Livestock and Deserts

Questions of whether or not we should all become vegetarian because the conversion rate of grain to meat is 10:1 ignore a lot in order to come to that conclusion. Sure cattle are terrible at converting grain to meat--but they're not really supposed to be converting grain to meat.
Any animal converting grain to meat is a worst-case scenario. And cattle are the worst of all. Pigs do much better at 5:1, and chickens are just over 2:1. But one role of animals--particularly ruminants, is to bring otherwise un-farmable land into the food chain. Pigs excel at bringing food waste back into the food chain, and have long been raised on slops--otherwise unusable food. Pigs have even been used to manage human sewage and bring it back into the food chain--although that's not something I would recommend. And chickens are champion foragers. Given a bit of woodland and some pasture, and they do quite nicely at feeding themselves most of the year.
But most important is the role of animals, primarily ruminants, in building soil. People like Joel Salutin at Polyface Farm have found how to maximize this aspect of animal husbandry. Intensive rotational grazing by cattle followed some days later by rotationally-grazed chickens increase the speed of soil production, add nitrogen to the soil, and provides insect control.
Sustainable farming pretty much requires animals as part of a land management plan. They are just too darned efficient, and offer compact calories, access to nutrients that are difficult to acquire any other way, and the opportunity for increased income. Sustainability, after all, includes economic sustainability.
Alan Savory did this TED talk about the role of ruminants in wild systems. It's worth a watch.

Better Animal Husbandry

Le Point online and Time Magazine are both reporting an interesting story about better animal husbandry in France. In an experiment, Languedoc-Roussillon winemaker Jean-Charles Tastavy partnered with farmer Claude Chaballier after reading about Spanish ad Canadian studies indicating that happier cattle produced better tasting meat. Tastavy suggested that they try feeding a couple of animals on the pomace from his wine-making operation. The cattle were not adverse to the pressed grape leavings washed down with water, and eventually the two decided to try the cattle on wine. Tastavy and Chaballier scaled the wine recommendation for humans up to cattle, and began trying them on ~1.5 litres per day.
Yes, the cattle seemed happier than their teetotal counterparts. But after slaughter, it was noticed that the meat from the imbibing cattle was different. As Time reports:

Michelin-starred chef Laurent Pourcel had a taste of the “viande de luxe” — luxury beef — and hedges that there’s a bustling market for it among a foodie crowd. It has a “very special texture, beautiful, marbled and tender, which caramelizes while cooking.”

Tastavy and Chaballier are expanding their pilot program in the coming year. Because, even though the feeding costs have tripled (from $6 to $18), the price the Vinbovin-labelled meat fetches has gone up as well--to ~$122/kilo. Which, for a small producer, is a heck of a nice return.