Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
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]