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Since artificial insemination is currently practiced in most equine breeds (except Thoroughbreds), processing semen for cooling and transport is a common task in most equine reproductive centers. However, processing a dilute ejaculate--one with a relatively low concentration of sperm--requires modified procedures to get enough viable sperm in each breeding dose. At the 2008 American Association of Equine Practitioners convention, held Dec.6-10 in San Diego,...
In all species, penetration of the oocyte by sperm requires motility, intact receptor proteins on the sperm to bind to the zona pellucida, and the ability to undergo an acrosome reaction and bind to the plasma membrane of the oocyte. Different in vitro penetration assays have been developed to address each of these attributes [35]. Zona pellucida (ZP) sperm binding Zona penetration assays evaluate sperm motility, zona binding and penetration, sperm...
Can we select against insect bite hypersensitivity?
Insect bite hypersensitivity (IBH) is the most common seasonal recurrent allergic skin disorder in horses, caused by bites of certain Culicoides species. IBH causes an intense itch, which results in self-inflicted trauma. The welfare of affected horses is seriously reduced and some affected horses are even unsuitable for riding or showing purposes. Horse owners encounter economic losses due to...
As breeding season begins Dr. James Brendemuehl, an equine veterinarian at the University of Illinois Veterinary Teaching Hospital in Urbana, is often consulted about broodmare health. Dr. Brendemuehl explains that nutrition is key to ensuring a healthy pregnancy. Proper nutritional support of broodmares improves fertility and promotes normal growth and vigor of the developing fetus. During the first 8 months of gestation, mares' energy needs are the same as those for...
The only horse semen extender that operates at ambient temperature has been developed and released by Tolga Ltd. The new EquYX © extender, currently available for breeders, requires no refrigeration in storage or shipping. Horse semen extended with EquYX © may be kept at room temperature or in the fridge and can withstand temperature swings from 0°C to 38°C (32°F to 100°F)....
Chromosomes are large segments of DNA wound around special proteins within each cell's nucleus. They contain nearly all of the body's genetic material. Horses have 64 chromosomes (or 32 pairs) including the two sex chromosomes (XY in males and XX in females). The sire and dam each contribute 32 chromosomes to their offspring. Modern cytogenetic methods enable the identification of all 32 pairs of chromosomes based on their unique features. The features of each chromosome pair are compared in...
Q: My mare acts up when she is in heat. We aren't planning on breeding her so we are considering having her spayed. What are our options?
A: You do have a few options. However, it is important to make sure the ovaries are the cause of the behavior problem. Medical treatment involves adjusting her hormones so she doesn't come into heat. The most commonly used drug is progesterone (Regumate®) . Inserting an...
Few things in this world are more awe inspiring than watching a broodmare give birth. The anticipated foal, which began as an idea of mating just the right sire and dam bloodlines, will represent not only his ancestry but also the knowledge and skill of his breeders, owners and trainers.
However, the decision to breed your mare should not be taken lightly. There are many considerations that need to be taken into account before making the commitment to breed your mare and raise the...
The placenta from each foaling mare should be examined for completeness shortly after foaling (1). If a section(s) of placenta remains in the uterus, infection (endometritis, pyometra) and toxemia (resulting in laminitis) may result. Persons inexperienced at looking at the mare's placenta may mistake normal structures as lesions.
The mare's placenta is made up of two distinct membranes, the amnion, the opaque membrane which immediately surrounds the foal, and the chorioallantois...
Researchers from the University of Queensland have found hairy caterpillars are responsible for causing abortions in Australian mares. Dr Judy Cawdell-Smith and Professor Wayne Bryden, from UQ's School of Animal Studies, found mares exposed to processionary caterpillars were likely to miscarry. "This is an unusual form of abortion that was first reported in Australia in 2004 and is similar to a condition reported in Kentucky in 2002," Dr Cawdell-Smith...
The skeletal anatomy of a horse's front and hind limbs is comparable to the anatomy of the human hands and feet. The horse's cannon bone, or metacarpal, is the same as a bone in the palm of a hand. The human phalanges, or finger bones, are comparable to the bones making up a horse's hoof and pastern. Fortunately, most humans and horses are born with normal limbs. However, both children and foals can be afflicted with contracted limb abnormalities. When a child is born with...
Mares are long-day breeders. This means that the majority of mares in temperate climates are stimulated to come into heat by increasing day light. Their normal ovarian cycle peaks in May to June. Most mares do not cycle during the shorter days of fall, winter and early spring. As day length increases in late spring, mares enter a transition period. This is the time when the ovaries return to cyclic activity by producing eggs or follicles. During transition, the follicles do not always ovulate...
As a mare owner, cooled semen gives you access to stallions all over the country, and to some extent internationally. In addition to the stud fee, most stallion owners charge fees per shipment, typically $250 and up, making it within your interest to only ship once per cycle when possible. Since cooled semen is only viable for about 48 hours after collection, in order to achieve a single shipment breeding you need to closely monitor your mare and have a clear understanding of the...
Many stallions are being retired from racing, showing and performance to enter the breeding shed. Their value as potential breeding animals is based more on exceptional performance than on their ability to sire foals. Reports indicate that at least 11 percent of breeding stallions are subfertile or infertile (Rossdale and Ricketts, 1980), contributing to the low conception rate of 60 to 65% generally observed in the horse industry today. When is a stallion fertile, subfertile or...
If you own a horse used for breeding or manage a breeding farm, there are certain things you should check for after each use, particularly with natural cover. Call your veterinarian if the stallion has: blood on the penis, damage to the penis, a swollen scrotum and/or colic. While you wait, safely try to figure out where the blood is from (the mare needs to be checked also), take vital signs that you are comfortable with, and if the penis is out, apply cold water using the...
Not having your mare in optimal condition to conceive when you are ready to breed her results in lower fertility, frustration, and financial losses that can extend through this season and into the next. The critical things to check for are: is she having regular heat cycles, does she have a uterine infection, and is she in good body condition? Her maintenance healthcare including vaccinations, deworming and preventative dental work should also be reviewed and updated several weeks before...
Horse producers face many decisions that require them to understand the foaling process and the needs of newborn foals. Parturition in the Mare Gestation Length The normal gestation length of mares ranges from 320 to 380 days with an average of 338 to 345 days. Gestation length will be variable between mares and even the same mare from year to year. Gestation lengths shorter than 320 generally are considered...
Confusion often surrounds the terminology used to describe birth defects in horses and other animals. The terms “congenital” and “genetic” are used interchangeably by many. Actually, “congenital” merely refers to any defect present at birth. It may indeed be due to a genetic or inherited problem, but it also describes defects due to non-genetic causes, such as developmental problems caused by toxins, infection, poor uterine environment, or malposition. Genetic defects include anything that is...
The placenta provides protection for the fetus and regulates the fetal environment. Previous work in the United Kingdom has examined placental parameters associated with normal births. A study was undertaken in the Central Kentucky area by veterinarians from the Hagyard Equine Medical Institute to examine placental parameters associated with foals making a normal transition to extra-uterine life. This study comprised observations from 168 foalings during a two-year period on three farms....
Experts report that eastern tent caterpillars are now wandering and population levels are among the highest they’ve seen since the 2001, when Mare Reproductive Loss Syndrome (MRLS) hit Central Kentucky particularly hard. “The eastern tent caterpillar populations are dramatically up this year -- the highest I’ve seen since the MRLS crisis. The larvae are full size, many trees are totally defoliated and I’ve seen very large numbers of caterpillars moving along fence rails and...