Bioscientifica Proceedings

Summary. The corpus luteum (CL), via progesterone production, plays a central role in the regulation of cyclicity and in the establishment and maintenance of pregnancy in ruminant species. In the absence of an embryonic signal, the CL will regress functionally and then structurally. Pulses of prostaglandin F2α (PGF2α) from the uterus reach the ovary via the vascular utero-ovarian plexus causing the demise of the CL. Although it is well established th...

The corpus luteum is a transient gland, which is only functional for 17–18 days in the cyclic cow or for up to 200 days in the pregnant cow. Regression of the corpus luteum is essential for normal cyclicity as it allows the development of a new ovulatory follicle, whereas prevention of luteolysis is necessary for the maintenance of pregnancy. Evidence acquired over the past three decades indicated that PGF2α is the luteolytic hormone in ruminants. Neverthe...