What method is primarily used to induce parturition in cows?

The primary method used to induce parturition in cows is the administration of prostaglandin F2alpha (PGF2α) injections. This hormone is instrumental in the process of parturition as it helps to cause luteolysis, which leads to a decrease in progesterone levels. The decline in progesterone is critical for the initiation of labor, as it facilitates uterine contractions and helps prepare the reproductive tract for delivery.

When PGF2α is introduced into the system, it stimulates the uterus and prepares the cow for calving by promoting cervical dilation and the rhythmic contractions of the uterine muscles. This timely and effective response is why PGF2α is the favored choice for inducing parturition.

Other methods, while they may have a role in the reproductive management of cows, do not primarily serve the purpose of inducing parturition as effectively as PGF2α. For instance, oxytocin is often used to enhance uterine contractions after parturition has begun but is not the primary agent used for inducing labor. Mechanical induction and estrogen treatment are methodologies that may be used in certain situations, but they are generally less common and not as effective as PGF2α for inducing parturition.