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CSI-Dairy: Environmental mastitis


Numerous ‘culprits’ exist on dairy farms, robbing herd performance and injuring the dairy’s bottom line. Identifying and arresting the offender isn’t always easy, and often requires a full investigation, gathering and analyzing evidence on the farm and in the lab. This month’s investigation finds a common enemy – environmental mastitis – can be addressed with common tools.     


By Jorge Delgado 


Last summer I was invited to a dairy farm in Southwest Minnesota to do a dairy audit and to train the milking technicians on milking procedures. This dairy was losing animals, production and performance due to environmental mastitis, so I had to look very deeply into their basic dairy management. 


The investigation

First I observed the cows’ environment. This dairy used shavings for bedding, and every pen was bedded once a week, including lime application on top of the organic material to reduce bacteria proliferation. 

Then I watched the milking routine. The prep routine for this dairy was: 1st step – pre-dip and strip; and 2nd step – wipe and attach. 

The interesting part of this procedure was that they were using Clorox to pre-dip the cows. This is when we have to think about using common, proven tools that have been used for years for the reduction of bacteria at milking time, where new infections take place when teat end is forced to be open.  


My first recommendation was based on common sense and using common tools available ... add bedding more often to stalls to keep a dry environment, and avoid undesirable bacteria growing where the cows lay down to reduce new intramammary infections. Now pens are bedded twice a week instead of just once. It is cheaper to buy inorganic bedding materials than treat a case of mastitis, or even worse, lose an animal to mastitis. When applying lime to stalls, the amount must be very aggressive to make a difference on bacteria count in this kind of environment. In other words, it is impractical to apply lime to reduce bacteria count vs. applying bedding more often to stalls.

The second recommendation involved altering their milking routine. Good teat disinfectants should have four major characteristics: 1) they should be effective against major mastitis pathogens, 2) be economical, 3) be easy to apply, and 4) should maintain or promote good skin condition. 

Therefore the Clorox they were using fails in three significant areas: 1) it is very harsh on the teat skin and can cause skin chapping and cracking, and even increase new intramammary infection rates; 2) it has not been tested for use as a teat disinfectant, and 3) it is not approved by the FDA for use as a teat disinfectant. This product was also causing irritation to milker’s hands, so I immediately stopped the use of this product and they start pre-dipping cows with 0.5% iodine ... a common tool to combat a common problem.


Other changes to milking routine

Besides replacing Clorox for iodine, we made some minor changes on the milking routine to improve prep lag times and hygiene during milking. 

The steps the dairy follows now are:

1st step: Brush (remove shavings) and pre-dip. This improved the contact of iodine on teat skin, increasing killing performance, while reducing organic matter accumulation on pre-dip cups and cross contamination through milker’s gloves. It also added more udder stimulation.

2nd step: Wipe and flip towel over to clean teat ends. This step allowed the milkers to do a better job when wiping teats because I separated this step from the first one.  Now they can concentrate more on this important step, especially on teat ends where environmental mastitis was hiding before.

3rd step: Attach. This step was placed third to improve prep lag time from first touch to attach. Before, the timing was too short and this was not allowing good milk letdown, creating a better environment for bacteria growth when cows were returning to the pens with residual milk.  

After making these changes and training the milkers on the “why’s” of the milking procedures, they had a better understanding the process. With the addition of organic selenium to the diet to increase immune system response, SCC dropped from >400,000 cells/milliliter to <250,000 c/ml. There was also a reduction in the percentage of cows needing treatment for mastitis, which went from more than 3% to less than 1%.

Again, let’s use common tools available to solve a common problem ... environmental mastitis.



Jorge Delgado, a third-generation dairy farmer from Ecuador, joined Alltech in 2011. Jorge’s bilingual (English and Spanish) background and his special interest in labor management are fundamental assets for Alltech’s Dairy Advantage program. Contact him via e-mail at jdelgado@alltech.com or by phone at 605-692-5310.