By Dr. Linda Tikofsky, Professional Services Veterinarian, Boehringer Ingelheim Vetmedica, Inc.
Have you ever treated a case of clinical mastitis but weren’t sure what type of bacteria you were up against?
On-farm milk culturing can help answer this question, reduce the amount of antibiotics being used, and increase milk quality and profitability. Culturing milk from cows with clinical mastitis can help determine which cases will benefit from intramammary antibiotic treatment. It is important to note that studies have shown that most mild to moderate Gram-negative mastitis cases, including E. coli, will spontaneously cure without antibiotic treatment.1
Of course, there are many cases of mastitis that do require treatment, often combatted with an intramammary tube. Two recent studies headed up by separate university researchers showed outcomes that suggest advantages to utilizing a two-tube treatment of cephapirin sodium as opposed to a once-per-day, five-tube treatment of ceftiofur hydrochloride when treating Gram-positive mastitis.
Common culture profiles for U.S. dairy farms often reveal this distribution of culture results: 25-30% gram-positive, 25-30% gram-negative and 40-50% no growth2. This means a 1,000-cow dairy with a 30 percent mastitis rate could use 900 fewer tubes of antibiotics a year if it implements a two-tube cephapirin sodium protocol. Furthermore, a 12-hour, two-tube treatment of cephapirin sodium can reduce the time cows spend in the hospital pen by 35 percent when compared to a five-day treatment.
First- Versus Third-Generation Cephalosporins
Dr. Ynte Schukken of Cornell University conducted a study to determine the effectiveness of the two-tube treatment of cephapirin sodium (a first-generation cephalosporin) as opposed to a once-per-day, five-tube treatment of ceftiofur hydrochloride (a third-generation cephalosporin). From the results of this head-to-head trial, the authors concluded, "These results indicated that the first-generation cephalosporin was not inferior with regard to clinical cure and bacteriological cure of Gram-positive bacteria."3
Another conclusion indicated that, "herds that do not utilize a culture-based approach for the treatment of clinical mastitis may have an economic benefit from selecting cephapirin, with a shorter non-saleable milk duration [4.5 vs. 8 days], as the first treatment of choice."
Active Metabolites of Mastitis Treatments
Dr. Pamela Ruegg and associates at the University of Wisconsin, Madison, looked at the distribution of minimum inhibitory concentration values for the parent compounds and metabolites of cephapirin sodium and ceftiofur hydrochloride, two common mastitis treatment options.4 It’s important to realize that when an antibiotic is administered into a cow’s udder— in vivo — the active ingredient begins to rapidly metabolize into a new compound; cephapirin sodium metabolizes into desacetylcephapirin, and ceftiofur hydrochloride metabolizes into desfuroylceftiofur.
Both the parent (cephapirin) and the metabolite (desacetylcephapirin) are compounds that have been proven through extensive in vitro testing to be highly effective against the following gram-positive organisms: Strep uberis, CNS and Staph aureus, whereas the metabolite of ceftiofur (desfuroylceftiofur) has limited activity against these pathogens
Dr. Ruegg encourages producers to culture milk from cows with mastitis to determine which treatment path to take. "We need to stop training ourselves to just grab a tube and treat every single case," says Dr. Ruegg. "Extended-duration intramammary therapy should not be the routine treatment for all cases of mild and moderate clinical mastitis."
As university researchers continue to increase the industry’s knowledge and understanding of this common and costly disease, working with your veterinarian to implement new science and farm-specific protocols can show serious returns to your bottom line. Setting up on-farm culture capabilities can not only help reduce your overall antibiotic use, but also get saleable milk back into your bulk tank faster and keep cows out of your hospital pen.
1Hess JL, Neuder LM, Sears PM. Rethinking clinical mastitis therapy. Presented at the 42nd Annual Meeting of the National Mastitis Council; Jan. 27, 2003; Fort Worth, Texas.
2 A Lago et al., 2011
3Schukken YH, Zurakowski MJ, Rauch BJ, et al. Non-inferiority trial comparing a first-generation cephalosporin with a third-generation cephalosporin in the treatment of non-severe clinical mastitis in dairy cows.
4Cortinhas CS, Oliveira L, Ruegg PL, et al. Minimum inhibitory concentrations of cephalosporin compounds and their active metabolites for selected mastitis pathogens. Am J Vet Res 2013;74(5):683–690.
5Martín Pol,Carla Bearzi, Julia Maito,Javier Chaves, On-farm Culture: Characteristics of the Test. Lactodiagnostico Sur, Olivos,Buenos Aires, Argentina. La Polvorilla Dairy Farm, Castelli, Buenos Aires, Argentina. Presented at the 48th Annual Meeting of the National Mastitis Council; Jan. 25–28, 2009; Charlotte, N.C.