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Extension > Agriculture > Dairy Extension > Milk quality and mastitis > Gear up for warm weather mastitis management now

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Gear up for warm weather mastitis management now

Jeff Reneau, Professor, Dairy Management
Published in Dairy Star April 14, 2012

When it's the first days of spring and it feels more like summer everyone is smiling but maybe not the cows. Let's face it, cows like cool. March 2012 had the warmest recorded March average daily temperatures in Minnesota history. Eight new daily high temperature records were broken and on March 17th it was 80 degrees. Lawn mowers are already in action and snow blowers hardly got used this winter in many parts of the state. At a farm the other day it was hard to believe that with all the circulating fans running, cows were still panting. If the rest of spring continues with higher than normal temperatures, it will not too early to implement summer herd management now!

Environmental mastitis bacteria love the heat and humidity. Their growth rate in warm weather is exponential. As long as they have the necessary nutrients they will double incrementally with increasing temperatures until nutrients run out or unfavorable growth conditions occur. As a consequence, the number of mastitis causing bacteria greatly increase during warm weather assuring higher numbers of bacteria in bedding materials with greater risks of contaminating teats. The bottom line is that mammary gland infection is directly correlated to the number of bacteria in bedding material and on the teat surfaces especially at the time of milking. We can see the "normal" seasonal effect reflected in the warm season increase in the herd BTSCC (Figure 1). This year, unless we take steps to get ahead of this earlier than expected arrival of warm weather, the surges in clinical mastitis and BTSCC will begin much sooner. Considering also the additional challenge this spring of meeting the new EU 400,000 SCC limit, keeping control of SCC is more important than ever.

Figure 1 is not only a good example of the impact of season on BTSCC it also provides an excellent lesson. Note that while all herds have some increase in BTSCC during the warmer months, the BTSCC increases are much greater in the higher BTSCC herds. Previous studies show that greater management intensity on farms with low BTSCC will hold both clinical mastitis and BTSCC in check in spite of warmer conditions. For example, in our study of daily bulk tank milk pick-up on 1500 herds, we found that herds which never once in 3 years had a single BTSCC greater than 400,000, averaged 177,000 BTSCC and had a BTSCC pick-up to pick-up variation of 29,000 (see Table 1). During the warmer summer months these same herds averaged 194,000 BTSCC with a 39,000 BTSCC variation. Although these herd's BTSCC did increase some, they were able to cope well enough during warmer weather to keep BTSCC in check. It's not necessarily that these herds do anything so different, BUT they do apply mastitis management practices with more precision and greater consistency than higher SCC herds.

Figure 1. Two-year monthly milk pick-up BTSCC average of 1500 upper midwest dairies showing seasonal variation between low BTSCC and high BTSCC herds.

Beach with palm tree

Table 1. Three-year BTSCC averages and pick-up to pick-up variations for herds not exceeding BTSCC categories of 200,000, 300,000 or 400,000.

Herds with no BTSCC in 3 years greater than: BTSCC 3-year average Average 3-year BTSCC pick-up to pick-up variation
400,000 177,000 29,000
300,000 128,000 21,000

Checklist to gear up for summertime Mastitis control

This is not an all inclusive list but a good start to coping with summer mastitis control. For more details and mastitis diagnostic information, take the online milk quality self-assessment test ( to identify your mastitis control opportunities. Check out the newly revised online Quality Count$ materials for the latest mastitis control information.

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