【作者】 张文广；

【导师】 李金泉；

【作者基本信息】 内蒙古农业大学 ， 动物遗传育种与繁殖学， 2004， 博士

【摘要】 本文从内蒙古绒山羊育种的实际需要出发，在利用内蒙古白绒山羊种羊场1997-2003年的实测数据并获得群体育种学、生物学和经济学等参数基础上，利用系统分析法研究并确定了优质高产内蒙古绒山羊育种的目标性状；采用差额法计算了各目标性状的边际效益并给出相应的计算公式；采用基因流动法和ZPLAN专用程序研究了内蒙古绒山羊开放式核心群的优化育种规划；在对现行育种方案预期育种效果分析的基础上，研究了不同群体规模、不同群体结构、公母羊使用年限和近交风险等因素对群体综合育种进展和育种效益的影响；并且提出了改进现行育种规划的措施和最优化育种方案。在这些研究工作中，笔者主要得到了以下结论。根据内蒙古绒山羊育种现状和国际、国内羊绒市场情况，通过边际效益分析得出，优质高产内蒙古绒山羊育种目标性状应包括绒用、繁殖、生长发育三类七个性状（净绒量、绒细度、绒长度、断奶羔羊数、断奶体重、育成体重、成年体重）。这三类性状的相对经济重要性分别为78.7%、11.7%和9.6%，这一点说明内蒙古绒山羊的绒用特点突出，具有较高的经济价值。通过优化分析，其结果表明现行育种方案的世代间隔为4.57年，投入产出比为1：3.96，尚未达到最佳育种效率，还可以有较大的改进余地；现行育种方案在群体规模、育种群比例、种公羊利用情况和开放程度等方面尚未处于最佳状态。通过优化分析认为：当群体规模为3000只基础母羊时，核心群、繁殖群和生产群比例分别处于7-9%、11-13%和80%，而且核心群母羊开放程度小于20%时，其综合育种进展和育种效益最高；育种群公、母羊育种年龄，使用年限对育种效益有较大影响，若改变育种群公、母羊的使用年限，将引起群体结构的变化，改变育种效益，使得整个育种体系发生较大改变。本文研究认为，当核心群验证公羊使用1年，其他公羊使用3-4年，母羊使用5年，生产群20-40%的母羊由核心群公羊配种时可获得理想的育种效益。在育种群比例固定的情况下，群体规模越大，育种群规模也越大，群体所获得的育种进展也就越大；同时，育种所用的固定投入将会随群体规模的扩大使每只羊的育种投入减少，并且获得较高的经济效益。在有限规模群体中极易出现由于选择引起的群体遗传方差下降和近交程度上升的问题，这一问题会在在一定程度上影响了育种效益和遗传进展，考虑到二者给育种规划带来的风险，在其他参数不变的情况下，应合理控制现有群体近交系数的上升。可以采用的方法有：一是限定公羊的使用年限；二是扩大留种公羊的数量；三是使用交配选择指数（Mate Selection Index）控制选配。除此之外，还可以根据血统组建不同的育种系以及建立完全开放式育种体系，通过导<WP=3>入外血解决这些问题。本文通过综合分析，优化全部影响因素后，群体达到最佳状态时世代间隔为4.06年，综合育种进展可达到21.90元，育种效益为70.49元，分别比现行育种方案提高27%和13%，育种的投入产出比为1：4.20。更多还原

【Abstract】 It is expected that the inclusion of high quality and high yield in the breeding objective has some consequences on the design of progeny testing scheme in Nei Mongol Cashmere Goat (NMCG). The study was carried out on the utilization of the field data in Inner Mongolia White Cashmere Goat Breeding Form from 1997-2003. The breeding objective traits of NMCG were studied and determined by system analysis method based on the population parameters, biology coefficients and economic parameters. The marginal profit for each objective trait was estimated using the balance method and the relative computing formula for the objective traits were presented also. A complex deterministic approach (ZPLAN), which is based on the gene flow theory and systematic analysis theory, was used to optimize the opened nucleus breeding programs for NMCG. Annual monetary genetic gain and discounted profit were used to evaluate alternative breeding strategies. On the base of analyzing the expected breeding effects of current breeding scheme, the following factors which affect annual monetary genetic gain and discounted profit are considered: size of population, structure of breeding system, pattern of use of seedstock, and risk of inbreeding. The strategies to improve current breeding scheme and optimized breeding plan were proposed.Marginal profits were analyzed on the present situation of NMCG breeding and the condition of cashmere trade both in domestic and international market. With regard of the analysis result, the breeding objective traits of NMCG included three basic functions: female production (pure cashmere weight, cashmere fibre diameter and cashmere fibre length ), reproduction (number of kids weaned), and growth of the young (live weight for weaned kid, yearling goat and doe). The relative economic value (calculated as sum of weights of individual traits scale to genetic standard deviations) of the three category traits were 78.7%, 11.7% and 9.6% respectively. The economic weighting showed more prominent cashmere purpose feature and higher economic value for NMCG.Optimum analysis result proved that the mean generation interval of the population is 4.57 years and the ratio of input and return for the programme is 1:3.96. It could be concluded that the current breeding scheme did not meet the optimum breeding efficiency <WP=5>and kept some room to be improved. The current breeding scheme was not in the optimum state in the aspects of size of population, proportion of nucleus vs. reproduction vs. production herd, utilization of bucks, and level of opening. To find the optimum breeding scheme, optimum analysis considered that better annual monetary genetic gain and discounted profit could be reached as the proportion of nucleus vs. reproduction vs. production herd were varied 7-9 vs.11-13 vs. 80 percent, the proportion of nucleus does imported from reproduction flock should be less than 20 percent. Breeding effects was influenced by breeding age and lifespan of both bucks and does in the breeding herd to great extent. The change of them would cause the change of selecting method, selection index and population generation interval so as to change breeding profit and genetic gain per year. The study proved that ideal breeding effects could be obtained if lifespan of tested old bucks in nucleus herd was 1 year and other bucks were utilized 3-4 years, that of does was 5 years, the proportion of semen supplied from nucleus bucks for does in production herd was varied from 20 to 40 percentage.Criteria for evaluation of different schemes are annual monetary genetic gain and discounted profit accounting for variation of costs under different schemes. Under the circumstances of the proportion of breeding population was set to a limit, the larger population size was, and the faster breeding development of population was. At the same time, better economic profit could obtained because the regular breeding cost decreased for less breeding cost of each goat with the population size enlargement. For many breeders, staying in business is as i更多还原