There is not, however, additional food in the country; nor any unproductive labourers or animals, as in the former case, whose food is set free for productive purposes.

然而该国没有多余的食物，而且也不象在前面的例子中那样，可把一些非生产性劳动者或动物的食物转用于生产目的。

youdao

Scientists already modify the genes of farm animals and agricultural plants to make them more productive or stronger.

科学家们已经改造了家畜和农作物的基因，使得他们更加多产或强壮。

youdao

Horse is one of the earliest domesticated animals by humans. In the civilization of farming and nomadic, the horse is an indispensable helper of people. Horse is a symbol of the productive forces.

马是人类最早驯化的动物之一，无论在在游牧文明还是农耕文明中，马是先民不可缺少的帮手，或者说马就是生产力的象征。

youdao

She wants to buy more productive animals like cows.

CNN: From Beverly Hills to shoveling manure on a farm

Several other farmers are keen to take slurry to spread on their own fields, and ways to deal with worries over water pollution are being squared with the EA. As for animal welfare, Peter Willes, one of the dairies' co-owners, points out that it is in his own economic interests to keep his animals happy and productive.

ECONOMIST: Industrial dairy farming

Mass screening of this sort is not, itself, a new idea in the search for drugs, but extending it so that it can study effects on entire animals rather than just isolated cells should make it even more productive.

ECONOMIST: A better way to find novel antibiotics