title: Prevalence and effects of intramammary infection in beef cows.
abstract: Prevalence and effects of intramammary infection in 322 beef cows was determined during three calving intervals. Intramammary infection was confirmed in 37% of cows and 18.1% of quarters. Coagulase-positive staphylococci accounted for 17.9% of infections with Staphylococcus aureus isolated from 7.1% of cows. Coagulase-negative staphylococci and micrococci accounted for the remainder of infectious organisms. Butterfat and total protein levels were reduced 27.3 (P less than .05) and 25.5% (P less than .01), respectively, in milk from quarters infected with S. aureus. Somatic cell counts were elevated (P less than .001) with 3,827 X 10(3) cells/ml for S. aureus-infected quarters as compared with 555 X 10(3) cells/ml for uninfected quarters. Somatic cell counts were negatively correlated with 210-d calf weaning weights. Staphylococcus aureus-infected cows weaned calves weighing 19.1 kg less (P less than .01) than uninfected cows. At a present market value of $1.65/kg, economic losses were placed at $31.43/calf from cows infected with S. aureus in one or more quarters.
mesh_terms: D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000254:growth & development; D005260:Female; D007774:Lactation; D008414:Mastitis, Bovine / Q000453:epidemiology* / Q000503:physiopathology; D008460:Meat / Q000191:economics; D008892:Milk / Q000382:microbiology; D011247:Pregnancy; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000503:physiopathology