• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Animal >Breeding objectives for sheep should be customised depending on variation in pasture growth across years
【24h】

Breeding objectives for sheep should be customised depending on variation in pasture growth across years

机译：羊的育种目标应根据多年牧草生长的变化而定

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Breeding programmes for livestock require economic weights for traits that reflect the most profitable animal in a given production system, which affect the response in each trait after selection. The profitability of sheep production systems is affected by changes in pasture growth as well as grain, meat and wool prices between seasons and across years. Annual pasture growth varies between regions within Australia's Mediterranean climate zone from low growth with long periods of drought to high growth with shorter periods of drought. Therefore, the objective of this study was to assess whether breeding objectives need to be adapted for regions, depending on how reliable the pasture growth is across years. We modelled farms with Merino sheep bred for wool and meat in 10 regions in Western Australia. Across these 10 regions, mean annual pasture growth decreased, and the CV of annual pasture growth increased as pasture growth for regions became less reliable. We calculated economic values for nine traits, optimising management across 11 years, including variation for pasture growth and wool, meat and grain prices between and within years from 2002 to 2012. These economic values were used to calculate responses to selection for each trait for the 10 regions. We identified two potential breeding objectives, one for regions with low or high reliability and the other for regions with medium reliability of pasture growth. Breeding objectives for high or low pasture growth reliability had more emphasis on live weight traits and number of lambs weaned. Breeding objectives for medium reliability of pasture growth had more emphasis on decreasing fibre diameter. Relative economic weights for fleece weight did not change across the regions. Regions with low or high pasture reliability had similar breeding objectives and response to selection, because the relationship between the economic values and CV of pasture growth were not linear for live weight traits and the number of lambs weaned. This non-linearity was caused by differences in distribution of pasture growth between regions, particularly during summer and autumn, when ewes were pregnant, with increases in energy requirements affecting the value of lambs weaned. In addition, increasing live weight increased the intake capacity of sheep, which meant that more poor quality pasture could be consumed during summer and autumn, which had more value in regions with low and high pasture reliability. We concluded that breeding values for sheep production systems should be customised depending on the reliability of pasture growth between years.
机译：牲畜育种计划需要对具有一定经济效益的性状进行权衡，以反映给定生产系统中最有利可图的动物，从而影响选择后每个性状的反应。绵羊生产系统的获利能力受季节之间以及多年间牧场增长以及谷物，肉类和羊毛价格变化的影响。澳大利亚地中海气候区内不同地区的年牧草生长量有所不同，从长期干旱的低速生长到短期干旱的高速生长。因此，本研究的目的是根据牧场多年的生长可靠性来评估是否需要针对地区调整育种目标。我们用西澳大利亚州10个地区的美利奴羊为羊毛和肉类饲养的农场建模。在这10个区域中，平均牧草的年均增长率下降了，而随着牧草对各地区的可靠性下降，牧草的年均增长率也有所提高。我们计算了9个性状的经济价值，优化了11年的管理，包括2002年至2012年之间以及几年之内牧场增长以及羊毛，肉类和谷物价格的变化。这些经济价值用于计算对每个性状选择的响应10个地区。我们确定了两个潜在的育种目标，一个目标是可靠性低或高的区域，另一个目标是牧草生长具有中等可靠性的区域。高或低牧草生长可靠性的育种目标更多地关​​注活体重性状和断奶羔羊的数量。牧草生长的中等可靠性育种目标更加注重减小纤维直径。各个地区的摇粒绒重量相对经济权重没有变化。牧场可靠性低或高的地区具有相似的育种目标和对选择的响应，因为牧场价值的经济价值与牧场价值之间的关系对于活体重性状和断奶羔羊数不是线性的。这种非线性是由地区之间牧场生长的分布差异引起的，尤其是在夏季和秋季，当母羊怀孕时，能量需求的增加影响了断奶羔羊的价值。此外，活重的增加增加了绵羊的摄入能力，这意味着在夏季和秋季可食用质量较差的牧场，这在牧场可靠性低下和高的地区具有更大的价值。我们得出的结论是，应根据几年间牧场生长的可靠性来定制绵羊生产系统的育种价值。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号