What's in your milk?

Dairy Pipeline: August/September 2005

Sue Puffenbarger Dairy Science Extension Agent, Franklin County smp@vt.edu

With one of the hottest summers of the last few years upon us, cases of clinical mastitis have been on the rise and, along with that, an increased used of antibiotics to try to cure the infected quarters. With chronic environmental infections, some herds are using extralabeled drugs on the advice of their veterinarians to increase cure rates. With products formulated specifically for intra-mammary mastitis treatment, withdrawal times are known and can be relied upon, often with a guarantee from the manufacturer. But how sure are you that an extra-label antibiotic is totally cleared from your milk? In addition, more and more herds are going to pre-treating heifers with either a dry cow or lactating cow intra-mammary treatment. Do those first lactation animals, with smaller udders and better penetration of antibiotic through the udder, have longer or shorter withdrawal times? Even the best managed herds can have simple things happen, such as forgetting to band treated cows, forgetting to remove the milk line from the tank if treated cows are milked last, not thoroughly cleaning equipment after milking a treated cow and surprisingly, employees leaving the treated quarter out of the tank, but putting the other quarters in the tank. Let's also not forget the labor issues everyone seems to have now, such as the turnover rate of employees increasing and the challenge of training new labor correctly on how to manage treated and fresh cows. The only reliable way to tell if an antibiotic has cleared from a cows system is the use of on farm testing. There are many tests out there available for purchase from your milk cooperative, the most common being the Delvotest® and SNAP®. These tests are easy to use and only take 15 minutes to three hours for results, depending on the test. Heater units for these tests require an initial investment of $200 on average. Costs for running samples are anywhere from $1.10 - $3.00 per sample. That's too expensive you say? Consider the average herd in Virginia of 147 cows making 70 pounds of milk, on every other day pickup. That equates to 20,580 pounds of milk. At a $13 Class II price, that equates to a loss of $2700 if the tank was contaminated with antibiotics and needed to be dumped. Additionally, if that tank of milk made it on to the truck, it can cost you upwards of another $4000 to pay for the rest of the milk on the truck if it isn't caught soon enough. With $2700 you can purchase anywhere from 900 - 2000 individual antibiotic residue tests. Doesn't that seem like a fair investment? And isn't it cheap insurance, with the need to manage financials more tightly than ever because of the ever changing target of milk price? For more information on which test is right for you, call your local Co-op representative or Dairy Extension Agent.

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