Science - June 14, 2018

Endangered pigeon sperm goes in freezer

Tessa Louwerens

To prevent Dutch fancy pigeon breeds from extinction, the Centre for Genetic Resources, the Netherlands (CGN) will freeze the breeds’ sperm.

The Groninger Slenk is one of many Dutch fancy pigeon breeds threatened with extinction. © Dik Hamer

‘Most pigeon fanciers are retired and many Dutch breeds will disappear if no new younger pigeon fanciers take their place,’ explains Agnes de Wit, who works at CGN. ‘For example, a breed like the Hagenaar had only 50 birds left in the Netherlands in 2017.’

The sperm that the CGN will be freezing will serve as a kind of emergency backup. ‘Of course it is better to keep a breed alive with sufficient genetic diversity. But if a breed becomes extinct, the frozen sperm can be used to cross-breed it back. If you use the sperm to inseminate female pigeons of a different breed, it takes about nine generations to get back a 99 percent pure version of the original breed.’

The researchers at CGN are currently developing a protocol for freezing pigeon sperm, says De Wit, as the protocol needs to be different for every animal species. First, the researchers are investigating whether the method for freezing the sperm of cockerels is also suitable for pigeons.

They will also look at how the sperm can best be collected. De Wit: ‘The first time you collect sperm, the quality is usually poor. That’s because the animals aren’t used to it yet.’ So far, the quality of the frozen sperm has not been good enough, with only 10 percent live sperm cells. ‘We are aiming for 50 percent.’ The researchers will be training the cock pigeons first so that they get used to the sperm collection and the sperm is of better quality. If that works, they will then look at how they can improve the freezing procedure.

According to De Wit, freezing ova is not an option as a complete egg has to be formed around the ovum after fertilization. That is why in vitro fertilization (IVF) is not possible with birds. It is possible to freeze the ovaries, though, says De Wit. If you implant them in pigeons of a different breed, you can bring back the old breed in a single generation. But this is banned in the Netherlands.

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