A ranking assessment of holstein and black-and-white bulls with respect to the intactness of calves and the productive life of their daughters

摘要

The ranks of bulls as regards the intactness of their progeny and the productive service life of their daughters are similar, but differ substantially in the productive properties of the daughters. The progeny of Holstein bulls are somewhat inferiorto the daughters of black-and-white ones in the intactness and productive life, but are superior to them in the milk productivity.