b'YOUR GUIDE TO THE 2017 AAEP CONVENTION SPONSORED BYembryo recovery attempts) on every otherWhats the Best Way to Predict mare. They recovered embryos in 46.2%Foaling? of attempts with complete flush mediaIt takes approximately 11 months from and 57.1% of attempts with Hartmanns. conception for a mare to produce a foalOn Days 14 and 25 they performedemphasis on the word approximately. pregnancy exams on recipient mares andAnyone whos waited long nights for foals found that results with the complete flushto arrive knows mares gestation lengths media and Hartmanns solution groupscan vary substantially. While caretakers were essentially the same: 80.5% andcan use various methods to predict foal-80.8% pregnant, respectively, on Day 14,ing, some are more accurate than others. and 78% and 76.6% pregnant on Day 25. A research team led by Mariana Diel Therefore, veterinarians have multiplede Amorim, DVM, DVSc, Dipl. ACT, media type options for embryo recovery.now lecturer in theriogenology at the Ambulatory vets can carry one type ofCornell University College of Veterinary COURTESY DR. RYAN FERRISmedia (Hartmanns solution) for bothMedicine, in Ithaca, New York, set out to A healthy embryo recovered from embryo transfer.uterine lavage and embryo transfer, saidcompare foaling prediction methods. Ma-Ferris, adding that Hartmanns solutiontherapy can be especially advantageousdonna Morrison, DVM, a recent gradu-might also be more cost-effective.for matching a specific recipient with aate of the University of Prince Edward 2.What options are available if a cyclingdonor mare. Islands Atlantic Veterinary College, in recipient mare is not available? 3. Does the recipient have enough proges- Canada, and a member of the team, pre-One of the more important factorsterone to support pregnancy? sented the results. They collected mam-affecting the likelihood of establishing aThe mares corpus luteum (the struc- mary secretions from 40 Standardbred pregnancy after embryo transfer is donor- ture formed after ovulation) producesmares starting between Day 320 and Day recipient synchrony, said Ferris. In otherprogesterone thats critical to maintaining330 of gestation and tested several foaling words, the donor and recipient marespregnancy. The minimum level of pro- prediction methods, including:estrous cycles must be in sync.gesterone needed to support a pregnancy The calcium titration method (measur-Ideally, the recipient ovulates one dayis approximately 2.5 ng/mL. Its been as- ing the secretions calcium concentra-before to three days after the donor does.sumed that recipient mares progesteronetions, which rise significantly from 72 However, many clinics dont have a largelevels five days after ovulation are above 4to 24 hours before foaling);enough pool of cycling recipient mares tong/mL, said Ferris. A digital pH meter (mammary secre-match the donor population, particularlyTo confirm this, his team evaluatedtions normally have a pH above 7; when its early in the breeding season.progesterone production in 456 recipientwhen they drop to below 7, the mare In these situations, vets commonlymares with normal detectable ovulationswill likely foal within 24 hours);administer hormones to recipients tofive days post-ovulation. They found that pH test strips (the same concept as us-mimic the rising estrogen from growing 5.5% had levels below 4 ng/mL and 0.9%ing a digital pH meter, but using com-follicles and rising progesterone levelshad levels below 1 ng/mL, the latter indi- mercially available test strips);after ovulation. But how does this affectcating a corpus luteum never formed. Water hardness test strips (which mea-pregnancy rates? Normal corpus luteum function aftersure calcium and magnesium);To find out, Ferris et al. transferred: ovulation does not occur in a small per- A Brix refractometer (measures 65 embryos into naturally cyclingcentage of mares, said Ferris. colostrum-specific gravity, which rises recipient mares; Overall, he said, these techniques canas mares get closer to foaling); and40 embryos into noncycling maresallow clinicians greater flexibility to over- A commercially available foaling moni-treated with two days of estrogen tocome common challenges in embryo re- toring system. The team used Foalert, mimic estrus, followed by five to sevencovery and recipient mare management. which is sewn onto the mares vulva days of progesterone to support thelips to detect separation by the foal.pregnancy; and They analyzed samples from three days14 embryos into naturally cycling(Day -3) before foaling to foaling (Day 0) mares early in estrus (without a domi- and found significant differences between nant follicle) treated with the afore- the tests on Days -3, -1, and 0:mentioned hormone therapy. Both the calcium titration and pH Ferris said there was no statisticallyElizabeth Schilling methods (seem) to be the best meth-@efsdvm significant difference between pregnancyods for predicting foaling, Diel de rates among all groups. Only during #AAEP2017Amorim told The Horse; Estrogen and progesterone in non- do you hear optimal The foaling monitoring system alerted cycling recipient mares can result in ainsemination in casualthe team when 82% of mares were foal-similar pregnancy rate as recipients withconversation as you walking; it produced false alarms 19% of natural ovulation, he said. Hormonepast the bar.the time. A32 TheHorse.com/AAEP2017 AAEP Wrap-Up THE HORSEMarch 2018'