Final answer:
After administering a proper dose of PGF2alpha to a cow with a mature corpus luteum, the cow should be in estrus within 2 to 3 days.
Step-by-step explanation:
When a cow with a mature corpus luteum (CL) is given a proper dose of PGF2alpha (prostaglandin F2alpha), you can expect the cow to return to estrus, commonly referred to as heat, within approximately 2 to 3 days. The administration of PGF2alpha is a common practice in veterinary medicine to control or synchronize the estrous cycle in cattle. This prostaglandin causes regression of the corpus luteum, leading to a drop in progesterone levels and eventual onset of estrus. It is a vital part of reproductive management and synchronizing estrous in herds for planned breeding.