Long-Standing Theory of Pregnancy Recognition in Cattle Challenged
08.10.2026
Our new study challenges a fundamental principle of reproductive biology by demonstrating that interferon tau (IFNT), long considered essential for pregnancy recognition in ruminants, is dispensable for successful pregnancy establishment and full-term development in cattle. Using CRISPR-Cas9 gene editing, we generated bovine embryos lacking all functional IFNT genes. Remarkably, these embryos developed normally, established pregnancies, and progressed to full term, resulting in the birth of healthy female calves. These groundbreaking findings overturn a decades-old paradigm and suggest that alternative embryo–maternal signaling mechanisms can sustain pregnancy. This discovery opens new avenues for understanding reproductive biology, fertility, and reproductive biotechnology in livestock.