Leslie M. Dalton1, DVM; Todd R. Robeck1, DVM; James F. McBain2, DVM
Dystocia (abnormal labor or delivery) in beluga whales does not appear to be an uncommon condition. Two of five beluga whales at Sea World of Texas required medical intervention to assist with delivery of their calves. A third animal delivered a calf in, what we considered to be, an atypical position.
A dystocia in any mammal may result from inadequate size of the maternal reproductive tract, fetal size, shape or position, or inadequate uterine contractions. We consider a normal delivery to be a longitudinal, posterior presentation in a dorsosacral position, the pectoral flippers project caudally with the ventral surface of the flippers against the body.
The birthing process is considered dystonic when the animal has shown active signs of labor without observable progression toward delivery. Treatment may be chemical, physical, or a combination of both and should be directed at preserving the health of the mother. Chemical treatment to consider if the posture and presentation of the fetus is normal would be oxytocin alone or in conjunction with calcium, to initiate or increase uterine contractions. If this fails, then traction alone or in conjunction with a fetotomy must be considered.
Assisted deliveries using traction, regardless of how gentle, cause trauma to the reproductive tract. When a fetus is delivered with traction rather than being expelled with normal uterine contractions, the vagina will become elongated and constricted. The uterus, cervix, vagina, and/or vulva may be bruised or lacerated resulting in hemorrhage.
Case 1 presented with a cow displaying clinical signs of uterine inertia possibly secondary to fatigue. A blood tinged vaginal discharge was observed at 2130 hours and fetal fluke tips were noted protruding from the cow at 0430 hours. The cow displayed signs of active contractions for two hours, i.e., the flukes extending out and then retracting back. During the third hour, no contractions were observed and the cow swam continuously with her eyes closed. At 0730, she was caught, a blood sample collected and 140 Units of oxytocin given IV. The animal was released and active contractions were observed almost immediately. A viable calf was delivered at 0930, 5 hours after flukes were observed. The calf weighed 62.7 kg and was 150 cm in length at 2 days of age.
The dystocia in case 2 resulted from size and improper fetal position. A blood tinged vaginal discharge was observed at 1600 hours and fetal fluke tips were noted at 2200 hours. The cow continued to show signs of active labor up to 1200 hours the next day or 14 hours after the appearance of the fluke tips. No contractions were observed from 1200 hours to 1400 hours. The decision was made at that time to administer 160 Units of oxytocin IV and 110 ml of Calphosan R IM. The calf was also palpated for size, position, and any abnormalities that may exist. The calf was viable and no abnormalities could be detected. Gentle traction was also applied as the cow actively contracted. No progress was made in expelling the calf. A second IV injection of 160 Units of oxytocin was given at 1442 hours. Mild contractions continued over the next several hours. The cow did not appear in distress and continued to try to deliver the calf prompting observations for the following 16 hours. The cow showed no further evidence of delivery by 0600 hours of the following day or 32 hours after the fluke tips were first observed. She was stretchered and placed in left lateral recumbency on foam at 0700 hours. The vaginal opening was cleansed with Betadine R and lubricated with KY Jelly. The calf was determined to be dead by palpation. A soft rope was applied to its peduncle and constant tension maintained until the calf could be eviscerated and removed. The placenta was then removed since it was free in the uterus. A 12 cm longitudinal vaginal tear with no palatable perforation was created on the left side starting at the mucocutaneous junction. The tear was sutured with 2-0 chromic gut. The uterus was flushed with 1 liter of isotonic NaCl containing 1 mg/kg of amikacin. 160 IU of oxytocin was administered immediately after the flushing to expel fluid and encourage involution. The placenta was normal. The animal was placed on Ditrim R at 10.56 mg/kg bid for 14 days. Recovery was uneventful. The calf was large, i.e., 64.5 kg and 150 cm in length. The right pectoral flipper was in an anterior position with the dorsal surface against the body and the left flipper was in a normal position.
A third case involved what we considered to be an atypical delivery, not a true dystocia. The cow showed active contractions throughout delivery with the calf being expelled 6 hours and 37 minutes after the flukes were first observed. The calf was delivered with the left pectoral flipper in a cranial position with the dorsal surface flat against the body and the right pectoral flipper was caudal with the dorsal surface against the body. This calf's small size, i.e., 53.6 kg and 140 cm length, probably made delivery without assistance possible.