The overuse of drugs against parasitic worms which infest stock animals means that these, too, are becoming drug-resistant.

人们对家畜身上的寄生虫过分使用药物，这让它们也有了抗药性。

But they included transplanted grass species that have gone wild, yet provide grazing for stock animals, and introduced forest trees that yield timber for construction.

但他们研究了移植后开始大量生长，可以作为牲畜饲料的草种，以及引入的可用于生产建筑用木材的林木。

But that is now seen as unusual. It may not be in the future, however, as research conducted in Australia and New Zealand suggests algavory of this sort may reduce greenhouse-gas emissions from stock animals.

但现在看来，这是不寻常的。但以后可能就觉得正常了，因为在澳大利亚和新西兰进行的研究表明这种藻类可以减少家畜的温室气体排放。