A survey of clinical mastitis in South-East Queensland dairy herds.
A survey if clinical mastitis in 26 South-East Queensland dairy herds supplying more than 300,000 litres of milk annually, revealed a quarter incidence of 2.6% with a cow incidence of 9% over a 3-month period. Secretion samples from cows yielded Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus Uberis, Coliforms, Pseudomonas spp and other bacteria in 38.5%, 12.5%, 6.6%, 3.4%, 2.6%, 0.6% and 2.0% of cases respectively. Samples from 38% of the cases were culturally negative while at least 38% of the clinical quarters had shown a previous clinical episode of mastitis. There was a significant association (P less than 0.025) between herd and the likelihood of a negative culture result on samples from clinical cases. Twenty-one percent of cases occurred in the first month of lactation and 10.3% in the first week. There was a significant association (P less than 0.005) between the age of cow and the stage of lactation in which clinical cases occurred in that cows in the 2 to 5 year age group were more likely to suffer attacks in the earlier part of lactation. There was a highly significant relationship (P less than 0.005) between cow age group and the proportion of affected quarters and it was calculated that the change with each year of age was a 55% increase over the previous year. Forty-five percent of the isolates of S. aureus were resistant to penicillin.
D000367:Age Factors; D000818:Animals; D001315:Australia; D002417:Cattle; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000662:veterinary; D005260:Female; D007774:Lactation; D008414:Mastitis, Bovine / Q000453:epidemiology* / Q000382:microbiology; D010403:Penicillin Resistance; D010406:Penicillins / Q000627:therapeutic use; D011247:Pregnancy; D011552:Pseudomonas Infections / Q000453:epidemiology / Q000662:veterinary; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000662:veterinary; D013211:Staphylococcus aureus / Q000187:drug effects; D013290:Streptococcal Infections / Q000453:epidemiology / Q000662:veterinary
D010406:Penicillins