24hrs after first standing heat and 12hrs later for sows and 12hrs for gilts in general. Know your breeding gilts and sow's cycles they vary. Normally after discharge the next day they should be in good estrus.But like i said they can vary in heat cycles. Have a journal for your breeders. Check your...

Give Nate Joseph a call, he has a boar called American One that give you what you need.