Friday, 22 April 2016

Only 6% difference in fertility between sexed doses and conventional doses

When a farmer want to decide the genter of the calf, he chooses sexed semen. Semen cells carrying either male or female genes, and when making a sexed dose, they are separated to provide the farmer with a calf of desired sex. It is a revolutionary technique used by many farmers worldwide. But as every method, it is not free of drawbacks and the two main issues are; sex rate and fertility. 

Sex rate
The most important question is how can we ensure that farmer will get the wanted sex of the born calf? Unfortunately, there is no guarantee for that. Before release, each sexed dose is quality-controlled and we measure so called “purity”. That means that we measure what the percentage of semen cells carrying wanted sex within dose is. Only doses with “purity” 90% or more are released, meaning that if you order an X-Vik-dose, in nine out of ten births, you should get a heifer.  

Fertility
Fertility is another concern and none of the farmers are willing to risk fertility to drop in their herds. A sexed dose contains only 2 million semen cells, compared to 15 million semen cells in a conventional dose. This is the explanation why a sexed dose has lower fertility than conventional doses. 

It has been a focus point for several years for scientists and manufacturers, to try to improve sorting method and fertility. 

In February 2014, Viking Genetics started to use a new sorting method called “Ultra” and fertility of sexed semen has been increasing since then. The latest fertility results from the field show an average increase of 3.4%. That means that farmers should be less worried about the fertility of their cows as difference in fertility between sexed and conventional semen has been reduced from 10% to 6.6%.  This is a clear progress and more work will be done to make sexed semen as fertile as conventional.          

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