Page 14 - 30 March 2012

OFF-THe-Track mares
considerations when breeding race mares.
There are significant challenges that face the mare as she moves from the training barn to the breeding farm.
Louisiana Center
for Equine Reproduction
(337) 407-0708 www.laequine.com
by Eddie Cramer, DVM
It is always an important moment in the life of the racing mare when the decision is made to breed her. Historically, this event would mark the end of
her racing career and the beginning of her life as a broodmare. While this is often still the case, many times it is now a decision to quickly pull an embryo or two out of her before she is returned to race train- ing. Whatever circumstances surround the individual decision, there are significant challenges that face
the mare as she moves from the training barn to the breeding farm.
So, what’s so different about the young mare
off the track and the older broodmare that has had several foals? In a word, STRESS. It is the proper management of the changing stressors in this mare’s life that will often determine if her first year to be bred is successful or not.
While on the track, horses are conditioned to be in the peak of athletic fitness; this often means that these mares are not carrying enough body condi- tion to cycle properly. Further, exposure to artificial lighting, as well as certain medications, can result in significant fluctuations in reproductive hormones. Furthermore, once the decision has been made to breed the mare, she is moved into a new environment and undergoes new procedures. All of this occurs just as we are expecting her to conceive her first foal.
The key to limiting stress during this transi-
tion is to introduce changes as gradually as possible. Ideally, the mare would be retired from race training a minimum of several months prior to the begin- ning of breeding season. This gives the mare time to gain body condition, regulate hormone levels and be treated for any training related injuries. This is also an ideal time to assess the mare’s maturity and suit- ability for breeding. It is advisable to have a breeding soundness exam performed prior to the breeding season to rule out any pre-existing problems.
While it is ideal to provide the mare with a period of rest prior to the beginning of breeding season, it is often not practical to do so. Many of these mares will be rac- ing well into the spring of the year and many more will be returning to competition once they serve as embryo donors. In these cases, time is always of the essence.
When dealing with fillies directly off the track, it is critical to change their lifestyles as gradually as pos- sible. These horses have been treated as individuals their entire lives and usually do not adjust quickly to living in a herd setting. If it is necessary to introduce
them to a herd, it is best to begin by putting them with a single other horse. This will encourage them to “buddy up” and will help both of them as they are introduced to larger groups. Herd life can be par- ticularly stressful at feeding time. It is imperative to develop methods that minimize competition among horses and allow all the members of a group to access their rations.
An additional complication of breeding fillies right off the track is that their estrous cycle is often suppressed while they are in training. This means that the breeding farm is often dealing with her first cycle of the year. This cycle tends to be particularly unpredictable and may not respond as expected to the usual reproductive medica- tions. Furthermore, there is some evidence suggesting that mares that become pregnant on the first cycle of
the season may not produce enough progesterone to maintain the pregnancy. A simple blood test, taken at the time of pregnancy diagnosis, will indicate if supple- mental progesterone is needed.
Once the mare is checked in foal, it remains quite important to continue all of the practices mentioned about minimizing stress and making gradual changes to her lifestyle. As the breeding season winds down and we move into summer, the effects of heat stress should also be considered. Providing mares with adequate shade and fresh water will help maintain body condition and overall health.
On the other end of the spectrum, maiden mares do present some special considerations when it comes time for them to have their first foal. Although things usually happen without any complications, it is particularly important for maiden mare foalings to be attended. These mares may have an inadequate supply of milk, especially right after the foal is born. While this condition usually responds to medical treatment, it is essential that the foal receive adequate colostrum and nutrition in the meantime. Furthermore, there
is a higher incidence of foal rejection among maiden mares. In this case, prompt intervention may prevent the injury or death of the newborn.
In the long run, it is difficult to over-emphasize the negative effect that stress has on reproductive performance in the mare. This effect is often seen most dramatically when breeding maiden mares directly from the track. However, good husbandry and a little common sense can go a long way to mak- ing the transition from the track to the breeding shed a smooth one.
12 SPEEDHORSE, March 30, 2012
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