A team of Japanese veterinarians said on Monday they had succeeded in artifically inseminating pigs using semen which had been frozen for nearly 23 years.

The success may pave the way for international trade in frozen swine semen and help prevent diseases with long periods of incubation, which can be spread through natural mating, Iwate University professor Tazaemon Niwa said.

Niwa and the livestock laboratory of the Gunma prefecture artificially inseminated five sows about five months ago.