The four join the roster alongside DDB London, the commission's incumbent agency, which will continue handling advertising for the British Pig Executive.
Burnetts has been assigned work for the English Beef and Lamb Executive.
The MLC announced in March that it was lining up agencies to pitch for an above-the-line project for the English Beef and Lamb Executive and was preparing to take on a roster. A statutory review of the MLC's account was launched in October last year.
The body works with the British meat and livestock industry to improve its efficiency and competitive position. It also aims to stimulate the markets for British meat at home and abroad while taking into account consumers' interests.
The review was overseen by the MLC's marketing director, Richard Lowe, and follows a period of significant change at the commission.