Thank you to Dr. Pat McCue from the Equine Reproduction Laboratory for last month’s article, Progesterone Therapy for Pregnant Mares – Part 1, in which he reviewed the formulations and use of progesterone therapy in mares. Dr. McCue did a yeoman’s task in outlining the formulations and principles of therapy available to veterinarians for the suppression of estrus, pregnancy support, and treating cases of suspected or diagnosed placentitis. However, the maintenance of pregnancy is by far the most common area in which we receive questions about supplementing mares with exogenous (therapeutic) forms of progesterone.
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Progesterone Therapy for Pregnant Mares-Part 2: Common Questions
Progesterone Therapy for Broodmares: Part 1
In preparation for our annual SBS Affiliate meeting, I was speaking to Dr. Patrick McCue (my friend and mentor and honored guest speaker this year’s meeting) about the commonality of questions I have from clients. By far, the most discussed topic is supplementation of progesterone to pregnant mares to help them maintain a pregnancy. Many times, the questions stem from the necessity of such therapy, duration, and efficacy of supplementation. Sometimes, even with the best therapy, we fail to reach a good outcome, but the following discussion about the forms of supplementing progesterone is well worth a quick read for any breeder.
Care of the Newborn Foal
What transpires in the first 24 to 48 hours of a foal’s life is critical to his health and well-being from early life and up through weaning. As a foaling attendant there are several “milestones” to keep in mind as you watch the behavior of both the baby and the mare post-foaling. In this article we discuss the milestones they both should make within the few hours after the foal’s arrival into his new world. The care delivered, attention to detail, and respect for the nature of the horse will help set up your foal up for a healthier adolescence.
Oxytocin Use in the Mare
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.
How to Manage the 'Slow' Stallion in the Breeding Shed
Juvenile and older males entering a new career as a breeding stallion don't have the luxury of a changing cascade of hormones or an event like parturition to jumpstart their innate nature to show them how to be a stallion. There is likely only a change in routine, location, or in their training schedule that cues them into their new roles as breeding animals. Many stallions make the transition seamlessly. Simply acting on the behavior they have been trying to use for years, allowing their behavior to mimic their springtime rise in testosterone. When exposed to a female, they have little doubt about the job at hand and will readily take to live cover or phantom training. Additional information for training the young stallion for collection can be found in our article, Collecting Semen from the Young Stallion. However, for some, the transition proves far more difficult and oftentimes frustrating for the stallion and for the staff at the shed.
How to Prepare the Older Mare for Breeding Season
Older mares have a knack for being the sweetest and gentlest mares on the farm. We see them year after year, either carrying their own foals or returning to donate embryos if their reproductive status requires. Oftentimes, these mares are considered “special” patients, requiring a unique combination of diet, exercise, and metabolic support to maintain their physical and reproductive health. We often see older performance mares that are being bred for the first time following a long and successful show career. Reproductive problems such as cervical adhesions and uterine infection can be common in older mares which affect their ability to carry a foal or donate an embryo.
Cryopreservation of Equine Embryos
Embryo vitrification doesn't sound much like "freezing embryos,” but the end product certainly is a cryopreserved equine embryo, frozen in liquid nitrogen for the preservation of genetics and transfer into a recipient mare at a later time. For the sake of some readers of this blog, an embryo is the result of fertilizing an oocyte (egg) with sperm and allowing the initial stages of development to occur. Embryo vitrification is the process whereby we freeze equine embryos for storage for indefinite periods of time prior to transfer into a recipient mare. We have the technology to cryopreserve equine sperm and equine embryos, but not equine oocytes. Herein lays the answer to the most common question that comes up in conversation regarding this blog topic. Some readers assume that since we can freeze the male generated sperm, we can likewise freeze the female generated oocyte. Unfortunately, due to some very sensitive cytoskeletal components in the oocyte, the technology does not exist to freeze equine oocytes. As we proceed, you will understand the process of embryo vitrification and we will delve into areas of research that are improving the success rates of vitrified embryos in generating live foals.
Why Freeze Equine Embryos?
What is Short Cycling a Mare?
It seems daily that I am asked by clients to bring a mare into heat at a desired time to facilitate breeding, show schedules, stallion availability, synchronization with other mares, maximize early season breeding dates, or line up recipient mares with donor mares. For such a common request, and in fact, a common procedure, there are certain cases when knowing the nuisances of manipulating the length of diestrus in the mare can make or break the overall success of a reproductive cycle. In this blog article Dr. David Scofield reviews the process of short cycling mares.
Progesterone and Estrogen Therapy (P&E)
Managing the equine estrous cycle is a common procedure performed by many broodmare managers and veterinarians. Copious research has elucidated many aspects of the equine estrous cycle and allowed veterinarians the tools to manage a mare’s cycle to provide the optimal breeding times, effectively use artificial insemination, induce ovulation, synchronize mares, induce superovulation, advance the onset of the breeding season, terminate pregnancy, as well as a manage a host of other reproductive conditions and diseases. In this article Dr. David Scofield reviews the use of progesterone and estradiol (P&E) therapy in the mare.
How to Find a Good Equine Reproduction Veterinarian
Owning an animal, be it a household pet, horses, or livestock can be wonderfully rewarding. There are times, however, when the responsibility of animal ownership requires the consultation of a veterinarian to ensure the health and well being of your animals or livestock. Most of these appointments will be for routine care, whereas other visits may require specialized services, like lameness diagnosis, surgery or reproductive management. Many horse owners use different veterinarians or vet clinics depending upon the services they require. However, those in more isolated or rural areas may be limited to a general practice veterinarian who routinely works with all species, being neither an equine or reproduction specialist. A breeder can still be equally successful in both situations, so long as they are prepared and have done their research to find the best veterinarian available to suit their needs.