two strains of streptococcus uberis , one ( 0140j ) resistant to killing by purified bovine polymorphonuclear leucocytes suspended in milk and the other ( ef20 ) readily killed by polymorphonuclear leucocytes were each infused into a mammary quarter of 18 lactating and 10 pregnant non-lactating cows .
C0026131
milk
C0006141
mammary