Accurate Pregnancy Diagnosis in Female Dogs
The duration of the gestation in dogs is 57-70 days from breeding and about 61-64 days in cats.Abdominal palpation may detect uterine swellings between days 20-13 of gestation.Abdominal radiography can detect fetal skeletones 42-45 days of gestation and the number of fetuses can be counted. Radiographs are also useful to predict problems at parturition (dystocia). Transabdominal ultrasound is the most informative method to confirm pregnancy. Ultrasonography can usually detect the fetal vesicles between 16-20 days of gestation. If a definitive diagnosis cannot be made, a reevaluation may be warranted in 1-2 weeks.
The fetal heart beat and embryo can be detected via ultrasonography at days 23-25 days and fetal movement at 34-36 days.If the time of breeding is known, pregnancy can usually be rulled out 30-33 days of breeding in dogs and 15-20 days after the last breeding in cats. based on the negative ultrasonographic examination.
Dog Pregnancy Tests
On the next day, after breeding with a male. Fertilization of ova may take anywhere from 48 to 73 hours. For pregnancy diagnosis in dogs several methods are used. Some physical methods like evaluation of teats, weight gain, and abdominal enlargement are not reliable methods of pregnancy detection. More reliable methods include abdominal palpation (30 days gestation), measuring the level of relaxin hormone in the blood (26 days gestation), ultrasonographic examination of the abdomen (starting at 21 – 30 days gestation), and lastly radiographs of abdomen (mainly lateral view) (after 45 days gestation). Though these methods also vary in their ability to positively identify the number of foetuses and fetal viability.
Palpation:
Small ovoid swellings can be palpated manually along the uterine horns 21-30 days post breeding. These ovoid swellings increase and become double in the size every week until days 35 to 38; they then become confluent and difficult to differentiate. Abdominal palpation in pets is not as reliable as other methods for evaluating pregnancy in dogs. Neither fetal viability can be verified with palpation nor the exact number of foetuses can be determined without experience.
Relaxin Hormone:
Relaxin hormone is produced by the placenta and found in the bloodstream of the female dogs when the fertilized egg implants in the uterine wall, about 21 days (3-4 weeks) after mating. This hormone continues to circulate through the blood throughout the pregnancy, peaking around day 40 to 50. Witness Relaxin, Relaxin Pro, ReproCHEK etc are the current test kits in the market that measures relaxin in canine blood. This test can also be used continuously throughout the pregnancy to verify if total abortion has occurred. Pseudopregnant bitches do not test positive for election. This test cannot determine the number of foetuses present in the bitch. A false negative test is possible with lower relaxin levels when litter size is very small. It may be cost effective in comparison to ultrasound. And relaxin based diagnostic test kit results are fast, accurate and reliable and seldom gives a false reading.Female dogs naturally produce higher levels of progesterone for two months after the stages of heat cycle. It is regardless of the breeding or mating. Therefore levels of progesterone in female dogs are not a reliable indicator of pregnancy.
Ultrasound:
Ultrasound is the best method used to visualise and evaluate the pups in the womb/uterus. Ultrasonography is the best tool for determining the pregnancy in dogs 21-30 days after breeding. Ultrasound done prior to 21 days can give false negative results. Ultrasound is a good method to differentiate between pregnancy and pyometra/ pseudopregnancy.Fetal viability can be determined by ultrasound through visualisation of fetal heart. The number of foetuses can be estimated, though it can be less accurate in bitches carrying larger litters, or when done later in gestation. Cost of ultrasound is higher than relaxin based kits and radiography. Cost of ultrasound depends on the region and expertise of the veterinarian or technician performing it.Ultrasonogram of gravid dog uterus showing foetuses (Anechoic contents with hyperechoic foetus)
Radiographs:
At 28 days into pregnancy, the bones of the foetus begin to become calcified. At 42 -45 days of pregnancy, radiographs can be taken to visualise the pups in-utero. However, for best results, radiographs should be taken after more than 47 days of mating, when fetal skeletons are more readily visible. Radiographs can help in determine the number of foetuses, though it is less accurate in bitches carrying larger litters. Fetal viability cannot be determined by radiograph unless advanced lesions exist in the foetus, such as skeletal collapse or gas within the foetus or emphysematous foetus.
Radiograph showing single mummified foetus in the uterus. (Osteophyte formation between 3rd and 4th lumbar vertebrae is concurrent finding)
Pseudopregnancy / False Pregnancy / Canine Pseudocyesis:
This is also called phantom pregnancy, in this case a female dog exhibits same physiological symptoms of pregnancy like enlarged abdomen, weight gain, milk let down but foetus is not actually present. Best way is to rule out pyometra / mucometra / pseudopregnancy is ultrasound.
WHELPING
The approach of whelping is signaled by mammary gland and vulvar enlargement, and decreased activity. Your bitch may also exhibit restlessness, nesting behavior and lack of appetite for 12-24 hours before parturition starts. There are three stages of the birth process:
Stage 1: 6-12 hours. Panting, restlessness, onset of contractions. Body temperature drops 1-1 1/2 degrees. (Usually below 100F)
Stage 2: 2-4 hours. Contractions and expulsion of fetus. Pups come every 10-30 minutes – often two will be born in a short period of time, then the bitch will rest for 45 minutes to an hour. Allow the bitch to break the cords and clean all the puppies. She may want to eat the placentas. This is normal, but not necessary. Do not allow her to eat more than 2 or 3, or an upset stomach is likely. Count to be sure there is a placenta for each pup.
-Active contractions go for 30 minutes with no pup born.
-There is more than 2 hours between pups.
Stage 3: Expulsion of remaining placentas and uterine involution. Call IF 12 hours go by without expulsion of all the placentas (retained placenta).
Handle the newborn pups as little as possible for the first few days. Do not allow other dogs in the nesting area. Keep the number of people visiting to an absolute minimum, and do not allow them to touch the pups for the first 3-4 weeks to avoid disease transmission.
LACTATION
Milk starts forming in the mammary gland 1-2 weeks prepartum, and may drip for a day or two before birth. The composition is very different from the milk of other animals, therefore cow’s milk is inadequate as a substitute. If the bitch has insufficient milk for a large litter, special milk replacers (such as Esbilac) must be used. Healthy, satisfied pups will wake, cry for a few moments, nurse, then sleep again. Unhealthy or hungry pups will cry for extended periods, then fall quiet as they weaken. These pups need immediate attention!
Some bitches will experience hypocalcemia (low blood calcium), especially if they are nursing large litters, in the first 3-4 weeks of lactation. These bitches are nervous and restless, progressing to panting, whining, incoordination and collapse. This is a medical emergency! Feeding calcium supplements during pregnancy increases the problem.
FEEDING
Ensure a good-quality ration for your bitch, not a local or elevator brand. Feed her normally for the first 3-4 weeks of pregnancy, then start adding puppy food to the ration for the last 4 weeks. This will ensure protein, vitamins and mineral levels adequate for the growing pups. DO NOT feed calcium supplements to a pregnant bitch – this will only increase the chance of hypocalcemia. During the nursing period, feed her puppy food. Start offering the puppies food at 4 weeks – moisten dry puppy food to a mush with water (not milk). When they are completely weaned, fast the bitch for 24 hours to decrease milk production, then place her on her pre-pregnancy ration. Puppies can be completely weaned by 6 weeks, but should remain with their littermates until 8 weeks to ensure normal behavioral development.
FAQs:
Que: how to terminate or abort a dog pregnancy at home?
Ans: Aborting a dog requires medication and should only be used under veterinarians’ prescription. Commonly used drugs for this purpose are cabergoline and bromocriptine.
Ques: how to prevent dog pregnancy after mating?
Ans: Preventing a dog pregnancy is different than aborting it. Most commonly used is hormone delvosterone and medicines like cabergoline and bromocriptine. But these must be used under supervision of a registered veterinary practitioner.
Que: Will a human pregnancy test kit work for dogs?
Ans: No. Pregnancy test kits designed for human are based on hCG (human chorionic gonadotropin) which is found only in women. Urine is used in such test kits while female dogs are tested for relaxin hormone which is found in blood.
Que: Are there over the counter tests / tests kits available for pregnancy diagnosis in dogs?
Ans: No, relaxin based test kits are available through registered vets or can be purchased online through websites / suppliers. But will need blood/serum to perform the test using a dog pregnancy kit.
DR RAMESH TRIPATHY,CANINE SPECIALIST, NEW DELHI
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