Female dogs typically enter their first heat cycle between 6 and 24 months of age , with timing heavily influenced by breed size.

Age by Breed Size

Smaller breeds often start earlier, around 6-7 months , while medium breeds hit it at 7-9 months , and large or giant breeds may wait until 12-24 months. Some pups surprise owners by cycling as young as 4 months, or delaying past 2 years.

Heat Cycle Basics

The estrous cycle repeats roughly every 6 months for most dogs (twice yearly), though larger breeds might go longer between cycles. Each heat lasts 12-20 days , marked by bloody discharge, vulva swelling, and behaviors like restlessness or attracting males.

Breed Size| Typical First Heat Age| Cycle Frequency
---|---|---
Small| 6-7 months 1| Every 6 months 7
Medium| 7-9 months 1| Every 6-7 months 7
Large/Giant| 12-24 months 39| Every 6-12 months 9

Signs and Management Tips

  • Vaginal bleeding and swollen vulva signal proestrus (first 7-10 days).
  • Frequent urination, clinginess, or "flagging" (tail aside) during estrus.

Keep her leashed, use doggy diapers, and separate from intact males to prevent surprise litters.

Spaying eliminates heats entirely and cuts risks like pyometra or mammary cancer.

TL;DR: First heat averages 6-12 months but spans 6-24 months by size; cycles recur semi-annually.

Information gathered from public forums or data available on the internet and portrayed here.