| Aohan Merino Sheep variety is used both for wool and meet for which we took local Mongolian sheep as it's female parent and former Soviet Union Merino Sheep as male parent which was cultivated successfully by hybridization improvement, trans-crossover fix, self-population breeding as well as transduction of 25% percentage blood of Bellhuaz sheep and Australian Merino sheep according to the plan of our nation and Inner Mongolian. The variety was named in 1982 and is famous for its thin wool and wool length. Aohan stud sheep farm begun to construct Aohan Merino Sheep breeding core population to speed up the merino sheep industrial and to develop rapidly and doing it stronger. It is still short of breeding theory system to support it although the work of Aohan Merino Sheep breeding and selection has become stronger. After the practical investigation for production and administration system of Aohan Merino Sheep, the study defined biological and breeding technique parameters, population economics and genetic parameters, population construction parameters, investment parameters and so on .On this basis the economic traits of Aohan Merino Sheep were determined with the methods of systematic analysis and calculated marginal utility of breeding objective traits of Inner Mongolian Aohan Merino Sheep with difference method at the same time . Genetic judge for Aohan Merino Sheep was passed and genetic parameters of breeding objective traits of Merino Sheep were estimated using animal model Best Linear Unbiased Prediction (BLUP) and Multiple Trait Derivative-Free Restricted Maximum Likelihood (MTDFREML). The genetic judge for breeding scheme was done currently in effect taking gene flow method as the core and along with the combining conventional breeding technique, quantitative heredity computer imitation theory with calculation by software ZPLAN. The results were shown as follows:(1) The three types and six breeding objective traits of Aohan merino sheep were determined. The three types of the breeding objective traits were wool traits, reproduction traits and growth traits respectively. The six breeding objective traits were wool yield, wool fineness, wool length, number of kids weaned, weight of adult female sheep after shearing and weight of the young sheep after shearing. The marginal benefit of the three types and six breeding objective traits were calculated by the difference method on the present market and production condition, and the results of wool yield of adult female sheep, wool yield of young sheep, wool fineness of adult female sheep, wool fineness of young sheep, wool length of adult female sheep, wool length of young sheep, weight of adult female sheep after shearing, weight of young sheep after shearing, and the number of kids weaned is 32.081, 30.477, -5.633, -5.351, 3.010, 2.860, 0.774, 2.114, 90.353 respectively. The economic weight proportion of the three type traits is 71.398:17.705:10.898, similar to 7:2:1, which means the wool traits of Aohan Merino sheep have the largest economic value.(2) Estimated genetic parameter of Aohan merino sheep by BLUP and MTDFREML soft wares and the heritability of wool yield, wool fineness, wool length, weaning litter weight, one-age live weight and after shearing weight of adult female sheep is 0.12, 0.12, 0.16, 0.21, 0.10 and 0.12. The maternal additive heritability of weaning litter weight is 0.03. The estimated genetic correlations of wool yield with wool length, weaning litter weight, one-age live weight, after shearing weight of adult female sheep and after shearing weight of adult female sheep with wool fineness, weaning litter weight, one-age live weight is 0.50, 0.20, 0.22, 0.32, 0.05, 0.40, 0.37 respectively. All have a middle level of positive correlation. The estimated genetic correlations of wool fineness with wool yield, wool length, weaning litter weight, one-age live weight and wool length with after shearing weight of adult female sheep is -0.30,-0.40,-0.24,-0.06,-0.01 respectively.(3) Evaluated the breeding effect of the current breeding scheme by the ZPLAN software on the basis of marginal benefit calculated and genetic parameter estimated for the breeding objective traits. The results showed that the contribution proportion for the genetic progress and breeding gain rams higher than ewes groups and the selection of stud rams is very important in the whole breeding process. The selection accuracy is over 0.84 and plays an important role for genetic progress and breeding benefit of the whole population. In the current breeding scheme, the annual genetic progress of wool production, wool yield, wool fineness, wool length, number of kids weaned, one-age live weight, after shearing weight of adult female sheep and weaning litter weight is 0.0629kg, 0.1123kg, -0.0768μm, 0.0401cm, 0.0009, 0.3303kg, 0.5855kg, 0.0853kg respectively. The mean generation interval of the population is 4.176 years and the total breeding gain is 63.198 Yuan. The breeding gain of the wool yield, wool fineness, wool length, number of kids weaned, one-age live weight and after shearing weight of adult female sheep is 48.2007 Yuan, 5.4279 Yuan, 1.6114 Yuan, 0.1999 Yuan, 4.8686 Yuan, 2.8898 Yuan respectively. The breeding cost is 49.766 Yuan, breeding benefit is 13.433 Yuan, and the ratio of input and return for the program is 1:1.27. |
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