Data collected from 14,591 dairy herds in Wisconsin indicates larger dairies tend to have better quality milk. University of Wisconsin Food Science Professor Steve Ingham says they divided the dairy herds into three categories: 12,866 small farms with less than 118 cows; 1,565 large farms with 119 to 713 cows and 160 Confined Animal Feeding Operations (CAFOs) with more than 714 cows. The study used bulk tank standard plate counts (SPC) and somatic cell counts (SCC) to determine quality of milk.
The study found the CAFO group had a mean 35,000 SPC and 240,000 SCC. The large farms averaged 36,300 SPC and 273,000 SCC while the small farms had a mean 58,700 SPC and 369,000 SCC. Ingham notes in all three groups, the SPC and SCC were far below Grade A maximum levels.
Ingham says the larger farms may have an advantage in that they have more money to spend on good equipment and are in a position to cull cows with mastitis more quickly.
The study if published in the August 2011 issue of the Journal of Dairy Science.
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