Good Cow Hygiene Keeps SCC Down
"The environment in which we place the dairy cow has an impact on hygiene status, lying time and in some situations, it may be responsible for trauma and injury. If our dairy cows are to have longer and more productive lives, we must improve the environment in which we keep them in order to reduce levels of lameness and mastitis." (How the Environment Affects Cow Longevity by Cook and Nordlund, U of WI-Madison, School of Vet Med.)
No doubt, there is a correlation between a milking cow's hygiene and her individual somatic cell count (SCC). On the dairy farm, dairy producers can have dirty cows, dirty udders and dirty teats. Everywhere the cow may walk, lie down, eat and drink, the area must be kept as clean as possible. Dairy cows have to be managed in such a way as to attempt to keep them clean 24 hours a day, everyday. It is a very challenging task and it takes excellent management. There is the issue of keeping stalls and facilities clean. If cows are in an open lot, dairy producers often have the extra challenge of contending with weather conditions such as rain, melting snow and mud. Clean cows and excellent teat sanitation year round will aid in low numbers of non-ag strep and coliform bacteria. Whatever affects the producer's ability to keep cows clean affects the ability to produce high quality milk.
The Cow Hygiene Scorecard is a management tool that can help producers better analyze and evaluate their dairy herd's cleanliness. This can be especially helpful for herds that have predominantly environmental mastitis problems as indicated by bulk tank cultures.
The areas of the cow's udder and lower rear legs and feet can significantly affect SCC because when cows lie down, the teats can touch the rear legs and feet. The scorecard tool uses a scale of 1 to 5, ("1" indicates the cow is absolutely clean; "5" indicates a very dirty cow). Simple drawings of the udder and lower rear legs are used to illustrate the degree of cow hygiene (see diagram below).
Illustration from "The Minnesota Easy Culture Environmental Monitoring System," U of MN Laboratory
for Udder Health, St. Paul
There is a supporting article entitled, Relationship of Cow Hygiene Scores and SCC written by University of Minnesota Animal Science faculty members Jeff Reneau, Tony Seykora, Bradley Heins, Russell Bey and Ralph Farnsworth. They conducted a study on 1,093 cows in 9 dairy herds within 2 days of the DHI test day. Comparisons were made between the results of the scorecard and the SCC of the cows from test day. They found that as udder, rear legs, and udder-rear legs composition scores increased, the linear SCC on test day also increased. Their conclusion was that in similar herds with predominance of environmental mastitis infections and similar SCC levels, one may expect to see a 40-50,000 change in herd SCC for each one unit change in cow hygiene scores.
The environment of the cow, which is wet, dirty or muddy lots, poorly cleaned stalls, milking wet cows, poor cow prep, wet dirty bedding, and/or old bedding, can all cause high somatic cell problems. Even if the teats are routinely dipped before and after milking, in an unclean cow environment, it isn't going to help much.
Clean cows, udders and teats also reduce the amount of time needed for preparing the cow for milking. And, what person doesn't want to get done with milking sooner rather than later? It takes more effort to get teats clean and may even require washing with sanitizer beyond pre-dipping. The additional effort required may lead to short cuts resulting in teats not getting clean enough when the milking unit is attached.
So, how clean are the cows on your dairy farm? If your feed consultant, veterinarian or milk plant fieldman came to your farm tomorrow, how would they score the cleanliness of the milking herd? How would you score them? Scoring the cows might even be a good project for the employees or family teenagers on the farm, then compare and talk about the results.
No doubt, it is very challenging to keep cows clean. But, failure to do so can be costly to a dairy farm's profitability. Dollars can be lost from reduced milk production, elevated culling losses, added veterinary expense, milk discarded due to drug residues, and extra labor to handle or treat infected cows. By focusing on why legs, udders and teats should be kept clean,then the task of minimizing teat exposure to environmental pathogens becomes more important and a high priority in managing the dairy herd.
Published in Dairy Star May 26, 2007