Download ARE THE SOMATIC CELLS GOOD OR BAD

ARE THE SOMATIC CELLS GOOD OR BAD CELLS? SOMATIC CELLS DEFINITION:
T
Dr. Edmar Freitas, DVM, Ph.D.
Ruminant Nutritionist
he word “somatic” is derived from the Greek word soma,
meaning “body”. Hence, all body cells of an organism – apart
from the sperm and egg cells, and undifferentiated stem cells – are
somatic cells. Short definition: somatic cells are any of the cells of a
plant or animal except the reproductive cells.
Van Beek Nutrition
Why are milk somatic cell counts so important ?
Milk somatic cell count (SCC) is used to monitor inflammation of the mammary gland, and represents the
most accepted criteria for measuring udder health and
milk quality. The cells found in normal milk consist of
about 75 percent white blood cells or leucocytes and
about 25 percent epithelial cells (table 1).
Table 1 - Cells in milk
How to use SCC to evaluate cow health?
Most studies showed that cows with SCC of less than
100,000 cells/ml represents uninfected cows and cows
with SCC from 100,00 to 200,000 cells/ml are not likely
to be infected with major mastitis pathogens. Cows with
SCC between 200,000 and 300,000 are presenting some
infection while cows with SCC greater than 300,000 usually are infected with significant pathogens.
Cell Type
Normal Milk
Mastitis Milk
What is the legal limit for SCC in US?
Total Cells
<100.000
>250.000
The current legal limit for bulk tank SCC is 750,000 cells/
mL for Grade A producers. Nationally, average test-day
herd SCC during 2010 was 228,000 cells/mL, with 18%
of tested herds presenting SCC higher than 400,000 cells/
mL. See bellow the SCC limits for other countries.
White blood cells >85%
Macrophages
35%
Neutrophils
25%
Lymphocytes
25%
Epithelial cells
<15%
>99%
99-100%
<1%
Country/group
United States
Canada*
European Union
New Zealand
Australia
Switzerland
Limit (cells/ml)
750,000
500,000
400,000
400,000
400,000
400,000
Leukocytes are cells of the immune system involved in
defending the body against infectious disease and foreign materials. Their responsibility is to destroy invading bacteria. However, if they cannot, an immune response is elicited, and more white blood cells are called
in to fight the infection.
* In 2012 the limit in Canada will be 400,000
This way, the concentration of somatic cells serves as
an indirect measure of the level of infection in the
cow’s mammary gland. Typically, the more severe the
infection, the higher the SCC will be.
ARE THE SOMATIC CELLS GOOD OR BAD CELLS?*
Monthly SCC variation
How much does high SCC cost you?
According to Animal Improvement Programs Laboratory (USDA - AIPL RESEARCH REPORT SCC12 (2-11),
the average somatic cell count (SCC) from Dairy
Herd Improvement herds during 2010 was 228,000
cells/mL, with a range from 207,000 to 251,000 (for
Michigan the average SCC was 182,000 cells/mL). The
SCC increased from May through August with higher
value in July and then declined quickly from September through November. The highest quality milk was
produced in November.
Since high SCC is consequence of mastitis, it can impair your profit in many ways:
 Reduced milk production
 Treatment cost
 Discarded milk
 Death and premature culling
 Decreased genetic advancement
 Reduced milk quality.
During mastitis, the types of somatic cells present in
the milk change to mostly white blood cells (see table
1) , which add many proteolytic and lipoytic enzymes
to milk. In addition, more blood serum leaks into the
milk than usual. These enzymes break down milk protein and fat. This enzymatic action (especially the damage of a milk protein called casein) greatly reduces the
dairy product quality and yield.
Methods of Evaluating Somatic Cell Counts.
The methods of evaluating somatic cell counts (SCC) are:
1) Bulk Tank SCC [BTSCC] - The BTSCC is usually based on
a single sample of milk from the bulk tank.
2) Weighted SCC [WTSCC] - The WTSCC is calculated on
Final Notes
samples from individual cows and is weighted or adjusted
based on each cow’s level of milk production. The WTSCC
1.) As a result of increasing world trade in milk and
for all milking cows in a herd should approximate the
milk products (In 2011 we will export 14% of our
BTSCC.
milk production), it probably is necessary that the
3.) Somatic Cell Count Score [SCCS] - The SCCS is based on a
conversion of the actual SCC to a linear score as shown in
U.S. attain the world standard for SCC.
Table 3.
2.) Optimal bulk tank cell count is between 50,000 –
Table 3. Relationship between SCC Scores, Somatic Cell Counts and
milk loss.
SCC
Score
SCC Range
0
1
2
3
4
5
6
7
8
9
0 - 18,000
19,000 - 35,000
36,000 - 71,000
72,000 - 141,000
142,000 - 283,000
284,000 - 565,000
566,000 - 1,130,000
1,131,000 - 2,262,000
2,263,000 - 4,523,000
4,524,000 - 9,999,000
Estimated Daily
Milk Loss Per
Cow
0%
0%
0%
1.5%
3.0%
4.5%
6.0%
7.5%
7.5%
10.5%
200,000.
3.) Reduction of cell count is a logical process and
achievable for every farm.
4.) Work with your veterinarian, and/or your nutritionist to implement strategies to keep SCC in acceptable ranges.
5.) Identify and treat or cull high SCC cows.
6.) Implement management practices that can help to
prevent mammary gland infections.
7.) Have nutritional and management practices that
enhance cows immune system.
8.) Somatic Cells are good guys trying to protect the
cow.
®
NUTRITION
Cows with SCCS of 0-3 are generally considered uninfected while cows with a SCCS of 4-9 are considered infected.
*References omitted due to space limitations, but are available upon request. Dr. Edmar Freitas, DVM, Ph.D.
Ruminant Nutritionist
Van Beek Nutrition
3537 West YZ Ave.
Schoolcraft, MI 49087
Ph. 269-350-0584
[email protected]