Early detection is crucial in fighting Staphylococcus mastitis, a South Dakota State University specialist says.
SDSU Extension Dairy Specialist Alvaro Garcia says an article published in the June 2006 issue of the Journal of Dairy Science addressed the therapeutic success of treating cows with staphylococcal mastitis. Some important factors identified were parity, somatic cell counts before treatment, duration of high somatic cell counts, and quarter location.
"The authors suggest that to improve the staphylococcal mastitis cure rate, it is important to treat cows that have a reasonable probability of success, and one key component is early detection," Garcia says. "Chances of success in cure rate improve with infections of shorter duration, and this is a reason why earlier detection is a key component for successful treatments."
Early detection implies monthly screening for somatic cell counts, and identifying infected quarters through the use of the California Mastitis Test. Milk samples from cows with high California Mastitis Test should be cultured immediately and a sensitivity test run on them.
Information that producers should have at hand is cow parity, stage of lactation, pregnancy status, production, and mastitis and somatic cell count history.
Producers should have a protocol to decide on the choice and duration of the treatment. Cows with a low chance of cure should be milked last and eventually culled, whereas cows with higher chances of cure can be treated.
There are several factors that influence the decision on whether to treat or cull a cow, Garcia notes. Among them are: expected milk production, possible antimicrobial resistance, prevalence within the herd, contagiousness, price of milk, cull cows, and replacement heifers.
"Somatic cell count monitoring should be continuous and consistent, with follow-up and treatment of new cases," Garcia says.
Lower cure rates should be expected as cows age, with more infected quarters, with infections of longer duration, or in cases with high somatic cell counts before treatment. Hind quarters have shown significantly lower cure rates, as they have higher infection risks.
Keep in mind that Staph. aureus mastitis is highly contagious, so early detection of cows with a subclinical infection will reduce the incidence and prevalence of the infection in the herd, Garcia says.
"Chances of cure are greatly increased with prolonged duration of treatment. Sometimes this isn't economical, particularly when one considers the risks associated with cow-to-cow transmission. The study that is reported in this journal article suggests that if we are in the presence of mastitis due to penicillin-resistant strains, treatment is rarely successful or economically justifiable," he says.