UNIVERSITY PARK, Pa. — More than 60% of dairy cows in the United States are bred via artificial insemination. While significant advances have been made in understanding cattle genetics, particularly in relation to milk production and other economic traits, there is still much to learn about the genetics underlying the reproductive organs and cells in cattle, according to a team of researchers in the Penn State College of Agricultural Sciences. The U.S. Department of Agriculture (USDA) has awarded a grant to the team to study the genetic mechanisms underlying the development of the testis, the male organ that produces reproductive cells, in cattle and its role in sperm production.

The $650,000 grant, awarded by USDA’s National Institute of Food and Agriculture, will fund research led by Wansheng Liu, professor of animal genomics. Liu and the team will specifically investigate transcriptome dynamics — how all the messenger molecules expressed by an organism’s genes interact to regulate cellular functions — and gene regulatory networks during testis development and sperm production in cattle.

“Our focus is on male reproduction to better understand the genetic factors that affect health and productivity in cattle,” Liu said. “This research is important for the cattle industry, which relies heavily on artificial insemination.”

One of the goals for the project, Liu explained, is to identify genetic markers associated with bull fertility. This will help scientists pinpoint genes that influence fertility traits, enhancing the ability to select for these traits in breeding programs.

Tae Hyun Kim, assistant professor of avian biology and an Early Career Chair in Penn State’s Huck Institutes of Life Sciences, will collaborate on the study, with the aim of filling this knowledge gap in the regulatory dynamics of development and differentiation of sperm and fertility throughout a bull’s life.

“This project is crucial for completing the bovine genome map and understanding the genetic processes underlying testis development and sperm production in cattle,” Liu said.