2,600 animals are now living wild in several breeding populations across the country. The largest of these populations is in the Forest of Dean, but wild boar are also present in parts of South East and South West England, South East Wales and North West Scotland.

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