Cathleen C. Williams and Gary M. Hay

Mastitis – an infection and inflammation of a cow’s udder – is one of the most common and costly diseases in the dairy industry. Therefore, mastitis control should be a continuous process in all dairy herds. An effective control program should be a team effort and involve cooperation among veterinarians, extension specialists, milk plant field representatives and dairy producers. The LSU AgCenter plays a major role in mastitis control, with many key individuals working as part of the team. Several services available to our dairy producers aid in the detection, diagnosis, treatment and prevention of mastitis.

The LSU AgCenter has two programs dairy producers may use in assessing the mastitis situation in their herds.

The Dairy Herd Improvement Association (DHIA) is housed at the Dairy Improvement Center on the Baton Rouge campus. Through DHIA, dairy producers work with the field services supervisor and their local DHIA field technicians to collect milk samples and production information from each cow in their herds. The samples are analyzed at the DHIA lab in Baton Rouge for somatic cell counts (SCC) and milk components. Somatic cell counts are extremely useful in assessing the mastitis status of the herd because they are an indirect indication of mammary infections.

The primary advantage of DHIA somatic cell counts is to identify individual cows that may have mastitis infections. This information helps producers become aware of mastitis problems in their herds. DHIA somatic cell counts are used to identify management practices that may be contributing to mastitis problems in a dairy herd. Cows with high somatic cell counts can be further examined to determine if they need to be treated for an infection.

Cell counts alone, however, normally are not used to determine whether individual cows need to be treated for mastitis. The DHIA somatic cell count program at the Louisiana DHIA lab on campus can be a highly effective component of a mastitis control program in a dairy herd. The DHIA program helps dairy farmers produce a safe, nutritious, high-quality product for human consumption by helping dairy farmers control mastitis in their herds.

Another valuable service in mastitis control available through the LSU AgCenter is the Mastitis Research Laboratory at the Hill Farm Research Station in Homer, La. This laboratory offers bacterial culture analysis of milk from potentially infected cows. Technicians there are able to determine whether a cow is infected and positively identify the type of infectious organism. Producers can then work with their extension specialist and their veterinarian to determine which treatment method is best for their herds.

In herds with high bulk tank somatic cell counts, the problem is usually a high prevalence of subclinical mastitis. In these herds, a reliable diagnosis of the herd problem can be made by culturing milk from a representative sample of cows selected on the basis of increased DHIA somatic cell counts.

Through the LSU AgCenter’s dairy extension specialists, county agents, the state extension veterinarian, DHIA laboratory and the Hill Farm mastitis lab, Louisiana dairy producers have access to a sound program in mastitis detection, diagnosis and control. These individuals work together as a team to ensure the state’s dairy producers receive the assistance they need to achieve their goals in dairy production and management.

Cathleen C. Williams, Gerald A. Simmons Professor of Dairy Science and Associate Professor, and Gary M. Hay, Professor, School of Animal Sciences, LSU AgCenter, Baton Rouge, La

(This article was published in the winter 2009 issue of Louisiana Agriculture.)