Months after the downer-cow scandal of last winter, USDA chief Ed Schafer announced plans to ban all downer cows from the food supply.

The rule involves cows that get sick after an initial inspection by veterinarians before slaughter. Under old rules, such cows could be reinspected by vets and then cleared for slaughter if the vet decided they posed no threat.

In the press release announcing the proposed new rules, Shafer had this to say:

Last year, of the nearly 34 million cattle that were slaughtered, under 1,000 cattle that were re-inspected were actually approved by the veterinarian for slaughter. This represents less than 0.003 percent of cattle slaughtered annually. As you can see, this number is minimal.

If I’m understanding him correctly, the secretary is saying the problem was always pretty small and thus never much of a big deal — and will, at any rate, be solved by this new rule.

I think he’s being cheeky; I think pressure on packers to force sick cows through the slaughter line and into the food supply will remain strong.

First of all, the “under 1,000” number reflects cases where the beefpacker followed proper procedure: identified downers, had them inspected and approved by vets, and ushered them into the food supply.

But at Westland/Hallmark, the California beefpacker that sparked the downer controversy in the first place, procedure broke down. To avoid having sick cows deemed “downers” and thus in need of re-inspection, workers tried to make them walk — by subjecting them to all manner of torture.

How many downer cows made it down the kill line that way in 2007? Well, Shafer has no comment on that. There’s no way of knowing — but we do know that downergate revealed all manner of gaps in the meat-safety system.

Then there’s the structural issues that create incentives to a) make cows sick, and b) force them through the kill line. To illustrate, let’s review a few of the facts of the scandal at Westland/Hallmark, the California beefpacker that sparked the downer controversy in the first place.

• The unfortunate beasts being led to slaughter were spent dairy cows on their way to becoming hamburger meat for schoolchildren. Conventional dairy farming is an incredibly low-margin activity; slaughtering the old cows for meat is an important source of income for dairy farmers.

Conventional dairy farming is also a brutal process for cows; by the time they’ve been squeezed to the last drop of their production abilities, they’re in pretty sad shape, pumped full of all manner of stuff that isn’t good for them: corn (which ruins their livers), ethanol waste products (corn stripped of its starch, with industrial residues added), hormones, and antibiotics. The USDA downer ban will not prevent spent dairy cows from entering the food supply — except ones that are too sick to walk.

• Westland/Hallmark was a relatively small company ($100 million in annual sales), competing against giants like Cargill ($75 billion “and growing”) and Tyson ($27 billion). Westland/Hallmark had developed a niche selling to the federal government’s school-lunch program — at $1.42 per pound of hamburger meat, the L.A. Times reported in February. Small meatpackers operate under razor-tight profit margins, and will continue to have an incentive to squeeze as much revenue as possible out of any cow that comes their way.

The new rule amounts to a necessary but insufficient measure. Of course we need to keep downer cows out of the food supply. But the change does nothing to improve the sick food system that pressures farmers to make cows sick in the first place — and that gives processors incentive to push those sick cows onto our plates.

Shafer has spoken forcefully about banning downer cows. What does he have to say about the latest market-share grab in the beef industry — the one that will end with three massive companies slaughtering as much as 90 percent of U.S. cows?

What will he say about corporate machinations in the dairy industry, wherein — according to recent lawsuits — mega-processor Dean Foods has been colluding with a corrupt dairy farmers’ cooperative to hold down the milk price paid to farmers? Again, low prices drive farmers to squeeze as much milk out of their cows as they can, by any means necessary — and sell the abused beasts’ bodies to the meat industry when they can no longer deliver milk.

Until these structural issues are confronted head on, it seems risky to trust what comes out of our meatpacking plants — regardless of the new USDA downer ban.