Milking parlor clean-in-place systems are about to get some needed design and control guidelines, thanks to studies at the University of Wisconsin-Madison Milking Research and Instruction Lab.

“Improper control of air and water flow during cleaning is a common cause of cleaning failure. Commonly used design guidelines often result in excessive vacuum pump size, hot-water use, and operational costs,” according to Doug Reinemann, an agricultural engineer at UW-Madison”s College of Agricultural and Life Sciences.

Manufacturers” clean-in-place recommendations have been variable and usually not well-defined, Reinemann says. This project aimed at developing design recommendations for cleaning systems, and designing tests and procedures to adjust the system and make sure it”s working right.

Reinemann and his colleagues tested single units and milking systems. The researchers developed a standardized dirty milking machine, then tested the cleaning process by changing flow, water temperature and chemicals. (To make a dirty milking machine, they injected a solution of milk and bacteria, then let the solution incubate until it got nice and sticky.)

Improper location and timing of the air injector can be a major problem with a big milking system, according to Reinemann. Air and water have many different flow paths through a milking system. If the air injector is not located or timed properly the air and water will not end up in the right place. Based on studies of cleaning flow characteristics in the milking lab, the CALS researchers developed an air-injection strategy that optimizes cleaning flow throughout the system.

If you don”t have weigh jars or milk meters, you don”t need an air-injection system for cleaning the milking units, just for the milk line. If you do have weigh jars or milk meters, Reinemann suggests using sequenced air injection. You”ll use two air injectors, timed independently for the two parts of the system: the milkline, and milking units and weigh jars. The two parts have very different optimal flow-rate requirements, and sequenced injection lets you control flow rates in both parts, he points out.

“Shock treatments” using super-high concentrations of chemicals aren”t necessary if the cleaning system is operating properly. Shock treatments shorten equipment life, they”re expensive and dangerous to do, and they don”t correct the source of the problem, Reinemann notes.

A well-adjusted system will save 25 percent in chemicals and hot water costs over a poorly tuned system, but the big savings are in quality premiums, according to Reinemann. For example, he got a call from one Wisconsin farmer whose 300-cow farm was losing $15,000 a month in milk quality premiums due to a flow problem.

You may need a professional to do a major tune-up on a cleaning system, but things you can do right now may save headaches down the road, Reinemann says.

Watch a complete cleaning cycle, and make sure the system is doing what you think it”s doing. Many problems have easily fixed causes, he says, such as a burned-out water heater, a kinked hose, or a hose that”s fallen out of a jar. A bulk-tank quality test (standard plate count, lab pasteurized count, coliform count) costs $25 to $30 a month. Done monthly, the test will let you know a problem is developing before it turns into a crisis that costs you a quality premium.

R.W. Peebles and G.A. Mein also worked on this project. Reinemann has incorporated the results of these studies into an Extension bulletin, Troubleshooting High Bacteria Counts in Farm Milk, which will be released later this year. The step-by-step guide to troubleshooting milk-quality problems will also be published in Spanish and Russian, and as a document for the Babcock Institute for International Dairy Research and Development.