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Slashing wild boar population with feed contraception

A new solution has been launched in Texas, USA, where the feral hog population has exceeded 2.6 million. Contraception through feed has to limit the growth of the wild pig numbers.

Across Europe, North America and elsewhere, wild hogs represent an enormous problem, causing damages to crops, negatively affecting wildlife and more. In Europe, wild pigs also continue to be a very serious factor in the spread of African Swine Fever.

Efforts to reduce wild pig populations all over the world have included targeted shooting and trapping, but these methods have had little effect. Populations of wild pigs continue to climb in places like Canada and Germany. In Texas, their numbers now exceed 2.6 million.

Female wild pigs can produce a new litter roughly every three months, and in the southern US, litters can reach up to 20 piglets.

Feral pig numbers continue to grow in North America. - Photo: Shutterstock
Feral pig numbers continue to grow in North America. - Photo: Shutterstock

Contraceptive solution for wild boar?

On June 1 2021, a new method of wild pig control was launched in Texas, a male contraceptive product called HogStop. It was developed there by Dr Dan C. Loper and his team, which includes his son Daniel. 3 Years ago, they started running tests on commercial wild boar that had ingested the product. “We found a 60% reduction in sperm motility and also morphology changes that, combined, significantly reduce fertility,” said Daniel Loper. “We observed these results even in boar that had ingested the product only for 5 days.”

HogStop is the first widespread birth control option for wild pigs of which the HogStop team is aware. Lope notes, however, that ingested contraception products exist for other species such as pigeons and rats.

Mode of action for birth control

The active ingredients of HogStop are proprietary, and the product is described as a “mixture of natural feedstuffs.” HogStop does not contain hormones or endocrine disruptors, nor does it actively work to affect hormones. It stays in the testes of a boar and does not travel throughout the boar’s body.

It should only be fed in hog-specific feeders designed to keep out all other species, as males of other species such as deer can be affected similarly if large enough amounts are consumed.

The company officially recommends 2 feeders. The ‘Barclay Feeder’ has a weighted pressure plating system and a ‘scent grate’ at the lower front to attract hogs.

The other feeder, WPF, is a patented pig-specific feeding system that keeps out larger animals with ‘bear bars.’ It comes with optional remote monitoring of feeder use and feed level.

Feral pigs in Texas and beyond

The product is currently being rolled out across Texas. Daniel Loper said, “We approached the Texas ag commissioner Sid Miller a few years ago about the development of the product and he’s been tremendously supportive, so we wanted him to announce the market launch.” 

However, use of HogStop is expected to quickly increase across the southern US through the company’s partnership with US feed manufacturer and distributor Hipro.

Use of wils boar contraceptive in other countries

HogStop is already categorised as an approved ‘25 (b)’ pesticide by the US Environmental Protection Agency, and approval for the product is being sought for use in other countries.

Because it’s categorised as an approved pesticide, it’s likely that HogStop will be a tax-deductible expense for farmers and ranchers in the US. This is expected to speed adoption.

Whilst the HogStop team has not estimated how much use will severely reduce the wild pig population in a given area, obviously the more it’s used, the better the expected results.