When it comes to milk quality, maybe not
Dairy industry leaders often trumpet the claim that the U.S. has the safest, highest quality milk in the world.
While the U.S. milk supply ranks among the top nations, it may not be the absolute best according to reports based on somatic cell counts (SCCs) presented at the National Mastitis Council (NMC) annual meeting in San Diego in January.
It gets a bit confusing because some countries report their averages as simple arithmetic means and others as geometric means. The geometric mean, just by the nature of the calculation, is always lower.
New Zealand, at 187,000 cells/ml, and Great Britain, at 191,000 cells/ml, both use arithmetic means in NMC reports. The U.S., at 206,000 cells/ml, uses a geometric mean in its report.
These numbers, of course, are open to further interpretation. The U.S. numbers, submitted by Jason Lombard, a USDA veterinarian, rely on data from Federal Milk Marketing Orders. Not included, therefore, are cell counts from non-Federal Order states such as Idaho and California.
These states, with their larger average herd sizes, also tend to have lower somatic cells counts. If their cell counts were included in the national average, the U.S. average might be somewhat lower.
Even within the Federal Orders, however, SCCs have been falling steadily. In 2005, the average SCC was 258,000 cells/ml—and has been on downward slope since.
The key difference from other countries is that the U.S. SCC regulatory limit remains at 750,000 cells/ml. That’s likely to change later this month at the National Conference of Interstate Milk Shipments, where the National Milk Producers Federation is proposing to lower the limit to 400,000.
(There’s also been a defacto limit of 400,000 cells/ml since last year, so that USDA could issue dairy export licenses to the European Union.)
Nevertheless, the other reporting nations have cell count limits of 400,000 cells/ml. Canada was the latest to adapt. "In August 2012, all 10 Canadian provincial jurisdictions adopted a 400,000 bulk tank SCC penalty level," says Greg Keefe, a veterinarian and milk quality specialist with the University of Prince Edward Island.
In Ontario, an industry-led program challenges producers to maintain bulk tank SCCs below 200,000 cells/ml.
Doing so reduces costs, increases production and improves cow health and milk quality for consumers.
"With relatively small herd sizes, particularly in eastern Canada, SCC values can be relatively volatile," Keefe says. "Modeling suggests that these herds need to be consistently below 250,000 cells/ml in order to avoid occasional spikes and subsequent penalties."
New Zealand dropped below 200,000 cells/ml only last year, says Eric Hillerton, a milk quality specialist with Dairy New Zealand. Part of that came as a result of good weather.
"Coupled with proactive management initiatives launched by Fonterra (the dairy cooperative with nearly 90% of New Zealand’s milk supply) in December 2011 and a favorable season, the average milk cell count for Fonterra dropped from 212,000 cells/ml in the 2010/11 season to 187,000 cells/ml for the 2011/12 season, a 12% drop," he says.
But New Zealand has financial penalties that kick in at 400,000 cells/ml, and milk shipments from a farm are suspended if cell counts exceed 700,000 cell/ml for two consecutive tests.
- April 2013