5FOX L K, GAY J M. Contagious mastitis[ J]. Vet Clin North Am Food Anim Pract, 1993, 9 : 475 -487.
6OLIVER S P. Frequency of isolation of environmental mastitis cau- sing pathogens and incidence of new intramammary infection during the nonlactating period [ J ]. Am J Vet Res, 1998, 49:1789 - 1793.
7BRADLEY A J, GREEN M J. Adaptation of Escherichia coli to the bovine mammary gland [J]. J Clin Microbiol, 2001, 39: 1845- 1849.
8HOGAN J, LARRY S K. Coil form mastitis[ J]. Vet Res, 2003, 34:507-519.
9BRADLEY A. Bovine mastitis: an evolving disease [ J ]. Vet J, 2002, 164: 116-128.