As a result, the byre collapsed (7)
I believe the answer is:
thereby
'as a result' is the definition.
(I've seen this before)
'the byre collapsed' is the wordplay.
'collapsed' indicates anagramming the letters.
'byre' anagrammed gives 'reby'.
'the'+'reby'='THEREBY'
(Other definitions for thereby that I've seen before include "For that reason" , "about that amount" , "In consequence" , "By that means" , "As a result of that" .)