Beast of burden all over mother (5)
I believe the answer is:
llama
'beast of burden' is the definition.
(I've seen this in another clue)
'all over mother' is the wordplay.
'over' shows that the letters should be reversed in order.
'mother' becomes 'ma' (ma can mean mother).
'all' back-to-front is 'lla'.
'lla'+'ma'='LLAMA'
(Other definitions for llama that I've seen before include "Peruvian beast of burden" , "Andean beast of burden" , "As bearer of burdens" , "Wool producer" , "Andean 'camel'" .)