Research On Definition Of Bio-Economic Model And Optimiztion Of Breeding Objective For Snow Dragon Beef

Based on the production and breeding conditions of Snow Dragon Cattle (a commercial trade mark, representing a beef herd under selection), Bio-economic model was employed to estimate the economic value of traits contained in breeding objectives for Snow Dragon Cattle. Furthermore, we have done the optimization analysis of various factors influencing production efficiency. The main results are as follows:1. Bio-economic model was constructed to evaluate the economic values of each objective trait in different feed systems, namely cow-calf system (CCS), fattening cattle system (FCS), and integrated production system (IPS). The input, output and production efficiency are different in three systems. In the CCS, the production input is lowest overall; and in the IPS the production input is the highest. But the production efficiency is highest overall in the IPS, and is minimum in the CCS. The results show that during the real Snow Dragon Cattle breeding processes, more attention should be paid to the selection of production system, so that the biggest economic benefits can be achieved.2. In the current market conditions, the marginal benefit of the target traits:in the CCS, economic values of birth weight (BWT, kg), weaning weight (WWT, kg), mature weight (MWT, kg), calving interval (CI, day), productive life (PL, parity) are:RMB 7.90,3.45,0.73,13.45, and 33.35 respectively. In the FCS, economic values of BWT, WWT, MWT, fattening period daily gain (DG, kg/d), marbling score (BMS, score), rib-eye muscle area (REMA, cm2), back fat thickness (BFT, cm), CI, and PL are, RMB 0.59,2.35,0.09,2.35,73.48,18.38,4.39,0.54 and 15.44 respectively. In the IPS, economic value of birth weight (BWT, kg), weaning weight (WWT, kg), mature weight (MWT, kg), fattening period daily gain (DG, kg/d), marbling score (BMS, score), eye muscle area (cm2), back fat thickness (BFT, cm), the calving interval (CI, day), productive lifetime (PL, parity) are:RMB 4.32,0.43,0.29,250.18,67.37, 15.38,0.25,12.74,32.00 respectively.3. In different cultivation system, the importance of selection targeted traits are different. In the CCS, the absolute importance of CI can reach its maximum of 67.242%, the relative importance between growth performance related traits and reproductive traits was 30.4:69.6 (approximately 1:2). In FCS, growth traits, meat quality traits and reproduction traits were considered simultaneously, relative importance to these three categories were:14.7%,43.3%,42.0%(approximately 1:3:3). When reproductive traits were not considered, REMA and BFT are traits with the highest absolute importance, and relative importance of the growth traits and meat quality traits were25.4% and 74.6%, respectively. In the IPS, and the results are slightly different, relative importance to these three categories were:11.4%,32.4% and 56.4% (approximately 1:3:5). So reproductive traits is very important for production efficiency, and more concern must be paid. When reproductive traits were not considered in the IPS, the relative importance of targeted traits were similar to that in FCS. In order to achieve maximum economic benefits, breeding goals consisting of multiple traits should be adopted in the breeding scheme.4. The feed prices is the most critical factor for Snow Dragon Cattle feeding efficiency, based on sensitivity study.