Peripheral blood levels of progesterone in female camels during various reproductive stages.

Determination of serum progesterone concentrations over a period of 2 years in female camels during various reproductive stages (estrus, pregnant, nonpregnant, and lactating) suggests that the progesterone levels exceeding 1 ng/ml are reached only if mating is fertile. A cycling camel does not have a luteal phase and mating is probably indispensable for ovulation to occur.