Forget sending bull semen for complicated lab tests to find out if the farm animal is very manly. Soon, a quick and easy method – reminiscent of a home pregnancy test – can tell if a breeding bull has what it takes.
Borrowing from nature, scientists and feeding chemists at Cornell University have developed a system – they call it RHEOLEX – that can accurately indicate the level of fertility in bulls. Their research was published March 14 in the journal Lab on a Chip.
“With this new RHEOLEX method, you can perform better selection and breeding of bulls and cows, which can result in higher quality and higher quantity products like improved milk and meat,” said said Alireza Abbaspourrad, Youngkeun Joh Assistant Professor of Food Chemistry and Ingredient Technology. in the Department of Food Science, College of Agriculture and Life Sciences. “It saves time for breeders and producers.”
Nature uses a biological process called rheotaxis, in which the bull’s semen swims upstream in the cows’ reproductive tract. Traditionally, semen quality is assessed using computer-assisted semen analysis, which measures swimming speed and concentration. However, computer-assisted analysis ignores rheotaxis, the strenuous process of sperm moving against the female’s biological flow.
In this scientific effort led by PhD student Mohammad “MJ” Yaghoobi, the group mimicked the dimensions of the female reproductive tract and the hydrodynamic characteristics of the cow in a microfluidic model, to quantify the rheotaxic ability of sperm.
Working with the Cornell NanoScale Facility, scientists have fabricated a microfluidic device (with pathways slightly larger than human hair) in what looks like a home pregnancy test. The platform measured sperm count – during the rheotaxis pathway – at varying flow rates.
The stronger the rheotaxis power, the better the reproductive quality of the seed.
“This combination, together with determination of motile sperm concentration (fast velocity), can quickly predict fertility levels during artificial insemination,” Yaghoobi said. “We can predict the in vivo sperm fertility level of the bull in five minutes.”
Samples of thawed bull semen were tested in the device and the results showed a better quality of rheotaxis, indicating a higher level of fertility.
Unlike conventional sperm quality parameters, which do not provide statistically significant predictions, RHEOLEX is an easy biomarker for determining male fertility in vivo, Yaghoobi said.
“We basically take the rheotaxis results and translate them into signals that tell us the fertility level of the bulls,” Abbaspourrad said, “which is great because it can save companies a lot of money selecting the best bulls. We use nature’s selection process and that’s a huge difference.”
In addition to Abbaspourrad and Yaghoobi, other co-authors of the research, “Rheotaxis Quality Index: A New Parameter That Reveals In Vivo Male Mammalian Fertility and Low Sperm DNA Fragmentation”, are Morteza Azizi and PhD students Amir Mokhtare and Farhad Javi.
The Cornell NanoScale Facility is a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation. Abbaspourrad is a faculty member at the Cornell Atkinson Center for Sustainability.
Source of the story:
Material provided by Cornell University. Original written by Blaine Friedlander, courtesy of Cornell Chronicle. Note: Content may be edited for style and length.