International Giant Otter Studbook Husbandry and Management

The general guideline that food/formula should be offered in the amount of approximately
20% of the cub’s body weight in a 24 period remains the same during weaning. (I.e. as
cub weight increases, the amount of food offered should be increased). Some healthy cubs,
although, may require up to 30% of their body weight in a 24 hour period. This total
amount should be divided by the number of feedings per day (see Section 8 for feeding
schedules during weaning). Cubs must learn to drink plain water (i.e. in addition to their normal
milk formulas) at least during early weaning and preferably just before weaning begins. To
introduce water, a small amount of milk formula should be added to the water to make it taste
familiar and eventually the milk should be reduced until the water is plain. Free-choice clean
drinking water must always be provided during early weaning and onward. This is
especially critical when milk formulas are mixed with fish, as they will not provide enough
fluids/water necessary for cubs (especially as fish ratios are increased). Cubs must be
monitored to determine if they are drinking enough water to maintain good hydration. If
they are not, water should be hand-feed until the otters drink enough on their own. Bottle
feeding, teaspoons/tablespoons and large plastic syringes (esp. when formulas thicken), can be
used until cubs learn to eat and drink from bowls. Feeding and water bowls/dishes, such as
small heavy ceramic bowls, that cannot be tipped over or be destroyed (e.g. chewed apart)
should be offered. Cubs must be cleaned and dried after feeding, as they can get very dirty
when eating (see Section 15).
See Chapter 2 Section 19 for information on fish diets, vitamins etc. that are necessary during
weaning. Unused fish and formulas must be kept refrigerated and they must not be used more
than one day. Formulas should be made fresh daily and heated portions should not be reheated.
The goal of weaning is to gradually (i.e. slowly) reduce milk formula amounts as fish
amount and fish texture (size of fish pieces etc.) is increased. Ample amounts of milk
replacer must still be offered during early weaning. If the fish ratio is increased too
quickly, it may result in health problems. Weaning should be started by gradually adding
very small amounts of mashed minced fish filet to the cub’s milk formula (Burnette 1994).
Caretakers should filet the fish (remove bones, scales and skin) and dice/mince/cut the fish into
very small fine pieces. The minced fish can then be added to the normal strength milk replacer
formula and a pulverized blended mash can be made from it (using a blender at high speed
helps). It initially can be served in a bottle, but then eventually a plate, bowl, or dish will be
needed as the formula thickens. This diet should be warmed before it is served (See Section 6).
The percentage/ratio of fish (in the fish to milk formula ratio) and the size (texture) of the fish
pieces should be gradually increased over the weeks. This should be done according to the
otter’s acceptance and abilities to digest the food in a healthy manner with healthy stool. Each
individual will vary somewhat in its acceptance. For example, weaning can be started by adding
approximately 10% fish to the cub’s milk replacer. (I.e. the same milk formula strength/dilution
as has been offered should be continued and total diet amounts should be offered as
recommended). Free-choice drinking water must always be available and cubs must be
monitored to determine if they are drinking enough water for proper hydration. The fish ratio
should be increased gradually so the diet thickens to a porridge or gruel like texture (Burnette
1994). Some (i.e. a small amount) additional 100% milk formula can be made available in
another bowl as the milk formula fish mash increases in thickness as the change-over
progresses. See also at the bottom of the following paragraph another successful technique that
can be used to first introduce fish into the giant otter cub’s diet.
As tolerated and later on (i.e. when the mash is accepted and digested well and cubs start
chewing more), small pieces of fish filet can be mixed in the milk formula fish mash. “As
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