Study On Optimization Of Nucleus Breeding Scheme For Luxi Cattle

The objective of Luxi cattle is defined and obtain the parameters of biology and economics, nutritional science, and breeding techonoloy by analysis and calculation in this paper. The marginal profit for each objective trait are calculated using the balance method and the relative computing formula for each objective trait are given; Meanwhile, the gene-flow method, systematic theory and ZUPLAN program were used to study Nucleus Breeding Scheme for Luxi cattle. The measures to improve current breeding scheme and optimized breeding plan were proposed. The influences of some factors on population multiple breeding gain ,breeding cost and return and breeding profit were studied on the base of analysing the expected breeding effects of present breeding scheme, which were such factors as different population structure which is constituted by ratio of active herd ,number of selected sire and tested sire, percentage of seed dam in breeding herds ,use-age of dam and sire, and population size .The conclusion are as follows: 1.Combining condition of Luxi cattle production ,breeding ,market and further developing trend,calculated the marginal profit of the three kind traits-growth, carcass quality and Reproduction by balance method. Breeding goal traits including 6 economic traits which is yearling weight ,feed gain , growth capacity carcass quality, age of first calving and calving interval are developed. The ratio of relevant economic importance of the three type traits is 0.62:0.14:0.24 and approximates 5:1:2. The relevant economic importance of the six traits respectively are 0.24, 0.10, 0.28, 0.14, 0.07, 0.17. in which ,growth capacity and yearling weight in growth and calving interval in reproduction occupy relative larger economic weight. 2.The mean generation interval of flock is 7.270 years of the current breeding scheme and the ratio input and output is 1:5.76. But the present use-age of dam and sire is irrational. So the present breeding program the larger improvement margin. 3.The population multiple breeding gain and breeding profit will increase as active herd ratio,...