Apparently it is at least more tender and has a sweeter taste, though I have not had the opportunity to try it myself. I can however think of many reasons why it would be healthier. Pairing red wine with beef has a specific health advantage, in that the iron in the hemoglobin – this is what makes red meat red – is a potent oxidant neatly counteracted by red wine’s antioxidants. The fats from beef are also tempered in their cholesterol-promoting tendencies by wine polyphenols. Whether these wine benefits are enhanced by wine in the cows’ diet is a matter of speculation, but there’s more.
Again, this is just an idea, but wine polyphenols have natural antibiotic capabilities and so they alter the demographics of intestinal bacteria. With E. coli being such a concern this could translate into a real asset. Then there is the possibility that less stressed cows develop healthier meat, due to stress hormones or other factors.
There are potential environmental benefits too. One little-appreciated fact is that cattle are a major source of methane, a greenhouse gas, so there is a large carbon footprint from every steak and burger. Under normal circumstances, cows expel up to 50 gallons of gas a day, and one calculation puts an estimate of 17% of all greenhouse gas emissions from cattle ranching. But wine cows are believed to produce less methane (perhaps related to an alteration in their intestinal bacteria?).
I don’t know if ranch hands are about to morph into sommeliers, but if this catches on I propose that we update “caballero” to “cabernero.” What do you think?