Occurrence of clinical and sub-clinical mastitis in dairy herds in the West Littoral Region in Uruguay.
Twenty-nine dairy farms were selected to determine the incidence of clinical mastitis, prevalence of sub-clinical mastitis and bacterial aetiology in the West Littoral Region of Uruguay. In samples taken by the owner and frozen at -20 degrees C during a week the incidence rate of clinical mastitis was determined as 1.2 cases per 100 cow-months at risk. Staphylococcus aureus was the most common isolated pathogen in 37.5% of 40 milk samples from clinical cases obtained in 1 month. No bacteria grew in the 32.5% of the total samples. A sub-sample including 1077 dairy cows from randomly selected farms was used to determine the prevalence of sub-clinical mastitis. These samples were taken on one visit to each farm. The prevalence was 52.4% on a cow basis and 26.7% on an udder quarter basis. In 55.1% of the quarters of the selected animals with more than 300,000 cells/ml there was no growth. The isolated pathogens from sub-clinical cases and their relative frequencies were: Staphylococcus aureus 62.8%, Streptococcus agalactiae 11.3%, Enterococcus sp. 8%, coagulase-negative staphylococci 7.4%, Streptococus uberis 6.4%, Streptococcus dysgalactiae 1.8%, Escherichia coli 1.5% and Staphylococcus hyicus coagulase-positive 0.6%.
Gianneechini
R
R
Department of Microbiology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Concha
C
C
Rivero
R
R
Delucci
I
I
Moreno López
J
J
D000818:Animals; D002417:Cattle; D003612:Dairying; D016983:Enterococcus / Q000145:classification / Q000302:isolation & purification; D004926:Escherichia coli / Q000302:isolation & purification; D005260:Female; D015994:Incidence; D008414:Mastitis, Bovine / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology* / Q000473:pathology; D015995:Prevalence; D012720:Severity of Illness Index; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013292:Streptococcus agalactiae / Q000302:isolation & purification; D014583:Uruguay / Q000453:epidemiology