Cow reproduction is vital to producers, and USDA's Agriculture Research Service scientists discovered one of the reasons cows may not get pregnant.
The researchers examined reproduction data on about 6,400 female cows.
Females normally get an X chromosome from each parent while males inherit the Y from the father. However, some female cows have the male Y chromosome fragmented in their DNA.
In the scientists’ studies, 20 to 25 percent of animals with low reproduction had significant male chromosome markers and none of the highly reproductive animals had the markers.