A study at the University of Georgia (UGA) suggests the somatic cell count (SCC) of an infected quarter at the time of antibiotic treatment might affect cure rates.
“Infected quarters that actually cured as a result of antibiotic therapy had relatively low SCC at the time antibiotic therapy was initiated,” says Steve Nickerson, a mastitis and milk quality specialist with UGA. “On the other hand, infected quarters having very high initial SCC were in fact treatment failures.”
Quarters with average SCCs of 587,000 cells/mL were destined to cure, while quarters with an average SCC of 2,994,000 cells/mL were destined to fail. This pattern continued regardless of if the mastitis was treated. The average SCC of coagulase-negative staphs destined to cure was 343,000, while those destined to fail was 949,000. The average SCC of Staph. aureus destined to cure was 661,000, while those destined to fail was 3,350,000. The average SCC of Streptococci destined to cure was 888,000, while those destined to fail was 2,676,000.
Results are still preliminary because just 30 lactating cows were included in the trial. “[But] we believe that dairy farmers may be able to use these benchmarks when deciding if an infected quarter should be treated,” Nickerson says. “For example, if the SCC is 500,000 +/-200,000, then the chances for a cure are good. If the SCC is 3,000,000 +/-1,000,000, then chances are poor and treatment would not be advised.”
Note: This article appears in the January 2018 magazine issue of Dairy Herd Management.