Cows Can Become Pregnant Without "Essential" Embryonic Protein

Researchers at Ludwig-Maximilians-Universität München (LMU) have challenged a decades-old scientific model concerning cattle reproduction. Their study, published in Nature Communications, shows that cows can establish and maintain pregnancies, leading to the birth of healthy calves, even without the protein interferon tau (IFNT).

Traditionally, IFNT has been considered indispensable for the embryo to signal its presence to the mother and prevent hormonal changes that would otherwise end the pregnancy. However, genetically modified embryos from LMU, completely lacking functional IFNT genes due to CRISPR-Cas9 editing, successfully established and maintained pregnancies.

Two healthy female calves, confirmed to lack functional IFNT genes, were born in February 2026. The results suggest that communication between the embryo and the mother can occur through mechanisms other than IFNT, a protein previously thought to be essential. The researchers are now investigating potential alternative signaling pathways, such as the role of prostaglandin E2.

The findings could open new avenues for understanding early pregnancy loss and improving reproductive efficiency in livestock breeding. The research at LMU's Gene Center was led by Dr. Asghar Ali and Professor Eckhard Wolf.