Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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The OB/GYNs of the Dog World

Pet Column for the week of March 13, 2006

Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
Kim Marie Labak
Information Specialist

facing veterinary issues such as genetics, fertility, and nutrition, dog breeders call upon the expertise of veterinary obstetricians--known as theriogenologists, the fertility specialists of the animal world.

Breeders can consult theriogenologists through all phases of breeding, from determining the proper timing for mating through post-natal care of pups.

Dr. John Herrmann, board-certified theriogenologist at the University of Illinois Veterinary Teaching Hospital in Urbana, explains that the veterinarian's goal for breeding is quite simple: "We want healthy puppies and a healthy mom in the end."

The first step is to find a suitable mate. Reputable breeders and veterinarians check the pedigree of both dogs, or family trees, to make sure they are not too closely related. Dr. Herrmann explains that inbreeding is somewhat inherent with pure breeds, which were developed by mating dogs with similar desirable qualities. This manner of selective breeding can limit the gene pool and perpetuate undesirable qualities.

For example, brachycephalic breeds (breeds with short, broad heads such as bulldogs and Pekinese) tend to have problems with the nasal cavities and trachea, and several large breeds are genetically predisposed to bone cancer. If a dog has a personal or family history of a genetic disease, veterinarians may recommend not breeding those two specific dogs.

Another factor in finding a mate is determining how suitable each animal is for breeding through a breeding soundness examination, or BSE. For males, the BSE involves examining testicles and acquiring a semen sample to test the viability of the sperm. For a female, the BSE involves assessing the regularity of the estrous cycles and a pelvic exam of the birth canal and reproductive tract.

After a match is made, a theriogenologist now has to determine the best time to attempt insemination. Herrmann explains, "Timing is key. Dogs are a very fertile species--if we can't get them to reproduce, it's usually due to poor timing." A series of blood progesterone tests and microscopic examination of vaginal smears can help a veterinarian predict the date of ovulation.

Once the veterinarian and breeder know the ideal window of time for insemination, they choose a method for breeding the pair. The pair may be allowed to mate naturally, or if the female (in canines, also known as a bitch) rejects the male, the veterinarian and breeder may perform "assisted natural breeding" by manually collecting the semen from the male, then immediately inserting it into the female using a thin plastic pipette, or straw.

Another option is artificial insemination (AI) with cooled or thawed frozen semen. Cooled semen can be shipped overnight across the country or internationally, so a dog in Europe could father puppies in the United States. Semen of a show champion can be frozen and stored for years for later use. When using cooled or frozen semen, precise timing of insemination is even more critical since this form does not survive as long in the female tract. as that of fresh semen.

For AI, semen can be inserted into the vagina using a standard plastic pipette, or via the more successful but more expensive trans-cervical method (through the cervix and directly into the uterus) using fiber optics.

Pregnancy diagnosis can be performed by a number of methods at various times after breeding. Ultrasound exam can diagnosis pregnancy as early as 18-20 days. Manual palpation, with a cooperative female, can pick up pregnancies as early as 23-24 days. Radiographs can be used to not only diagnose pregnancy at around 42 days but can also give an accurate head count near term, which is 63 days.

Once a female becomes pregnant, a theriogenologist will continue to see her throughout her pregnancy. In the third trimester, x-rays can indicate how the puppies are developing.

Veterinarians don't usually get involved in whelping unless complications arise. The most common complication Herrmann has seen is uterine inertia, or failure of the uterus to contract. This problem is common in certain breeds and in mothers that don't get enough calcium during their pregnancy, since calcium is needed for muscle contraction.

If a mother is having difficulty whelping, a veterinarian may help deliver the pups manually or may perform a cesarean section. In some cases, breeders may plan a c-section to minimize the potential for birthing complications. Herrmann points out, "Again, with c-sections, timing is crucial. If the pups stay in too long, they will not survive, but if they are taken out too soon, they will have not fully matured, so if we plan to do a c-section we need to know the exact date of ovulation and calculate the birth date accurately."

Once puppies are born, if all goes well the veterinarian won't have to see them for a few weeks, when they come in for a routine check-up, de-worming and vaccinations.

For more information about canine breeding, pregnancy, and whelping, consult your veterinarian.