Lowering SCC with Records and Emerging Technology

For decades, the dairy industry has strived to produce and supply higher quality milk. Dairy Herd Improvement programs have aided in the production of quality milk through testing for individual somatic cell count from cow milk samples. Today, producers and milk quality advisors want to have more information about mastitis cows; want to identify the source of infection, and want to identify factors contributing to a high SCC. In order to satisfy this need, independent and local laboratories, like the one at Lancaster DHIA, have been established to provide bacterial identification of mastitis organisms in the bulk tank (overview of herd mastitis), cow (cause of high SCC), and individual quarters (cause of mastitis and high SCC). In addition, bacterial culturing of bedding samples and towel samples is another service provided by culture laboratories and can be used to further troubleshoot and identify cause of high SCC.

Producers are increasingly aware of management practices, and have used new resources like culture laboratories to decrease their herd average SCC. The average rolling herd SCC for herds tested through Lancaster DHIA was 306,000 in 2008 and has decreased to date in 2009 to 269,000. Producers have discovered that by lowering their SCC they have not only increased milk income through higher milk quality bonuses, but can also increase milk production. Research has demonstrated that lowering the Somatic Cell Score by 1 point will result in an average 1.5 pound increase in milk per cow per day. With an increase in milk production of this magnitude, the potential increase in milk revenue, independent of milk quality bonuses, could be as much as $5,000 annually.

In the current economic landscape, maximizing milk production and quality is of utmost importance for success. Enhanced culturing systems to identify not only mastitis pathogen, but molecular characteristics of pathogens can be beneficial to further troubleshoot cause of high SCC. Molecular techniques can be used to identify and quantify the DNA (molecular characteristics) of bacteria. This allows for more in depth descriptions of mastitis-causing bacteria in a dairy herd. For example, Staph. aureus bacteria may or may not carry the ß-lactamase gene. If Staph aureus have this characteristic, beta-lactam antibiotics, like Penicillin, will not generally work to cure the infection. If a cow has a mastitis infection – caused by Staph. aureus carrying the ß-lactamase gene, the cow will be less likely to respond to treatment if treated with a beta-lactam antibiotic. Conventional culture and susceptibility testing systems would not identify presence or absence of this characteristic. DNA or molecular techniques can also be used to better identify bacteria-potentially resulting in fewer 'No Growths'. Laboratories and research finds that typically 25 to 40% of conventional milk cultures result in no bacterial growth. Paying for a 'no growth' result when you know the cow or quarter has a mastitis infection can be very frustrating. Molecular techniques can be used to more clearly define similar or dissimilar DNA patterns to better identify mastitis-causing bacteria in milk samples. This can result in fewer 'no growth' results. Rapid turn-around of information for quick decision-making and reduced cost of enhanced milk diagnostic testing is making it possible for commercial laboratories to offer these new services.

Lancaster DHI, like other microbiology laboratories is working to explore enhanced molecular technologies to provide better diagnostics for improved producer decision making, and improved milk quality. A system for identification of molecular characteristics of mastitis-causing bacteria is being launched by Lancaster DHI later this year. More information will be available in the near future.

Please contact Lancaster DHIA directly if you have questions about any of the services we offer.

Jere High

Lancaster DHIA

General Manager

1-888-202-3442

------- Jere High, Lancaster Dairy Herd Improvement Association