What is the breeding cycle of a cow?

It is very rare for a cow to cycle while pregnant. When the cow is in calf (pregnant) the corpus luteum (a group of follicular cells which secretes progesterone and maintains pregnancy) will continue to function, persisting in its progesterone production and preventing further estrous cycles. When a cow or heifer is breed, and comes into cycle the following month, this will mean she did not catch (eggs were not fertilized, therefore, no corpus luteum is present).