How a fridge could unlock modern dairy cattle breeding

A Hiroshima University-led project has secured a $1.8 million grant from the Gates Foundation to develop a way to store bull semen using simple refrigeration instead of costly liquid nitrogen, a shift that could remove a major barrier to modern dairy cattle breeding that has long excluded farmers in low-resource regions. If successful, the technology is expected to deliver far-reaching benefits on food security and livelihoods in local communities.

The project, headed by Professor Masayuki Shimada of Hiroshima University’s Graduate School of Integrated Sciences for Life, received the grant in October 2025, marking the second time his laboratory has secured funding from the foundation.

Building on their 2019 discovery that identified functional differences between X-bearing (female-producing) and Y-bearing (male-producing) sperm, the team developed a simplified and low-cost sex selection technique that would help farmers reliably produce more female calves. The deployment of this technique has already begun at dairy farming sites in India, where it has attracted attention for its ease of use, even by small-scale farmers.

However, expanding the technology’s use globally requires a safe method of transporting and storing the processed sperm. In many countries, liquid nitrogen is used for cryopreservation. But in the developing world, a stable supply of liquid nitrogen cannot be guaranteed, creating a major barrier to adoption.

Under the new grant, the team will develop a storage method that allows bovine sperm to be stored at about 5 degrees Celsius, roughly the temperature of a household refrigerator, eliminating the need for liquid nitrogen. The work builds directly on the group’s previous research clarifying how sperm move, how they generate energy, and how low temperatures cause cellular damage. If preservation and transport become possible at refrigerator temperatures, artificial insemination could become far easier to use.

Supporting food security and livelihoods in India and Africa

The project is being carried out in collaboration with agricultural organizations and government-affiliated research institutes in India, along with research groups within Hiroshima University.

Milk is both a vital source of nutrition and a major source of income in many regions of India and Africa. However, small-scale farmers often struggle to obtain highly productive cattle, and this has become one of the contributing factors to food insecurity and poverty. If this technology becomes widespread, it is expected to increase milk production, stabilize incomes for small-scale dairy farmers, and improve children’s nutritional status.

Shimada’s laboratory already hosts doctoral students from government agencies in countries where the technology is expected to roll out, including Nigeria, Mozambique, and Bangladesh. A framework is also in place to train local experts and roll out the technology on the ground.

By developing artificial insemination technology that can work even in regions where liquid nitrogen is hard to obtain, the project aims to expand the possibilities of global dairy farming and the future of food.