Top tips for preventing mastitis this winter

Mastitis has long been recognised as a scourge among dairy farmers. The disease reduces the quality of the milk, reduces milk yield and leads to penalties and deductions in milk prices.

It presents in two forms: high somatic cell count (SCC) milk, which may be sub-clinical mastitis, or clinical mastitis, which typically presents as clots in the milk, swelling of the udder and general pain and discomfort of the cow.

The mastitis-causing pathogens are easily spread in the milk or in the environment, so good hygiene has long been seen as a way of reducing the spread of mastitis.

The winter period is often one of the highest risk times for the spread of mastitis, as cows are kept in close proximity and there are more environmental pathogens around. The following is some advice around ways to reduce the risk of mastitis this winter.

1.Dry off high-SCC cows

These high-SCC cows in late lactation are usually chronically infected and need a longer dry period to cure and heal. They often pose a greater risk of spreading mastitis to other cows at this time of year, whether in the parlour or while housed. They also contribute more to the bulk tank SCC. The only way to identify these high-SCC cows is through milk recording, which should be done one month before drying off.

2. Maintain good hygiene

In late autumn and early winter when milking cows are moving between grazing and housing, the risk of mastitis increases. Grazing outdoors is a very clean environment for cows, as they tend to lie down on their own patch of grass. Therefore, the teats don’t usually come in contact with faeces or urine. Whereas in a shed situation cows are limited regarding where they can lie and contaminants such as urine and faeces are present everywhere. Keeping cubicle beds clinically clean just isn’t possible, but keeping them as clean as you can will be a big help when it comes to reducing the risk of infection. This involves making sure passages are cleaned regularly and that cubicle beds are cleaned down to remove faeces. Teagasc recommend this is done twice per day when housed.

3. Use disinfectant

Disinfectants such as ground limestone increase the pH of the cubicle bed to a level that bacteria cannot survive. Lime increases the pH of the lying area up to around a pH of 12.4. Once the pH of the lying area goes above 12, most bacteria should not be able to survive. There are three types of lime on the market – ground limestone, hydrated lime and a mix of hydrated and ground limestone, at varying percentages of hydrated inclusion. Hydrated lime is more caustic, so the higher the amount of hydrated the higher the pH of the bed will be, but this needs to be balanced against applying too much hydrated lime – which could cause some teat end sores. The general principle is to apply no more than one fistful of hydrated lime per cubicle bed, but it can be difficult to achieve even coverage when only one fistful is used. Other disinfectants, such as liquid disinfectants, are also available and some farmers, particularly those with outdoor cubicles, will use these during periods of wet weather.

4. Use data to select teat sealer only

As all farmers are now obliged to use selective dry cow therapy, it’s important that the correct cows are selected for sealer only. Whatever limits are used, the best way of selecting the cows is to use the ICBF Herdplus website on herds where cows are milk recorded and mastitis events entered. The list of cows that are suitable for SCC can be filtered at the top of ‘milk recording SCC’ profile, by inputting the maximum SCC that you want to try into the ‘to’ tab over each column. For example, if you only want to use SDCT on cows with an average lactation SCC of less than 100,000 then put 100 into the ‘to’ tab above ‘Avg Current Lact’ column. You can also filter out cows that had an SCC of greater than say 200,000, by putting 200 into the ‘to’ tab above each of the previous milk-recording dates for the current lactation. By putting ‘0’ into the ‘to’ tab over ‘No. Treats’ will deselect any cows that have been treated for mastitis during the year.

In short