What does ‘Need a turn on the butcher’s block’ mean in cutting down the U.S. Government spending?

Question

I came across a phrase a turn on the butcher’s block in the following sentence appearing in an article of Time Magazine (Dec. 19, 2010 issue) titled Can Washington Tackle Its Deficit Cows.
I know how butcher’s block looks like with pictures, and I understand Washington must touch on big chunk of deficit sources. But what does this figurative expression need a turn on the butcher’s block really mean?
Can somebody teach me?

The list of reasons for our looming economic disaster is long: a tax-cutting and spending spree when economic times were good; the financial crisis, with its blow to tax revenues and massive spending in response; two long wars in Iraq and Afghanistan. There are also plenty of ways we can get out of hock. The Bowles-Simpson plan has spotlighted some of our government's long-standing sacred cows — ones that may finally need a turn on the butcher's block. Here are three of the most expensive ...
—Spending on Military Machine, Social Security, and The American Dream Subsidy

Answer 1

When the author of the article says

The Bowles-Simpson plan has spotlighted some of our government's long-standing sacred cows — ones that may finally need a turn on the butcher's block.

he is using a metaphor. He is equating certain government programs with sacred cows (in India, cows have traditionally been considered sacred and could not be killed) and he extends the metaphor to say they should be considered for slaughter (that is, they need to take "a turn on the chopping block", a heavy wooden table where meat is cut up, which is what happens to slaughtered beef). Calling something a sacred cow is a cliché, but the writer rescues the metaphor by extending it and freshening it up with the chopping block reference.

Also, in case you're wondering about what take a turn means, it comes from games and rides at the amusement park and the like. To take a turn at something means to be involved in a process by which a number of people wait to participate in the process one (or more) at a time. Baseball is popular in Japan, so I know you will understand that when a team is at bat, each player comes up and takes a turn at the plate to try to hit the ball.

Answer 2

I'd guess they're referring to the fact that one of the things a butcher does is trim fat off the meat. The implication is that they think the three "sacred cows" contain "fat" (i.e., unnecessary spending) that could (and by implication, should) be stopped.

Answer 3

As reported by the NOAD, a butcher's block is a a sturdy wooden kitchen table with a square top on which food may be chopped.

The metaphor used is between the meat that is cut on the butcher's block and the tax cut (or between the fat that is cut off the meat, and the tax cut).