Equine Gestation Timeline

First Trimester

Day 0: Date of Ovulation
Days 14-16: Initial pregnancy ultrasound and evaluate for twins
Day 18: Additional ultrasound examination may be needed for evaluation of twins
Days 25-30: Second pregnancy ultrasound (heartbeat), evaluate for twins
Days 45-60: Third pregnancy examination with ultrasound to confirm fetal heartbeat and viability of pregnancy
Days 60-90: First deworming for mare, fetal sexing can be performed via ultrasound examination

Second Trimester

Day 114: Second trimester begins
Days 120-150: Fetal sexing can be performed via transabdominal ultrasound examination
Day 150: First vaccination for EHV-1, second deworming
Day 210: Second vaccination for EHV-1

Third Trimester

Day 226: Third trimester begins
Day 270: Third vaccination for EHV-1
Day 300: Increase mare’s nutrition in preparation of foaling, third deworming for mare, open caslicks, administer additional vaccination according to veterinarian recommendations (EHV1/4, EEE, WEE, Tetanus, Flu, West Nile Virus & Rabies, in endemic areas: Potomac Horse Fever, Strep. equi, Botulism, Rotavirus), move mare to area where she will foal to stimulate immune system and develop antibodies
Days 320-365: Normal foaling date range
Day 340: Average foaling date

Post Foaling

  • UF Neonatal Foal Unit – UF veterinarians and staff are available 24/7 for every neonatal foal issue
  • Preparing for Foaling – Read about the tools to have on-hand prior to foaling, warning signs, post-foaling, and more.
  • Routine & Emergency Foal Care – Read about the foal’s first day, normal clinical signs, foal nutrition and restraint, warning signs, and more.
  • Neonatal Foal Diseases – Read about Neonatal Isoerythrolysis (NI), Sepsis, Neonatal Encephalopathy, Prematurity, and more.

More Information

  • UF equine reproduction specialists offer breeding management using fresh, cooled or frozen semen and can perform pregnancy diagnoses at any time.
  • Ultrasound examinations can be performed at the UF Large Animal Hospital or on-farm by our ambulatory service throughout the entire pregnancy.
  • UF specializes in high-risk pregnancies that require an increased amount of veterinary management. Mares with problems during pregnancy are monitored 24/7 until foaling. Our state-of-the-art equine neonatal ICU is available post-foaling.
  • UF offers concierge foaling services for that special mare. Reproductive specialists are available to deliver your foal to ensure the right start to its life.
  • If your mare is not pregnant, UF reproduction specialists are adept at infertility evaluation and treatment of problems. Intensive mare management to overcome breeding problems is one of our strengths.
  • The UF Large Animal Reproduction service provides vaccinations, parasite control and other preventive veterinary care for your mare as necessary during pregnancy.
  • Dystocia management and management of retained placentas are available to all large animal patients at the UF Large Animal Hospital. We are available 24/7 for all reproductive emergencies.
  • Mare and foal monitoring and maintenance are available at UF. Board-certified veterinary internal specialists and highly trained staff are available 24/7.
  • Some clinical signs may be obvious while others may be more subtle. Call the specialists at the UF Equine Neonatal ICU if any problems arise post-foaling.
  • Video camera monitoring is available in the neonatal ICU and all stalls contain dividers for mare and foal to remain together while one is being treated.
  • For on-farm services visit the UF Large Animal Ambulatory Reproduction Services page.