Complex sentence: The proestrus is relatively long at 5--7 days (9 days), while the estrus may last 4--13 days, with a diestrus of 60 days followed by about 90--150 days of anestrus.
Split into simpler sentences: The proestrus is relatively long at 5--7 days (9 days), while the estrus may last 4--13 days. With a diestrus of 60 days followed by about 90--150 days of anestrus.