| Cultivated by forage grasses center of Yunnan Province, the BMY beef cattle are hybrid of Murray Grey and Brahman from Australia and Yunnan cattle in the foundation of"Project of Yunnan animal and pasture of China and Australia technical collaboration". This research is to cultivate new beef cattle that suit tropics, the subtropics climate of China. The high body-weight, mature-early, high reproduction rate, quick growth speed, fattening and well meat performance, the good carcass quality, the anti-tick, heat-resisting, the compatibility broad are the characteristics of BMY Cattle. 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 BMY cattle. The heredity parameter were studied and determined by the animal model and the DF-REML analysis method. The breeding objective traits of BMY cattle were studied and determined by system analysis method. 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 breeding 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. The strategies to improve current breeding scheme and optimized breeding plan were proposed1. The heredity parameter of breeding character was studied in BMY beef cattle. The growth character of traits-birth weight, weaning weight, yearling weight, 18-month weight, 24-month weight and fattening daily gain is 0.34, 0.38, 0.34, 0.40, 0.48 and 0.54. With the increase of age, it gains. The propagation character of the age of first calving, calving interval is 0.12 and 0.09. The heritability of BMY beef cattle's in the research is in the scope of literature report.2. It is negative correlation between hereditary domino offect of growth character and maternal influence (-0.30~-0.98), shows that the effect of maternal influence to growth character is negative.3. It is important to character relativity in the selection process of BMY cattle. Heredity correlation of traits-birth weight and weaning weight, yearling weight , fattening daily gain are all above 0.52, of weaning weight and yearling weight, 18-month weight, fattening daily gain, the age of first calving are above 0.57, of yearling weight and 18-month weight, fattening daily gain, the age of first calving are also above 0.57 newborn heavy. It is important to select traits-birth weight, weaning weight and yearling weight in the selection process of BMY cattle as beef cattle.4. The research analyzes the growth capability, reproduction capability, expenses of feed and management, energy need, feed using and energy-containing of feed, and various feed using of BMY beef cattle. Combining condition of BMY 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 and confirmed the breeding goal traits. These characters'economic weighting including traits-growth, reproduction and carcass quality were measured. The ratio of relevant economic importance of the three kinds of traits-growth, reproduction and carcass quality is 58%∶24%∶18% and approximates 3∶1∶1. The ratio of relevant economic importance of the eleven objective traits-birth weight, weaning weight, yearling weight, 18-month weight, 24-month weight, fattening daily gain, growth ability, the age of first calving, calving interval, carcass quality and marbling, is 4%, 13%, 10%, 15%, 8%, 8%, 7%, 9%, 15%,15%and 3%. The marginal profit is $8.69,$8.64,$4.01,$7.95,$3.65,$375.18,$0.06, $2.37,$4.95,$784.08,$156.82。So 18-month weight, calving interval and carcass quality occupy largest economic weight, better than yearling weight and the age of first calving. It is important to select carcass quality, the growth capability and reproduction capability in the selection process of BMY cattle as beef cattle.5. In the condition that planning period is 30 years and the size of population is 1.2 thousand, optimum analysis result proved that the return for the annual monetary genetic gain is $24.88 for each calving period, current breeding scheme is $372.68, breeding input is $92.67, the breeding profit is $279.81, the mean generation internal of the population is 4.87 years, and the ratio of input and return are 1:4.02. Compared with domestic and foreign research kept some room to be improved. The genetic gain of every selecting trait for every selecting period respectively is that birth weight gains 1.9112 kg, weaning weight gain 2.5321kg, yearling weight gains 3.8100 kg; 18-month weight gains 2.1506kg, 24-month weight gains 1.8125kg, fattening daily gain increases 2.3654kg, growth ability improves 1.1060kg; the age of first calving shortens 0.5010 days, and calving interval shortens 0.5210 days, carcass quality and marbling improve 0.0002 commercial grade respectively.6. With the increase in the proportion of breeding groups, annual monetary genetic gain, breeding return and breeding profit all will increase, but breeding input will decrease. Annual monetary genetic gain and breeding return and breeding profit will increase as the ratio of seed bull increased in breed herd. But the population multiple breeding gain increases to some climax and begin to decrease slowly. Annual monetary genetic gain and breeding return and breeding profit will increase as the ratio of tested bull increased in breed herd, but breeding profit will increase in the first instance, and then will increase. With size of population increase, the breeding input will decrease, but annual monetary genetic gain, breeding return and breeding profit will increase.7. Breeding return, breeding profit and breeding profit will increase as the proportion of seed cow increased in breed herd. Annual monetary genetic gain will increase and come to a head and then will decrease slowly. The proportion of seed cow in breed herd is 20%, and then annual monetary genetic gain will decrease.8. By optimum analysis, the best optimal breeding scheme for the utilization lifespan for different selecting groups is that the lifespan of seed bull and general bull were utilized 1 year, seed cow and general cow were utilized 5-6 year, tested bull was utilized 1-2 year, tested cow was 4-5 year, production bull was utilized 1 year, and commercial cow was utilized 6 year.9. Through comprehensive analysis in the study, breeding efficiency of the current breeding scheme and breeding efficiency of the utilization lifespan optimized were optimized by contrast analysis, the result is ,optimize all affect factors, population can reach optimal generation alternation is 3.9825 years, increased 18.2% than mean generation alternation 4.87 year; Synthetical breeding development can reach $36.3306,the optimized synthetical breeding development is 46% higher than current scheme $24.88; Breeding output can reach $403.3218,which is 8.2% higher than current scheme $372.68;Breeding profit can be $320.4219,which is 14.5% higher than current scheme 279.81;Optimized breeding input an output ratio is 1:4.34, which is higher than current scheme 1:4.02.
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