You And Your
Vet
BY Merry Fitzgerald, DVM.
How do I calculate my bitch’s whelping date? The most accurate calculation of the whelping date is to count 65 days from the LH (luteinizing hormone) surge. This requires collection of daily blood samples and a laboratory that is capable of determining LH levels. Measurement of progesterone levels is more readily available. The time of the LH surge can be estimated as the day that the progesterone level first exceeds 2.0 ng/ml, as long as the progesterone level continues to rise. The whelping date will be 65 days – plus or minus one day- from the date the progesterone level reaches 2.0 ng/ml and continues to rise.
Will having my bitch palpated for pregnancy harm the puppies? The ideal time for abdominal palpation is 28-30 days after the last breeding. At this stage the gestational sacs are distinctly round and easily distinguished from other abdominal organs. Depending on the size of the bitch, the sacs range in size from a marble to a golf ball. At four weeks along, the fetus is the size of a bean and is safely encased in the amniotic fluid of the gestational sac. Palpation will not harm or dislodge the fetus. 26 Dog News
Are sonograms recommended during pregnancy? Ultrasound examination is a safe way to confirm pregnancy and monitor the development of the fetuses. Pregnancy can be detected as early as day 2022 by an experienced sonographer, but is more reliable at day 30, especially with small litters. It can also detect problems in the uterus, such as resorption of the fetuses. This allows you to provide appropriate supportive care and medication, as needed. During the procedure, the probe of the ultrasound ma-
chine moves continually over the abdomen as it scans both horns of the pregnant uterus. As a result, the actual count of fetuses can be inaccurate. A radiograph taken in the last week of the pregnancy will give you a more definite puppy count.
Is there a test to determine if she is definitely pregnant? Yes. The presence of significant amounts of the hormone relaxin is a reliable indicator of canine pregnancy. The WITNESS RELAXIN kit made by Synbiotics Corporation can determine pregnancy by measuring relaxin levels in blood samples. The kit detects relaxin produced by the developing placentas as early as day 20 after the LH surge. Factors such as the breed, size of the bitch, and litter size affect the level of relaxin in the blood. Approximately 80% of pregnant bitches test positive between day 20 and 28 post-LH surge, although some may not show a positive result until day 31. I have found the test to be 100% accurate when testing 35 days after the last breeding. The test can be performed by your veterinarian in about 10 minutes. A small amount of blood is drawn and the test is run with either a serum or plasma sample. Any negative result is considered indicative of non-pregnancy; however, two negative results one week apart may be required to confirm the negative result, especially when the date of mating is unknown. A positive result indicates pregnancy. A weak positive result may be observed early in the pregnancy or with a very small litter. Continued on page 60