Pennsylvania and Somatic Cell Count Levels
The good news is U.S. herd SCC continues to decrease.
U.S. Herd Somatic Cell Levels
Did you see the recent summary in Hoards Dairyman (June 2007 issue) on somatic cell levels (SCC) in the U.S.? The good news is U.S. herd SCC continues to decrease. In 2006, the average SCC reported by Dairy Herd Improvement Associations was 288,000. This is down from the 296,000 reported in 2005. Likely, herds going out of business may have made an impact. In addition, state programs focused on milk quality appear to have made a difference in specific states like New York and Wisconsin. Herds contributing to the U.S. average SCC increased in cow numbers from about 90 to 115. As expected, herd-test days that were above 750,000 decreased from 4.7 to 3.9 percent. There was little to no change in herd test days with SCC greater than 400,000. Values were 25.8 percent in 2005 and 25.2 percent in 2006.
Pennsylvania Herd Somatic Cell Levels Compared with other Major Dairy States
So how did Pennsylvania do in this summary and compared with the other major dairy producing states? See Table 1 for a quick review.
| State | Cows per herd | Average Daily Milk Yield (lbs.) | Average SCC (cells/ml.) | Percent Herd Test Days with SCC greater than 750,000 cells/ml | Percent Herd Test Days with SCC greater than 400,000 cells/ml. |
|---|---|---|---|---|---|
| California | 653.8 | 73.0 | 291,000 | 4.0 | 20.7 |
| Idaho | 581.1 | 75.4 | 282,000 | 5.0 | 21.4 |
| New York | 103.1 | 70.9 | 256,000 | 2.5 | 21.0 |
| Pennsylvania | 57.4 | 69.5 | 306,000 | 3.6 | 26.0 |
| Wisconsin | 74.4 | 74.3 | 258,000 | 3.5 | 19.9 |
| U.S. | 115.5 | 71.2 | 288,000 | 3.9 | 25.2 |
Pennsylvania is at the bottom, meaning as a state, the herd average SCC is substantially higher than the other top milk producing states. In fact, there are 25 other states with herd average SCC lower than in Pennsylvania. Pennsylvania state average SCC from herds on test was 306,000 compared with a range of 256,000 to 291,000 for the 4 other major milk producing states. Interestingly, both California and Idaho had more test days with SCC herd averages above 750,000 than Pennsylvania. However, both had herd test days with SCC above 400,000 that were substantially lower. This just means that likely there were more test days with very high herd average SCC (above 750,000) in California and Idaho, compared with Pennsylvania. However, there were fewer test days with SCC between 750,000 and 450,000 for California and Idaho compared with Pennsylvania, leading to a lower state herd average SCC
So why is this important?
Likely, most producers are not motivated by Pennsylvania's milk quality ranking compared with the U.S. or the other top dairy producing states. More likely, you are motivated by your herd's individual production challenge areas. However, this information should motivate state government and education, and industries with profits influenced by milk quality (milk processing plants) to take action. This information should also motivate individual producers that believe that a herd SCC average above 300,000 is the norm to recognize that improvements can and should be made. High herd SCC affects individual farm profits. High state herd SCC affects perception of milk quality. We also know that high SCC impacts milk processing plant costs.
A common argument heard is that large herds can not reduce their herd SCC below 350,000 to 400,000, so why bother. If this is true, why are states with the highest cow numbers also some of the states with the lowest herd average SCC (See Table 2)? In Table 2, all states, except Florida, with average herd sizes above 200 cows had a state herd average SCC far below Pennsylvania. Based on average herd size, likely many of the herds with low SCC are large herds.
| State | Cows per herd | Average Daily Milk Yield (lbs.) | Average SCC (cells/ml.) | Percent Herd Test Days with SCC greater than 750,000 cells/ml. | Percent Herd Test Days with SCC greater than 400,000 cells/ml. |
|---|---|---|---|---|---|
| Arizona | 1276 | 69.0 | 283,000 | 0.4 | 14.3 |
| California | 653.8 | 73.0 | 291,000 | 4.0 | 20.7 |
| Colorado | 550.9 | 72.2 | 257,000 | 0.3 | 12.8 |
| Florida | 655.8 | 69.0 | 319,000 | 11.1 | 55.8 |
| Idaho | 581.1 | 75.4 | 282,000 | 5.0 | 21.4 |
| Nevada | 448.1 | 76.6 | 276,000 | 5.8 | 18.2 |
| New Mexico | 1295 | 74.2 | 269,000 | 4.6 | 18.0 |
| Texas | 359.7 | 64.1 | 282,000 | 1.3 | 18.5 |
| Washington | 230.4 | 75.1 | 251,000 | 2.0 | 9.3 |
Another common argument heard is that Pennsylvania has a higher state SCC because of the number of small herds compared with other states. Although Pennsylvania does have more small herds than any other state, it is difficult to believe that herds below 50 cows are responsible for the high state SCC average. There is tremendous variation in herd SCC regardless of herd size. There are both large herds and small herds that pay attention to milk quality and those that do not. It is true that a single cow with high SCC and high milk production can have a greater impact on bulk tank SCC or herd average SCC in a small herd than in a large herd. However, there are also cost effective management strategies that can be implemented to negate the impact of an individual mastitis infection on bulk tank SCC.
Regardless of the reasons why Pennsylvania has a higher state SCC compared with its colleagues, it is time for state service agencies, industry, and individual herds to take action to reduce the state average somatic cell count. Other states continue to make progress and Pennsylvania herds can make progress too.
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- Sandy Costello, PhD
- Penn State Dairy Herd Health Extension Educator – Capital Region
- Cumberland County
