“We all use benchmarks to compare our performance to some standard,” said Frank Welcome, DVM, MBA, Quality Milk Production Services, Cornell University. “These standards are used to indicate how well we are performing, if our businesses are profitable and if our efforts to improve are effective.”
Speaking at the 2011 American Association of Bovine Practitioners meeting in St. Louis, Welcome said the basic goal used to measure milk quality and often milk value is the bulk tank SCC. “The BTSCC goal most often cited by producers I work with is 200,000 cell/ml; however many producers are stopped short of that goal and just can’t figure out why.
Figure 1 (below) demonstrates an organized approach to determining the cause of producers’ inability to reach their goals. “It is a great tool and helps veterinarians and dairy farmers better identify and understand the obstacles to their success,” Welcome explained.
In herds where more than 2% of the milking herd is contributing somatic cells to the bulk tank SCC goal, you need to determine the type of infection contributing to the problem. Infection rates can be classified in a variety of ways. New infections represent that portion of a herd where current test day linear scores are above 4.0 (200,000 cells/ml) but the previous test day linear score was below 4.0. Chronic infections, which are most often the cause of persistently high BTSCC are represented by cows where both the current and previous test day linear scores were greater than 4.0.
An important but often overlooked cause of high bulk tank cell counts are fresh cows and heifers, Welcome added. “The infection rate of fresh animals with a linear score of 4.0 or higher at first test after calving is referred to as the HiFresh infection rate. These infection rates are our bench marks for measuring our ability to control mastitis infections in our herds. They are our Key Performance Indicators.”
The benchmarks or infection rates seen in Figure 1 were determined by analyzing linear score data of herds enrolled in Dairy One. The herds were ranked by test day average SCC and divided into five equal sized groups. The New, Chronic, and HiFresh infection rates were determined for the test day average SCC of each group. The best herds had test day average SCC below 200,000 cells/ml. Those that fell into the “needs help” category were usually 400,000 cells or higher.
To calculate infection rates you need information which are easily provided by DHIA cell count data. That information can easily be analyzed by computer software such as Dairy Comp 305, or the information can also be easily calculated by hand for smaller herds.