Effectively managing udder health on dairy farms requires a good record keeping system and routine monitoring of somatic cell count (SCC) data. Michigan State University Extension dairy educators recognize the importance of using SCC data to determine the overall udder health status of dairy herds. SCC data for individual cows also help focus on those specific cows with udder infections.
Dairy Records Management Systems (DRMS) offers the Udder Health Monitor report (DHI-427) to summarize SCC data collected through DHIAs (Dairy Herd Information Associations). Data from individual cows are used to calculate the overall SCC average for the herd and to monitor udder health of subgroups of cows based on lactation number or stage of lactation. Newly infected cows or cows with chronic udder infections also are identified.
The Udder Health Monitor report contains various graphs, tables and lists to look at current SCC infection rates, current SCC averages by lactation and stage of lactation, changes in infection rates during the past 12 months, and infected cows. For several of the graphs and tables, dairy producers, dairy farm managers and herd consultants can see how their herds compare to the Top 20 percent Herds within their herd size category. The three herd size groups are: 1-199 cows, 200-999 cows, and 1,000+ cows.
The Current SCC Infection Rates graph and table provide the total number and percentage of infected cows for several subgroups of cows. Users can evaluate differences in infection rates based on lactation number (first, second, or third and greater). They also can determine if they are meeting their goals to minimize the number of new and chronic infections and the number of infected fresh cows.
Monitoring average SCC and infection rates by stage of lactation will help pinpoint the potential source of udder infections. For example, high SCC in fresh and early-lactation cows could be lowered by making management changes in the dry cow groups or maternity pens. The Current SCC by Stage of Lactation graph shows the percent of cows by SCC level for 3 stages of lactation: 5-29 days in milk (DIM), 30-220 DIM and 220+ DIM.
Graphs of monthly trends in infection rates will illustrate progress resulting from management changes to improve milk quality. Or the graphs may alert herd owners and managers when infection rates begin to trend upward. Trends in new and chronic infections as well as infections in fresh cows are graphed for the past 12 months.
Comparing a cow’s SCC at the previous test day to the current test day SCC in her current lactation in a scatter-plot graph shows the prevalence of cows in these 4 categories:
- Not infected – previous and current SCC < 4.0
- New infection – previous SCC < 4.0 and current SCC >=4.0
- Cure – previous SCC >=4.0 and current SCC < 4.0
- Chronic – previous and current SCC >=4.0
In addition to summarized SCC herd data, the Udder Health Monitor report includes lists of infected cows that may need specialized attention. Milk samples may need to be collected and cultured, cows may benefit from treatment or other action may be required.
The Udder Health Monitor report (DHI-427) is available on a monthly or quarterly basis. More information about these reports can be obtained from the herd’s DHI information specialist or technician.
Managing udder health in dairy herds requires routine monitoring of individual cow and herd SCC information. The Udder Health Monitor can be a valuable tool for herd owners and managers as well as herd veterinarians to identify potential problems in the herd mastitis control program and opportunities for improvement.