Canine Reproduction: What’s New and What’s Coming?

Used with permission from Today’s Breeder, Nestl? Purina PetCare Company.

Since the 1980s an increased awareness and availability of artificial breeding and reproduction techniques have provided dog breeders with alternatives
to traditional breeding.

An increase in artificial breeding as well as improved techniques has led to an increase in the number of collection centers that collect, freeze and store
canine semen and perform artificial and surgical insemination.

Some centers offer a 24-hour, seven-daya-week prenatal service designed for a home setting. Breeders may lease a uterine contraction monitor and a
fetal heart rate Doppler. The equipment transfers information collected by the breeder over the phone line for interpretation by the center’s obstetrical
personnel. Not only does a prenatal

service center offer the latest management tools available for whelping, it also

confirms the start of labor and helps to identify problems early when a timely referral should help resolve any medical issues.

“Around 1982 veterinarians and breeders became aware of the benefits mainly better-than-average fertilization results of using frozen semen to impregnate
a bitch,” says William Truesdale, D.V.M., a private practice veterinarian in Seekonk, Mass., who has a special interest in reproductive issues and
has bred and/or owned more than 90 champion Boxers.

Frozen semen continues to be a popular technique used for breeding today. Current methods used to breed bitches with frozen semen include standard artificial
insemination (Al), in which a polypropoline rod and syringe containing semen is inserted deep into the vagina and deposited in the cervix.

Surgical Al involves a veterinarian taking a concentrated volume of thawed semen and carefully infusing it into the uterus using laparoscopy.

Newer techniques include transcervcial Scandinavian breeding, in which a veterinarian palpitates a bitch’s uterus and cervix with his hand from the outside
while inserting an Al tube through the cervix. Endoseopic transeervical breeding allows a veterinarian to monitor the Al procedure on a television

Timing in breeding is very important as conception occurs precisely three to four days after ovulation, Truesdale says. Methods of determining proper timing
include the old-fashioned way of watching for changes in the bitch’s behavior. A bitch may roll her tail to the side and stand very upright in the
back to facilitate the male’s ability to mount her.

Vaginal smears can be used to indicate a bitch’s most fertile time when breeding should take place, and vaginoscopy can be used to determine changes in
a bitch’s vaginal appearance as she becomes close to her most favorable breeding time. Both techniques can be learned and perfected by a breeder, Truesdale

Hormone testing includes monitoring levels of luteinizing hormone (LH) and progesterone, the gold standard for determining the proper time to breed.
Radioimmunoassay (RTA) technique allows for accurate progesterone testing by telling exactly when a bitch is ovulating.

Different methods are used to confirm pregnancy. More traditional methods include palpitation, in which a veterinarian feels a bitch’s uterus for fetuses
at three to four weeks after the last breeding. X-ray can readily confirm pregnancy and number of fetuses, but not until the seventh week of pregnancy.
“The gold standard for pregnancy determination is ultrasound, in which you can determine the number of puppies,” Truesdale says. “However, ultrasound
has been underutilized in canine pregnancies, probably because of the cost factor or the lack of clinics with the technology available to them.”

A newer canine pregnancy test is a relaxin assay test that measures a protein relaxin, which is only present when fetuses have implanted to the uterine
wall. This test is best done 21 to 30 days post breeding and is available as an in-home test so turnaround time is a matter of minutes to hours.

Determining a bitch’s whelping date can be done using a whelping chart that counts forward based on the date of breeding. A veterinarian can estimate the
whelping date based on the size of the fetuses when ultrasound is utilized. Software is available that when skull measurements are determined and related
to a given breed, a precise due date can be determined.

So what does the future hold? “Improved freezing techniques will make it easier to use frozen semen, and introcytoplasmic sperm injection, which is the
microinjection of sperm into the ovum, will help in the efficiency of fertilizing ova in superior yet low fertile males,” Truesdale says.

This method also holds possibility of selecting gender by using either the X or the Y chromosome-caring sperm. “The technology is available in other species,
but certain anatomical logistics make this technique very difficult in dogs,” Truesdale says.

“Great advances have been made in canine reproductive science,” Truesdale says. “However, there still is a need for research in canine fertility, both
in maintenance and treatment, and breeder education. Research is the only way we can overcome the breeding obstacles set in front of us.”

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