It is difficult to pinpoint any particular reason for continuing problems with SCC in Irish dairying.
Ending Teagasc/Co-op mastitis control programmes in the late 90s was a major contributor. Bonuses for high quality milk and realistic penalties for SCC milk were delayed too long.
Seasonal adjustment for SCC prolonged the problem, enabling farmers with very high SCCs to continue without getting rid of the root causes, at huge cost to themselves and their co-ops.
The modern emphasis on milking speed often lowers milking standards.
Also, only about 50% of our herds are milk recorded, and often very poor use is made of recording reports.
Most co-ops operate a mastitis/SCC control programme now. Very often, the best way to investigate problems is to be present during milking, to spot problems that will not be revealed by testing a milking machine, particularly regarding milking and hygiene practices.
If cows are restless in the parlour, it may indicate electrical problems, cows packed too tightly, a milking machine fault, or poor milking practices. Teat end damage is a major tell-tale sign that something is wrong.
Taking clusters off under some vacuum is still fairly common in problem herds. This may be due to faulty shut off valves or poor milking technique. Clusters should be taken off and put on without any noise of air or vacuum. Otherwise, there will be teat end damage which will lead to mastitis and high SCC. Teat end damage also results from vacuum being too high, poor pulsation or inadequate fall in milk line (very common in older machines).
Inadequate use of teat disinfectants is quite common, often due to faulty sprayers or the wrong type of sprayers. Proper usage of teat spray requires 15 mls per cow, and teats should be sprayed even-ly all around.
In a minority of high-SCC herds, it is difficult to identify the cause, and a lot of investigation is required. Disinfecting clusters between cows was found to be a major deterrent to spreading mastitis within infected herds. Alternatively, if there are only a few problem cows, they could be milked last.
In summary, the main reasons for high SCCs include faulty milking machines, faulty milking technique such as taking clusters off under vacuum, poor hygiene, inadequate teat disinfectant, inadequate SCC records and culling, problems with power supply, and inappropriate antibiotic use in problem herds.
The aim should be to keep SCCs consistently under 200,000 and have very few cases of mastitis. The SCCs of first lactation animals should be consistently under 80,000. If the SCCs of first calvers and other young cows are rising, there is certainly something wrong, and urgent action should be taken.
If SCCs average over 200,000, it indicates some level of infection in the herd, which is likely to give rise to sporadic outbreaks of mastitis. Diseases such as BVD can depress the immune system and give rise to SCC problems.
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