In Japan, cattle breeding is generally performed by artificial insemination, but the rate of conception by this method has decreased in recent years.

With the conventional motile spermatozoa collection technologies, only a small number of spermatozoa can be collected, and so far have not succeeded in field practical application, i. e. artificial insemination.

The researchers have developed a new semen pretreatment technology for selecting and collecting healthy spermatozoa, and conducted joint demonstration experiments with Morinaga Rakunou Co., Ltd., National Livestock Breeding Center, Saga University, Saga Livestock Experiment Station, National Agriculture and Food Research Organization, Toyama University, and Toyama Prefectural Agricultural, Forestry and Fisheries Research Center. Through experiments using this newly developed technology, bovine spermatozoa which swim in a meandering (zigzag) manner are found to be more advantageous for conception than spermatozoa which swim in a straight line.

The researchers developed a motile spermatozoa selection device with microchannels, which was designed based on numerical fluid dynamic calculations. The characteristic flow created by the microchannels of the developed device guides motile spermatozoa and selects spermatozoa based on their upward swimming ability. Furthermore, this technology can collect healthy spermatozoa in number applicable to artificial insemination. The developed technology is expected to contribute to improving the fertility of cattle and other livestock.