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Somatic cell count (SCC) is an important measure of milk quality. A high SCC reduces the processing quality of the milk and it indicates a high level of infection in the herd, either clinical or sub-clinical mastitis.
February can often be a bad month for SCC, with some high levels recorded, particularly in the first few loads of milk delivered to the co-op. SCC levels above 400,000 cells/ml are not uncommon, even in herds which normally have relatively good SCC.
This is due to the low volume of milk and the fact that the risk of infections is high at calving time. The risk is extra high this spring because nearly all herds have been housed since calving, either full-time or part-time.
It’s important to get on top of it now, before it develops into a significant problem. The longer it is left, the bigger the problem it will become, as high-SCC cows could be shedding infection and passing it on to other cows.
Solution
In all likelihood, there are a small number of cows contributing to the problem. Even though the milk filter sock may be clean, there is probably a cow or two with clinical mastitis.
Another culprit can be a cow that was only milking on three quarters last year being milked on four quarters this year. That quarter could be very high SCC.
Identifying these cows is the next challenge. There are three ways of doing this, but all involve a fair degree of hardship.
The first is to milk record the whole milking herd. As most herds have only between 40% and 60% calved now, it’s probably not very effective at gathering valuable data other than SCC. Plus, it may take a week or 10 days between booking the recording, doing it and getting the results back.
Individually testing each cow for SCC on the farm is probably the most effective, if time consuming. This can be done in two ways – using the Californian milk test (CMT) and paddle or using an electronic version that gives an SCC indication.
The CMT test is probably the way to go. It’s cheap, effective and you get a fool-proof result instantly
Both methods involve testing samples from each quarter. For me, the CMT test is probably the way to go. It’s cheap, effective and you get a fool-proof result instantly, but it is time consuming and tiring to do a full herd at once, so you will need extra help.
When using the CMT test, have equal amounts of milk in each paddle cup. You can achieve this by tilting the paddle and letting the excess spill out.
Pour in the same amount of CMT solution as there is milk in each paddle cup. Swirl the paddle cup for about 10 seconds. Results should be obvious immediately.
Any thickening of the milk or gelling is an indicator that the SCC in that quarter is high. The thicker the milk, the higher the SCC.
High SCC cows should be treated. Talk to your vet about the best treatment options. Some vets will suggest taking a sample of milk and getting it tested for the type of mastitis and a sensitivity test can be performed to identify which antibiotic will work best.
Regulator
The cause of high SCC is not always down to unhygienic housing conditions. Is the milking machine working correctly? Check that the vacuum pressure is correct. The vacuum regulator could be acting up resulting in the vacuum being out of kilter. Most milking machines require a vacuum of 48kPa.
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