b'8 STEPS FOR BREEDING YOUR MAREbreeding soundness evaluation is meant to problem-solve or to provide prognostic information, so that the owner can make informed decisions.For most broodmares that have not had any breeding-related issues, Wolf-sdorf starts by examining the mares reproductive anatomy, including perineal conformationwhich involves the vulvar lips, the vestibular-vaginal fold and/or the hymen, and the cervix. If a mare has poor perineal conformation, she is at risk for reproductive tract contamination with fe-ces, air, and microbes. To prevent this and possible resulting infection, veterinarians can suture the vulvar lips together (a pro-cedure called a Caslicks), later removing SHELLEY PAULSONthe stitches for breeding and foaling. An exam will also include transrectal palpation and an ultrasound examina-tion. These tools help determine the stage of the mares estrous cycle. They canThe value of a teasing stallion is to identify the mares signs of heat and when shes ovulating.also allow the vet to verify the size and functionality of her ovaries and identifyics. Evaluating endometrial tissue cantherapy. (For more on getting a mare to potential abnormalities within the uterushelp the vet predict the probability of acycle, see TheHorse.com/166159.) and vagina, such as excessive fluid, whichmare becoming pregnant and maintain- As nights become shorter and day-can be a sign of inflammation or pooring the pregnancy to term.light increases (or as artificial lighting uterine clearance.If a veterinarian needs further informa- or hormone therapy takes effect), says Macpherson says she performs an ul- tion on a mare, he or she can perform aWolfsdorf, melatonin levels in the body trasound exam every time she evaluates ahysterocopic exam, which involves insert- lower, prompting gonadotropin-releasing mare prior to breeding. I think the toolsing an endoscope into the uterus to lookhormone (GnRH) secretion.of palpation are extraordinarily impor- for abnormalities such as foreign bodies,GnRH will then go to the anterior pi-tant, but theres so much that we can seeadhesions, or fungal/bacterial plaques.tuitary gland, which functions to release with an ultrasound that makes an impactThe information gathered during thefollicle-stimulating hormone (FSH) and on breeding management, she says.breeding soundness exam can guide yourluteinizing hormone (LH), she explains. Palpation and ultrasound examinationveterinarian to recommend certain man- And those influence the ovaries, stimu-results often determine the next steps inagement techniques or treatments beforelating follicular development. abnormal cases, says Wolfsdorf. Whatbreeding.The mare builds and regresses follicles we see in her uterus will dictate what typeuntil a dominant follicle forms that pro-of culture and cytology we may want toStep 3: Get the mare cycling duces enough estrogen to cause a strong do, to confirm and identify pathogens,Now that your veterinarian has diag- first estrus, also known as heat. she says. nosed and treated any possible reproduc- Then luteinizing hormone induces She says she most commonly performstive issues, you must make sure yourovulation (in the dominant follicle), this in mares that have a baggy, saggymare is cycling normally before breeding.Wolfsdorf says. The mare goes from an-uterus, such as older broodmares, thoseMares are seasonally polyestrous, mean- estrus, where shes not cycling, through a that have had multiple foals, or onesing they cycle and come into heat duringtransition period that usually lasts about with a history of endometritis, to look forperiods of long day length, such as during60 days prior to (this) first ovulation. inflammation and infection. These maresthe spring and summer. However, some might also be more prone to breeding-mares cycle year-round.Step 4: Track the mares estrous induced endometritis because of im- Many breeders, especially Thorough- cycle to know when shes ovulatingpaired uterine clearance.bred breeders, try to get their maresA mares estrous cycle lasts 21 days, but An endometrial biopsy adds anotherpregnant in late winter or in spring soshe will only come into heat and be recep-piece of information to the evaluation.they foal early in the year. Therefore, youtive to breeding for five to seven days With this procedure the veterinarianmight need to get the mare cycling inat the beginning of the cycle. Ovulation evaluates a piece of the endometriumwinter, when shed normally be in anes- occurs during the last 24 to 36 hours of microscopically to look for abnormalities,trus (a time of no estrus). Breeders canbehavioral estrus.such as inflammation, scar tissue aroundstimulate mares to cycle using methodsBreeding as close to ovulation should glands and vessels, and dilated lymphat- such as artificial lights and/or hormonealways be the goal, says Macpherson. TheHorse.com|The HorseDecember 201921BreedingMares.indd 21 10/31/19 2:21 PM'