Experimental staphylococcal mastitis in the mouse: the persistence of chronic infection from one lactation to the next.

Chronic staphylococcal mastitis was established in 50 mammary glands of 25 mice. The mice were mated and in the subsequent lactation there was alveolar mastitis in one of 50 glands. A further five glands had abscesses that contained staphylococci but there was no alveolar mastitis. The results are discussed in relation to the large number of infections that persist from one lactation to the next in cows not subjected to mastitis control measures.