Bridle Up - Mare
Anatomy
By Karen
Berk
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I love
horses! Any breed, age, gender, color or discipline. I drove my parents crazy
from the time I could talk. Foolishly, they thought I would outgrow my fantasy.
Instead it directed my life and became my adult reality. I embraced my
obsession with such tenacity that soon, riding, showing, teaching and even
judging were not enough. If I had been blessed with artistic talent, I would
have painted, drawn, or sculpted endlessly in an effort to recreate the essence
of perfect beauty and harmony which is the perfect horse. But no such talent
did I possess. Then, one day, by pure accident, I stumbled on a stallion who
took my breath away.
I had never considered owning a stallion, nor did
I have the facility to keep one. An hour later, that stallion was on his way
home with me, and together we began a journey. It is now seventeen years later,
and my quest to create the perfect horse has taken me to two Universities and
three continents. I have sought out great breeders, and studied legendary
stallions to add to my pallet. I have also encountered many like minds with the
same goals and frustrations. Creating true genetic quality, both genotype and
phenotype, is not a toss of the dice. History has shown us great and thoughtful
horse breeders since the earliest written records.
Today we have
understanding and technology available to the public never before imagined.
Stallion Collection, Shipped Chilled Semen, Artificial Insemination,
Cryopreservation, Embryo Transfer, Diagnostics, and on and on. We have more
colors on our pallet to create then ever. But with new techniques come fear and
misuse. Proper handling, collection, and evaluation, greatly increase
conception rates. Yet this has not been the case across the board, due to
shortcuts and greed.
How many of you on ordering shipped semen have
asked, how many progressively motile cells are being shipped per dose, that
ejaculates concentration, motility and how they arrived at that dose? The
correct dosage to ship is ONE BILLION PROGRESSIVELY MOTILE CELLS, in a volume
of under fifty mls. if possible. Many breeding centers will get call for
threeshipments, and regardless of correct dosage, extend the sample and just
divide it three ways and ship. If there were only two billion cells, no one
gets a correct dosage and conception chances are severely reduced. If only two
had been sent, the odds would have favored two satisfied customers and two
foals next season.
How about on the mare owner's end. Does you vet or
tech use a non spermicidal syringe, and evaluate the sample for viability after
insemination? As the recipient, consumer, of the semen, you have the right to
ask questions and receive a written evaluation of what you ordered. This should
be included in the packaging. If not, this constitutes mail fraud. There are
stallions so potent that error seems not to effect their success. But, this is
the exception not the rule. When your dollars and cents are on the line, you
must remove the blindfold. I do not believe, or even wish, we will ever breed
the perfect horse. He or she must remain in the fertile fields of our own
imaginations. It is there that we seek perfection that is individual ourselves,
and allows new ideas to benefit all. AN EDUCATED BREEDER WITH A GREAT MARE HAS
THE WORLD AT HIS/HER FINGERTIPS. Remember a foal takes on sixty to seventy per
cent of it's dam's physical, genetic and athletic traits.
The mare is
by far the most important contributor to the quality of the foal. A stallion
that can override the majority of a mare's genetic traits and replace them with
his own is called "prepotent," and is an exception rather than a rule. When
this happens, these great ones become the icons of their breed, and by all
means should be revered. By finding a stallion that "nicks" with a mare, a good
breeder can produce a superior foal of championship potential year after year.
A stallion is always dependent on the quality of the mares booked to him.
Regardless of your affection for your mare, or perhaps she was a great buy, you
should take a hard look before you decide to breed.
First, pedigree; if
all her well known ancestors or champions are stallions, take another look. The
most important line in a pedigree is the "TAIL FEMALE LINE." This is the bottom
most line on the dam's side of the pedigree. These are the strongest
inheritable genes.
Second, Age; Mares of more than fourteen years of
age have significantly more inflammatory and degenerative changes of the uterus
and less contractile activity than younger mares. Physical conformation of the
vulva may make a "Caslick" procedure imperative. On the other side of the coin,
clients have brought me two and three year olds who were not reproductively
mature, regardless of cycling.
Third, General Health; A good
nutritional diet, suited to your mare's age and level of activity has been
proven to be an important contributor to conception and development of the
fetus. Inoculation, and worming history, with continuation throughout pregnancy
should be routine. Before breeding, a vet should perform a "Breeding soundness"
exam. Also an excellent idea before purchase.
Lastly, know or try to
find out your mare's past breeding history. Subfertility in mares is
multifaceted. If I were to attempt to group reasons, they would fall into three
categories:
- Age
- Contamination and
infection of the reproductive tract
- Malfunctioning of
the hormonal system.
At times these will
overlap. THE HORMONAL SYSTEM OF THE MARE IS PERHAPS HER MOST IMPORTANT
ANATOMICAL STRUCTURE AND THE LEAST UNDERSTOOD BY THE BREEDER.
I would
like to give you a quick review of what happens when your mare's body prepares
her for pregnancy:
- First the mares eyes
bring in added light which is recorded by the Pineal Gland, with either the
advent of spring or artificial lights. This stimulates the Hypothalamus Gland
which is located in the tissues of the mid brain. It starts the reproductive
cycle by producing Gonadatrophic Releasing Hormone of GnRH.
- When GnRH is
secreted in the proper amount, the Pituitary Gland located at the base of the
brain is stimulated.
- The Pituitary Gland
then secretes 2 hormones that effect the ovaries. The first is called Follicle
Stimulating Hormone (FSH.) It travels in the bloodstream to the ovaries where
it stimulates the development of one or more follicles. When the follicles
reach 20 to 25 millimeters in diameter, they secrete Estrogen.
- This hormone
stimulates estrus (heat) activity, causes relaxation of the cervix, stimulates
contractions along the mares reproductive tract, and signals the Pituitary
Gland to stop producing FSH and at the same time stimulates the second
gonadatrophic hormone, Luteinizing Hormone or LH.
- LH facilitates
maturation of the growing, egg bearing follicle. Ovulation occurs when the
mature egg eaves the follicle and begins it's trip through the oviduct.
Following ovulation, the Estrogen level begins to fall, and the remains of the
ovulated follicle are converted to a form of Corpus Luteum, or yellow body.
- These Luteal cells
secrete the hormone Progesterone. It is it's job to stop heat stimulating
hormones, and to set the stage for maintaining pregnancy. It subdues the
contracting reproductive tract, and tightens and closes the cervix. It also
prohibits the secretion of FSH and LH from the Pituitary, thereby putting the
mare out of heat.
Obviously,
progesterone is a highly important hormone in maintaining pregnancy. In some
sub-fertile mares the correct amount of progesterone is not secreted. When this
happens the other hormones swing into action and terminate the pregnancy,
bringing the mare back into heat. Fortunately, progesterone levels can be
checked and monitored. Supplemental progesterone can be administered to the
mare throughout her pregnancy. Proper timing and appropriate levels of al
hormones are required to maintain a balance during breeding and pregnancy.
Wherever there is an imbalance, breeding problems will follow.
If your
vet has found no physical, internal, or conformational reason for a mare's
sub-fertility, ask him/her to do a hormonal assay. Perhaps your mare is a
nervous type, or age, or physical disability or makes travel undesirable, or
simply the stallion of you choice is beyond your geographic reach. Transported
semen may be perfect for you. As we discussed earlier, properly timed and
executed, it has a very high percentage of conception on first cycle, with less
risk and expense.
At the risk of repeating myself, the first step should
be to call your vet for a breeding soundness exam. In the case of a mare that
has just foaled, you should be certain there were no tears or complications
post partem. Mares that have been open should have a culture AND cytology. A
large percentage of problem mares have clean cultures but will show up "dirty"
on a cytology. A cytology is an added test, inexpensive, taking twenty-four
hours to ascertain a wide range of infection and contamination. Most mare
owners ask for a culture not realizing this is not an accurate picture, and
many vets do not recommend further tests if not asked.
Another
suggestion, particularly on aged mares is a uterine biopsy. A small sample is
excised, cultured, and gives a very good picture of the uterus. This, coupled
with a sonogram, will arm you with enough information to make an educated
decision as to go on with the further expense of contracting a stallion and
transporting semen.
Next step, your mare comes into heat. Once again
contact your vet. He/she will want to palpate your mare on about day threeto
assess her follicle and coordinate with the stallion manager. You do not want
to order semen too early. Semen should arrive no earlier then twenty-four hours
prior to ovulation, and not more then six hours after. Keeping in mind mares
ovulate between four in the morning and ten a.m. If your shipment arrives and
your vet says she has just ovulated, do not panic. This is still good timing.
The egg will rest in the Ova Fossa for a few days. This is the site of
conception. If you inseminate too early, the sperm arrive but are weakened by
the time the egg does.
Your Vet or A.I. technician should work closely
with the stallion manager to coordinate timing of shipment and ovulation. When
the shipment arrives do not open the container. I strongly suggest your vet or
tech have a microscope to check the semen AFTER insemination. Do not warm the
packet or let it come to room temperature. The mare's body is the perfect
incubator. Do not use more then one dose id you think she is going out of heat,
and you don't want to waste any. The calculated dose is sufficient, and
according to the studies at Colorado State University, inseminating with more
then fifty mls., is actually detrimental to conception.
Do ask your Vet
or tech to use a non-spermicidal syringe. These are all plastic. The black tips
on regular syringes are spermicidal to many stallions semen. Do be sure to wash
and dry your mare's parinatal area thoroughly with warm water and mild soap,
making sure there is no residue remaining. Towel dry with clean, white paper
toweling. The dose will be drawn into a syringe, (or in the case of an Equine
Express container being used, it is already in the proper syringe) a pipette
attached. It is then inserted vaginally, passing through the soft and open
cervix. The procedure is quick. Since the semen is placed in the uterus, you
don't have to worry about "dumping" the inseminate, as you do with natural
cover.
If you have covered your basics and followed a sound reproductive
program, the result will be a win / win situation for all the players, and you
will have the quality of foal to be a contender. Whether your goal is the show
ring, trail, or adding another beloved family member, breeding success = good
horse cent$.
Next month is the stallion issue and so we will address the
subject of the breeding stallion, anatomy, semen evaluation and the effect of
adding artificial light on a stallion's libido and potency. |
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