Is livestock followed by a plural form of the verb?

The noun 'livestock' is normally considered to be plural, meaning 'domesticated farm animals', for example cattle or sheep.

'Mr Johnson's livestock were kept in the field at the far end of his farm.'

However, the Word would be singular if you were considering livestock as a single entity rather than a number of individual animals.

'Although Mr Johnson describes himself as an arable farmer, his livestock contributes part of his income.'