Quality milk is a cornerstone for a profitable dairy operation. A key component to improving milk quality is understanding your milk quality report.
Milk quality reports typically contain the weight, date, time and temperature at the time of sample collection. This is important because delays in sample submissions or temperature irregularities can invalidate certain laboratory tests. In addition, warmer temperatures can also contribute to bacteria growth.
Reports also contain information on milk components, which include water, butterfat, protein and other solids. Changes in milk protein and butterfat values can indicate problems with herd nutrition or health.
The most significant and helpful section of your milk report is that which shows bacterial levels, somatic cell count (SCC) and other test results. These test results are important indicators of herd health, hygiene and sanitation. Test results include:
Somatic cell count (SCC): The number of white blood cells per milliliter of milk or measurement of the number of somatic cells in a sample of milk. SCC is used as an indication of the level of mastitis infection in a herd. A Grade A milk permit requires SCC of below 750,000 cells per milliliter, but most processors and milk marketing organizations require results below 400,000. Milk quality premiums are often offered at levels lower than this.
Standard plate count (SPC): An estimate of the total number of viable aerobic bacteria present in raw milk. A Grade A milk permit requires less than 100,000 SPC, while most industry standards are for an SPC of less than 20,000.
Lab pasteurized count (LPC): The number of bacteria per milliliter of milk that survive laboratory pasteurization at 143° F for 30 minutes. LPC should be below 200°.
Preliminary incubation count (PI): An estimate of the number of psychrotrophic , or cold-loving, bacteria in milk. The PI count is conducted by holding a milk sample at 55° F for 18 hours, then performing a SPC test. PI count should be 20,000 or less per milliliter. Milk quality reports also detail the freezing point of milk and milk urea nitrogen (MUN). Any freeze point more than -530° Horvath suggest that milk contains some added water or milk composition has been altered somehow. The concentration of MUN in milk indicates how cows utilize crude protein and should be between 9 and 12 milligrams per deciliter. Your milk quality report provides a wealth of information to analyze and help you understand how effective your quality controls are and make adjustments as needed. Most important is to keep bacteria and SCC levels low and ensure that hygiene standards are well managed so you are consistently providing a high-quality product to the market.
Resources for improving milk quality
Much more information on milk quality and ways to improve can be found online at:
- myDFA – Log in at dfamilk.com
- National Mastitis Council – nmconline.org
- National Dairy Farmers Assuring Responsible Management – nationaldairyfarm.com
- Pfizer Animal Health Milk Quality Focus – milkqualityfocus.com