Investigation of mastitis problems on farms

Mastitis is generally considered the most costly disease of dairy cattle. Financial losses due to mastitis occur for animals experiencing both subclinical and clinical disease. Losses resulting from clinical mastitis are usually apparent and consist of discarded milk and transient reductions in milk yield [1]. Additional losses include the risk of antibiotic residues and culling or death of affected animals [1]. For most farms, subclinical mastitis is the most economically important form of mastitis because of long-term reductions in milk yield. It has been estimated that production losses due to subclinical mastitis cost the dairy industry I billion dollars annually [2]. Failure to receive quality premiums is an additional source of reduced profit for many dairy producers. Although premiums vary regionally and depend on individual processors, the monthly premium opportunity for 54 Wisconsin dairy farmers was reported to range from $6.70 to $15.02 per cow per month [3]. Mastitis is a serious concern of most dairy farmers and their veterinarians due to these profound economic consequences. Despite significant financial consequences of mastitis, many veterinarians are not actively involved in providing milk quality programs (Table 1). Only 29% of a group of Wisconsin dairy producers indicated that they routinely consult with their veterinarians regarding milk quality [4]. The provision of milk quality programs and mastitis problem solving is an area of financial opportunity for many veterinary practitioners. General herd problem-solving paradigms have been developed and can be easily adapted to investigate mastitis problems on dairy farms [5]. This article introduces a mastitis problem-solving format that begins with a discussion of strategies used to identify mastitis problems and continues by introducing a structured investigative strategy based on (1) verification of the scope and type of mastitis problem, (2) determination of a case definition for both clinical and subelinical mastitis, (3) identification of risk factors for infection, (4) formulation of conclusions, and (5) planning preventive measures.