HIGH CELL COUNT

To comply with EU milk quality standards, milk purchased from all farms must have a somatic cell count (SCC) of less than 400,000 cells per millilitre of milk. Somatic cell count is a measure of the level of infection in a cow's udder. In response to the infection a cow will produce white blood cells to help fight the infection. The higher SCC the higher the infection and the less acceptable is the milk for human consumption. Since mid summer a number of farmers have experienced problems meeting the SCC standard.

Sub-clinical mastitis infection is the major reason for high somatic cell counts. Stress due to a range of factors including weather, nutrition, poor milking routine and attention to detail all influence SCC. In addition, on a few farms stray electricity voltage in the milking parlour has increased somatic cell counts. With increased automation of parlours this may be occurring and requires immediate action as a danger to both cow and operator.

The cell count from normal healthy cows can vary according to pregnancy status and stage of lactation and farmers need to take this into account. Those farmers who are monthly milk recording have data which is useful in identifying cows with high cell counts If this milk goes into the bulk tank it could raise the bulk tank average putting the tank of milk into the penalty bracket. Therefore immediate action can be taken to withhold the milk from the bulk tank. At Greenmount College a routine mastitis control strategy is practised allowing the farm manager to identify any potential problems at an early stage.

Recent increases in SCC may have been caused by a number of factors including:

• Cull cows retained and milked longer than anticipated due to the Foot and Mouth Disease outbreak.
• Low milk quota leasing prices encouraging farmers to milk as many cows as possible including older problem cows prone to mastitis infection.
• Cutbacks in parlour maintenance in response to reduced profits.
• Reduced veterinary intervention to control mastitis.

If you have problems meeting cell count targets at present:

• Use milk recording to identify the SCC history of cows in your herd.
• Cull cows with consistently high cell counts.
• Have your parlour tested to ensure correct operation and to eliminate any stray voltages.
• Dry cows off abruptly, do not milk cows at the end of lactation once per day or every other day.
• If cows are being treated with antibiotics with zero milk withholding periods, keep milk out of the bulk tank while cows are showing clinical signs of mastitis.

In the longer term, to lower average somatic cell counts, put into practice an effective mastitis control strategy in consultation with your veterinary practitioner or agricultural adviser. Remember attention to detail will pay dividends.