Buzz
Spring is the breeding season for mares when the weather is warm and daylight is abundant. Throughout spring and summer, a mare may go into estrus every three weeks. If you own a mare and she has mated with a stallion during her estrus cycle, you may need to check if she is pregnant. The gestation period for horses is 11 months, and mares typically do not show noticeable abdominal changes until the final three months of pregnancy. Here’s how to determine if a mare is pregnant.
Steps
Use Non-Chemical Methods
Observe the mare's behavior around a stallion. A suspected pregnant mare can be introduced to a stallion 14 days after mating to monitor her behavior. If pregnant, the mare will likely reject the stallion’s advances and will not position her hindquarters toward him as she would during estrus. However, mares may also reject stallions for reasons unrelated to pregnancy.
Observe signs of estrus in the mare. Some mares raise their tails, open and close their vulva lips, squat to urinate, or discharge mucus, which are clear indicators of their estrus cycle. If these behaviors occur 21 days after breeding, the mare is likely not pregnant.
Have a veterinarian perform a rectal palpation. A vet can conduct this procedure 16 to 19 days after mating. By inserting a hand into the mare’s rectum, the vet can examine the uterus for signs of pregnancy, such as its size, shape, and any ovarian swelling.
Use an ultrasound to diagnose pregnancy in the mare. This involves inserting a probe into the rectum to capture images, allowing the vet to confirm pregnancy. A fetus can be detected as early as 16 days post-breeding, and its gender can be determined between 55 to 70 days of gestation.
- Ultrasound uses sound waves to image the uterus and can monitor the fetal heartbeat.
- It is the most reliable and commonly used method for tracking equine pregnancies.
Use Chemical Methods
Conduct a blood test for the mare. Pregnancy can be confirmed by detecting pregnancy-specific hormones. This method is particularly useful for mares with small rectums, making non-chemical methods challenging.
- A veterinarian will draw a blood sample and send it to a lab for analysis.
- Analyze the serum levels of PMSG (Pregnant Mare Serum Gonadotropin) between 40 to 100 days post-breeding.
- PMSG tests may yield inaccurate results if the mare has experienced a miscarriage.
- Measure Oestrone sulphate levels after 100 days of gestation. Elevated levels indicate pregnancy, but they return to normal if the pregnancy is lost.
Urine Testing for Horses. When verifying pregnancy, oestrone sulphate can be detected in the urine of female horses. This urine test can be conducted at home by a veterinarian or a breeder.
- Purchase home pregnancy test kits from feed stores or online.
- Test the mare's urine between 110 to 300 days post-breeding.
- Cut a container of about 2 to 3.8 liters in half. Use the bottom part to collect the horse's urine.
- Follow the instructions provided with the pregnancy test kit to analyze the horse's urine. Typically, it takes about 10 minutes to get the results.
Confirming Pregnancy Test Results. Using chemical tests as mentioned above can indicate whether your horse is pregnant, but it is best to have these tests conducted by a veterinarian, whether chemical or non-chemical, to ensure the fetus is not at risk of miscarriage. Additionally, chemical tests are sometimes improperly conducted, so veterinary intervention is recommended for the most accurate results.
Advice
- Horse owners often invite veterinarians to perform initial pregnancy tests to determine if their horses are carrying twins. Twin pregnancies can be dangerous for your horse.
- Mares often miscarry or deliver prematurely within the first 100 days of pregnancy. Home pregnancy test kits are a cost-effective method that can be used for the second pregnancy test after the initial 100 days of pregnancy.
