1College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, P. R. China
2State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, P. R. China JFIF d d Ducky d qhttp://ns.adobe.com/xap/1.0/