"Maximizing Neonatal Survival"
Multiple studies have indicated that 20-30% of all puppies of normal gestation length die before reaching 6 months of age. Of the many causes of neonatal death, prolonged labor, hypoxia, and dystocia are among the primary causes. To avoid puppy loss, the breeder and the veterinarian need to be aggressive when signs of labor problems appear. A cesarean section is a commonly performed surgical procedure that can be rewarding to both the client and the veterinarian.
WHY PERFORM CESAREAN SECTIONS?
1. Puppies are not deliverable. Pelvic shape or size, an overly large puppy, or a mal-positioned pup necessitate quick action to save the litter.
2. Uterine inertia. The progesterone level dropping below 2.5 ng and the pre-whelping temperature drop (a monitoring of the progesterone level dropping) returning to normal (101-102F) should initiate active labor. Treatment with oxytocin at this time may help to actuate labor. Any signs of fetal stress should suggest a more aggressive approach.
Oxytocin will stimulate uterine contraction and initially increase the blood flow to the uterus, thereby increasing the oxygen level to the feti. If oxytocin is continued to be given, the uterine blood vessels dilate and the blood pressure to the uterus drops, subsequently robbing the puppies of oxygen. The only factors affecting the oxygenation of the puppies in utero are the uterine blood pressure and the fetal heart rate.
A good "rule of thumb" when using oxytocin to aid delivery is to give one dose either intramuscularly or subcutaneously . If no response is noted in the bitch within 20 minutes, a second injection of oxytocin is given. If there is still no response after the second infection <sic>, a c-section should be performed. Further injections of oxytocin can be detrimental. *
3. Signs of in utero fetal stress. Black, red, or green vaginal discharge before any puppies are delivered signifies placental separation and blood leakage. The puppies should be immediately evaluated for stress by monitoring the fetal heart rates. Normally the fetal heart rate should be twice that of the bitch. The use of ultrasound and doppler will evaluate the strength and rate of the fetal heart. A slowing of the fetal heart can be the deciding factor as to whether a c-section is needed. The evidence of fetal bowel movements in utero can also indicate fetal stress.
4. Convenience. A planned c-section can be a method for the breeder to assure the most live puppies. Timing of the c-section is critical to assure fetal health.
Puppies need a full gestation period to be ready to survive outside the womb. A bitchs anticipated due date can be calculated as 63 days post ovulation or 65 days post luteinizing hormone surge. Breeding dates cannot be used to calculate the exact whelping date of a bitch.