Effect of Abrasion of Teat Orifice Epithelium on Development of Bovine Staphylococcal Mastitis

Abstract

The predisposing effect of teat damage on mastitis caused by staphylococci and the pathogenicity of Staphylococcus aureus, Staphylococcus hyicus, and Staphylococcus epidermidis were investigated with an experimental model. The study included three experiments in which the teat canal orifice of 5 cows was slightly abraded. Experimental and control quarters were challenged with a staphylococcal suspension, and the status of the quarters was monitored. Virulence of the staphylococcal strains was studied using a protein-binding test with 125I-labeled proteins (fibronectin, fibrinogen, vitronectin, collagen type I and II, and IgG). Abrasion on the teat orifice epithelium was a predisposing factor for staphylococcal infections. Teat canal infection or colonization developed in 93% of experimental quarters and in 53% of control quarters; IMI developed in 73% of experimental quarters, but in none of the control quarters. Quarter IMI developed more consistently when the contaminating agent was S. aureus. Staphylococcus hyicus was very effective in causing teat canal infections, but S. epidermidis appeared to be less infectious. The S. aureus strain had strong binding sites for most of the proteins tested. The S. hyicus and S. epidermidis strains showed no binding, or only very weak binding, which correlated with lower infection rates.