DVMs can help clients understand behaviors during, after delivery

Q I see a few novice pedigree dog breeders in my practice. Pleaseprovide a concise review about natural delivery of puppies and informationthat these novice breeders could benefit from reading.

 A At the end of last year, I published a simple articleon natural delivery of puppies and some of its associated problems - HoskinsJD: Whelping and care of newborn puppies. Pedigree Breeder Forum 9(3):7-13,2000. Some of the information in this column is presented in that articlefor client reference.

Preparation time

As natural delivery of the puppies approaches, bitches may change theireating habits. Some bitches will eat more than a normal amount of food andconstantly beg for more; others will reduce the amount they eat or eat verylittle.

At least 24 hours before natural delivery of the puppies, it is a goodidea to clip short the long hairs surrounding the nipples and the vulvato prevent interference with delivery and nursing. Approximately 18 to 24hours before natural delivery, the bitch's rectal temperature should drop1F to 2F below the normal rectal temperature. The normal rectal temperaturefor adult dogs at home is 100F to 101.8F. Rectal temperature can be takentwice a day. When the rectal temperature drops, it is important to stayclose because delivery is near.

Natural delivery

Natural delivery has three stages. Stage 1 begins with contractions ofthe uterus and ends when the cervix is fully dilated. It takes about sixto 12 hours.

Bitches may appear restless and nervous and may shiver, pant, vomit orpace. Most bitches seek a place to "nest" near the end of thisstage. Stage 2 begins with full dilation of the cervix, entry of the firstpuppy into the birth canal, and rupture of the membranes that surround thepuppy. Stage 2 ends with delivery of the last puppy. The bitch shows obviousintense abdominal contractions in her attempt to deliver the puppies.

The time between initiation of stage 2 and delivery of the first puppyvaries (it is usually less than four hours). The time between deliveriesof subsequent puppies also varies (usually 20 to 60 minutes), but can beas long as two to three hours. Stage 3 begins after delivery of the puppiesand ends with passage of all membranes. If the bitch has multiple puppies,she may alternate between stage 2 and stage 3.

Difficulty in natural delivery

The natural delivery problems of puppies usually involve a small or deformedbirth canal, an oversized puppy or weakness of the uterus (that is, insufficientforce of the uterus to propel a puppy through the birth canal).

Natural delivery problems are present if the bitch has had 30 minutesof persistent, strong, abdominal contractions without expulsion of a puppy.

Other problems include:

• If more than four hours have passed since the onset of stage 2 to delivery of the first puppy;
• If more than 2 hours have passed between delivery of puppies;
• If the bitch fails to deliver a puppy within 24 hours after rectal temperature falls below 99°F or within 36 hours of serum progesterone being <2 ng/ml.

A natural delivery problem also exists if the bitch cries and displayssigns of pain and constantly licks her genitals when trying to deliver.The normal length of pregnancy is 63 days from the last breeding. Naturaldelivery problems exist if the pregnancy is prolonged (that is, more than70 days from day of first mating, more than 59 days from the first day ofdiestrus (the time when the bitch will not allow the breeding act to occur),or more than 66 days from the peak in the serum luteinizing hormone (LH).

Assisted natural delivery

Assisted natural delivery is used when a puppy is lodged in the birthcanal during delivery. Preferably, a veterinarian should be used for assistednatural delivery.

The veterinarian will apply lubrication liberally on a gloved hand andplace the bitch in standing position. Use of gloved fingers is the safestand most reliable approach to manually pulling a puppy through the birthcanal.

If the birth canal is too small for fingers to move and lubrication isadequate, the veterinarian can use instruments.

Breeders should never use instruments in attempting assisted naturaldelivery of live puppies. These instruments can do great harm to the puppyand to the bitch.

The veterinarian will place a gloved finger in the birth canal to directthe instrument. A spay hook or a non-ratcheted forceps is used, and tractionshould be applied to deliver the puppy in a posterior and ventral direction.Traction on a single leg is definitely contraindicated. The veterinarianwill perform a cesarean section if the puppy cannot be delivered within25 to 30 minutes.

Cesarean section

Two types of cesarean sections are generally performed in dogs: unplannedand planned. An unplanned c-section is necessary in the bitch with the following:weak contractions of the uterus, unresponsiveness to the hormone injectionoxytocin to stimulate contractions of the uterus, pelvic or vaginal obstruction,a puppy in an uncorrectable position, oversized puppies, puppy stress ora dead puppy still in the uterus. Planned c-section is necessary for breedshighly prone to failure of natural delivery and bitches with a history offailures in natural delivery.

Establishing immediate maternal behavior

Establishing maternal behavior of a birthing bitch involves a varietyof hormones, experience as a birthing bitch, hereditary tendencies and thestimulus provided by the newborn puppies.

Vaginal-cervical stimulation, which is caused by the passage of the puppythrough the birth canal, causes oxytocin release by way of spinal afferentswith neural connections to the hypothalamus. The cells that produce oxytocinare located in the hypothalamus.

These cells have axons that carry the hormone either to the posteriorpituitary gland, where it is released into the peripheral blood stream,or to other parts of the brain, including the olfactory bulb. In the olfactorybulb, oxytocin stimulates the release of monoamines and opiates, which theninitiates a sensitive period during which the bitch will identify the smellof the puppies as her own. The period during which a bitch will form a bondwith a specific puppy is probably less than 24 hours.

Apparently, a decline in circulating estrogen and prolactin, an increasein oxytocin (and possibly prolactin), cervical stimulation and the presenceof a small puppy with a foreshortened face and wet with amniotic fluid areall factors involved in establishing the bitch's maternal behavior.

Puppy rejection

Problem: Puppy rejection is an immediate problem with some birthingbitches. Immediate puppy rejection usually occurs in primiparous bitches.Experience with being a nursing mother once seems to be very important.Multiple rejection episodes are uncommon, possibly because owners do notbreed the bitch again after she refused to nurse her puppies the first time.Solution: Sometimes characteristics of a newborn puppy can be used to inducea new mother to accept her puppy if she is not naturally maternal or tomotivate a bitch to accept a puppy that is not her own.

These characteristics are that it is small, uncoordinated, and wet. Wettingwith amniotic fluid is the best way, but amniotic fluid is usually not available.Wetting the puppy with warm water can be effective. Be sure that the puppydoes not become chilled as a result. The bitch will lick the puppy, thusdrying it and possibly triggering the natural maternal acceptance.

Problem: C-section is frequently associated with immediate rejectionof newborn puppies. Case example: Immediately following surgery, the puppiesare introduced to the bitch in her cage in the hospital's observation andrecovery area. She immediately kills a puppy. The owners then take the puppiesand handle them before representing them to the bitch in their van. Apparently,the combination of a more familiar place as in their van and the owner'sscent on the puppies was enough to inhibit aggression and allow the bitchto recognize the puppies as her own.

Solution: It is important when introducing the bitch that hashad a recent cesarean section performed to her holding cage in the hospital'sobservation and recovery area that the holding cage be warm and as freeof noise as possible. The newborn puppies should already be in the holdingcage and making sounds that indicate hunger.

It is also extremely important to allow sufficient time to pass for thebitch to establish her maternal behavior before she is transported to thehome or a new location. Birthing in familiar environments always helps toreduce aggression toward newborn puppies.

Problem: Occasionally, puppy rejection can lead to cannibalism.In some cases, the bitch eats the placenta and chews the umbilical cordand she may keep on chewing up the umbilical cord and begin consuming thepuppy. Solution: There is nothing one can do to stop cannibalism of a litterof puppies once it starts other then to raise the newborn puppies as orphans.