Miller R H, Pearson R E, Rothschild M F, Fulton L A
J Dairy Sci. 1981 May;64(5):832-7. doi: 10.3168/jds.S0022-0302(81)82654-9.
Estimated somatic cell counts and incidence mastitis were measured on 163 daughters of two groups of bulls selected by two alternative criteria. Yield bulls were selected solely on progeny test for milk in first lactation; Merit bulls were selected by independent culling levels on fat-corrected milk yield, percent daughters culled in first lactation, and udder type conformation of daughters. Daughters of Yield sires exceeded daughters of Merit sires by 685 kg milk in first lactation. Groups did not differ significantly in measures of clinical mastitis or in measures of estimated cell counts of milk. Also, groups did not differ in kilograms milk discarded because of antibiotic treatment for mastitis, in spite of the large difference in total milk yield. Mean milk discarded per lactation completed was 171 kg, representing 64,243, and 207 g for parities one, two, and three.
对根据两种不同标准选出的两组公牛的163头女儿进行了体细胞计数估计和乳腺炎发病率测定。产奶量公牛仅根据初产泌乳期牛奶的后代测试来选择；优秀公牛则根据脂肪校正奶产量、初产泌乳期淘汰女儿的百分比以及女儿的乳房类型形态等独立淘汰水平来选择。产奶量公牛的女儿在初产泌乳期的牛奶产量比优秀公牛的女儿多685千克。两组在临床乳腺炎指标或牛奶体细胞计数估计指标上没有显著差异。此外，尽管总产奶量差异很大，但两组因乳腺炎接受抗生素治疗而丢弃的牛奶千克数也没有差异。完成的每个泌乳期平均丢弃牛奶171千克，头胎、二胎和三胎分别为64.243千克和207克。
