Actually, I apologize for replying to myself, but I couldn't resist going off and coming up with some numbers. There's a pretty darn strong and unexpected correlation between the price of a Big Mac and the number of cows per head population.

I could only get good cows-per-person numbers for the big beef producers, but here goes:

Country Cows per person Big Mac Price

Australia 1.28 $4.94

Argentina 1.26 $4.64

Brazil 1.07 $5.68

Colombia 0.59 $4.54

USA 0.31 $4.20

Mexico 0.29 $2.70

Pakistan 0.18 $2.89

Russia 0.15 $2.55

India 0.15 $1.62

China 0.06 $2.44

So there ya go, the more plentiful cows are the more it costs to get one cut up and put on a bun. (Or, perhaps, the more you can sell your beef for, the more likely you are to be a cattle rancher.)