International Giant Otter Studbook Husbandry and Management

that was fed was nearly the same as that which was fed at Philadelphia before 2/1997: approx.
6-7 pounds per animal per day. Also given at Dortmund were the following: once per week
vitamin B1, 200mg per animal, vit. E 350mg per animal, vit. D3 1000 I.E. per animal, and 3
times a week multivitamins (A/D2/C). (It was reported that the animals were not overweight.)
Normally the giant otter diet at Dortmund Zoo consists of 90% local freshwater fish that include
mostly Rutilus rutilus (Redeye) and Abramis brama (Brachsen) (Gatz, pers. comm. 2/1998).
Perca fluviatilis (River perch) and Tica tinca (Tench) are only occasionally offered. Small fish
are usually fed and they are of high quality. Occasionally, when there is an absence of local
freshwater fish, this diet is replaced by 90 % rainbow trout, although we try to limit the time that
large amounts of rainbow trout are given, because it can become difficult to encourage the otters
to return to their normal diet after they have had trout for longer periods (e.g. for a 4 week
period). Ten percent of the diet consists of herring and mackerel as it is used during husbandry
training and to hide medication and vitamins within. All fish are stored below minus 20 °C and
thawed at the day of feeding. Live fish, which is given up to three times a week, consists mostly
of rainbow trout (Sa/mo irideus), but it also includes Rutilus rutilus and Abramis brama. Each
animal eats approximately between (2-3 kg) (4.4 lbs. to 6.6 lbs.) of fish each day, given at three
to five different times. As well vitamins were offered as follows: Optovit 500 (vitamin E) two
times/week; vitamin B1 two times/week; Vigantolette 1000 two times/week; and Multivitamins
(Lichtenstein) 5 times/week. A more current diet is also listed in Chapter 2 Section 19.
An approx. six year old female giant otter, living in Chestnut Centre in England (Heap, pers.
comm. 1997), was reported to suddenly display significant problems and walking difficulties
involving her hind legs and lower back. [I.e. the animal was seen dragging its hind end, hind
legs and tail on the ground and having acute hind leg stiffness etc. (Heap, pers. comm. 1997 &
1999.] A course of cortico-sterioid tablets, administered for treatment, resolved her problems.
(I.e. her problem resolved soon after it first occurred.) The cause of her problem remains
unknown. (An approx. 7 year old male giant otter lived together in the same enclosure with the
female and they lived there approx. 4 years before the female had this particular health problem.
This pair were brother and sister.) The otters had access (all year) to an expansive natural
outdoor enclosure with an appropriate land to water ratio and an indoor enclosure. (See a
detailed description of the outdoor enclosure in Chapter 2 Section 1C and the indoor enclosure
in the same chapter Section 9). All of the surfaces in the outdoor enclosure were soft (i.e. soil)
and they were offered a sand deep digging area and could also dig in the soil. The land area
indoors is covered with soft loose substrates. Chestnut Centre fed live fresh water rainbow trout
(Salmo gairdneri) (3 to 5 lbs. per day per animal) as the principal diet and also offered sprats (½
lb. per day per animal). (The trout was fed live.) Also 2-3 day old chicks were given daily per
animal and a ½ lb. of minced beef was offered per animal twice weekly. The otters were fed
twice per day. They gave vitamin supplements daily (Aquavits. one tablet each) and one dessert
spoon of cod liver oil daily. This diet was fed at least until late 1999. The 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. The otters were
not reported to be overweight and they also did not appear overweight in 1999. At least until
late 1999 no further occurrences of this health problem were reported to be seen.
It seems that all of the above reported occasions of severe acute walking difficulties observed
among these giant otters can be linked and regarded as a single specific type of health problem
(i.e. verses being considered unrelated ailments). (It seems reasonable to assume that this health
problem is a different type than the ongoing progressive walking difficulties known to occur
among giant otters.) With this assumption and based on the theories posed about what may
cause this acute problem, analysis should be made about the amount of hard surfaces that these
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