问题描述：
英语翻译
When used at levels higher than those covering animal requirements
and up to 175 mg and further to 250 mg/kg feed,copper impacts on
the growth and feed conversion of young pigs,from weaning to a
body weight of approximately 25 kg (8 to 10 weeks of age).
When used at levels higher than those covering animal requirements
and up to 175 mg and further to 250 mg/kg feed,copper impacts on
the growth and feed conversion of young pigs,from weaning to a
body weight of approximately 25 kg (8 to 10 weeks of age).
问题解答：
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