10 AUGUST 2016
The dry period for a cow represents a great opportunity to cure chronic and sub-clinical mastitis cases (high SCC), but also provides us with a tremendous challenge of keeping healthy udders just that, healthy.
The success of managing udder health through the dry period is measured by looking at SCC movement from late lactation through to early lactation. The movement of that SCC is than placed into 1 of the following 4 categories:
1. High to High 2. High to Low 3. Low to High 4. Low to Low
The ideal scenario here is of course that every cow sits in category number 4. She had a low SCC going into her dry period and a low SCC at the start of her next lactation. This shows that udder health was good in lactation and that the drying off procedure, antibiotic and teat sealant use and the cleanliness of the environment were all excellent.
The next best scenario would be category number 2. These are cows that had a high SCC (over 200,000 cells per ml) in the last few recordings of their previous lactation, but where targeted use of appropriate antibiotics and sealants have ‘cured’ that cow and she has calved into the following lactation with a lower SCC level. This scenario allows us to successfully monitor a herds ‘dry cow cure rate’, and the more cows with higher cell count levels that can fall into this category the better.
Both of the remaining 2 categories point to failings, with regard to udder health, somewhere in the period from late lactation through the dry period and into the next lactation.
With category 1 cows, the high SCC level in one lactation has been carried right through the dry period and into their next lactation. For some reason, either the load of bacteria at the teat end has been overwhelmingly high, or the cows’ immune system is compromised and she can’t fight the infection off. If this situation is occurring regularly it’s definitely worth talking to your vet about using the right antibiotics and any other health issues that could be holding groups of cows back.
The final category to look at is category 3. This scenario can actually be a quite disheartening one and can be measured as the ‘dry cow infection rate’. These are cows that had a low SCC towards the end of lactation but then became infected at some point through the dry period and had a cell count or mastitis problem at the start of their next lactation.
With all of these situations, it is well worth reviewing your farms drying off protocols to try and minimise the risk of introducing a new infection at that stage. With more and more focus on selective antibiotic use at drying off, the sterility of that protocol will really start to be tested.
Another area to look at is the environment that dry cows are housed in. It needs to be clean, dry and well ventilated to minimise the risk of over loading the teats with bacteria.
A final area to consider would be nutrition and particularly mineral nutrition. A mineral deficiency through lactation and through the dry period can have a significant impact on udder health through this crucial stage of a cows’ production cycle.