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.

The UF Large Animal Hospital veterinarians treat equine and large animal patients from the Gainesville, Ocala and Jacksonville areas, including Alachua and Marion Counties in Florida, and our clients come from all over the United States. Contact us to speak to one of our specialists or to make an appointment.

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