International Giant Otter Studbook Husbandry and Management

vitamin B 1 tablet and one 400 IU vitamin E geltab per otter daily, and in addition 1 tablet of K-
dec 3 times/week per adult otter.] This was offered until at least June 1999. Their diet before
Feb. 1997 consisted of mainly fresh water rainbow trout (Salmo gairdneri), fresh water channel
catfish (Ictalurus punctatus), mackerel (Scomber scombrus), and red salmon (Oncorhynchus
nerka). (Salmon was not offered when it was out of season.) (Note herring (Clupea harengus),
common carp (Cyprinus carpio), bass (Micropterus sp.), and tilapia were also offered at times.)
In 2/1997 the salt-water fish mackerel and herring were eliminated from their diet and catfish
and salmon were no longer offered. Also, at this time their principal diet was changed to fresh
water rainbow trout. This diet remained basically unchanged until at least June 1999. (The
otters were fed three to five times per day and all fish had been frozen and thawed.)
The same acute severe problem that was observed to be displayed by Banjo on Feb. 1, 1997 at
the Philadelphia Zoo was also observed to occur, on one occasion, in an almost 3 year old male
giant otter, that was held in Dortmund Zoo in Germany (Osmann, pers. comm. April 6, 1997,
2001 & unpublished report 2004). I.e. the animal was seen dragging its hind end, hind legs and
tail on the ground and having acute hind leg stiffness etc.. This occurred on January 29, 1993.
Corticosteroids, phenylbutazon and antibiotics were administered over a period of two weeks.
The otter recovered and this acute severe problem as just described above was reported to never
occur again (this report was concluded in June 2004). An x-ray of the vertebral column (done in
March 1993) showed a slight lesion on one lumbar vertebra. It was assumed, as no other
reasons for this occurrence were evident, that perhaps the animal might have been hit by a
wooden trunk while it was playing. Note: on occasion, between March 1993 and May 1993 this
otter exhibited hind leg stiffness and was found shuffling his hind legs/feet on the floor rather
than lifting them normally off of the floor when he was walking. Mild to severe cases of this
type of problem were reported, although none of these cases were as severe as that which
occurred in January and the animal did not act if he was paralyzed in the hind end/lower back
and hind legs as he acted before. Between March and April some medications were
administered for this problem, but they did not resolve the problem. Then finally in May 1993
a nonsteroid antiphlogisticum called “Metacam”/Fa. Boehringer Ingelheim (drog: meloxicam)
was administered together with phenylbutazon and he recovered completely during the next
weeks.
This affected otter was held in an enclosure with mostly all hard surfaces, although the
enclosure had an appropriate land to water ratio. The otter did have access to a deep sand area
for deep digging in his outdoor enclosure, although access was limited during colder
temperatures. The affected otter and his brother, both from the same litter, were held in the
aforementioned enclosure together. Both of the animals were held in this enclosure for approx.
2 years before the acute severe health problem described in the paragraph above first occurred.
(The otter that did not have problems was sent to another zoo approx. one year and 3 months
after his brother was first affected.) These otters were not exposed to stairs within any of their
enclosures and the otters did not encounter other structures/surfaces where they had to regularly
climb on to access or utilize it. (Note: Years later, the affected otter was observed to have
developed on-going walking difficulties because of continued exposure to hard surfaces. He
fully recovered, without any medical treatment, after the land and floor surfaces of his
enclosures were covered with soft loose natural substrates.)
The giant otters at Dortmund were fed mainly with fresh water fish to avoid the high fat content
found in sea fish (Osmann, pers. comm. April 6, 1997). (The specific type of fish were not
listed in this pers. comm., although see below for the fish types that were fed in 1997/1998 that
were similar to the diet fed in the early 1990’s.) Osmann also reported that the amount of fish
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