Having worked in Ireland's Climate Change Division of the Department of Ag for 5 years, I have often herd that the facile answer to our Ag emissions is to cull the cattle herd and reduce meat consumption - all very well, but the gap would be taken up by South American countries whose meat production systems are very questionable - carbon export. This would make no difference to emission levels from agriculture worldwide and would probably make things worse globally.
The reality is that the demand for meat is escalating, particularly in Asia with a rising middle class - our system is not perfect but is still pretty efficient