Achieving low somatic cell counts (SCC) is not a matter of luck or the weather. It's about consistency and control.
A recent study of more than 1,500 Upper Midwest dairies shows that day-to-day variation is a good indicator of how likely a dairy is to keep below 400,000 cells/ml.
"Cows love to be bored,” says Jeff Reneau, a University of Minnesota veterinarian and milk quality specialist. "They milk best when routines are the same time after time.”
In the study, Reneau and grad student Joanna Lukas found that day-to-day variation is much greater at high cell-count levels than at low.
Yes, herd size makes a difference. Small herds, those with fewer than 100 cows, are more affected by one or two high cell counts in the bulk tank.
Yet even in herds with more than 100 cows, the day-to-day variation is 41,000 at an average cell count of 400,000. If the herd's SCC average is 100,000, the day-to-day variation will be just 15,000.
Inconsistent milking procedures, teat dipping and stall management are as much a plague on large dairies as they are in smaller herds, Reneau says. By calculating your day-to-day variation, you can determine if it's your consistency or the process itself that is the problem.
"If a farm has a higher than desired bulk tank SCC but day-to-day variation in SCC is low, compliance and consistency in the current procedures is good,” Reneau says.
If you have low variation, walk around the dairy to see what's causing the high cell-count average. It's often sanitation: cow prep procedures, bedding management, even nutrition deficiencies that result in immune response dysfunction.
"If, on the other hand, both bulk tank SCC and day-to-day variation are high, you need to focus first on become more consistent in applying procedures and then think about improving processes,” Reneau says.
Do milkers get every teat end clean? Is each teat dry before unit attachment? Is there at least 90 seconds of lag time before attaching units for every cow? Is every teat of every cow postdipped completely? Is feed always available after cows are milked to ensure teat end closure? Is every stall cleaned and groomed after each milking?
"Monitoring variation is not a panacea that will automatically solve all problems on the farm,” Reneau acknowledges. "However, experience in nonagricultural industry has shown that taking a closer look at variation can be very helpful in spotting emerging problems early as well as discovering root causes.”