Udder Cleanliness and Somatic Cell Count

Dr. Allen Young
USU Extension Dairy Specialist

I am always concerned when I visit dairies and see dirty cows. Dirty cows are an indicator of udder health problems. The French reported a study where they categorized commercial dairies on the basis of 5 levels from clean to very dirty. Not surprisingly, there was a linear relationship between increased somatic cell count and dirty udders. Others have found similar relationships. I believe most dairy farmers won’t argue too strongly over whether this association is real, but they may not look at the situation in a systematic, measurable way. I always like cheap, easy and useful management tools to assess different aspects of a dairy. This article describes a quick, easy way to determine the cleanliness score for the cows on your dairy.

Workers from Wisconsin have developed a scoring procedure based on a scale of 1 to 4 (clean to dirty) for 3 areas of the cow. The areas are udder, lower legs, and flanks and upper legs. Each area is to be scored individually and the proportion of cows with a score of 3 or 4 in each area is calculated. The reason is that you want to know what percent of your herd is unacceptably dirty, especially the udder. A color picture guide showing examples of each of the 4 levels of cleanliness for each of the 3 areas, along with scoring cards, can be found at the following web site:
http://www.vetmed.wisc.edu/dms/fapm/fapmtools/hygiene.htm

According to the scoring guide, if the herd size is <100, then all cows should be scored. If pen sizes are greater than 100, then at least 25% should be scored. I would suggest 2 individuals score at the same time and compare percentages, or have someone not associated with your dairy do the scoring. The average free stall dairy might have about 20% of cows with a score of 3 or 4 in the udder region, 60% on the lower legs, and 20% on the upper legs and flank areas. The goal suggested by the researchers is that the proportions of cows with a score of 3 or 4 should be 5% for udder, 24% for lower legs, and 6% for upper legs and flank areas.

Other research has shown that cows with dirty udders (score of 3 or 4) were 1.5 times more likely to have major pathogens isolated from composite milk samples. Cows with dirty lower legs were 1.3 times more likely to have major pathogens. Other researchers found similar results, but also found that dirty legs were as important as dirty udders. They also suggested that a 1-unit decrease in cleanliness score was associated with a decrease of 40 to 50,000 somatic cell count.

I realize things can happen on a dairy that are out of your control. However, putting up with dirty cows should be an unacceptable practice on any dairy. If you find your problems are at an unacceptable level, then I suggest having an in depth look at the environment your cows are in and then make whatever changes are necessary to improve udder scores. The list of actions could range from removing hair on the udder, leg and flank region to doing work on the free stalls. Improving udder health will result in money in your pocket and an increase in consumer confidence. If you want more information, or a copy of any of the mentioned material, let me know and I will get it to you.