Dog, rushed into duties, recalled across river (2,7)

I believe the answer is:

st bernard

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'dog' is the definition.
(I know that St Bernard is a type of dog)

I can't explain the remainder of the clue.

(Other definitions for st bernard that I've seen before include "Large dog trained for Alpine rescues" , "Large dog trained to rescue Alpine travellers" , "Dog associated with mountain rescue" , "Large breed of dog" , "Large dog trained to rescue travellers in the Alps" .)

I've seen this clue in The Times.

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