Issues Associated with Lowering Somatic Cell Counts

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Issues Associated with Lowering Somatic Cell
Counts
TWENTY-NINTH SOUTHERN DAIRY CONFERENCE

• Dr. Stephen C. Nickerson
• Department Head and Professor

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Issues Associated with Lowering Somatic Cell
Counts
In recent years Proposals submitted to NCIMS to
lower the legal limit for SCC
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Pasteurized Milk Ordinance PMO

• Upper limit for somatic cell counts in raw bulk
  tank milk 750,000/ml

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Lowering the Legal Limit of SCC to Enhance Milk
Safety
SCC X 1000
Based on S. aureus and drug residues
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How SCC limit lowered in 1993

• Idea proposed to Dairy Division of NASDA.
• National Association of State Departments of
  Agriculture
• Based on S. aureus and drug residues.
• Agreed to support reduction in theory.
• DPC brought up issue with FDA, who agreed there
  were public health concerns.
• DPC and NMC resolved to support drop.
• Reduce SCC legal limit to 750,000/ml.

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How SCC limit lowered in 1993

• By time of NCIMS, it was agreed by most states
  that a reduction would occur, and FDA would agree
  to a drop to 750,000.
• Proposal passed by NCIMS
• FDA reviewed for concurrence
• FDA, NCIMS negotiated to agreement

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29th National Conference onInterstate Milk
Shipments

• At least 2 proposals to change the 2001 PMO by
  lowering the legal SCC limit
• 1- Stepwise over 4 yr to 400,000 in 2007
• 2- Stepwise over 8 yr to 400,000 in 2011

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Proposal 1 to lower legal limit to 400,000/ml by
July 1, 2007
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Proposal 2 to lower legal limit to 400,000/ml by
July 1, 2011
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Goal To provide a high quality and safe
product to the consumer
Raw Milk Supply - Residue free - Low SPC
- Low SCC
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EPITHELIAL CELLS
SOMATIC CELLS
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Milk Leukocytes
Neutrophil
Lymphocyte
Macrophage
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Enzymes
Bacteria
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Normal udder 100,000/ml
Udder producing 60 lb gt3,000,000,000/day for
surveillance
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Bacteria reach the milk-producing alveoli
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Bacteria multiply and release toxins, e.g.,
endotoxin
Message sent to blood via TNF, IL-1, and IL-8
Expression of adhesion molecules on endothelium
to recruit neutrophils
Somatic Cells
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If the microorganisms are killed by somatic
cells, the infection is resolved.
If the microorganisms persist, subclinical
infections follow, often with clinical flare-ups.
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Inflammatory Response
Movement of leukocytes and fluids into the udder
tissues
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Clots
Somatic cells
Flakes
C\slides\pdpw
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SCC in milk from uninfected cows 50,000 200,000
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A quarter SCC of gt200,000 cells/ml is indicative
of intramammary infection
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Most mastitis is subclinical in nature
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Association of Bulk Tank SCC with Herd Infection
Status
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A High Somatic Cell Count Signals Presence of
MASTITIS
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One infected quarter produces 1,600 lb (720 kg)
less milk
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Cost of Mastitis
Loss /Cow
of Total
Source of Loss
Reduced Milk Production Discarded Milk Early Cow
Replacement Costs Reduced Cow Sale
Value Drugs Veterinary Services Labor
116.10 24.44 13.60 9.94
9.68 4.84 2.42
64 14 8 5 5 3 1
181.02
Total
100
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Losses from Mastitis (Figured at 180.00/cow)
Total Loss
Herd Size
9,051 13,576 18,102 27,153 36,204 72,408
50 75 100 150 200 400
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Milk Income lost per cow per 305 days
Linear score
SCC (cell/ml)
Milk loss-pounds per 305 days
1 2 3 4 5 6 7 8
25,000 50,000 100,000 200,000 400,000 800,000 1,60
0,000 3,200,000
0 0 460 915 1,370 1,830 2,290 2,745
56.58 112.55 168.51 225.09 281.67 337.65
168 x 100 16,800
Number of somatic cells in milk. Milk valued
at 12.30/cwt.
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Relationship between herd SCC and mastitis
prevalence
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SCC LIMIT 750,000/ml
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Proposed New Limit
600,000? 500,000? 400,000?
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Benefits to lowering SCC limit

• Lower herd level of mastitis
• Increase milk yield and quality
• Increase cheese yield/shelf life
• Improve organoleptic properties
• Increase profits to
• producer

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Lower SCC Greater Income

• Herds with BTSCC lt 200,000
• 104/cow vs
• Herds with BTSCC 200,000 400,000
• Herds with BTSCC lt 200,000
• 292/cow vs
• Herds with BTSCC gt 400,000

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Benefits to lowering SCC limit

• Reduced bacteria count (human pathogens)
• Toxic E. coli L. monocytogenes in high SCC
  herds
• Reduce antibiotic residues
• Violations increase 2 to 7 fold
• Promote consumer acceptance
• Enhance production of elite products
• Conform to EU/world standards/SCC

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National Average SCC/ml

• Switzerland 112,000
• Norway 125,000
• Finland 129,000
• United Kingdom 160,000
• New Zealand 180,000
• Western Germany 195,000
• Sweden 200,000

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National Average SCC/ml

• Denmark 247,000
• Eastern Germany 276,000
• Ireland 300,000
• Japan 300,000
• United States 350,000
• Israel 382,000

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Benefits to lowering SCC limit

• Enhance animal well-being
• Possible decreased exposure to
• S. aureus
• E. coli
• Campylobacter jejuni
• Yersinia enterocolitica
• Listeria monocytogenes
• Salmonella spp.
• Clostridia spp.
• Mycobacterium paratuberculosis
• Reduce risk of developing resistance

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Cons to lowering SCC limit

• Least producer friendly way to reduce mastitis.
• Could put many producers out of business.
• Division among regions, large herds vs. small
  herds loss of unity around common cause.
• Not a human safety issue a quality issue.
• No scientific evidence that SCC are hazard.
• Eliminate need for milk quality incentives.

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Quality Incentives

• Effects on current quality incentives
• Probably will not be offered if limit too low
• Co-ops milk quality incentives 10/02
• .25 for SCC lt 300,000/ml
• .25 for SPC lt 10,000/ml
• Already seeing decreases in ave SCC after 4
  months of implementation results after a yr?
• Creating a desire among producers based on
  incentives more effective than mandating a SCC
  limit that is too low, at this time

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Cons to lowering SCC limit (cont)

• Low milk prices/high feed costs
• Every spent on compliance cuts profit margin
• Nationally a 40 decrease in farm income 20 yr
• By emphasizing the possible human health hazards,
  will media give milk a bad name?
• Current depressed feeling among producers
  regarding low milk price and the economy.
• If SCC lowered, and cannot prove that there are
  human health reasons for excluding a farm, then
  co-op could be at risk of litigation.
• Most farms already below 400,000 trade hurdles
  minor, so concern is minimal.

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Cons to lowering SCC limit (cont)

• Increased risk of antibiotic residues
• Health agencies ill equipped
• Budget cutbacks
• Sampling bulk tanks
• Testing of samples
• Enforcement
• No need for US to conform to EU
• Environmental regulations
• Ex EPAs water rule 150 M annually.
• Percent reduction 750,000 to 400,000

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Lowering the Legal Limit of SCC to Increase Milk
Quality
SCC X 1000
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Cons to Lowering the SCC Legal Limit (continued)

• Delegate problem with 400,000 limit as proposed
  over multiple years
• Current trend in SCC
• 304,000 324,000/ml
• Locked into limit not attainable in time frame
  that is set. Previous reductions 25 to 33

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Somatic cell counts continue to rise
Year Cows/herd (no.) Average Daily Milk Yield (lb) Average SCC Cells/ml, 1000s
1995 50.0 65.3 304
1996 55.5 64.7 308
1997 57.4 66.4 314
1998 60.8 66.8 318
1999 67.0 68.2 311
2000 73.3 69.1 316
2001 79.1 69.0 322
2002 83.2 70.1 324
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Why Are SCC Increasing?

• Climate?
• Herd expansions?
• Regional?
• Genetic?
• Johnes?
• Mycoplasma?
• Extending lactation?
• Decreased culling?
• Stress?

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Cons to Lowering the SCC Legal Limit (continued)

• Delegate problem with 400,000 limit as proposed
  over multiple years
• Current trend in SCC
• 304,000 324,000/ml
• Locked into limit not attainable in time frame
  that is set. Previous reductions 25 to 33

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Lowering the Legal Limit of SCC to Increase Milk
Quality
SCC X 1000
19 yr
7 yr
10 yr
Lower to 600,000/ml and monitor progress?
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Is There Consensus?
Better to make changes w/ consensus than to
force a proposal onto an industry

• NASDA
• NCIMS
• Milk Co-ops
• DPC
• NMPF
• NMC
• AABP
• AVMA
• Dairymen
• Processors

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Options to lower SCC

• Federal Order Premiums
• Uniform programs for SCC premiums
• Incentives and penalties
• Lower SCC
• Market driven
• Grassroots educational campaign
• Producers
• Practitioners
• Creating desire among producers
• Enhance quality
• Promote safety

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Provide tasty, nutritious, and safe dairy
products to consumers
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Lowering legal limit will enable producers to
make progress in milk quality and yield.
SCC X 1000

• To which level?
• When to initiate?

?
?
?
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The End
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To lower herd Somatic cells counts

• Teat dip
• Vaccinate
• Treat infections
• Dry cow therapy
• Check replacements

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Problem with Geometric Means

• Reprogram computers for SCC calc
• Require two systems of enforcement
• SCC (Geom means)
• Bacteria (3 out of 5)