University of Minnesota

Dairy Initiatives

Dairy

Department of Animal Science


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Minnesota DHI SCC is High and Getting Higher

JEFF RENEAU, RUSS BEY, and RALPH FARNSWORTH
University of Minnesota

Nationwide, somatic cell count (SCC) has increased at an alarming average rate of 2,400 cells per ml each year since 1995. Worse yet, Minnesota has the highest DHI herd SCC average of the top 10 dairy states (Table 1). High SCC is bad news because it means lower milk production, lower farm profitability, lower product yield at the milk plant, and poorer product quality for the consumer. Everyone loses when milk quality is poor.

TABLE 1. Milk Quality in the Top 10 Dairy States, 2001
State in Order of
Milk Production
Average No.
Test Day Milking
Cows/Herd
Average
Test Day Yield
(lb/Cow)
Average Herd
Test Day SCC
(Cells/ml)
Percent Herd
Test Days
> 400,000 SCC
         
  1. California
450
73.7
298,000
21.0%
  2. Wisconsin
53
69.5
297,000
25.4%
  3. New York
67
67.3
280,000
22.7%
  4. Pennsylvania
47
66.7
317,000
27.2%
  5. Minnesota
53
66.4
420,000
48.5%
  6. Idaho
227
75.3
320,000
24.7%
  7. Michigan
70
70.0
287,000
23.4%
  8. New Mexico
584
74.2
311,000
29.5%
  9. Washington
175
78.5
275,000
13.5%
10. Texas
223
64.8
342,000
32.0%

Source: R.H. Miller and H.D. Norman, Somatic Cell Counts of Milk from Dairy Herd Improvement Herds During 2001 (www.aipl.arsusda.gov/docs/dhi/dhi01/scc01.htm)

As a state, we think we need a kick in the pants. We need to turn this trend around!
What caused Minnesota's SCC to skyrocket during 2001? Likely explanations include last summer's heat, poor sanitation for dry cows, poor sanitation for the milking herd, poor premilking cow prep, retention of high-SCC cows that should have been culled, reduced premium incentive due to component pricing, and insufficient regulatory pressure (legal limit is 750,000).

What can you do about your high herd SCC?

  • Use more "elbow grease"! Excellent sanitation and low herd SCC go hand in hand. Keep teat surfaces clean and prevent bacteria from entering the teat end.
  • Ask your veterinarian, milk plant field rep, milking equipment dealers, and Extension educator to help you reduce SCC.
  • Do individual cow SCC tests monthly to identify herd trends and pinpoint the infected cows.
  • Run a monthly bulk tank culture through a reliable laboratory to find out what kinds of bacteria are causing mammary infections.
  • If your bulk tank culture shows you have a lot of contagious mastitis pathogens (staph aureus, strep ag, or mycoplasma), identify the culprit cows by individual cow culturing. Take steps to reduce cow-to-cow spread and remove the high SCC quarters from the milk supply.
  • If your bulk tank culture shows you have a lot of environmental pathogens (non-ag streps, coliforms, or staph species), improve bedding management. Replace ALL bedding in every stall weekly with clean bedding. Every day, replace the bedding in the back half of the stall with fresh, clean bedding. If you use sand bedding, add fresh, clean sand at least once per week. Keep stalls leveled and remove soiled sand daily.
  • Improve your milking procedures. Include a pre- and post-milking teat dip, 10 to 20 seconds of cleaning, at least 30 seconds of contact time for the teat dip, and a thorough teat end wiping before attaching the milking unit.
  • Forestrip during cow prep to identify high SCC quarters and keep milk from these quarters out of the bulk tank.
  • Improve herd reproduction and heifer replacement rearing so you can cull high-SCC cows that do not respond to therapy.
  • Treat every quarter in dry cows with an approved dry cow intramammary tube.
  • Consider using a dry-cow barrier dip.
  • Provide dry cows with adequate space, ventilation, and clean bedding. (DHI records indicate that an average of 35 percent of cows and heifers calve with high SCCs.)
  • Keep cows as cool and comfortable as possible during hot weather.
  • Control flies.

SCC Risk Quiz

Studies have shown the following are characteristics of low SCC herds (<150,000 SCC). Give your farm a score of 1-5 for each item, with 5 being the best and 1 the worst.
 

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Cows have no visible manure or dirt on flanks, udder, or lower rear legs and feet.
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Udder hair is removed every three months.
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Stalls are cleaned frequently. Soiled bedding is removed at each milking. Fresh organic (sawdust, straw, etc.) bedding is added daily, or fresh sand bedding is added weekly.
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Generous amounts of bedding are used.
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Dry cows are checked daily for evidence of clinical mastitis.
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Calving pens are clean. Pens are completely cleaned and fresh bedding is added between calvings.
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Milking parlors are clean. There is no buildup of manure or dirt on the milking equipment.
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Milk is kept out of the bulk tank at least 48 to 72 hours after calving.
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Post-milking teat dip is used consistently.
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All quarters of all dry cows are dry-cow treated.
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Transition diets and nutrient supplementation are used for springing heifers and dry and lactating cows.
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Producers and employees keep abreast of current practices to improve milk quality and udder health by reading and/or attending workshops.
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Detailed herd records, including clinical mastitis treatment records, are kept.
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Milkers enjoy milking cows.
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Emphasis is on getting the job done right rather than getting the job done quickly.
 SCORE:
 
61-75:
46-60:
31-45:
<30:

Excellent. Keep up the good work!
Good job. However, there is still room for improvement.
Fair. Time to get serious about milk quality.
Get with it! Are you producing food, or running a summer
camp for bacteria?


D A I R Y    I n i t i a t i v e s    N E W S L E T T E R
Volume 11    Issue 2    Summer 2002