at what age does a female newfoundland come into heat
When does a dog first come into heat? Female dogs come into their first heat between 6 and 24 months of age, with small breeds coming into heat sooner and large breeds later.ogs come into their first heat between about 6 and 24 months of age, with small breeds coming into heat sooner and large breeds later. Dogs typically have two heats per year, and each lasts about 18-24 days. The first signs of heat are typically a swollen vulva and a bloody vaginal discharge.