Sheep hearts I've taken up into bed (7)
I believe the answer is:
cheviot
'sheep' is the definition.
(Cheviot is an example)
'hearts i've taken up into bed' is the wordplay.
'hearts' becomes 'h' (abbreviation used in card games e.g. bridge).
'taken up' is a reversal indicator.
'into' is an insertion indicator.
'bed' becomes 'cot' (cot is a kind of bed).
'ive' backwards is 'evi'.
'h'+'evi'='hevi'
'hevi' going inside 'cot' is 'CHEVIOT'.
(Other definitions for cheviot that I've seen before include "Northumberland hills; sheep" , "One of flock" .)