432-436

 

Normal Parturition

• Relaxin is thought to be important in relaxation of the soft tissues around the pelvis. Detectable after 25 days of gestation relaxin from the fetal-placental unit declines abruptly at parturition.
• Prolactin from the anterior pituitary increases at day 35 and peaks at about day 50 of gestation to term. Prolactin is important for mammary development, evident around 24-48 hours before parturition, and subsequent lactation.
• Estradiol concentrations are variable during pregnancy but the concentration surges about 9 days before parturition.
• It is theorized that initiation of parturition in the queen is similar to that documented in the ewe. An initial fetal cortisol rise alters placental progesterone production into estrogen. The estrogen causes a release of prepartum prostaglandin. The prostaglandin, or the abrupt decline in progesterone, may have a hypothermic effect on the queen; an effect observed in a drop of the rectal temperature of the queen during the first stage of labor.

• The queen can control parturition to some extent, therefore it is important that the queen be in a secluded, comfortable area for queening. Provision of a queening or nesting box 7 days prepartum will give the queen familiar surroundings for parturition. She may be placed in total isolation, in a prepared queening box, in an area of the queen's choosing, or in the company of a trusted human companion.
 

Normal Delivery

• Parturition may last as long as 24-36 hours, but kittens are usually expelled after a mild labor of 30-60 minutes and a 5-10 minute period of intense labor. After the birth of a single kitten, the queen may not exhibit signs of labor for 30-120 minutes. Usually each individual placenta is passed after each kitten or it may be passed after a subsequent kitten. The queen commonly ingests the placenta and then cleans the kittens.

Abnormal Parturition (Dystocia)
• Dystocia is not normally a problem in the healthy, physically conditioned queen.
• Dystocia is most commonly associated with the birth of the first kitten.
• After delivery of the first kitten, parturition usually proceeds normally.
 

Diagnosis

• Diagnosis of dystocia can be based upon any of the following observations during queening:
• 1) 20 minutes of intense labor without a kitten being delivered;
• 2) 10 minutes of intense labor when a kitten is visible in the birth canal;
• 3) acute depression;
• 4) elevation of body temperature; or
• 5) the presence of fresh blood for more than 10 minutes.
 

Maternal vs fetal

• When a dystocia is diagnosed, it is important to differentiate between a fetal and maternal dystocia in order to proceed with the correct therapeutic measures.
• Fetal dystocias are caused by oversized or malpositioned fetuses in the uterus or birth canal.
• Maternal dystocias are caused by failures of the queen to pass normal sized kittens.
• Maternal dystocias include uterine inertia, small pelvic diameter, uterine torsion, uterine rupture and ectopic pregnancy.
• Fetal dystocia can usually be corrected if the kitten can be palpated per vaginum by liberally applying lubricant, and allowing the queen to continue with parturition.
• Cleanliness is essential when entering the birth canal, because introduction of bacteria into the uterus during manipulations can be a major cause of postparturient metritis.
• If the kitten cannot be palpated per vaginum, it is best to radiograph the queen to determine the kittens' position and relative size.
• Very small litters tend to have larger, oversized kittens that cause dystocia. In these cases, cesarean section is the preferred method to correct the dystocia since excessive manipulation or use of instruments harm the kittens and queen.
 

Treatment

• Maternal dystocias are most commonly caused by uterine inertia. Uterine inertia occurs when the birth process has exhausted the uterine musculature making contractions impossible or
• non rhythmic (secondary uterine inertia). It can also occur when the uterine musculature has insufficient uterotonic stimulation from oxytocin (primary uterine inertia).
• Uterine inertia can be treated by administration of oxytocin at a dosage of 2-4 IU IM every 20 minutes. If oxytocin fails, 1-2 ml of 10% calcium gluconate solution can be administered
• slowly intravenously.
• Cesarean section should be considered the best option for saving the litter if these efforts fail.
• Because the duration of normal parturition may be up to 24 hours, determining exactly when a queen is experiencing dystocia may be difficult. It must be remembered however, that normal parturition can be prolonged and that placing a queen in a secluded queening area may be the best option for the queen and the client. Because the queen can voluntarily control parturition, excessive intervention by humans can actually prolong the length of parturition or delay its onset.
• If the queen has signs of acute depression, elevation of body temperature or fresh blood coming from the vagina; uterine torsion, uterine rupture, or ectopic pregnancies should be considered. Although these are uncommon signs, upon seeing them, the dystocia is best handled via laparotomy to maximize the queens chances for survival.