Cow perhaps having drink at home with insect (8)
I believe the answer is:
ruminant
'cow perhaps' is the definition.
(cow is a kind of ruminant)
'drink at home with insect' is the wordplay.
'drink' becomes 'rum' (rum is a kind of drink).
'at home' becomes 'in' (similar in meaning).
'with' means one lot of letters go next to another.
'insect' becomes 'ant' (ant is a kind of insect).
'rum'+'in'+'ant'='RUMINANT'
'having' is the link.
(Other definitions for ruminant that I've seen before include "Eg, sheep, giraffe, cow" , "meditative" , "Beast that chews the cud" , "Animal that chews the cud" , "One chews the cud" .)