With a little bit more consideration for both horse and rider winter riding
can be an enjoyable experience.
Photo: Keith Larson
There might be times when you wish you could ride your horses more during
the winter months, even in the coldest of weather. When conditions are not
slippery, riding can be excellent exercise for rider and horse. What to Remember
If you are riding in cold
weather, you must take special care when cooling out horses, or you will
be guilty of inflicting another form of winter stress.
Other stresses are
decreased water intake, increased energy needs (increased calorie requirements)
and seeking comfort (standing out of drafts or standing in the sun).
In addition, your horse's
work/training schedule might become somewhat altered or stopped in the
winter months. Therefore, your horse could get somewhat out-of-shape and
not be ready for a full riding session. Instead consider a long walk or
gentle jog that can do the equine and rider plenty of good. If your horse
is out of condition do not force a lot of exercise during bitter cold
temperature.
Equids are very capable of
handling the cold temperatures and weather conditions that make most
humans huddle inside.
How to Cool Out Your Horse
If a horse has exerted
himself to the point where he is wet with sweat beneath the saddle, use
special care to prevent chilling. Sudden changes in body temperature, such
as a cold wind blowing on a sweaty back, can have harmful results.
Placing a heavy insulated
blanket on the horse immediately after unsaddling might do more harm than
good. The heavy covering can trap moisture between skin and blanket,
preventing the horse from drying. Place a light blanket over the sweating
horse in cold weather and lead it around until the hair is dryer.
Walking helps keep the body
from cooling too rapidly, and the light blanket protects from wind and
cold while allowing moisture to evaporate.
When the horse's coat is
dry, remove the now-damp light blanket and either turn the horse out or
cover him with a dry blanket.
If your horse is breathing
heavily with flaring nostrils after exercising, then you might need an
extra long cooling out period before returning the equine to the stall or
turnout area.
Riders Need to Dress Accordingly
You need to prepare
yourself for the cold, as well. Dress in layers so you can maintain a
comfortable body temperature. Just as you want to prevent your horse from
becoming chilled from perspiration, people should also avoid excessive
perspiration.
Layering apparel allows you
to add or remove clothing easily as your body temperature changes.
With a little bit more consideration for both horse and rider winter riding
can be enjoyed and both can experience the exhilaration of being in a winter
wonderland.
Researchers have defined a number of conditions affecting specific
breeds—many of which developed as a result of selective breeding, or breeding
for highly desirable qualities such as performance or appearance.
Photo: Thinkstock
By knowing what diseases certain horses are predisposed to, owners and
breeders can take steps to curb undesirable conditions
Appaloosas are prone to eye
problems. Quarter Horses tend to tie up. Arabians can produce immune-deficient
foals. Today it’s common knowledge that some breeds are more predisposed to
certain conditions than others. But it was only a few decades ago that
researchers first identified these genetic disorders in horses. Since then they
have defined a number of conditions affecting specific breeds—many of which
developed as a result of selective breeding, or breeding for highly desirable
qualities such as performance or appearance.
A classic example is researchers’ discovery that
linked the muscle disease hyperkalemic periodic paralysis (HYPP) to the Quarter
Horse sire Impressive. In 1996 the American Quarter Horse Association
established mandatory testing for all Impressive’s descendants to prevent
perpetuating the condition. Now any foal that tests homozygous for HYPP cannot
be registered with the organization.
But many owners across a variety of breeds know
nothing about their horses’ lineage. This means breeding continues to result in
foals with genetic conditions. Knowing which horses could potentially have
genetic conditions is important not only for buyers and breeders but also the
overall health of the breeds themselves.
Horses are affected by comparatively fewer
genetic diseases than humans, but the disorders are still too numerous to cover
in one article. Here we will highlight the more common disorders, presented on
a breed-by-breed basis. We’ll also describe some not-yet-fully-understood
equine conditions that are thought to be caused by genetic anomalies.
What is a “Breed-Related Disorder?”
This is really a catchall for something that goes wrong with a horse’s
genes—the body’s blueprint. The genes control everything from eye and coat
color to liver and kidney function. Even behavior has its roots in the DNA,
as evidenced by how certain lines are known for being calm or cantankerous.
Three types of genetic disorders can occur in horses:
The classic Mendelian or “simple” genetic
disorder, passed from one or more parents to the offspring. Most of the well-known disorders fall into this category. Take, for
instance, the widely studied severe combined immunodeficiency (SCID), which
primarily affects Arabian foals. Before we pull out some of the more technical
genetic language, remember that each parent has two copies (alleles) of every
gene and randomly gives one of the two copies to their offspring. The SCID
disorder is an autosomal recessive mutation, which means two copies of the
abnormal gene must be inherited—one from each parent, and not from the sex chromosomes—for
the mutation to occur. With SCID the mutation occurs at a specific location on
equine chromosome 9 (ECA9), resulting in foals without functional white blood cells, rendering
them unable to launch immune responses against pathogens.
Most other known genetic disorders described in this
article are “simple,” following either recessive or dominant modes of
inheritance similar to SCID.
An abnormality in the number of DNA-containing
chromosomes that a horse inherits from its parents. The most common type of this abnormality is the “63,X karyotype” that
can occur in female horses. Instead of having a full set of 64 chromosomes (32
from the dam and 32 from the sire), including two X chromosomes, affected
fillies are missing one X chromosome. Although viable and outwardly normal,
they fail to develop a normal reproductive tract. This mutation is spontaneous
rather than inherited.
Genetic disorders arising from abnormalities
of more than one gene. This third class of
genetic mutation requires the input of several genes, rather than the one gene
in simple disorders. With the sequencing of the entire horse genome, a number
of equine conditions now have a “genetic” explanation. For example, it has long
been suspected that osteochondrosis and recurrent laryngeal neuropathy
(“roaring”) have a genetic basis, but researchers are still working to confirm
this.
Genetic Conditions by Breed
Arabians The most
important simple genetic conditions affecting Arabians include SCID, lavender
foal syndrome (LFS), and cerebellar abiotrophy (CA).
Foals with SCID are highly susceptible to
infections. At birth these foals appear normal because they are receiving
antibodies from their dam’s colostrum. But by approximately 6-10 weeks they
begin to develop infections that “normal” foals would be able to fight.
Affected foals usually die by about five months of age due to a complete lack
of B and T -lymphocytes—specialized white blood cells that produce antibodies
required to fight infections.
The LFS genetic mutation occurs on ECA1 and results in a dilute
coat color (often appearing silver or lavender) as well as fatal neurologic
signs. These foals typically die or are euthanized within a few days of birth.
Cerebellar abiotrophy, a recessive genetic disorder
due to a mutation on ECA2, results in a foal with an awkward gait, wide stance, and head
tremors, among other signs that generally warrant euthanasia. Confirmed CA
carriers have been detected very rarely among other breeds—generally those with
strong Arabian lineage.
Researchers have described other genetic disorders
of Arabians, but the exact location or nature of these mutations remains
unknown. Examples include guttural pouch tympany (excess air in the guttural
pouches), juvenile epilepsy syndrome (JES, seizures beginning around 6 months
of age that typically resolve by 1-2 years of age), and occipitoatlantoaxial
malformation (an abnormal fusion of the skull bones with the first cervical
vertebra, causing incoordination and weakness). Researchers believe JES to be a
dominant trait, with a potential link to LFS.
Quarter Horses
Several specific genetic conditions beyond HYPP can plague Quarter Horses:
Polysaccharide
storage myopathy (PSSM type 1) is caused by a dominant mutation in the
GYS1 gene located on ECA10. Clinical signs of PSSM include muscle weakness and atrophy,
reluctance to engage the hind end, and muscle soreness. Halter lines of
Quarter Horses are affected far more frequently than other types.
Malignant
hyperthermia is a skeletal muscle abnormality caused by a specific
mutation of ECA10. Inhalant anesthesia can trigger episodes characterized by
severely increased body temperature, acidosis (a decrease in body pH), and
sometimes death.
Glycogen-branching
enzyme deficiency is a mutation on ECA26 affecting a particular glycogen-storage enzyme that results in
the overall malfunctioning of various muscles, including the heart.
Clinical signs include abortion or stillbirths; if the foal survives until
parturition, it experiences progressive weakness, seizures, respiratory
and cardiac failure, and sudden death.
HERDA
(hereditary equine regional dermal asthenia) is caused by a recessive
mutation on ECA1. Affected horses have hyperelastic, easily tented skin that
does not return to its natural position normally, and they readily develop
seromas (fluid-filled pockets under the skin); open wounds that heal
slowly; sloughed skin; scars; and white hairs in healed areas.
Overo lethal
white syndrome (OLWS) is an underlying recessive mutation caused by an
abnormality on ECA17. It appears in newborn foals born to a variety of Paint horse
patterns, including frame overo, highly white calico overo, frame blend
overo, sabino, tobiano, and even solid-frame breeding stock. Affected
foals are white or mostly white and show signs of colic and die within
hours of birth.
Draft Breed
PSSM type 1
Prevalence
Belgian draught
92%
Breton
63%
Percheron
62%
Belgian
39%
Shire
0.5%
Clydesdale
0%
Draft Horses Two of the most important genetic conditions in draft horses are PSSM
and junctional epidermolysis bullosa (JEB). According to researchers at the
University of Minnesota Equine Center, PSSM type 1 prevalence in some draft
horse breeds (that were randomly tested) can be quite high.
A recessive mutation on either ECA5 or 8 (two different
versions of the condition exist) causes JEB. Affected foals form deep ulcers in
the skin following even slight trauma, as well as eye and dental abnormalities.
Hooves often slough and foals fail to thrive, prompting euthanasia.
Warmbloods
Researchers believe German Warmbloods have a genetic condition that causes guttural
pouch tympany. In one report of a genome-wide analysis involving 373 German
Warmbloods, researchers identified a region on ECA3 they say might be
responsible, but they note that additional studies are needed to better
characterize the exact genetic mutation.
In a similar study scientists identified a region on
ECA20 they think is responsible (or at least plays a role in) equine
recurrent uveitis—a leading cause of blindness in Appaloosas, European
Warmbloods, and draft horses.
Friesians These
horses appear to be prone to megaesophagus (chronic dilation of the esophagus),
aortic rupture, dwarfism, and hydrocephalus (fluid on the brain). Researchers
at The Fenway Foundation and the University of Wisconsin have
been establishing Friesian breed-specific complete blood count and chemistry
value reference intervals to help veterinarians better evaluate and treat these
animals. Researchers (Lassaline-Utter, et al. 2014) also recently determined a
genetic link between the breed and corneal dystrophy.
Standardbreds, Trotters, Thoroughbreds Though it’s rare, Thoroughbreds can produce foals with OLWS.
Thoroughbreds are also known for tying-up, which is thought to have a genetic
component. Researchers believe various developmental orthopedic diseases, such
as osteochondrosis, have a genetic component in racehorse breeds, in
particular. Additionally, in a recent study scientists identified a heritable
component to atrial fibrillation (a heart arrhythmia) in horses.
A current genetic puzzle that Samantha Brooks, PhD,
of the University of Florida, and colleagues at CornellUniversity and MichiganState are trying to decipher is the genetic basis for “roaring” in
Thoroughbreds. The equine recurrent laryngeal nerve controls the arytenoid
cartilages’ motion. If it does not work properly, the cartilages droop into the
airway, impeding air flow to the lungs and causing a roaring sound as the horse
breathes. Roaring is a common performance-limiting condition in both
Thoroughbred racehorses (2-11%) and Draft horses (35-46%).
“Previous research suggests that taller horses are
more likely to have recurrent laryngeal neuropathy (RLN) and that affected
horses are more likely to produce foals with RLN,” Brooks says. “Both of those
findings support a genetic basis to this condition, but few genetics studies
have been conducted.”
Brooks and colleagues performed a genome-wide
association of 282 affected Thoroughbreds and 268 normal Thoroughbreds, meaning
they scanned each horse’s entire genome looking for markers that correlated
with the disease, finding a location on ECA3 that appeared to be associated with RLN. That site was also
associated with horses’ height, suggesting the link between this height marker
and RLN. The study authors identified two other locations, one on ECA18 and one on the X
chromosome, with candidate genes potentially capable of influencing muscle
physiology and growth.
“Our study results suggest that RLN is a polygenetic
trait and that horses can be selectively bred to reduce the incidence of RLN,
but that could result in slightly smaller horses,” Brooks says. “Additional
studies further exploring the relationship between genetics, equine growth
rate, and the prevalence of RLN are needed. In the long-term, this new genetic
information will enable us to better manage RLN in horses.”
Testing for Genetic Disorders
Because the mass institution of equine chastity belts isn’t feasible, the
best way to minimize the perpetuation of genetic disorders is testing. A wide
range of tests is currently available and, as we’ve noted, some breed
associations—such as those for Arabians and Quarter Horses—demand proof of
certain test results before you can register your horse. Such groups have
demonstrated the benefits to this practice.
The goal is not to stop breeding carrier horses—and,
thus, lose their gene pool—altogether, notes the World Arabian Horse
Organization. Rather, testing can help breeders avoid crossing carriers with
carriers while still retaining those bloodlines’ desirable pedigrees and
associated traits.
In 2013 British researchers highlighted the benefits
of genetic testing when they reported that they had identified the genetic
mutation responsible for foal immunodeficiency syndrome (FIS) and successfully
reduced disease incidence. This disorder, not to be confused with SCID, occurs
in Fell and Dales ponies and is caused by a fatal recessive mutation that
results in the lack of B lymphocytes. Scientists subsequently developed a test
that revealed 38% of tested Fell ponies and 18% of breeding Dales were FIS
carriers. After testing and avoiding carrier-to-carrier breeding, the number of
affected foals decreased dramatically in just two to three years.
In addition to FIS, there are several other equine
genetic diseases for which commercial tests are available (see chart on
opposite page).
Take-Home Message
Genetic diseases are rarely as simple as a parent passing a single gene to
his or her offspring, and researchers continue to identify “new” genetic
conditions. Therefore, it behooves all horse owners to breed responsibly,
research a horse’s genetic disease potential prior to purchase, and consider
the importance of testing. The equine genome will continue to help scientists
identify the genetic basis for many diseases and conditions and, potentially,
novel treatments for affected horses.
Many horses adapt well to and even prefer 24/7 outdoor living, and
pasture board can save you money on your board bill. Photo: Leslie
Potter
Horse ownership comes with its fair share of expenses, but fun and
worthwhile pursuits usually do. Still, just because there are costs
doesn’t mean you can’t look for ways to cut them! Here are a few
money-saving tips to consider: 1. Purchase hay off the field
If you live in a rural area and are able to purchase hay locally,
consider asking your hay supplier if you can purchase hay "off the
field.” This means that you pick up your hay on the day it was baled,
saving the farmer the trouble of putting it up in his barn and then
taking it back out to deliver. Many farmers prefer this, and you can
usually secure a lower per-bale price. Be aware, it can be a lot of
work, and you’ll have to have access to a vehicle and trailer suitable
for the task. If you don’t mind using your muscles, buying hay off the
field can be a valuable money-saver. 2. Allow your horse be used as a lesson horse
If you’re the lucky owner of a quiet, calm, and reliable horse and you
stable him at a boarding facility, you might be able to get a discount
on your board bill by allowing your horse to be used for lessons. It can
be a great way to save money and get additional exercise for your
horse—especially if you don’t ride frequently yourself. Plus, you’ll
have the added bonus of knowing that you and your horse are helping
others learn the pastime you enjoy so much. 3. Try ponies! (or a smaller horse breed)
There’s no denying that small equines are less expensive to care for
than large ones. Their smaller size means they consume less hay and
grain, and most pony breeds are naturally "easy keepers.” Many pony
breeds are quite athletic, and perfectly capable of carrying children,
teens, and even some adults. Ponies are also great for driving! Small
horse breeds offer similar benefits. Of course, small equines aren’t
right for everyone, but they’re certainly worth looking into. 4. Try pasture board rather than full board
Pasture boarding (in which horses are turned out 24/7), is typically
cheaper than full board, and this can be a money-saving option for some
horses and horse owners. As long as your horse is healthy and has access
to adequate shelter (such as a run-in shed) and 24/7 water, it can be
an acceptable choice in some situations. 5. Do chores in exchange for a discount
Your barn manager might allow you to do chores around the stable in
exchange for a discount on your board bill. This can be a great way to
save money, especially if you already love being around horses and don’t
mind a few extra stalls to clean, buckets to fill, or aisles to sweep! 6. Keep at home, don’t board
You may also be able to save money by keeping your horse at home. You’ll
need property and buildings suitable for the job, and you’ll also need
to consider that you’ll be fully responsible for your horse’s care.
While having your equine buddy at home can mean more time spent
together, it also means you’re solely in charge of the daily feeding,
cleaning, and general chores. But if you have the space and time and are
up to the task, keeping your horse at home can be a money saver. 7. Don’t cut the wrong corners
Don’t forget: there are some areas of horse ownership in which should
you never try to cut corners. Don’t cut back on farrier visits, vet
checks, vaccinations, and parasite control. Not only could limiting
these areas be unsafe for your horse, they really won’t save you money
in the long run, as avoiding or going too long between these items can
lead to health issues that might be far more costly to fix then they are
to prevent. So stay on a regular health care schedule, and enjoy your
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