Equine protozoal myeloencephalitis (EPM) is the most prevalent cause of neurologic disease of horses in the Americas (North, Central and South America). It is an extremely serious disease that can be difficult to diagnose due to the fact that its pre …

Early and accurate diagnosis of pregnancy in the mare is critical in determining her reproductive viability during the breeding season. Once a mare has been determined to be pregnant, her embryonic growth and fetal development may be accurately monit …

Shivers is a neuromuscular syndrome in horses that has been recognized for centuries.1 At certain times, this condition has been called “Shivers” or “Shivering,” but both refer to the same syndrome. Interestingly, the literature states that throughou …

People who love horses tend to really love horses, and that goes triple for the horse owner who has decided to move forward with breeding their mare. Whether it’s an individual horse owner with a prized mare or a breeding operation of pretty much any …

The gestation period of the mare is less well-defined as compared to many other mammals. In other words, the window for parturition in the mare is much broader than that of other mammals. Mares are seasonally polyestrus, which means that their breedi …

In relation to horses, and performance horses in particular, the word “fatigue” is typically used to denote a horse’s inability to continue to perform at the desired level. This may manifest as slowing down, not being able to jump as high as is opti …

As discussed several times in this space, mares seasonally polyestrus, which means that their estrous cycles depend on the season. A mare will undergo regular estrus cycles during late Spring, Summer and early Fall, and none during Winter. It is larg …

Many mares posses the bona fides that warrant breeding, such as good temperament, conformation, bloodlines and talent, but age is also a very important consideration. Despite the fact that it isn’t at all uncommon to find mares bred during their 20s, …

Horse owners and managers commonly report muscular fatigue of horses. Muscular fatigue can be caused by numerous disorders of several body systems, or it can be a function of (or a normal consequence of) prolonged exercise. The decreased ability of …

How long is a horse pregnant? Well, the short answer is 10 to 12 months, or from approximately 326 days to 354 days (although there have been cases where gestation for a mare has gone as long as 365 to 370 days). Most mares only carry one foal per pr …

Estradiol is a medication and naturally-occurring steroid hormone. It is an estrogen and is used mainly in hormone therapy. Estrogen therapy is currently being used widely by veterinarians treating intermittent upward patellar fixation (IUPF) in hors …

Clenbuterol HCl is a beta-2-adrenoceptor agonist; it is the only FDA-approved medication for horses with reversible bronchospasm and is often used to treat horses with inflammatory airway disease (IAD) and recurrent airway obstruction (RAO, commonly …

Standing sedation is a critical component in many key procedures done on-site and in the equine veterinary clinic. When choosing between the available sedation drugs, veterinarians must consider safety, cost effectiveness for the client and the pract …

Clenbuterol hydrochloride is a β2-adrenergic agonist that is used in horses as a short-term bronchodilator. In the short-term, it is typically employed in the management of airway obstruction (eg, severe equine asthma [SEA], formerly known as recurre …

Xylazine hydrochloride, an α₂ class of adrenergic receptor, has long been used for sedation, anesthesia, muscle relaxation, and analgesia in animals such as horses, cattle and other non-human mammals. In horses however, adverse effects included muscl …

Clenbuterol is a β2-adrenergic agonist that is used in horses as a short-term bronchodilator for the management of airway obstruction and for chronic breathing ailments in horses such as Chronic Obstructive Pulmonary Disease (COPD, also known as "hea …

Long ago, veterinarians discovered that there are many surgical and other medical procedures which can be carried out in standing horses if the appropriate combinations of physical and chemical restraint are employed. The ability to perform procedure …

Estradiol Cypionate is a pro-drug ester of Estradiol, a naturally occurring hormone that circulates endogenously within the human body. Estradiol is the most potent form of all mammalian estrogenic steroids and acts as the major female sex hormone. A …

Estradiol is a medication and naturally-occurring steroid hormone. It is an estrogen and is used mainly in hormone therapy. Estradiol cypionate (ECP) is used to induce estrus in horses. It is also used by veterinarians to treat estrogen-responsive in …

Diclazuril is a triazinone antiprotozoal that is effective for treating infections caused by Isospora spp., Toxoplasma gondii, and Eimeria spp. and has been used for treating coccidiosis.1 Initially, diclazuril was approved in Europe and in the U.S. …

Clenbuterol is a substituted phenylaminoethanol and a long-acting beta-2 adrenergic agonist with sympathomimetic activity. Pharmacologically, clenbuterol selectively binds to and activates beta-2 adrenergic receptors in bronchiolar smooth muscle, the …

Equine Protozoal Myeloencephalitis (EPM) is a neurologic disease in horses caused by infection with the protozoan Sarcocystis neurona. The parasite infects horses when they ingest the S. neurona organism in contaminated feed or water. The definitive …

Sarcocystis neurona is a protozoan apicomplexan parasite that causes the neurological disease equine protozoal myeloencephalitis (EPM) in horses residing in the Americas.1 EPM is considered to be the most serious infectious neurologic disease of hors …

Veterinarians first described the set of symptoms that would come to be known as equine protozoal myeloencephalitis (EPM) in 1968.1 In the 1970s, researchers determined that this this devastating neurologic illness was caused by a protozoan, although …

Diclazuril is a triazinone antiprotozoal that is effective for treating equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona. It is also used in treating infections caused by Isospora spp., Toxoplasma gondii, and Eimeria spp,1 and a …

Equine protozoal myeloencephalitis (EPM) continues to frustrate North American horse owners and veterinarians as one of the most common neurologic diseases in horses–and one of the most challenging to diagnose and treat.1 (EPM) is caused by the proto …

Equine protozoal myeloencephalitis (EPM) is a disease of horses that affects the central nervous system. The primary causative agent for EPM is Sarcocystis neurona, a protozoan organism. The disease was described in the 1960s as segmental myelitis. B …

Based on the available literature, the most favorable age group for breeding horses is with mares between the ages of 4 and 12. Once the mare surpasses the age of 12—and particularly if it’s a maiden mare—the conventional wisdom dictates that issues …

Many horse owners have come to their equine veterinarian or favored expert with the same question: They have a wonderful mare that they're thinking about breeding, but they're afraid she might be too old. Perhaps she's always been healthy, but they d …

Many horse owners have entertained the notion of breeding their own prized mare. The idea of producing a foal with traits similar to its mother (or superior to its mother) can be very attractive. It is advisable that the novice horse breeder is a …

On horse farms, the breeding shed is perhaps the most important place for accurate recordkeeping.1 Understanding as much as possible regarding the mare's breeding cycle can give horse owners and breeders an edge with regard to achieving their b …

Given the wear and tear so many horses undergo as a result of their lifestyles (and, to be fair, ours), the field of veterinary medicine is continually searching for novel medications and new methods for pain relief in horses. "Managing pain in h …

Muscle strains resulting in soreness can occur in a muscle or any group of muscles in the horse. Apart from serious injury, arthritis or other degenerative joint diseases (DJDs) however, back soreness is one of the most prevalent chronic issues i …

Whether it's the manager of a breeding operation with numerous horses and a schedule to keep, or someone with a beloved mare they'd like to see pass on their genes for the next generation of equestrians in the family, the question of when a mare …

Unlike most of the domesticated animals with which humans interact (dogs, cats, birds and the like), horses are often called upon to perform very hard work. Due to the nature of the activities in which horses engage, and in which many people enjo …

What horse owners and breeding managers would give for a resource or utility that would allow them to precisely predict the day a mare will ovulate! While there are numerous online resources and charts that can reliably predict parturition based …

Gastric ulcers are common in horses and can affect any horse at any age. In fact, the prevalence of gastric ulcers in horses has been estimated at between 50% to 90%, depending on the populations surveyed and type of activity in which the horse i …

Despite their relatively long gestation period of 335 to 360 days, horses have the potential for fairly high reproductive performance.1 Understanding as much as possible regarding the mare's breeding cycle can give horse owners and breeders an ed …

A working knowledge of the mare’s reproductive anatomy and physiology is essential in a horse breeding program. Familiarity with the mare's estrous cycle and the timing of events therein is equally important. These provide the basis on which all …

Even occasional equestrians—those who ride recreationally at the local stable or farm every now and then—can attest to the fact that running into a horse with a nervous disposition is extremely common. Sometimes, a horse's nervousness is apparent …

Due to the demands placed upon horses that have to work for a living, there is a wealth of information available regarding how to manipulate the mare's cycle in order to keep her out of heat.Typical signs that a mare is in season include holding …

The direct administration of anti-inflammatory drugs into joints to provide relief from discomfort remains a common practice in many sectors of the equine industry. Unfortunately, many of these medications are corticosteroids, which have become c …

Mares have a gestation period of about 340 days. Because of this relatively long pregnancy, they must become pregnant again shortly after giving birth in order to produce a foal at about the same time each year if this is desired by the owner or …

Equine protozoal myeloencephalitis (EPM) is a disease that affects the central nervous system of horses and which is caused by the protozoal organism. The name given to the protozoan organism shown to be the primary causative agent for EPM is Sarc …

Mares cycle when days are long and there is abundant daylight during most of the day, meaning that under normal circumstances, they cycle in the Spring, Summer and Fall. Mares do not cycle in Winter when daylight is short; this is known as anestr …

Equine protozoal myeloencephalitis (EPM) is a disease of the horse that affects the central nervous system. Equine obviously refers to the horse, protozoal refers to the type of organism that causes the disease and myeloencephalitis refers to tha …

Horse owners and breeders are continually on the lookout for ways to help improve their mares’ chances of becoming pregnant. One way that veterinarians are able to help is by administering prostaglandins.1 There are several forms of prostaglandin …

Generally speaking, the best time for mating of a mare and stallion is determined by several factors. These include the length of daylight (season), the daily temperature, the mare's general health, diet, the amount of rainfall, the climate, and …

Horse owners, managers and veterinarians are frequently faced with a need to to calm excitable horses or to provide relief from minor pain, or to facilitate minor or minimally-invasive procedures such as bronchoscopy, bronchoalveolar lavage, naso …

Mares are seasonally polyestrus; this means that they experience regular estrus cycles during late Spring, Summer and early Fall, with none occurring during the Winter. The typical mare cycles regularly between March and October, with each estrou …

There is a wide variety of pain relievers available for horses that can help alleviate pain and discomfort associated with injury or daily exercise, and enable easier, prompt treatment of the problem at hand.Methods of managing pain in horses ran …

During the fetal development of the mare itself, a pool of primordial follicles forms as ovarian tissue, and each follicle consists of prophase I oocytes surrounded with a single layer of flattened granulosa cells.1 By the time the mare reaches s …

Since mares are seasonally polyestrus, they experience regular estrous cycles during late Spring, Summer and early Fall, and none during the Winter. These cycles are controlled by hormones, which respond to increases or decreases in daylight dura …

Altrenogest is a progestational drug used in horses to suppress estrus or maintain pregnancy when progestin deficient. It is also used in pigs to synchronize estrus, and may be used in dogs for luteal deficiency or to prevent premature delivery …

The ovarian follicle is a fluid-filled sac surrounded by a group of cells that protect and nourish the ovum (egg). There are thousands of follicles in a mare’s ovaries, but usually only one begins to develop during each estrous cycle.1 By Day 16 …

In the case of a performance mare—one which races, for example—the reasons for preventing such a horse from coming into heat may be self-evident. The sort of behaviors often exhibited by mares in estrus—stamping, vocalizing, nipping, tail-swis …

"Even the quietest of mares can turn into a proverbial fire-breathing dragon during her estrous cycle, which can make riding, training, competing, or handling these horses a challenge for any equestrian."1 Fortunately, over the years, veterinaria …

The fact that the horse is seasonally polyestrous makes this species a reproductive challenge for horsemen and equine practitioners. Mares will show several estrous cycles during the breeding season, assuming pregnancy does not terminate estrus. …

A significant segment of the equine industry is involved with the breeding and of mares and the management of their breeding cycle. Given the sheer numbers of animals involved, this means that the economic considerations make it absolutely necess …

The estrous cycle (or oestrus cycle) is the group of physiological changes that occur in sexually mature female mammals which are brought on by reproductive hormones. The changes facilitate fertility and reproduction.Horses (mares) are seasonally …

Mares are seasonally polyestrus, meaning that they experience regular estrus cycles during late Spring, Summer and early Fall, and none during the Winter. These cycles are controlled by hormones, which respond to increases or decreases in dayligh …

Gonadotrophin-releasing hormone (GnRH) is a hormone produced by the hypothalamus in response to an increase in day length. As the hours of daily sunlight (or photoperiod) increase, melatonin levels subside, allowing GnRH to be produced. Productio …

Altrenogest is a progestin of the 19-nortestosterone group commonly used to suppress or synchronize estrus in horses. It is used extensively in the reproductive management of mares to control the reproductive cycle, help maintain pregnancy, and h …

Mares are seasonally polyestrus, which means that they experience regular estrus cycles during late Spring, Summer and early Fall, and none during the Winter. These cycles are controlled by hormones, which respond to increases or decreases in day …

Mares are seasonally polyestrus, meaning that they experience regular estrus cycles during late Spring, Summer and early Fall, and none during the Winter. These cycles are controlled by hormones, which respond to increases or decreases in dayligh …

The administration of hormones to mares during breeding management is an essential tool for equine practitioners. Proper and timely administration of specific hormones to broodmares may be targeted to prevent reproductive disorders, to serve as a …

Deslorelin acetate is a potent synthetic gonadotropin-releasing hormone (GnRH) analogue.1 According to the literature, the advantage to using deslorelin over hCG to induce ovulation is that it possesses a smaller molecular weight than hCG, making …

Buserelin is a synthetic luteinizing hormone–releasing hormone (LHRH) analog. Like naturally occurring LHRH that is produced by the hypothalamus, initial or intermittent administration of buserelin stimulates release of luteinizing hormone (LH) a …

In general, the estrous cycle (or oestrus cycle) is the group of physiological changes that occur in sexually mature female mammals which are brought on by reproductive hormones. The changes facilitate fertility and reproduction.Horses (mares) ar …

She stamps and squeals when other horses pass her stall. She forgets her manners, swishing her tail and trying to nip when you groom and tack her up. And when you ride, she's a total airhead, ignoring your aids, whinnying, jigging and dancing, …

The most common cause of Acute Encephalitis Syndrome (AES) in horses is thought to be viral infection, although it is believed that it can also be brought on by bacterial, protozoan or fungal causes. Some researchers have designated AES as a grou …

Veterinarians are the doctors of the animal world. They use their skills to evaluate patients, make diagnoses, and treat a wide range of conditions.1 For most people, the role of a veterinarian consists of maintaining their pet's (or pets') health …

Chlorpromazine is a phenothiazine tranquilizer. 1 While Chlorpromazine is often used by veterinarians as a centrally-acting antiemetic to prevent nausea and vomiting in dogs and cats, it has been widely used as a calming agent in performan …

In May 1998, the U.S. Food and Drug Administration (FDA) approved the use of a branded version of clenbuterol for the management of horses affected with airway obstruction, such as occurs in chronic obstructive pulmonary disease (COPD). In other …