NORMAL HEAT CYCLE
A “heat” refers to the time when a female dog becomes sexually responsive to a male dog in attempts to conceive a pregnancy. Most female dogs will demonstrate signs of their first heat sometime after she is 6 months old, with smaller dogs tending to start earlier than larger dogs.
Most dogs will have a heat cycle routinely every 6 to 8 months, with the heat lasting on average a total of 14 to 20 days. During this time frame it is normal to see a bloody vaginal discharge for the first 7 to 10 days. The female may not necessarily ovulate, or release the eggs, until this bleeding subsides. It is during this period when she will typically allow a male dog to breed her.
If successful, a pregnancy will last 60 to 63 days from the mating, although the time will vary depending on when the actual ovulations and fertility occurred.
MONITORING THE HEAT CYCLE
Occasionally, it is necessary to intervene in the natural mating process when natural breeding is unsuccessful. If it appears that the female has a problem conceiving, or if she refuses the male when all else appears normal, several avenues are available.
A series of hormonal blood tests can be done to determine when she is truly ready to ovulate and thus should accept a male. As the female nears ovulation, certain hormones will rise, indicating the timing for insemination.
Examining vaginal cytology is also a helpful tool to map out a cycle. The local cell morphology will mature as the dog nears ovulation.
In certain breeds, and sometimes in individual dogs, natural insemination may not be practical or advisable. With the help of hormonal blood tests and vaginal smears, artificial insemination may be used at the time of ovulation. Typically, this procedure may be repeated again in 24-48 hours to help increase the rate of conception.
If only chilled or frozen semen is available, a one-time surgical insemination is suggested. The dog is anesthetized and a small incision is made into the abdomen to allow direct insertion of semen into the uterine horns. Recovery is usually uneventful and the success of this procedure is quite high.
Expectant canine mothers may run into difficulty at birthing, or whelping. There are numerous reasons why whelping may not proceed as expected, including oversized puppies, inappropriate positioning, or a lack of energy or uterine tone to deliver the puppies.
At the time of distress, saving the mother is of utmost importance , but the ability to deliver live, healthy pups is an obvious added benefit. Early intervention to save mother and puppies is paramount. Immediate attention is necessary if active contractions do not produce any pups, or if there is a green/black vulvar discharge. Please contact your veterinarian immediately if you see these symptoms.
Planned surgeries are also performed on those females who have had higher risk factors for problems with whelping. These include previous problems with delivery, single puppy litters, oversized litters, and also females of certain breeds that are physically unable to deliver naturally. Hormonal blood tests can be taken before whelping actually starts to determine the best time for mom deliver live puppies in these cases. These surgeries are planned through normal office working hours to ensure adequate trained staff are available, increasing the likelihood of a healthy litter.