Adopting the cross design, 16 Holstein-Friesian cows of stable production performance were divided into group A and group B. The experiment was divided into two periods.
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- 试验选取16头生产性能稳定的荷斯坦奶牛,采用交叉试验设计,设计两个处理组(A组和B组),试验分为两个时期,两组在两期中互为对照。