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.
The Equine Gut Microbiome
The gut microbiome has become a popular topic of interest in recent years as scientists are beginning to understand the vast impact it can have on overall health and development in both humans and animals. A microbiome is defined as the collection of genomes of the microorganisms that reside in a specific environment . In regards to the gut microbiome, it is comprised of the genetic material of the microbes that inhabit an organism’s gastrointestinal system. In the horse, this microbiome includes bacteria, yeast, fungi and protozoa where the most functionally important microorganism is thought to be bacteria. Researchers have studied how this microbial community can affect not only the digestive tract, but also the immune response, endocrine system, behavior and even cognitive function.
Endocrine Diagnosis of Infertility in the Stallion
Diagnosis of infertility in stallions usually starts with a complete reproductive history and then collection of semen to evaluate seminal parameters, testis size and the potential presence of bacteria in the semen. A more detailed evaluation might also include drawing blood for hormonal analysis.
Measuring Hormone Levels in Mares
Endocrine diagnostics certainly have a place in the routine management of mares and stallions as well as in diagnosis of problems and diseases. However, there are likely more applications for measuring hormones in mares than stallions. Dr. Ed Squires will discuss the hormones tested in mares in this article and will then cover the testing of stallion hormones in a subsequent article.
Methods to Obtain the Concentration of Sperm in a Stallion Ejaculate
Knowing and keeping track of the concentration, or the number of sperm per milliliter, of each ejaculate for a stallion is very important for a variety of reasons. The concentration of his semen, along with the volume of his ejaculate, is used to determine the total number of sperm he produces in a given collection. These two numbers (volume and concentration) are used to calculate insemination doses. Also, keeping a record of each number can help stallion managers recognize if there are any changes in the reproductive health of the stallion. Slight variations are likely nothing to be concerned about. However, if the number of sperm in the ejaculate varies drastically, from collection to collection or a steady decrease in his total number of sperm over time, one may begin to ask what is causing the change. This information is valuable so that any concerns can be addressed as soon as they arise.
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.
Management of Late Gestation Pregnancy Loss in the Mare
Breeding season in the northern hemisphere is over and hopefully all mares are in foal. Waiting for the arrival of the foals next year has begun. But what if something goes wrong? Abortion after day 45 of gestation occurs up to 3 to 15% in different horse populations. Infectious and non-infectious causes can be involved. It is important, that as long as the etiology of the pregnancy loss is undetermined, every abortion should be assumed as infectious until proven otherwise. How do you best handle the situation when a mare aborts and how do you prevent further damage to the mare or her fellow broodmares?
The Major Causes of Damage to Sperm During Freezing…water and salts and ice, oh my!
I have always been fascinated by the exquisite design of biological systems. The more we humans understand about biology, the more we realize we don’t know. The process of mammalian fertilization is one of these complex biological systems that in nature requires the proper coordination of so many factors ranging from the behavior of male and female to biochemical changes at the cellular and molecular level. Defined as: “A process in sexual reproduction that involves the union of male (sperm) and female (ovum) gametes (each with a single, haploid set of chromosomes) to produce a diploid zygote”, fertilization requires that functionally viable sperm, at the right stage of maturity, are present in the oviduct of the mare during a brief window of time when a functionally viable oocyte is present.
Trends in Equine Assisted Reproduction
It has been almost 20 years since I started an assisted reproduction program at Colorado state University. The purpose of that program was to develop techniques to preserve equine genetics. It is beyond the scope of this article to discuss all the goals of that program but I would like to focus on production of foals from old mares and stallions via in vitro technology (aka test tube horse).