[Every effort has been made to ensure accuracy of information. However,
this is not a substitute for prompt veterinary care. Any similarity
to other publications is unintentional. Published
online at SealyHealthGuard.org, 5/25/11]
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On Friday, October 8, 2010 the ASTC was proud to host Dr. Robert Huchison
as he gave a delightful talk about how to maximize conception rates. The
talk lasted at least two hours and covered a lot of informative topics. He
kept it even more interesting & fun by sprinkling his talk with
many entertaining anecdotes from his years of practice. He allowed
plenty of time for questions, too.
He started out by stating that the #1 cause of losing puppies
during delivery is lack of oxygen because the delivery took too
long. His practice performs 400-500 Cesarean sections per
year. He's very aggressive in preventing loss of puppies
due to lack of oxygen. He went on to say that 25-30% of
those pups who make it to term are not alive at 6 months of age
for various reasons. Already a pup's eyes & ears continue
to develop outside the womb. If it's premature, the lungs
aren't totally developed. If it's 48 hours premature, the
liver is not fully developed. Knowing the correct due date
is critical. If the dam goes past the due date, the puppy
can outgrow the placenta's ability to support it. During
the last 12 days of pregnancy, the puppies double in size. Dr.
Hutchison also mentioned a singleton puppy will not produce enough
of a hormone to stimulate contractions.
Late date X-rays are still helpful. You want to know how
many puppies to expect. In a study about to be published
in England, 30% of bitches resorb some of the puppies. Also,
with ultrasound, it is often difficult to see the number of puppies. An
X-ray does not harm the puppies or bitch. Digital X-rays
are really fast and can tell you the number of puppies, give you
an idea of size, signs of abnormality & even if they're alive.
Studies have also shown if the mother has less than 3 or more
than 8 puppies, the chances of free-whelping all of the pups is
slim. If she has 12, the last two are small & often
dead because they're crowded in the upper parts of the uterus. The
uterus gets flaccid after birthing all the others in the litter.
Animal Clinic Northview, Inc. is a 17-vet practice & one
of the top three noninvasive surgical practices in the country. It's
open 24/7. They do laproscopic spaying. There are
four full-time reproductive vets. Clients arrive from all
over the country & even Japan. One of the services
they provide is to bring a bitch into an ovulatory heat cycle
using an implant. She will ovulate in 5-7 days & you
can plan & bring her to a specialty show to breed her. I'll
describe more about this later in the article.
Dr. Hutchison said that chilled semen can last for 30 days with
any extender. Another thing he's done now that there
are DNA tests for multiple sire litters is to use 3 to 4 sires
(frozen semen). Since frozen semen has more chance for
failure and you don't want to waste any seasons when you plan
to breed your bitch, this can be a good option. This could
be also helpful if one of the sires is older with lower-quality
semen. He later added that he's seen frozen semen last
for 26 years.
He also stated that there's no advantage in the bitch in skipping
a season for breeding. He had a Mastiff give birth to 18
live puppies. The next litter (next season), she had 13
live puppies. Expect any pup who is healthy genetically
to survive.
Youth is a friend of reproduction. Statistically, once
a bitch reaches 6 years old, her fertility drops 33.3% & continues
to drop with age. Litter size also decreases with age. With
every heat cycle, uterus health decreases. Pyometritis
can be due to age & disuse; infection is secondary.
People often assume the thyroid is a reason if a mating fails. Dr.
Hutch says the thyroid has little if anything to do with reproduction. There
was a study done at Michigan State University. Low thyroid
had no affect on sperm count. He said you don't need to
test beforehand. The body is lazy--if you give it thyoid
pills, it will produce less thyroid, so you don't want to medicate
if it's not actually low.
Another thing people often check is a vaginal culture. The
vagina is not sterile. Do not automatically give antibiotics
prior to breeding. It imbalances the tract: yeast & Pseudomonas
can increase as a result. It's also a waste of money.
There are six causes of infertility:
• Poor semen quality
• Did not ovulate--split cycles, progesterone-producing
cysts
• Incorrect timing
• Anatomical (obstruction in the vagina or uterus)
• Implantation [of the zygote] failure
• Resorption: was the body maintaining the progesterone? You
need greater than 5 nanograms of progesterone. Many Mastiffs & Leonbergers
now need supplementation.
He had a Dalmation that ovulated at day 32 & was successfully
bred on day 35. A bitch will either ovulate or go out of
season. There are silent seasons with no discharge.
The progesterone goes up and stays up for 9 or more days. Progesterone
inflames the uterus. The bitch ovulates into a progesterone
environment (all other species ovulate into an estrogen environment,
then the progesterone later increases).
The cervix is located in the abdomen above the bladder. In
a beagle, it's 6-8" from the outside of the vulva. Dr.
Hutchison performs transcervical insemination because the cervix
hangs and the opening is very small. It is difficult to
do vaginal insemination when ther are strictures or bands.
In the bitch, the eggs don't implant until day 17-18. Fertilization
takes place in the oviducts and stays there. The zygotes
communicate chemically so they distribute evenly in the uterine
horns. Then they communicate with the uterus & it swells. You
feel that swelling during palpation.
Physiology of the Male
The testicles are in the scrotum at 5 weeks of age. The
pup is usually fertile at 9-10 months. The male has a 4
billion sperm reserve. A healthy male can be used 5-7 consecutive
days without a drop in sperm count.
The left kidney is farther back than the right. The left
testicle hangs lower than the right, so it takes longer to descend. An
organ called the gubernaculum pulls them down into the scrotum. In
some dogs, when the testicles descend, they can seem to bob up & down
(not staying descended). The testicles reach maximum size
by 10 months old, then they stay down in the scrotum. Having
a testicle that does not descend is an autosomal recessive, sex-limited
trait: each parent contributes 50%, but you can't tell
if the dam has the gene until she has a male puppy. Mucopolysaccharide
is a chemical produced by the testicle that causes the gubernaculum
to retract. In the past, vets tried to give hormone injections
to try to make them descend, but they didn't work. During
neutering of a dog whose testicle(s) didn't descend, it's important
to see why. The testicle can wrap around the bladder or
twist (not genetic) or the cord is short (is genetic).
A male produces his maximum sperm count between the ages of 2 & 7
years old. It's best to collect when they're young (in
this age range). It takes 5 ½ days to make a sperm. You
can breed the bitch every 4-5 days because the sperm lives so
long in her.
Dr. Hutchison mentioned that persistent frenulums are seen often
in terriers--this can cause the penis to curve backward or to be
connected to the sheath. This excess tissue can easily
be corrected by a vet, under anesthesia, to allow breeding. It
is a congenital defect.
Semen Collection: Use a clean collection sheath & calibrated
tube. Avoid spermicidal agents: soap residue, KY
jelly, tween 20, glove powder, urine, even tap water because it
contains fluoride. Also things on the male's coat
like flea spray or coat conditioner can kill sperm. Wash
these off his abdomen ahead of time. A baby bottle liner
or baggie works well for collection. Pull the male's sheath
behind the bulb of the penis. Stimulate the male with a
bitch in estrus or a vaginal smear of one (you can use cotton
balls or Q-tips on a bitch in season ahead of time & store
them in the freezer in foil. These can then be thawed and
wiped on the back of a teaser bitch). The penis has cartilage
at the base; you can twist it & turn it to the rear like a
tie during collection. A couple of stimulations & the
bulbs will swell. You grip the bulbs and twist it between
his hind legs so you can see the ejaculate as it goes into the
bag or tube. There will be three phases or fractions: prostatic
fluid, sperm (milky) and watery prostatic fluid.
A tie is essential for conception--it stretches the vagina & releases
oxytocin & causes contractions which pull the semen up toward
the uterus. To simulate this in AI, the vet will stroke
the roof of the vagina.
A Colorado State University study found live semen in a bitch
11 days after breeding. Semen has great longevity if handled
properly. The semen is centrifuged (spun down) to get rid
of the prostatic fluid. Its components have energy for
sperm but it can interfere with preservation.
A shy breeder: it may be his environmental preferences,
not a testosterone deficiency (if you give a testosterone injection,
the brain senses overproduction & the body's own production
will shut down, possibly forever). Use care in bitch selection
for a young dog. Also, if you think you might plan to use
a puppy in the future, don't raise him surrounded by females that
pick on him.
Is he fertile? Semen characteristics:
• Volume: about
2.5-6ml, depending upon breed size
• Color: white
• Motility: >80%
motility
• pH: 6.2-6.6
• total count: .4
to 1.8 X 10 9
• morphology (shape): < 20%
abnormal
Males can have prostate problems with age. One symptom
can be dripping blood. Prostatic diseases include benign
prostatic hyperplasia (enlarged prostate), prostatitis (acute
or chronic), cysts, abscess, neoplasia (cancer). Neutering
does not prevent prostate cancer. Symptoms include severe
back pain.
You can't feel the prostate rectally; you have to use an ultrasound. It
looks similar to a peach.
Proscar (finasteride) is used to treat enlarged prostate. It
cuts the enzyme that changes testosterone to dihydrotestosterone. It
shrinks the prostate & gets rid of blood while preserving
sperm count. People should be careful handling it since
it can cause birth defects.
When assessing the sperm, the microscope slide should be warmed
to body temperature, so it doesn't affect motility. Do
not touch the surface of the slide; that can kill the sperm.
You can see different types of movement in sperm from different
males:
• Side to side
• Occasional forward progression
• Slow steady forward progression
• Rapid steady forward progression
Morphology [shape] of the sperm:
• cap- for
implantation in the egg
• head- contains
DNA
• midsection - energy
• tail- motility
If a sperm is immature, it can move but is not fertile. This
can happen if a male is overused or if something is shutting down
sperm production.
The Briard has some sperm morphology problems: the head
of the sperm can be too big, too small, pear-shaped, or the head
can be on sideways or the sperm can have a crooked neck.
Sometimes, the heads & tails of sperm pop apart. This
can be caused by the male laying on something warm (heats the
testicles too much), hot blow dryer, frostbite on the testicles,
infections.
Most breeders don't select for reproductive health.
Advantages of fresh chilled semen: no need to ship the
bitch, semen can be sent for freezing with DNA testing, allows
breeding when the male is not available, lasts easily 2-3 weeks
(can spin down & change the extender to prolong life). You
can use it internationally. Many countries have a lot of
rules in place for frozen semen but not yet for fresh chilled
semen.
When you use the chilled semen, do not warm the sample. That
way you conserve the sperm's energy until it gets in the bitch. Use
the sample 48 hours post-ovulation (48 hours after the progesterone
is over 5 ng/ml.
Managing the Bitch
She will have her first heat cycle before 24 months of age. The
average time between cycles is 7 months. The bitch is born
with 500,000 potential ova. Progesterone is the major hormone. Some
breeds cycle too often, like the Corgi & the Newfoundland. You
need at least 4 ½ months between cycles (135 days) because
the progesterone inflames the uterus. Ovaries never give
out, but the uterus does. Dr. Hutchison said that someday,
we may have the technology to harvest & use eggs in a foster
mother. [They commonly do this in show horses now.] The
Great Pyrenees & Newfoundland can have a septum in the middle
of the uterine wall. This is a dominant gene. One
client bred a Pyrenees with this problem, but did so because it
had perfect hips. Dr. Hutchison performed a C-section when
the litter was due. It's wise to check for any obstructions
like this before breeding, using a lubricated gloved hand.
The main hormones at work here are follicle stimulating hormone
(FSH) and leutinizing hormone (LH), produced in the pituitary
gland and progesterone & estrogen. FSH maintains the
placenta. There are blips of LH before the bitch's season.
Proestrus is estrogen-dominated. There is swelling, bleeding... Then
the cells around the follicles produce progesterone. This
corresponds with LH being released. Flagging begins 5 days
before ovulation. After ovulation, it takes the egg 48
hours to mature. Ovulation date is the date to calculate
the due date. In a study in Japan, they found that the
egg needs to go through that next division. If sperm are
present, the egg will just ride along until it matures and splits. If
you breed 72 hours after ovulation, you will get the largest litter
the bitch is capable of.
Litter size is dependent upon:
• Age of the bitch
• Genetics (breeding too close--produces lethal genes)
• timing
The only way to accurately time a breeding is with progesterone
levels, not physiological signs, estrogen testing or
LH spike.
Sperm survival times: fresh lives 4-6 days in the bitch,
chilled three days, frozen 12 hours.
Progesterone rise begins before or correlates with LH release. Stress
produces cortisol and this can affect progesterone. In
one bitch, the progesterone went up to 3ng/ml & leveled
off for a week then went back down. In 4-6 weeks, she came
into season again & then ovulated. This was a split
season.
If you're shipping the bitch, do it the day after she ovulates. Don't
do it early so she can "settle in;" she might be stressed & not
ovulate. Breed the next day.
One study showed that breeders were guessing the breeding date
and were wrong 4/5 of the time.
Estrus induction
Cabergoline: removes inhibition to heat cycle; has antiprolactin
effects. It is given orally for 14-30 days, 5ug/kg body
weight. It is 70% effective and works in 2-3 weeks.
Deslorelin: injectable gonadotrophin-releasing hormone
super-agonist. It stops the production of testosterone & estrogen. It
is used to inhibit LH & FSH. It was developed for mares
to prevent seasons (they come into season, then stay out). It's
from Australia. It's an implant (called Ovuplant for mares,
Suprelorin in dogs. See peptech.com) that's injected into
the lip of the vulva like a microchip. It must be removed
when no longer needed. It is 94% effective in inducing
a season in 5-7 days. It is also good for a silent season.
Estrus postponement: Why waste a season while she's performing? Postponing
it will protect the uterine lining. Progestational drugs
used in the '80's are now known to not be good choices (Ovaban,
Megace, Promone).
Mibolerone (Cheque Drops) is a male hormone (androgen)
derivative. Give every day, starting at least 30 days before
her season. The bitch must have had one season beforehand
or the drug will affect her growth plates. She will cycle
again about 70 days after stopping the drug, then you can breed
her on that first season. Side effects include cliteral
enlargement & vaginal mucous (puppy vaginitis), masculinization
(muscling), excess tear production. Do not give to bitches
with a risk of liver or kidney problems. It's wise to do
a blood panel first.
Dr. Hutchison gave a lively & incredibly informative talk. I
was glad to be able to see it in person & share it with those
of you who couldn't make it. I hope those who did attend
came away with some valuable insights that they can use
in their future breeding. He has DVD's available to buy
that can be purchased on both of the following websites:
http://www.northviewvet.com/site/view/102098_DrHutchisonsDVDs.pml
http://www.northviewvet.com/site/view/51530_ICSB.pml
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