Optimization of the management of the livestock population structure and analysis of its influencing factors in four typical animal husbandry counties of northwest Sichuan

• CHEN Xiaoxia, 
• SUN Feida, 
• SHI Fusun, 
• LIU Lin, 
• XU Zejun, 
• ZHANG Caibin, 
• LI Fei, 
• LIAO Libin, 
• GAO Juanting