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Repeated foaling can cause problems. This is especially helpful if the mare has a uterine or oviductal mxres, but Breeding older mares much help if the problem is due to the oocyte. The surgeon must remove the sutures before breeding and resuture Breeding older mares after and about 30 days before the expected foaling date to avoid damaging the reproductive tract. Another examination is required post-breeding, to ensure that ovulation has occurred and to assess any fluid accumulation. Older mare. The successful management of older mares should logically require some form of post-mating therapy such as uterine lavage, IV oxytocin, or intrauterine antibiotic infusion.
Lace toronto. Do You Plan To Breed Your Mare?
A simple lavage instillation and removal of warm saline solution can Breeding older mares uterine clearance in a number of ways. And before selecting an approach, be sure your particular breed registry permits it. Web page addresses and e-mail addresses turn into links automatically. Mares with cervical fibrosis are best only bred once per cycle. Dead Breeding older mares. Mares that are extremely Alex butts may have foaling difficulties and not produce as much milk. All-Around Hand. Blood tests may reveal that these mares have a chromosomal abnormality such as gonadal dysgenesis. Hypothyroidism can be difficult to diagnose, as testing usually does not produce Breeding older mares definitive diagnosis. Some older mares, especially over age 20, experience irregular inter-estrus intervals and have difficulty having normal ovulations as they approach ovarian senescence.
Contamination and infection, both of which can cause an inflammatory response, are primary reasons for reproductive failure in the older mare.
- Pregnancy Prohibitors.
- Jonathan F Pycock, B.
- Thomas R.
- Older mares have a knack for being the sweetest and gentlest mares on the farm.
Are you thinking about breeding an older mare next spring? Remember there are still steps—some simple, some cutting-edge—breeders can take to obtain a foal from mares with waning fertility. Fortunately, good management practices and veterinary advancements can help. And for that exceptional senior mare, avant-garde services add to your reproductive options when breeding older mares.
Until it is very clear that these mares are done, their owners may want to try to get one last pregnancy. From ages 4 to 15, mares are in their reproductive prime. But from 15 to 20, their fertility declines, says McCue.
Reproductive problems only continue to intensify in mares older than Of course, each mare is an individual with her own health history and genetic tendencies. But why does mare fertility decline with age, and what can be done about it? We talked with equine reproduction specialists about common fertility and pregnancy problems in this mare demographic to get some answers.
So basically, if a mare is 20 years old, her ovarian follicles, each of which contains an oocyte, are also 20 years old, says McCue. They might suffer a few defects that will make them less fertile. Mares are seasonal breeders, meaning they only cycle naturally during a particular time of year so that they will deliver foals, ideally, in temperate weather. Each mare is different and the time of year causes some variation, but there is a basic estrous pattern, or cycle, of 21 days from one ovulation to the next.
When a mare is in heat, which lasts four to seven days, the oocyte develops within its follicle, a fluid-filled sac of cells that protects and nourishes it. The enlarged follicle ovulates or releases the egg about 24 to 48 hours before the mare transitions back to diestrus. From there the oocyte travels into one of the oviducts—two tiny tubes that stretch from the ovaries to the horns of the uterus—where fertilization should occur.
The fertilized egg, now called an embryo, then stays in the oviduct about six days before entering the uterus. Then it travels through the uterus until it becomes fixed, about 16 days after ovulation.
Older mares might begin cycling later in the spring than younger mares, and the time between ovulations might lengthen. Problems can arise with ovarian follicle development, resulting in a longer time in the follicular phase and smaller follicles from a slowed growth rate. It is not uncommon to see mares above 20 years of age that take three to four weeks or longer to build a follicle suitable for breeding. McCue says the incidence of ovulation failure increases with age.
Even if they ovulate, there is a question of how normal the corpus luteum is to produce adequate amounts of progesterone to maintain a pregnancy. That corpus luteum, a temporary structure that forms on the site where the ovum is released, secretes the steroid hormone progesterone needed to establish and maintain a pregnancy.
Scar tissue could have developed as could endometrial cysts, which can present problems if they become large or are plentiful. These chronic degenerative changes in the uterine lining, or endometrium, are known as endometrosis, says Pinto. As a co-author on a study published in the October issue of Theriogenology , he discovered reduced blood flow in the uterus during early gestation in older mares as well as in those with significant endometrial degeneration.
Be aware that breeding an older mare can be expensive. While prices vary, here are a few to consider before you embark on the venture:. An important cause of embryo loss during early gestation is persistent post-breeding endometritis.
The primary problem associated with endometritis is poor evacuation of the uterus, or clearance of debris or other foreign material, which then produces a persistent endometrial inflammation hence, the -itis. All mares develop a temporary uterine inflammatory response after breeding because of the spermatozoa and, inevitably, bacteria introduced.
Typically, the fluid pushes out and the inflammation resolves on its own, says Pinto. But the older mare might lose her ability to evacuate that material.
Instead, the inflammatory fluid can remain there for days and lead to a secondary infection and chronic endometritis.
Another reproductive problem occurs in the oviducts, says McCue, which are lined with hairlike cilia that transport the egg and sperm. An accumulation of debris, such as cells and fibrin strands from previous ovulations or pregnancies, can block these tubes and prevent the egg, sperm, or developing embryo from passing. Pinto says problems might include worsening perineal conformation, such as vulvar defects, vulvar slope, urine pooling in the vagina also known as vesicovaginal reflux , and windsucking, as well as cervical defects.
Poor body condition can exacerbate this. These include:. The myometrium is the smooth muscle tissue of the uterus. The surgeon must remove the sutures before breeding and resuture them after and about 30 days before the expected foaling date to avoid damaging the reproductive tract.
Ovulation-inducing agents One technique that can help prevent endometritis, says McCue, is the administration of an ovulation-inducing agent to help direct when ovulation will occur. Veterinarians can then optimize timing for insemination, uterine lavage, or oxytocin administration after breeding to remove any accumulated uterine fluid, and administration of progesterone to help support the ensuing pregnancy. Oocyte transfer During this procedure, which is useful for older mares that can no longer produce embryos, the veterinarian sedates the mare in heat and passes a special ultrasound-guided probe with a gauge needle through her vaginal wall and into her ovary to aspirate the oocyte and follicular fluid from a pre-ovulatory follicle.
The recipient mare must either be cycling or treated with hormones to mimic a natural cycle. The veterinarian then inseminates that mare. Embryo transfer This service, useful for mares with reproductive disorders that prevent them from carrying foals to term or who are too old to risk delivering, requires two main procedures, says Pinto.
Pinto says this procedure is relatively uncommon and mainly performed in specialty clinics because of the laparascopic approach necessary, and he notes the success rates for older mares are low. In recent years the tools and assisted reproductive techniques available to veterinarians trying to get older mares pregnant have improved greatly.
Because these technologies are expensive and time-consuming, mare owners need to be aware of their success rates and determine if possible offspring justify the attempt.
And before selecting an approach, be sure your particular breed registry permits it. Hinrichs, along with her research group, cloned the first horse in North America and the third in the world. She describes some of the high-tech breeding services owners faced with declining mare fertility might pursue. Many breed associations will not register clones or their offspring. For instance, the American Quarter Horse Association recently won a legal battle on the subject and will not have to register clones.
However, some stud books, such as Zangersheide in Europe, will register cloned horses. The embryos are then transferred to recipient mares. Oocyte recovery from mares that are dying or will be euthanized This is a final chance to produce foals from a valuable mare. The veterinarian removes the ovaries from the mare just before or immediately after death or euthanasia and handles the oocytes similarly to those recovered from live mares.
Embryo vitrification This method of cryopreserving freezing embryos extends the breeding season for older mares. These mares often only cycle toward the middle of the natural breeding season, says Hinrichs. Using this method, embryos collected in the late summer or fall can be cryopreserved and then transferred in the spring. Treat each older broodmare as an individual, work with a good veterinarian, learn about possible problems, and practice good management. For instance:.
Breeding Older Mares Are you thinking about breeding an older mare next spring? Favorite Share:. Cycling Abnormalities Mares are seasonal breeders, meaning they only cycle naturally during a particular time of year so that they will deliver foals, ideally, in temperate weather. Carlos Pinto. Is It Worth the Cost? Acute or Chronic Endometritis An important cause of embryo loss during early gestation is persistent post-breeding endometritis. Oviduct Issues Another reproductive problem occurs in the oviducts, says McCue, which are lined with hairlike cilia that transport the egg and sperm.
Improved Reproductive Technology In recent years the tools and assisted reproductive techniques available to veterinarians trying to get older mares pregnant have improved greatly. Take-Home Message Treat each older broodmare as an individual, work with a good veterinarian, learn about possible problems, and practice good management.
For instance: Before committing to a breeding program, schedule a reproductive exam to find out if your mare has any issues. Stay on top of general herd health and the health of the older mare. That includes vaccinations, deworming, nutrition, and dental care so she can maintain her body condition, says McCue. The mare needs to ovulate on schedule and likely requires post-ovulatory exams and uterine lavages. Consider any arthritis, lameness, nutritional, or overall health issues the mare has.
Decide whether you want to consider assisted reproductive techniques. About The Author. Maureen Blaney Flietner.
As an aside, I usually have a discussion with breeding managers about the stallion and the semen availability of their chosen stud. Weekly Poll:. Do you clip your performance horse during winter? Quarter Horse Markings and Color Genetics. Using this method, embryos collected in the late summer or fall can be cryopreserved and then transferred in the spring. Journal Rates: Breeder.
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Older mare. How old is too old to breed? - Chronicle Forums
Jonathan F. Pycock looks at common issues affecting older mares who are being bred for the first time. Despite never being bred before, many older maiden mares are susceptible to post-breeding endometritis. It is particularly important to recognize and manage appropriately these mares. Many times, mares that have had a showjumping or dressage career may not be presented to be bred until they are in their teens, and these older maiden mares can be very difficult to get in foal.
Many of these mares have some common characteristics that resemble a syndrome. Endometrial biopsy samples reveal glandular degenerative changes and stromal fibrosis endometrosis as an inevitable consequence of aging, despite the fact they have not been bred. Another common characteristic of these mares is uterine fluid. An older maiden mare often has an abnormally tight cervix that fails to relax properly during estrus; as a result, fluid is unable to drain, and it accumulates in the uterine lumen.
In many cases, this fluid is negative for bacterial growth and presence of neutrophils PMNs. After the mare is bred, the fluid accumulation will be aggravated because of poor lymphatic drainage and impaired myometrial contraction compounded by the tight cervix. Endometriosis in mares Reduced fertility associated with fluid accumulation has been recognized for many years in broodmares.
This subfertility is caused by an unsuitable environment for the developing conceptus within the uterus, and in some cases, the ensuing endometritis persists and causes early regression of the corpus luteum CL. Persistent mating-induced endometritis has come to be recognized as a major reason for failure of conception in mares.
To maximize the fertility of these mares, it is vital that the veterinarian is aware of the possibility of this type of uterine and cervical pathology. Recently, endometrial vascular degeneration has also been considered a contributing factor in the delay in uterine clearance. Diagnosis can be difficult, because there may only be subtle changes in the uterine environment that are not readily detected by current diagnostic procedures.
Many mares show no signs of inflammation before breeding but will fail to resolve the inevitable endometritis that follows mating. Response to bacterial challenge has been used in a research setting. Demonstration of clearance failure using scintigraphic and other methods based on charcoal clearance has been used to make an accurate diagnosis of a mare that has a clearance problem, but they are difficult to apply in practice. Ultrasound detection of uterine luminal fluid has proved useful in identifying mares with a clearance problem.
The presence of free intraluminal fluid before breeding strongly suggests susceptibility to persistent endometritis. The mare may then need to have a large-volume uterine lavage before breeding. Significant intrauterine fluid present in the early post-breeding period h after breeding may also be an indication of poor uterine clearance. Intrauterine fluid during diestrus is indicative of inflammation and associated with subfertility because of early embryonic death and a shortened luteal phase.
The aim of the treatment should be to assist the uterus in physically clearing the normal inflammatory by-products of the response to breeding. Both coitus and artificial insemination can be a source of uterine inflammation.
It is well known that spermatozoa are responsible for initiating a marked inflammatory response that leads to a persistent endometritis in susceptible mares.
Therefore, susceptible mares should only be bred one time, regardless of whether natural mating or artificial insemination is used. Within 4 h of mating, the spermatozoa necessary for fertilization are present within the oviduct. Progesterone concentrations rise rapidly after ovulation, and it is preferable to avoid treatment involving uterine interference after 2 days post-ovulation.
The successful management of older mares should logically require some form of post-mating therapy such as uterine lavage, IV oxytocin, or intrauterine antibiotic infusion. These therapies may be used alone or in combination. For the susceptible mare, treatment should be implemented in the post-breeding period rather than after ovulation.
In the period between breeding and ovulation, the susceptible mare frequently accumulates a large volume of fluid, and bacteria are in a logarithmic phase of growth. Therefore, expedient treatment of these mares is critical to fertility. Oxytocin is the ideal method of treatment; it is a non-invasive technique and frequently provides early and complete elimination of any intrauterine fluid. The beneficial effect of oxytocin is widely accepted.
Oxytocin stimulates uterine contractions in the cyclical, pregnant, and post-partum mare. This therapy was first suggested to promote uterine drainage in mares with defective uterine clearance by Allen. Oxytocin is now widely accepted as an effective therapy in aiding mechanical clearance mechanisms and improving fertility.
In a recent study in reproductively normal mares, Paccamonti et al. Mares were given oxytocin 10 or 25 IU, IV on the day of or 2 days after ovulation. Neither dose of oxytocin nor day of treatment affected the half-life of the exogenous oxytocin. Larger doses of oxytocin 25 IU have been associated with a decreased pregnancy rate; however, this dose is frequently used in clinical practice, and no other studies have reported this finding. Smaller mares are given 15 IU of oxytocin.
Two IM injections of 0. Uterine lavage is a useful tool to aid in the mechanical evacuation of the uterine contents. The fluid is then siphoned out of the uterus by gravity flow. This process is repeated two to four times or until the effluent is clear. The optimum time for uterine lavage therapy in highly susceptible mares was found to be between 4 and 6 h in a study by Knutti et al. Eighteen barren mares with a mean age of 15 were selected. In nine mares, the standard protocol was repeated control.
Twice as many mares with the early lavage were pregnant compared with the group of mares not lavaged until h after insemination. In our practice, known susceptible mares are routinely lavaged the day after breeding. Mares believed to be highly susceptible to endometritis based on history or fluid accumulation should have the lavage performed within h. On one hand, Cadario et al. On the other hand, cloprostenal caused the uterus to contract for a longer time 5 h than oxytocin 45 min.
Cloprostenol is indicated in mares that have lymphatic stasis as shown by excessive edema within the endometrium or large lymphatic cysts. The infusion of broad-spectrum antibiotics after breeding is controversial. However, this was a controlled experimental-type situation in which a single bacterial species usually streptococci was infused into the uterus, and lavage treatment was performed at a fixed time within 12 h of mating.
Under live mating conditions, there is a mixed bacterial contamination, and lavage cannot always be performed within 12 h. For these reasons, the author prefers to use intra-uterine antibiotics as part of the therapeutic protocol.
The treatments have different effects on the uterus: the uterine lavage provides mechanical evacuation of intraluminal fluid and inflammatory products, whereas the single infusion of broad-spectrum antibiotics should prevent any growth of bacteria introduced during insemination or uterine lavage. Therefore, they cannot be compared with healthy mares used in experiments. Routine administration of intrauterine antibiotics has no negative effect on the pregnancy rate of treated mares.
Samper, J. Pycock and A. McKinnon, Saunders Elsevier. Email jonathan pycock. Pycock, This article, first published on Horsetalk. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment.
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