Sure, here's the first two that I looked up:

http://juharanch.com/

http://www.yellowstonegrassfedbeef.com/node/100

QED. I'm sure if you bother to research this you'll find many others.

If you stop and think about your question more deeply I think you'll unask it.

Organic produce farming requires manure. Something like 1/4 of the land mass of the USA requires grazing animals to maintain an ecological balance.

That manure and those animals are requirements, not luxuries.

Sustainable produce farming requires sustainable animal farming, because nature is inherently symbiotic.