How will I know when my English Mastiff is in heat?

Answer by  bloominred1 (28)

Several signs to determine if she is in heat: A personality change. She may be urinating more. Her vulva will become swollen and may have a blood discharge.

Answer by  Chris43 (32)

Just before going into heat, a female dog's vulva will swell noticeably. On the first day that she is in heat, she will bleed from the vulva. You may actually see her bleeding, or you may find blood on her bedding or on the floor.

Answer by  UOGuy (66)

Obviously you will notice that she will bleed from her vagina. Dogs differ in movement however as some will completely lay down while others will go about their normal day. She may have frequent urination or a bigger amount of urination. Her personality may differ as well. Keep her separated from other dogs!