The straw to last? Dairy industry considers sex sorting

February 02, 2016

When it comes to breeding cows, there are some dairy farmers that would rather not let nature take its course. Instead, some are willing to pay top dollar — up to $200 a vial — for bull semen that contains only X chromosomes and therefore increases the chances of producing only female offspring.

“As dairy farmers, what we’re trying to do constantly is become more efficient to feed the world population,” Jonathan Lamb, a dairyman in upstate New York said in a recent article. Lamb explained that he only uses sex selection in 5% of the 2,000 breedings per year he oversees. “It is expensive now and we would definitely use it more if the price came down," he said.

According to the National Association of Animal Breeders, the dairy industry embraced artificial insemination after World War II, with gender-sorted semen being used for only about the last decade.

Farmers use gender selection not only to propagate the milkers, but also to expand their herds, and eliminate the need to buy replacement cows. It has also been proven safer for heifers having their first calf, since female calves are smaller than males.

However, sex selection does not always go according to plan. As stated in the article, conception rates, for example, are lower for semen that has undergone the process, and with such a high price tag, few dairy farmers have been able to make such a large investment.

In addition, only a very small number of companies are offering sex-sorting technology, which is described as a machine that applies a fluorescent dye to cells that reacts differently on female X chromosomes than male Y chromosomes. As the dyed cells flow past a laser beam, the amount of fluorescence is detected and an electrical charge is applied, which deflects the cells into different containers. The sorted semen is then sold in vials known as straws.

A straw from the likes of “Modesty,” a top-performing bull, costs $200 a pop, with prices for run-of-the-mill bull semen starting at about $25.

There’s interest in this technology from other industries as well. While the procedure has worked in many species from gorillas to dolphins, techniques are currently being perfected for other livestock species, according to Jere Mitchell, technical director at the National Association of Animal Breeders.

Though the beef industry doesn’t widely use artificial insemination, it has an incentive to produce more males, as bull calves are more efficient at making meat.

But it’s the dairy farmers that find this technology especially powerful, Paul Paddock, co-owner of a breeding service company in New York, said. “Short-term, it’s more expensive. But long term, it’s an investment. More competition, in the end, [would] be better for the dairymen,” he added.

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Category: Genomics