Breeding Tips

Carolina Livi's interview with Cindy Backus, DVM, PhD

Carolina writes introduction to Dr. Backus:

Our first interview on the topic of Breed Health and research is with Dr. Cindy S. Backus, a large animal veterinarian specializing in equine reproductive work. She has a B.Sc. in Animal Science from Ohio State University, a M.Sc. in Reproductive Physiology from The University of Tennessee, a D.V.M. from the University of Tennessee, and a Ph.D. also in Reproductive Physiology from the University of Tennessee. She has worked in private practice for 18 years, and does mostly horse work, in addition to working on sheep, goats, alpacas, and other small ruminants. She started breeding horses with cooled shipped semen in 1997 at the time the quarter horse association lifted the registration ban. Her first attempt got produced a gorgeous palomino stallion that she still rides. Spring of the year brings dozens of mares to the clinic for shipped breeding and she has owners haul their stallions over to be collected and shipped. In the last 4 to 5 years they have been doing 20 or so Embryo transfers per year as well. She says it is becoming more and more popular but is still not as successful as AI.

Her clinical work also includes Farm Calls to a 50 mile radius or so to give routine care and emergency care. She really doesn't work on one breed of horse, but sees predominantly Quarter horses, QH-TB (Jumpers), and Tennessee walking horses because they are most popular in her area. She and her husband have a small farm and raise Quarter horses. They have 45+ head and stand anywhere from 2 to 4 stallions per year. They breed from 6 to 12 mares of their own each year and foal them out. She shows Reiners and loves it. One of the fillies she bred and raised won the Florida Reining Futurity last year. She says it makes it all worth it.

She attends over 40 hours of continuing education per year many in the form of specialization courses. This can be specifically Equine related such as the AAEP convention (american association of equine practicioners) which she is a member of; or Western Veterinary Conference which covers all species. Her masters and doctoral work have also specialized her.

Carolina asks: During the breeding phase, what do you recommend to your clients with regard to live cover, or artificial insemination with cooled or frozen semen?

Dr. Backus replies: First comes the decision on what stallion to use and the breeding method.

Live cover versus artificial insemination versus cooled shipped versus frozen semen. That is the question. There are advantages and disadvantages to all discussed below.

Live cover: You just can't improve on Mother nature. The further away you get the less the success. However; it is dangerous for you, the mare, the stallion. There is a higher risk for the spread of diseases. Distance to haul is often prohibitive.

AI on farm: Collect stallion on mount. Breed several mares with one collection. Again distance is prohibitive, but this is safer than live cover. Need to have ultrasound available.

Cooled shipped Semen (is my favorite): Distance is no longer an issue. Can breed to the best you can afford. Safer for handler, mare, and stallion. Need to have US available to know when to order semen. Timing is everything. Downside is that the semen lives 24-48hrs in extender and must get to the mare quickly. Coordinating transport can be challenging.

Frozen Semen: Highly labor intensive, as it requires multiple US. Semen has short life span and needs to be inseminated very close to ovulation. Have semen in tank and readily available. Do not rely on shipping or plane schedules as heavily.

Then comes the scheduling of the breeding season.

There are a lot of things to be done before the actual breeding or season and these depend on the age of the mare, maiden or not, barren, foal by side, when you are breeding, method of breeding, breeding contract, etc.

Everyone wants to breed in February or March, even sooner. I have gotten several phone calls this year about breeding mares early. Many folks do not realize that horses are seasonally polyestrous This means they only cycle part of the year (summer), and have several cycles in that time. They have a transitional period and then anestrous phase where the do not cycle (winter). Right now (March) we are in the transitional phase going into the regular fertile breeding phase.

If you do not trick your mare into believing it is summer, she won't cycle and you cannot breed her. To get her to cycle out of season takes about 8 weeks. I start in late November. Leave the lights on in the morning and later at night for a total of 16 hours per day. You can get a timer and a string of light bulbs and hang over the stall, or get a couple of flood lights with a clamp and attach to the stall. You need enough light to be able to easily read. This is how I gauge the quality of light provided. The other thing is to put a blanket on her so she is warm and again thinks its summer. This is also a good idea because she won't grow any hair or will shed early before outside temperatures rise. Not needed if you have a heated barn. I wish! If you do not use the lights, it will be the beginning of April or so before your mare begins to cycle. The first cycle of the season is not always fertile and if using shipped semen I usually skip this one.

So first thing we've accomplished is to have the mare cycling. I find that the more informed the mare owner is, the better I can communicate with them and let them know exactly what is going on. I have them watch the ultrasound (US) and explain the structures and what we have and what we want and where we need to go, and the time frame to get it all done in.

Carolina asks: Before the breeding season, what do you recommend your clients do in the case of a maiden mare? What about a mare that did not conceive the year before or had complications when having a previous foal? Is it warranted to routinely run a cytological exam or biopsy the uterus?

Dr. Backus replies: Then we need to look into each specific mare's needs.

In the case of a maiden mare, young, and in good condition, I usually do an US to be sure the uterus looks normal, the ovaries have normal structures, and it looks like she is cycling. A uterine culture is a good idea but if she still has a hymen probably not necessary. Some studs require a clean culture prior to breeding.

In the case of a barren mare (didn't conceive in the previous year), a culture is definitely needed in conjuntion with a US, cytology, and a biopsy. I check to see if she has a caslick (stitches used to close upper vulva) or if she needs one. Also need to check cervical integrity if she has had a difficult birth previously. US to see if any uterine cysts are present or if she is pooling any fluid. Also a good history will help. It may not have been her fault if she didn't conceive if the timing was off, poor body condition, raising a foal at foot, etc.

Carolina asks: If a mare has a chronic infection of the reproductive tract, what are the steps to recover their breeding potential?

Dr. Backus replies: In the case of a mare with chronic infection I would do the routine workup of biopsy, culture and sensitivity, and cytology. Probably need to lavage her until you get her cleared. I have a regime for chronic inflammation that works sometimes too. A Caslick will prevent wind-sucking and recurrent contamination. On these mares it is important to continuously US and keep the fluid from accumulation in the uterus. Post breeding flush is beneficial as well as immune stimulant.

Carolina asks: Do you routinely short cycle a mare to facilitate timing of ovulation? Do you recommend flushing the mare after insemination? What about the use of oxytocin aid in clearing the fluid? Is there an exam available to check whether or not the mare has sufficient contractions to clear the uterus and avoid infection?

Dr. Backus replies: Here are comments regarding routine management strategies and treatments.

I do not do a biopsy on every mare prior to breeding but I will do a culture including sensitivity (type of antibiotic that works best to control infection present) and cytology on most, as well as US. If a culture comes back positive, I will flush the uterus with sterile saline mixed with the antibiotic from the sensitivity. I have also used immune stimulants to help clear uterine infections. in severe cases, a uterine lavage helps.

Somewhere in all this it is important to mention that the mare needs to be in good body condition, not too fat, and not too thin. Obese mares do not cycle well and are harder to get pregnant in my experience. I don't like breeding skinny mares either as they need to have something to put into a growing baby. I like them where you can feel ribs but not see them.

Prior to breeding, get their yearly immunizations done and have them dewormed. I don'tlike to vaccinate or deworm them until they are 60 days or more pregnant as the organ systems form early during development and I try not to interfere. It is not the vaccine itself, but the transient fever that could potentially cause changes.

I do like to short cycle mares so the will ovulate on weekdays when it is possible to get a semen delivery. To have semen flown to the airport usually costs double or more and you have to pick it up at the airport instead of express delivery to my door.

After breeding, I keep the mare at our clinic until she has ovulated. If she does not ovulate she is bred again. Then, I routinely flush the uterus and give oxytocin. Estrumate can also be used up until ovulation to help clear fluid. If the mare needs a caslick she gets it at this time. Dead sperm have been shown to be highly inflammatory in the uterus. By removing them, we increase chances of conception. I also believe that having mares outside on pasture or exercising is beneficial over keeping them in stall during the breeding process although it is not always possible.

PS.: At Dr. Cindy S. Backus' suggestion, we will be covering breeding contracts in a future issue of "The BayWatch"