Choki Wangmo

With the introduction of sexed semen technology (SST) yesterday, the country is expected to see more heifers and boost in dairy production by the end of the 12th Plan.

The SST is specially-processed semen of bulls from which ‘Y’ chromosomes in sperm cells — which lead to the birth of a male calf—is either removed through a ‘sorting’ process or killed.

Semen that has only ‘X’ chromosomes can ensure that a female calf is born, increasing the genetic progress in a herd by increasing the number of superior heifers.

The technology, validated on trial in the country since 2014, has shown 90 percent success rate. The applied research on government farm and on-farm in dzongkhags resulted in 89.6 percent of female birth under the Bhutanese farming environment.

Programme Director of National Dairy Research Centre, Nar B Tamang, said that with increasing demand for heifers in the country among dairy farmers, choices of cattle breeds had become more important. But the imported breeds couldn’t adapt to the Bhutanese climate. “SST will intensify dairy breeding programme without having to import the improved cattle breed.”

Since October last year, 1,060 doses of imported frozen sexed semen were distributed to 15 dzongkhags. As of last month, 285 animals were inseminated across the country.

With 8,500 doses of sexed semen, 6,757 heifers are expected to be produced by the end of 12th Plan. A single dose of sexed semen imported from the US, UK, and Denmark cost  USD 20 compared wither other imported conventional semen at USD 5.

Last year, Nu 8.5 million was allocated for the programme.

About 25.25ml of sexed semen contain two million live spermatozoa, which is stored under liquid nitrogen at extreme frozen temperature of -196°C. During the breeding, the temperature is maintained at 37°C and inseminated artificially.

The improved breeds’ milk production is as high as 12 litres a day compared to two litres produced by the indigenous breeds. This, Nar B Tamang, said would reduce dairy import.

According to the records with agriculture ministry, the import of dairy product increased to 4,944.22 MT in 2019 from 3,597.12 MT in 2018, an increase by 37 percent.

Without sorting the chromosomes, the “conventional” semen resulted in production of male progenies, considered a financial burden to farmers. SST would also help reduce the increasing number of stray cattle by removing the male chromosomes, said Nar B Tamang.

The application of the technology, however, will be expanded in planned manner in all dzongkhags in the next three years. A guideline for use of SST modalities for heifer production was also launched.

George E. Seidel, a reproductive physiologist at Colorado State University in the US is credited for his pioneering research in the ‘sorting processes.’