Some dairy producers practice a second pre-dip. Why and what are the results?
We know that effective pre-dipping is important in reducing the number of new mammary infections caused by environmental bacteria. Milking prep procedures often involve massaging teats after teat dip is applied and forestripping milk. That process removes manure or dirt from the teat and gets the dip to the teat skin, while stimulating the cow.
Several months ago, an owner of a leading milk quality herd told a group that they dipped teats again after forestripping – in effect, a double dip prior to attaching the milking unit. The result for them was a further reduction in herd somatic cell count (SCC) from an average just above 50,000 to just above 40,000. I was surprised at those results given that they consistently do things well and stay on top of mastitis at a level where I assumed any improvement would have only a marginal impact.
Another producer in the group implemented double dipping after that and saw a similar reduction in herd SCC from a similar low starting point. I was still surprised to hear of these results. After all, if you do a good job of pre-dipping, why would there be any benefit to a second pre-dip?
Recently, I was called to visit a herd because the farm was experiencing an increase in SCC. As I watched the milking routine, I saw some deficiencies in teat end cleaning and forestripping. But what surprised me more was that when the milkers left the cow after the first visit, very little dip remained on the teat.
In this case, they applied the pre-dip with a sprayer and only achieved partial coverage. Their massage and forestripping distributed the dip around the teats. But in the process, especially with forestripping, they removed most of the dip from the teat.
I believe that this is the reason that a second dipping offers benefit. Contact time of the dip on the teat of 30 seconds means little if there isn’t enough dip left on the teat to be fully effective.
I asked the milkers to apply dip a second time using a dip cup and timed the process to see what impact it had on time from first touch until the unit was attached. Attachment was still within the 60-90 second target range and the second dip was on teats for at least 20 seconds until it was wiped off with a dry towel before units were attached.
In order to lower overall herd SCC, new infections must be reduced. The quality of the job done in prepping cows for milking strongly impacts the rate of new infections. In reading the write-ups of the 2012 National Dairy Quality Award Platinum Winners in the January 10, 2012 Hoard’s Dairyman, it noted that at least two (Tohls and Dellars) of the five farms practice double dipping. These high quality herd owners consider it an important part of their prep procedure.
A question that will be asked is that given the higher prices for iodine, is double-dipping worth the added costs? There are financial benefits from achieving higher quality milk and dairy producers can compare the results and returns from the changes. The producers that I talk with say that those added costs are fully worth it.
Research is needed to determine if there is a real difference in the kill rate of bacteria from teat skin whether teats are single or double-dipped during the prep procedure.
Double dipping is not a magic bullet. It is a good practice that works with other good practices to achieve great results. Recently, I watched milking at another farm and saw that they practiced double dipping, however their prep procedures were sloppy in other areas and their SCC was not exemplary.
Likewise, I know other herds that do not practice double-dipping but still run average SCC below 100,000. The key to improvement is always to address weaknesses and take steps to strengthen those areas.
Recommended prep procedures must be done consistently by everyone milking the cows, every time they milk. Certainly, managers of herds that can’t seem to reduce SCC need to look to their prep procedures, but it is also very important to evaluate the job actually being done in this critical area.
As you evaluate your prep for milking, take a look at the amount of dip still on the teats when milkers leave the cow. It may be that applying dip a second time will increase the bacterial kill and reduce the number of new infections, helping you to lower SCC and produce even higher quality milk.