YAK FROZEN SEMEN PRODUCTION AND CRYOPRESERVATION IN BHUTAN

A TECHNOLOGICAL BREAKTHROUGH

Abstract

This is a short research communication to inform on yak semen collection and processing, successfully conducted under Bhutanese condition. Although the technology existed in yak rearing countries elsewhere, this is the first time it was successfully done in Bhutan. Two rounds of semen collection were attempted: one during non-breeding season on induced heat using exogenous hormones, and another on natural heat during the yak’s breeding season. The first attempt conducted during non-breeding season did not succeed mainly due to poor response of female yaks to heat inducing hormones and failure of yak bulls to mount female not manifesting heat. The second semen collection trial was timed during yak breeding season. Yak bulls were trained to mount in-heat females restrained in a chute. Several trials were conducted prior to the actual successful semen collection. There was a major technological breakthrough in yak semen processing in Bhutan wherein over 220 doses of yak frozen semen  could be  processed and cryopreserved. The semen was of acceptable standard with >40% post thaw motility and had concentration of 27 million spermatozoa/dose when assessed after 24 hours. The scientific procedures and knowledge established including prior training of donor bulls to mount, timing of semen collection during breeding season and techniques to chill semen during transportation appropriate for Bhutanese farming environment is now understood. The procedures and techniques can further be improved and applied for quality semen production in Bhutan.