International Giant Otter Studbook Husbandry and Management

McTurk, where commercial brand milk replacer formulas for animals were used on cubs.
Dortmund Zoo (Germany) reported using Esbilac TM , Zoologic Milk Matrix 30:55 TM , or KMR TM
(Kitten Milk Replacer) on captive born giant otter cubs of various ages. Esbilac or KMR was
used on six cubs less than 2 weeks old and Milk Matrix 30:55 was used on 2 cubs that were 2
1/2 and 3 months old. No cub survived longer than 2 weeks during handrearing. Inherited
thyroid malfunctions due to severe inbreeding were likely to have prevented the survival of all
(13 litters/28 cubs) of the parent-reared and handreared cubs born at this zoo (Osmann & Wisser
2001). This was proven by necropsies (that revealed non-functioning or malfunctioning thyroid
glands) and similar cub symptoms seen in all of the observed cubs during hand-rearing and
parent-rearing. I.e. the cubs became severely underweight and physically underdeveloped at
some point in time during parent-rearing or/and handrearing. These cubs, at various ages,
became unable to process mother’s and/or replacer milk and they starved to death. It is
expected that this breeding pair at Dortmund will never reproduce successfully. In the case at
Dortmund, the formulas used can not be considered fairly tried or tested (therefore this data was
not used to draw references from). In addition, there was a report that at Hagenbeck Tierpark
(Germany) “an attempt at hand-rearing and one of fostering to a domestic bitch also failed”
(these captive born cubs were less than 2 weeks old and this occurred before 1990) (Hagenbeck
and Wünnemann 1992). Concerning these Hagenbeck Tierpark cubs, no other information is
available.
Information is still being sought to determine if other commercial brand formulas for animals
have been used successfully and to find the ages of the cubs these formulas were used on.
Esbilac TM is highly recommended and commonly used to successfully handrear river otter
species and otter cubs of all ages. It is a commercially prepared milk replacer formula
developed for carnivore species and it is used by zoos, vet hospitals, wildlife rehabilitators etc..
When mixed as instructed on the package, it is successfully used to raise river otters (Cain-Stage
1992/93; Pet-Ag, representative, D. Hoffmann, pers. comm. 2000; Reed-Smith 1994-95).
Esbilac, produced by Pet-Ag, Inc. (headquarters located at 261 Keyes Ave. Hampshire, Illinois,
60140, U.S.-Customer Service Department Phone #: 1-800-323-6878; mail@petag.com), is
available worldwide. It can be purchased (in powdered or liquid form) at some vet hospitals or
pet stores or can be ordered by telephone for international shipping. (See Section 7 for how to
switch cubs from mother’s milk or one milk replacer formula to another.)
Other commercially prepared milk replacer formulas for carnivores have been used alone and/or
were mixed with Esbilac to successfully rear river otter species (most reports concern use for the
species Lutra/Lontra canadensis). Pet-Ag, Inc. also recommends Zoologic Milk Matrix 30:55 TM
for rearing river otter cub species (including giant otters). This formula, also produced by Pet-
Ag, Inc., was developed for specific carnivore species, including river otters. Pet-Ag Inc. states
its nutrient contents are even more closely similar to Lutra/Lontra canadensis than Esbilac’s
(i.e. its fat content is higher etc.). It also reports it has been used to rear river otters with
success, although there was at least one report, where Lutra/Lontra canadensis otter cubs did
not thrive on it, so they were switched to and successfully reared on Esbilac (Reed-Smith 1994-
95). Powdered Zoologic Milk Matrix 30:55, when mixed at the recommended dilutions (1:1 or
1:2), has been found very difficult to mix (powder lumps are also difficult to remove) or/and
feed through a bottle (it is very thick) (Pet-Ag representative, D. Hoffmann, pers. comm. 2000;
Dortmund Zoo, pers. comm. 2000). Lactol TM (British counterpart to Esbilac) (Johnstone 1978),
KMR TM (Kitten Milk Replacer) alone, or Multi-milk TM with Esbilac or KMR (Cain-Stage
1992/93 citing Evans 1986) have also been used. In some countries/locations these milk
replacer brands may be difficult to attain or are unavailable. In these cases other commercially
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