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Somatic cell counts in milk

Low numbers of somatic cells in milk indicate a healthy, well managed dairy herd.
High numbers of somatic cells normally indicate a mastitis infection or udder damage often caused by a faulty milking machine or improper use of milking equipment.

SSC standard

The Dairy Products (Hygiene) Regulations (Northern Ireland) 1995, which implemented the requirements of the EC Milk Hygiene Directive (92/46), set standards for somatic cell counts (SCC). Producers are not permitted to sell milk for human consumption if their SCC is in excess of 400,000 per ml. This standard is based on the average SCC over a three month period. If the standard is exceeded, producers have three months to investigate and make improvements. However, if their SCC still exceeds the standard after this period they will not be allowed to sell milk for human consumption until the three monthly average falls below 400,000 per ml.

Benefits of a low SCC

The benefits of reducing your cell count are considerable. For example, a reduction from 500,000 to 300,000 per ml could increase returns by £5,000 per year for a 50 cow herd. This is mainly due to higher yields, improved compositional quality payments and lower SCC penalties. Other benefits include lower veterinary bills, less discarded milk, reduced risk of antibiotic residues in the milk, less time input and reduced stress on management.

How to reduce SCC

Adopt a sound herd replacement policy

In general, younger cows have low SCCs. Therefore, aim for an ongoing herd replacement rate of 20-25 percent either by rearing or purchasing suitable replacements.

Maintain your milking equipment in proper working order

An inefficient milking machine can cause elevated cell counts through damage to teats and udder tissues. Periodic testing of the milking plant is therefore essential and is recommended at least once a year. However, an efficient machine used improperly may also cause damage.

Draw up a SCC control programme

Your local Milk Inspector or Greenmount Campus Dairying Development Adviser can draw up a control programme suitable for your particular situation.
At all times:
  •  keep stalls, yards, passages and approaches clean;
  •  practise dry cow therapy;
  •  keep records of all treatments for mastitis infections;
  •  dry off cows promptly in late lactation;
  •  identify cows with high cell counts and treat or cull as advised by your Veterinary Surgeon.
At milking time:
  •  examine and reject foremilk before udder preparation;
  •  clean teats / udders using individual paper towels;
  •  do not over-milk;
  •  dip or spray teats with suitable teat disinfectant immediately after milking;
  •  do not allow cows to lie down for 30 minutes after milking.
Reducing high SCC can take a long time so at the first sign of this problem contact your local Veterinary Surgeon without delay.
For guidance on any of the points mentioned in this leaflet, contact your local Milk Inspector or your locally based Greenmount Campus Dairying Development Adviser.
Note: This leaflet gives general guidance only and should not be treated as a complete and authoritative statement of the low.