The bacterial flora in the teat duct of ewes can protect against and can cause mastitis Ilectra A. Fragkou, Vasia S. Mavrogianni, Peter J. Cripps, Dimitris A. Gougoulis and George C. Fthenakis Vet. Res., 38 4 (2007) 525-545 Published online: 30 May 2007 DOI: 10.1051/vetres:2007014