Breeding Soundness Exams for Broodmares

A healthy mare and foal in a pasture.
A healthy mare and foal in a pasture. kyslynskaha

Want to breed your mare - First step is an exam

A broodmare should be examined before breeding--preferably in the fall if she's barren, and soon after foaling if she was pregnant--to make sure her reproductive tract is healthy and capable of carrying a foal (or her next one) to term.

Issues for consideration are her age, general health and body condition, and reproductive history. A lameness or chronic problem that causes discomfort should also be addressed.

A mare that is in pain may not breed successfully, and a foot or leg problem may become worse with increased body weight during pregnancy.

A breeding soundness examination can be fairly basic, or more in-depth if you suspect that a mare might have a problem. A maiden mare should at least have a rectal examination, palpating the uterus and ovaries to determine if the reproductive tract is functional and that her vulva conformation is normal.

Even an older maiden mare may have some issues, even if she's never been bred before, just from changes due to age.

If it's a mare that had foals in the past but not recently, or has been bred and didn't have a foal, she should definitely have a thorough examination.

What the veterinarian does during the exam

Rectal palpation can give an indication about the general health of the uterus and ovaries (size, shape, texture, hardness). An ovary that is small and hard may be inactive.

Enlargement of the uterus or thickening of its walls could mean the mare had an infection that left scar tissue. A uterus that lacks proper tone and is flabby to the touch can be abnormal.

The veterinarian will probably also do an ultrasound, looking for things in the uterus that may not be palpable via the rectum.

The next step is to take a sample for a uterine culture (when the mare is in heat and her cervix is open), and possibly an endometrial biopsy to examine the uterine lining.

The biopsy is a diagnostic tool that can provide a lot of important information, and also helps predict the likelihood of this mare conceiving and maintaining a pregnancy to term. It can help assess scar tissue within the uterus.

Scar tissue is permanent and lowers the probability of the mare making it through a pregnancy. The veterinarian will also evaluate the vagina and cervix while taking the biopsy, checking for injury (from foaling), cervical tears or scar tissue that might interfere with maintenance of pregnancy.

History provides important clues

The veterinarian will consider the history of the mare, the findings of the rectal exam, ultrasound, the vulva conformation, endometrial biopsy, culture results, and can give you a fairly accurate probability of this mare conceiving or why she isn't conceiving and what might work to treat her.

It helps to know if the mare just retired from an athletic career (with possible athletic injuries, or drug therapy such as anabolic steroids that might hinder reproductive performance).

Past breeding and reproductive records are helpful--her heat cycle patterns, length of anestrus and transitional heats when coming out of anestrus, number of previous foals, how recently she had her last foal, gestation length, whether births have been normal or difficult, any foaling complications, retained placenta, and so on.

An accurate history can disclose factors that might directly or indirectly have an influence on her future reproductive abilities.

Sometimes owners don't realize how valuable the history can be, for determining the future success of that mare as a broodmare. If the mare hasn't conceived and the veterinarian has no other information, then he/she must go through the whole process of looking for the problem.

If the owner can elaborate and say that the mare hasn't had a heat cycle for 8 months, the veterinarian doesn't have to spend time looking at all the other possible problems and can focus on a hormonal problem--like a possible granulosa cell tumor in the ovary.

If an owner presents the whole history, it helps the veterinarian know where to focus, with specific diagnostic tests, rather than doing all of the tests.

Records (or evidence) of previous reproductive surgery such as Caslick's repair or correction of abnormal perineal conformation can indicate there was need for correction of a problem that might compromise conception or pregnancy.

Information about any prior uterine infection and previous treatment is also important.

Earlier data will be helpful when comparing results of subsequent examinations to determine whether the mare's condition/situation has improved, remained the same, or worsened.

Evidence of early embryonic death or early pregnancy loss during previous pregnancies (the mare checked in foal early on and later was open) is also important.

Good records can help determine the cause for loss of pregnancy, when combined with an examination of the mare's reproductive tract and diagnostic laboratory findings.

Those records, in conjunction with various aspects of the exam, will give the veterinarian a picture of what's going on, and how much time might be needed to correct it.

It's always helpful to do breeding soundness exams in the fall, to give more time to get a problem corrected before the next breeding season.

If there is inflammation or infection in the uterus, the longer it persists, the more likely there will be scar tissue present.

If the mare was bred this breeding season and didn't conceive, and she is examined in the fall, the veterinarian can do all the necessary tests and find out what's wrong, treat the mare, and maybe put her under lights in preparation for the next breeding season.

Early breeders at an advantage

It is always a good idea to get a mare ready for early breeding. This can get a problem mare started cycling earlier and gives you more time--early in the breeding season--to finish correcting any problem that might otherwise interfere with pregnancy.

A breeding soundness exam helps you prepare for the next breeding season, instead of going into it with a mare that's not fertile and you don&'t know what's wrong.

In that situation you might breed her several times and by the time you find out what's wrong you've lost the whole breeding season.

About the Author

Heather Smith Thomas

Author picture

Heather Smith Thomas has raised and trained horses for 58 years and has been writing about them nearly that long. She got her first horse at age 9 and began raising horses of her own while in high school, using them in 4-H and to help with cattle work on her parents’ ranch.

She began writing horse stories for children’s magazines and horse care articles for equine publications to help pay her way through college (University of Puget Sound), and has sold more than 10,000 stories and articles and published 24 books. Her first book, A horse in Your Life: A Guide for the New Owner, was written during the summer between her sophomore and junior year of college and published by A.S. Barnes & Company in 1966.

Most of her magazine articles deal with health care, breeding, training, horse behavior/handling or veterinary topics (horses and cattle). She and her husband raise beef cattle and a few horses on a ranch in the mountains of eastern Idaho, where they use their horses for cattle work.

What began as an expression of interest and love of horses (freelance writing) soon became a way to help pay the bills on a struggling family ranch; her writing became the equivalent of an “off farm job” that could be done at home at odd hours between riding range to check on cattle, delivering calves, etc.

Heather rarely leaves the ranch--staying home to take care of “critters” has been a way of life. After selling some of the cow herd to her son and his family, her part time writing job has become more full time. She now writes regularly for more than 25 farm and livestock magazines and about 30 horse publications,

Recent books include Storey’s Guide to Raising Horses, Storey’s Guide to Training Horses, The Horse Conformation Handbook, Stable Smarts, Beyond the Flames—A Family Touched by Fire, Care and Management of Horses, Understanding Equine Hoof Care, Good Horse-Bad Habits, Essential Guide to Calving, and Cattle Health Handbook.

Heather's most recent books include Horse Tales: True Stories from an Idaho Ranch, a compilation of horse stories telling about some of the interesting and challenging horses in her life. Cow Tales; More True Stories from an Idaho Ranch, and Ranch Tales: Stories of Dogs, Cats and Other Crazy Critters. Most of her books and articles deal with horses or cattle health care, breeding, or handling. Her goal has been to learn all she can about care and handling of horses and cattle and to share these experiences with her readers.

These days, she enjoys riding with her youngest grandchildren who live on the ranch are now ages 14 through 17. She has also appreciated the help of her oldest granddaughter (Heather Carrie Thomas) who graduated from Carroll College and is now married and living on a farm in Saskatchewan. “Grandma Heather” enjoys the special times with her grandchildren who share her love of horses.