The herd size is what makes pastoralism a bit economical, but once the herd size shrinks it becomes really uneconomical.

让游牧很经济的是畜群规模，但是一旦畜群规模缩小，游牧就会变得相当不划算。

youdao

But bizarrely as the size of the herd has gone down, the size of individual steers has gone up.

BBC: Smaller, fewer, thinner - the future for American beef?

The Al-Rafiqs plan to double the size of their herd, to 1, 000 goats, by 2010.

FORBES: Magazine Article

Despite introducing efficiencies and increasing the size of his herd to about 150 cows, Mr Downes said many of the costs he and fellow farmers faced were out of their control.

BBC: Richard Downes