Here's why:
* Egg cells mature one at a time: A female sheep only releases one egg cell (ovum) per estrous cycle, which is about 17 days long.
* Ovaries contain immature egg cells: The ovaries contain a large number of immature egg cells, but these are not ready for fertilization. They need to undergo a maturation process called oogenesis.
* Hormonal control: The release of a mature egg cell is controlled by hormones like follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
Therefore, it's not accurate to say that a female sheep has a specific number of egg cells ready for fertilization before mating. The number of eggs ready for fertilization depends on the stage of the estrous cycle.
It's important to note that this information is a general overview. The number of egg cells and the specifics of the estrous cycle can vary slightly between individual sheep breeds.