Prize cattle go for big bucks at auctions precisely for their breeding value. However, no matter how perfect any given cow is, she can only produce a calf a year in the natural order of things. Historically farmers have maximized her offspring’s value by breeding her to an equally superior bull. Even so, she still bore one calf at a time. But now farmers are increasingly harvesting prize cow eggs, fertilized beforehand or afterwards in-vitro, and transferring the embryos to lesser valued cows for birthing. In this way, a single high-value cow can produce far more offspring – even hundreds to thousands.
Embryo transfer (ET) is not a new thing. The process was first successfully done in rabbits in 1890 and in a cow in 1951. What’s different now is that the process is better perfected, is cheaper, and more eggs can be harvested at once than ever before.
That is not to say that the process is cheap – only less expensive than it was before. And it’s a bit laborious for farmers. But when done correctly, it can pay off for farmers pretty quickly.
Of course there is one downside farmers have to watch for – the possibility of inbreeding. Fortunately, ET can also be used to increase genetic diversity in the herd too.
“If ranchers choose to breed only offspring from a single cow, they can limit the herd's genetic diversity, potentially making them more vulnerable to disease,” writes Abby Wendle, the author of a NPR report detailing how one farmer uses this technique to his bottom-line advantage. “Paradoxically, ET can also help preserve genetic diversity. As Harvest Public Media's Luke Runyon has reported, the USDA stockpiles embryos from a wide variety of livestock breeds in Fort Collins, Colorado.”
ET can also be used to transfer desirable cattle traits from one region in the world to other regions of the world to improve meat and milk yields or to increase disease resistance and climate change resilience. Below is a video on how ET is improving cattle survivorship and yields in Kenya.
Embryo transfer is also important to many advances in genetic modification and synthetic biology.
In genetic modification, genes from other breeds in the same species or from a different species entirely are introduced to the genome.
In synthetic biology, scientists have the ability to read and write synthetic code to create something entirely new in an organism or to create an entirely new animal. These efforts too have promising implications for farmers but they also present new threats. For example, to understand how milk can be produced by yeast rather than cows, watch this interesting video by the University of Technology in Sydney, Australia.
The very nature of farming may be disrupted by synthetic biology developments. On the other hand, farming may become infinitely more efficient by the introduction of synthetic technology in existing livestock. Time will tell which will happen.
In any case, you can expect embryo transfer to become more frequent in more parts of the world for use in many different efforts to preserve and leverage resources in order to feed a growing human population.
Embryo transfer: from livestock genetic transfer to synthetic biology in farming