Genetic and environmental trends for first lactation milk traits in the South African Ayrshire breed

被引：0
作者：
Hallowell, GJ
van der Westhuizen, J
van Wyk, JB
机构：
[1] Agr Res Council, Anim Improvement Inst, ZA-0062 Irene, South Africa
[2] Univ Free State, Dept Anim Sci, Bloemfontein, South Africa
来源：
SOUTH AFRICAN JOURNAL OF ANIMAL SCIENCE-SUID-AFRIKAANSE TYDSKRIF VIR VEEKUNDE | 1998年 / 28卷 / 01期
关键词：
Ayrshire; fat; genetic trends; milk; protein;
D O I：
暂无
中图分类号：
S8 [畜牧、 动物医学、狩猎、蚕、蜂];
学科分类号：
0905 ;
摘要：
Estimated breeding values and genetic trends were obtained in Ayrshire cattle by using DFREML procedures for 9050 first lactation records calving down from 1977 to 1992. Environmental trends were calculated as the difference between the phenotypic and genetic values. The Ayrshire breed showed a positive trend of 19 kg per year for milk yield, with similar trends for fat and protein yield, while the trends for fat and protein percentage were negative.
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页码：38 / 45
页数：8
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