Heat Cycle Tracker (Dog, Cat, Rabbit)

Understanding your intact female's heat cycle is essential whether you're breeding intentionally or simply avoiding unwanted litters. This tracker records each observed stage — proestrus, estrus, diestrus, anestrus — and estimates the next expected cycle based on species-typical intervals: roughly every 6 months for dogs, every 2-3 weeks during breeding season for cats, and continuously receptive (induced ovulator) for rabbits. Consistent logging helps identify silent heats, split heats, prolonged bleeding, and pyometra risk factors long before they become emergencies.

Typical interval: ~180 days
Heat duration: 2-4 weeks

Most dogs cycle every 6 months. Small breeds sometimes every 4, giants every 12-18.

No entries yet — log your first observation.

Not medical advice. This tool provides general guidance based on common veterinary formulas. Always consult your veterinarian for medical decisions about your pet.

How it works

Canine and Feline Estrus Endocrinology, Hormonal Waves, and Cytology

Understanding companion animal reproductive endocrinology is vital for responsible breeding management and the prevention of life-threatening reproductive pathologies (such as Pyometra). Female canines (bitches) are monoestrous or diestrous (cycling every 5 to 8 months), whereas felines (queens) are seasonally polyestrous, induced ovulators cycling repeatedly every 2 to 3 weeks during long daylight photoperiods.

Under clinical theriogenology protocols from the Society for Theriogenology and the American College of Theriogenologists (ACT):

The 4 Stages of the Canine Estrous Cycle:
1. Proestrus (7–10 Days): Estrogen rising; swollen vulva, serosanguinous (bloody) discharge; attracts males but refuses mating
2. Estrus (5–9 Days - THE FERTILE WINDOW): LH Surge occurs; discharge lightens to straw-colored; female 'flags' tail and accepts mating
3. Diestrus / Metestrus (60–80 Days): High Progesterone; pregnancy or pseudopregnancy (false pregnancy) occurs
4. Anestrus (3–5 Months): Complete ovarian quiescence and uterine endometrial repair

The Lethal Risk: Pyometra in Intact Bitches

During diestrus, high progesterone levels cause the uterine endometrium to thicken and secrete fluid (cystic endometrial hyperplasia).

  • If bacteria (E. coli) ascend the cervix, the uterus fills with gallons of toxic pus (Pyometra), typically occurring 4 to 8 weeks after a heat cycle.
  • Pyometra is a critical surgical emergency with high mortality if untreated. Symptoms include lethargy, fever, excessive thirst (polydipsia), and foul vulvar discharge (in open pyometra).

Predict litter sizes with Litter Size Predictor, track gestation via Pregnancy Calendar, prepare whelping gear using Whelping & Kittening Checklist, and explore reproductive medicine at the Society for Theriogenology.

Examples

  • Golden Retriever, last heat 5 months agoWatch for proestrus signs in ~30 days
  • Indoor cat, springExpect 4-10 day estrus every ~3 weeks
  • Doe rabbit, unspayedFertile year-round — separate from bucks

Frequently asked questions

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