Courtesy of Select Breeders Services
Breeding mares on their foal heat is a strategy used to maximize reproductive efficiency. Since income is generated from selling offspring, yearly foal production is critical to offset maintenance and breeding expenses incurred by the mare owner. With an average gestational length of 333 to 345 days, mares must become pregnant within one month post partum to continue producing foals each year. Mating mares on the first postpartum estrus is one method used to improve the chance of maintaining yearly foal production. Reviewing this topic for us is guest writer, Dr. Margo Macpherson with an excerpt from the chapter Breeding Mares on Foal Heat co-authored by Dr. Margo Macpherson and Dr. Terry Blanchard in the 2nd Edition of Equine Reproduction.
The first post partum estrus generally begins 5-12 days after foaling; hence, the terminology foal-heat or “9 day heat.” In a large study involving Thoroughbred mares, ovulation during foal heat was reported on average at 10 days post partum, with most mares ovulating within 20 days post partum (Loy, 1980). Mares that foaled early in the year were less likely to ovulate by 10 days post partum than mares foaling later in the spring. Also, early foaling mares (January to March) were more likely to have a prolonged period of postpartum anestrus (> 30 days to first ovulation postpartum) than late foaling mares. While not proven, it is suspected that the postpartum anestrus seen in many foaling mares is thus related to length of days when parturition occurs. In this regard, supplementing artificial light to late pregnant mares has been shown to reduce the incidence of postpartum anestrus (Palmer and Driancourt 1983).
Advantages for mating on foal heat include:
In the normal foaling mare, several events occur to the uterus in the immediate post-foaling period. This is termed uterine involution. Inflammation helps rid the uterus of debris and contaminants that are present in the uterus for the week after foaling. This process results in the formation of fluid, called lochia, which is often seen coming from the mare’s vulva. This fluid is usually reddish-brown and does not have a foul odor. The uterus, which is a strong muscle, actively contracts after foaling to help evacuate the fluid and debris. Contractions are also important for returning the uterus to its pre-foaling size. Suckling by the foal and exercise are important stimulants for uterine contractions and evacuation. Tissue repair and uterine “clean up” are essential for re-establishing pregnancy. Involution occurs rapidly after a normal parturition. Within 30 days of foaling, the uterus should have returned to its’ pre-foaling state in both tissue health and size.
Major factors thought to be related to fertility achieved on foal heat breeding include an uncomplicated birth free from genital tract trauma, prompt passage of the placenta, rapid uterine repair/involution, and early return to regular estrous cycles. Selection of mares for foal heat breeding should be based on meeting these minimum criteria to optimize success.
Strategies For Breeding Mares on Foal Heat
Breeding mares on foal heat is not a recipe-driven event. Each mare must be treated as an individual and the conditions of her foaling considered. In general, young mares with uncomplicated foaling are better candidates for breeding on foal heat than older mares that have previously delivered several foals.
A general approach to breeding mares on foal heat starts in the week after foaling. First, all mares should be examined no later than 6-8 days after foaling. A visual examination of the mare’s reproductive tract will reveal the presence of urine pooling, pneumovagina or unresolved trauma to the vagina, vestibule or vulva. Although these conditions usually will improve over time, injured mares are not good candidates for breeding on the first postpartum estrus. Examination of the internal reproductive tract using an ultrasound should be performed to reveal the presence of intrauterine fluid accumulation and size of any developing follicle(s). These factors are monitored by repeating examinations at 1-2 day intervals. If fluid is present in the uterus at the time when foal heat breeding is anticipated, it is better to treat the mare to remove the fluid than to breed the mare. Mares judged to be involuting normally, with no significant intrauterine fluid accumulation, are good candidates for foal heat breeding. If the mare ovulates prior to day 10 post partum, breeding on foal heat can be bypassed and prostaglandin can be administered 5-6 days after ovulation to induce an earlier return to estrus for breeding. It is thought that this protocol allows the uterine environment more time for repair, as well as provides a shorter interval (1-2 weeks) to breeding than that achieved by waiting for the second postpartum estrus to spontaneously occur (typically around day 30).
Some mares will accumulate fluid after the foal heat breeding. Such mares should be treated to remove fluid and resolve any infection that may have been established. Performing uterine lavage (3-5L lactated ringers or saline solution) in these mares is important, and is thought to not interfere with fertility if the lavage is performed at least 4 hours after breeding (Brinsko et al 1991). Use of drugs to promote uterine contraction, such as oxytocin, can also be helpful when treating mares with uterine fluid. Often, oxytocin is combined with uterine lavage for fluid removal in the breeding period. While the inclusion of antibiotic infusions after breeding postpartum mares remains controversial, some individuals (Pycock, 1994) have reported that postpartum mares treated with antibiotics plus oxytocin had higher pregnancy rates than either mares treated only with oxytocin or mares that were left untreated.
In conclusion, not all mares are suitable candidates for breeding during the first postpartum estrus. However, using careful selection of mares, breeding during foal heat can result in favorable pregnancy rates in a highly efficient manner, and can reduce parturition to conception interval to help to maintain yearly foal production in mares.
Dr. Margo Macpherson received her DVM degree in 1990 from Michigan State University after which she completed a residency and Master’s Degree in Equine Theriogenology at Texas A&M University. After leaving Texas, Dr. Macpherson spent time at the University of Pennsylvania and in private practice in Central Kentucky. Currently an Associate Professor and Service Chief in the section of Reproduction at the University of Florida, Dr. Macpherson is primarily interested in conditions that affect pregnancy including twin pregnancy and placentitis.
Blanchard, T.L. and Macperson M.L. 2011. Breeding Mares on Foal heat. Equine Reproduction, 2nd Edition, Editors: A.O. McKinnon, E.L. Squires, W.E. Vaala and D.D. Varner, Wiley-Blackwell, West Sussex, UK.
Brinsko, S.P., Varner, D.D., Blanchard, T.L. 1991. The effect of uterine lavage performed four hours post insemination on pregnancy rates in mares. Theriogenology 35:1111-1119.
Loy, R.G. 1980. Characteristics of post partum reproduction in the mare. Vet Clin N Amer: Large Anim Prac 2:345-359.
Palmer, E., Driancourt, M.A. 1983. Some interactions of season of foaling, photoperiod and ovarian activity in the equine. Livest Prod Sci 110:197-210.
Pycock, J. 1994. Assessment of oxytocin and intrauterine antibiotics on intrauterine fluid and pregnancy rates in mares. Proc Amer Assoc Eq Pract 40:19-20.
Breeding Manager, Hilltop Farm
So one of the important topics that has been under discussion over the past ten years or so is this: Do the Young Horse classes really predict talent for the future FEI horse or are they rewarding extravagent movers that won't be able to handle more collected work that is the core of the FEI work? It's a complicated question, with many factors including pre-selection, training, etc but overall, I do believe we see a far greater number of these horses progress into the FEI levels.
I reviewed the USEF National Championships from 2011-2016 for the top 5 placing horses in the FEI 5-year old & FEI 6-year old classes to see what their own development has shown us. That gave me 51 horses to look at (some horses placed in the top 5 both years, and I didn't look at the 2016 5-year olds as they aren't old enough to compete in the FEI classes).
Of those 51 horses, 30 are competing at Prix St. Georges or above. That's a 'graduation rate' to the FEI ring of almost 59% (there are also 2 horses competing in the FEI 7-yr old Division but I didn't count them in my statistics). Nine of these horses have competed at least to the Developing Grand Prix level, and one was a member of the Pan-American Gold Medal Team. Keep in mind also that these horses currently range from ages 7 to 12. To add another layer, I also looked at how many of these horses were US-bred (Full disclosure: I did include one by a US-breeder who bred this particular horse in Germany). Fifteen of the 30 horses now competing at the FEI levels are US-bred. Those are some very strong stats for the top 5 finishers!
**US-Bred**Somer Hit (Sandro Hit-Rotspon), breeder Mo Swanson
Lauren Chumley/Alice Tarjan
3rd in 2011 (5yr) with 8.408/1st in 2012 (6yr) with 8.050
Showing Int II-Grand Prix by age 8
Sanceo (San Remo-Ramiros Son II)
4th in 2011 (5yr) with 8.116
Team Gold Medal at 2015 Pan-Am Games, Showing Grand Prix
Elfenfeuer (Florencio I-Sion)
2nd in 2012 (5yr) with 7.864; 5th in 2013 (6yr old) with 7.832
Showing Int II-Grand Prix by age 7
**US-Bred**Freedom (Feuri x Windjammer), breeder Barbara Cadwell
3rd in 2012 (5yr) with 7.612
Showing Grand Prix
Horizon (Hotline x Revue)
4th in 2012 (5yr) with 7.592
Showing PSG/Int I with Adrienne Lyle
Fashion Designer OLD (Faustinus x Forst-Design)
1st in 2013 (5yr) with 9.012; 3rd in 2014 (6yr) with 8.12
Showing Inter II with Cesar Parra
Fiderhit OLD (Fidertanz x Fleur)
Nadine Buberl/Cesar Parra
3rd in 2013 (5yr) with 8.620; 6th in 2012 (6yr) with 7.798
Showing in FEI Young Riders with Barbara Davis
**US-Bred**Qredit Hilltop (Quaterback-Dream of Glory), breeder Judy Yancey
4th in 2013 (5yr) with 8.480
Shown through Intermediate I with Michael Bragdell
**US-Bred**Benefactor RRS (Bonheur-Rubinstein), breeders Melinda Walton & Larry Smith
5th in 2013 (5yr) with 8.452
Emilion SA (Painted Black x Karisa)
1st in 2014 (5yr) with 8.680
Shown to PSG
Elian (Sir Oldenburg x Barliane)
3rd in 2014 (5yr) with 8.14
**US-Bred**Wakeup (Wagnis-Macho), breeder Beverly McLean Tetrick
1st in 2011 (6yr) with 8.736 (also won as a 5yr old)
Competed at 2010 World Young Horse Championships, won Developing PSG Championships & 2nd at Developing GP Championships, Showing Grand Prix
**US Breeder**Bon Chance (Belissimo M-Weltmeyer), breeder Marefield Meadows
2nd in 2011 (6yr) with 8.736
Shown to Grand Prix, now in U25
Aesthete (Trento B x Unusual)
3rd in 2011 (6yr) with 8.728
Now showing Inter II
Riccidoff (Riccione x Don Sarina)
4th in 2011 (6yr) with 8.084
Showing PSG/Int I with Adrienne Lyle
5th in 2011 (6yr) with 8.076
Simply Nymphenburg (Sir Donnerhall I x Wendy)
2nd in 2012 (6yr) with 7.796
Showing in FEI Young Riders with Barbara Davis
1st in 2013 (6yr) with 9.152
Showing PSG/Int 1 with Isabel Freese
Sunshine Tour (Sir Donnerhall x History)
2nd in 2013 (6yr) with 8.028
Winner of 2016 Developing GP Championships, showing GP
**US-Bred**Caliente DG (OO Seven x Satina), breeder DG Bar Ranch
3rd in 2013 (6yr) with 7.940
Showing PSG/Int I
**US-Bred**Clapton JP (UB40 x Liana), breeder Peggy Mills
4th in 2013 (6yr) with 7.782
Showing Grand Prix
**US-Bred**Ripline (Hotline x Riviera), breeder Oak Hill Ranch
1st in 2014 (6yr) with 8.612
Showing PSG/Int I
**US-Bred**Hemmingway (Hofrat-Archipel), breeder Angela Barilar
2nd in 2014 (6yr) with 8.572
Showing PSG/Int I
**US-Bred**Sir Steinerman (Stedinger x Donnabella), breeder Marlace Hughes
4th in 2014 (6yr) with 7.994
**US-Bred**Doctor Wendell MF (Don Principe-Sandro Hit), breeder Marydell Farm
5th in 2014 (6yr) with 7.976
Showing Int II/Developing GP, winner of 2015 US Dressage Finals at PSG
**US-Bred**Gallant Reflection HU (Galant du Serein-Rohdiamant), breeder Horses Unlimited
1st in 2015 (6yr) with 8.136
Showing Int II
**US-Bred**Floretienne (Florestan-Jazz), breeder Judy Yancey
Emily Wagner Miles
2nd in 2015 (6yr) with 7.836
Showing PSG/Int I
Ellert HB (Johnson x Alanda-B)
4th in 2015 (6yr) with 7.676
Lucky Strike (Lord Laurie x Heidi)
1st in 2016 (6yr) with 8.604
Competed at 2015 & 2016 World Young Horse Championships, showing Developing PSG
**US-Bred**Sternlicht Hilltop (Soliman de Hus-Rascalino), breeder Rachel Ehrlich
3rd in 2016 (6yr) with 8.028
Susanne Manz, Manz Dressage Horses
Twin Cities area, Minnesota
I attended the KWPN – North America Annual General Meeting in Lexington, Kentucky last week. It was a fun and educational event, offering the chance to meet and network with other breeders. It’s always fun to hear what other breeders are doing and to share experiences with them. Some of the more experienced breeders shared their experiences during a panel discussion.
Bert Rutten from the Netherlands was a special guest and provided insights on selecting, breeding, and developing dressage horses. As a member of the 1984 Olympic team and current head of the KWPN Stallion Selection Committee, Bert had excellent perspectives on dressage horse breeding and development at all levels. Bart Henstra from the Netherlands also attended and gave a clinic on linear scoring of KWPN horses as well as a presentation on the new OCD genome testing that the KWPN is doing. Dr. Scott Harper from Rood and Riddle discussed pre-purchase examinations and Dr. Debbie Harrison gave an update on the latest breeding information form AAEP.
We had a field trip to Spy Coast Farm where we watched horses in the jumping chute. Then on to the Kentucky Horse Park where we had some time to wander through the Horse Museum and visit the KWPN–NA office. On the second day we had a field trip to Valley View Farms. Willy Arts coached the Young KWPN–NA members on in-hand handling and presentation. It was fun to watch but I was glad I did not have to run the horses! We also had fun getting to see a harness horse presentation and discussion from Wim Cazemier and Sterling Graburn. Wim showed us his beautiful harness stallion, Colonist.
Thanks to the presenters but also to the owners of the beautiful demonstration horses! It takes a team effort to put together such an educational meeting. Having demonstration horses available makes a huge difference. It’s nice to see how other breeders share their knowledge and contribute resources to newer breeders like me. It was a warm, supportive environment. The KWPN–NA Board of Directors did an awesome job.
A couple of interesting points –
So, to my USSHBA friends and colleagues, meet the KWPN North American Association. And KWPN friends, please meet the USSHBA. Please visit the USSHBA booth at the FEI World Cup in Omaha at the end of March.
Blenheim EquiSports is proud to announce a new Young Hunter Program, which is divided by age, offers free entries, discounted stall fees and features a Championship in the fall. With this opportunity, plus the new structure for Green Hunters, the CPHA 3' & 3'3" Incentive Program and more, the show season offers ample opportunities to develop horses, compete and earn prizes in the Hunter divisions.
New Division, New Final and Free Classes!
In support of the new US Equestrian division, this year The Blenheim EquiSports Young Hunter Series & Final (an exclusive Blenheim EquiSports Program) offers divisions for 5, 6 and 7 Year Old Hunters with no entry fees and discounted stall fees. There will be sixteen $1,000 Young Hunter Classics, each of them qualifiers for the Final. The entry fee for each one - $0. Also note that all of the classes, classics, and championships count for US Equestrian HOTY Awards.
"With US Equestrian revamping the hunter divisions, we are pleased to offer expanded opportunities for young hunters like we've been able to do for young jumpers," said Melissa Brandes, Blenheim EquiSports VP of Marketing. "From free entries to a fall championship, it's going to be a great season for developing horses."
To participate, the age of horse must be verified in accordance with Federation policies prior to competing (only Breed Registry Papers will be accepted to determine proof of age and identity).
The 2017 qualifying season will commence March 22, at Spring Classic I, and concludes September 14, 2017. The Blenheim Fall Tournament, September 13 - 17, 2017, will host the inaugural $10,000 Young Hunter Final.
Dr. David Scofield
Select Breeders Services
Oxytocin is one of the most utilized hormones in broodmare practice. With so many possible clinical applications, a review of the use of oxytocin in the mare highlights the benefits of oxytocin, as well as necessary precautions with its use. Oxytocin is a nine-amino acid neuropeptide that is produced in the hypothalamus and released by hypothalamic neurons that terminate in the posterior pituitary. It is released in a natural pulsatile manner and exerts its effects by coupling with oxytocin receptors on various tissues such as the endometrium, myometrium, heart, kidney, pancreas, and fat tissue. There are also local effects of oxytocin and receptor binding, notably in the utero-placental tissues that help to increase the effect and intensity of pituitary derived oxytocin pulses. Clinically, oxytocin is available as a sterile injection, 20 IU (international units) per milliter. It can be administered intravenously or intramuscularly.
Non-Pregnant MaresUse in the non-pregnant mare is commonly based upon increasing uterine contractility to facilitate clearance of fluid. The correct dose of oxytocin causes a pulse of progressive uterine contractility that helps move free fluid out of the uterus. However, too high of a dose of oxytocin (> 30IU) will cause a tonic contraction of the uterus and prevent the evacuation of fluid. In our clinic, we use 20 IU (1ml) of oxytocin in the muscle every 4 hours. Oxytocin has a half-life of only 6 minutes. That means every 6 minutes, 50% of a dose is degraded and no longer active. With such a short half-life, more frequent administrations of a lower dose can have a better effect in uterine clearance.
Breeding MaresI routinely use oxytocin therapy in the 48 hours following breeding a mare to help with normal fluid accumulation following breeding and to help remove any remnants of uterine therapy such as infusions of antibiotics or uterine lavages. Mares produce fluid in their uterus as a normal response to breeding. If this fluid persists after 24 hours following breeding, she may be termed “susceptible to Post Mating Induced Endometritis (PMIE).” A common therapy utilized is intramuscular oxytocin administration to help fluid clearance. I will also administer oxytocin both intramuscularly (and possibly in the uterus in lavage fluids) to help a mare clear abnormal fluid accumulation.
Post Foaling MaresI also routinely use oxytocin in post foaling mares to help clear any lochia or normal post-foaling debris, during retained fetal membrane therapy and following lavages preparing mares for foal heat breeding. Small and frequent doses of oxytocin are a first line therapy to help mares that have not passed their placenta within three hours of foaling. The smooth muscle contractions induced by the oxytocin facilitate the passing of the retained fetal membranes as well as clearing bacterial and inflammatory debris that can accompany retained membranes. Oxytocin also has some therapeutic actions in the maternal bond and developing mothering ability and can be used to augment a mare’s behavior towards her new foal. It should be noted that a post foaling mare has a high up-regulation of the oxytocin receptor. This effect means a smaller dose of oxytocin has a much greater effect. In post-foaling mares, I only use 5-10 IU of oxytocin at a maximum.
One place I see oxytocin utilized incorrectly in the post foaling mare is when some owners try to increase milk production by administering oxytocin to a mare with low milk production. Oxytocin aids in milk let-down from the mammary tissue into the teat cistern, to be available when the foal suckles. This milk letdown process is coordinated from sights, smells and nuzzling of the foal near the udder. A mare will have a release of oxytocin from the posterior pituitary and allows milk to leave the mammary gland and enter the teat cistern. Administering a dose of oxytocin mimics this normal event and will cause milk letdown. Oxytocin increases letdown only, not the production of milk. The only method to increase actual milk production is to use a dopamine antagonist such as Domperidone or Sulpride.
Caution with the Pregnant MareNow, there is a major caveat. Oxytocin, can have a profound effect on a pregnant mare. If administered at the correct timing, it will induce delivery (or premature delivery) of a foal. If inadvertently administered, a late term mare will be induced into parturition, having devastating results to both the mare and fetus.
Some Additional UsesThere are a few other uses of oxytocin which involve medical conditions related to esophageal choke and estrus suppression (described in our article Suppression of Stallion and Mare Behavior).
The use of oxytocin is an extremely valuable tool for reproductive medicine. Its use is common but adequate knowledge about the physiology, half-life, and contra-indications are important to understand the benefits as well as the potential downfalls of its use in the mare.
A collaborative effort produced by the USSHBA Education Committee, USSHBA members, and our partners.