A doe bleat is a social call and can be used anytime of year. An estrous bleat is a form of distress call, and may or may not call in does early, although I doubt it will scare them off. I used the woods wise breeding bellow call in early season once, and had a doe charge in, she looked totally pissed. I suspect that she was the matriarch, and I was challenging her dominance.

Best bet is to set up on a travel route between bedding and a food source. Look for fresh sign and hunt it asap. Good Luck.