Clinical mastitis is caused mainly by environmental mastitis such as coliforms and Strep uberis. Staph aureus can also cause clinical mastitis but the importance of environmental bacteria causing clinical mastitis cases has increased as levels of Staph aureus have decreased.
The environment is the reservoir of infection with environmental mastitis. Infection is transmitted on or into the teats at three different times; between milkings if the cows are lying in dirty conditions or have faecal splashing onto teats after coming out of the parlour; during milking if there is poor teat preparation; or dry period infections.
Coliform infections mainly cause clinical mastitis while Strep uberis causes both clinical and subclinical mastitis and is often associated with straw bedding.
Mastitis infections can enter the udder during lactation and during the dry period. Lactation period infections occur when bacteria enter the udder during lactation, for example the spread of Staph aureus via the liner or an environmental infection if cows are lying on dirty beds.
Dry period infections are picked up when the cow is not lactating. These will almost always be environmental, such as coliforms and Strep uberis, as the risk of spread of contagious mastitis will be insignificant when a cow is not being milked.
Top tips to reduce environmental mastitis
Clean udders and teats
Udders and teats must be kept clean. The aim is to keep environmental bacte
ria away from the end of the teat. The best way to assess environmental cleanliness is to look at the teats and udder. You need to keep cows on clean, dry beds when housed. The beds are not clean enough if udders and teats are dirty when cows are housed. Tails should be trimmed and udders clipped or singed to minimise transferring dirt onto the teats. When cows are at pasture and weather conditions deteriorate, they often get dirtier than when housed.
Calving pens must be kept as clean as possible as freshly calved cows are most prone to mastitis. This is because their immune function crashes around the time of calving. This is why some cows get toxic mastitis at this time. It is important to ensure that cows are calving in clean and dry conditions. When cows are housed, you need to make sure that calving pens are cleaned out frequently.
Clean conditions can prove challenging when cows are at pasture, especially when block calving as happens in countries such as New Zealand and Ireland. There will be a high risk of mastitis if calving paddocks are dirty.
Aim for 5% to 10% more cubicles than cows. Cows like choice in where they lie. Cubicles need to be of the correct dimensions for the size of the cows and there must be plenty of room for cows to lunge forwards when they get up. A brisket board helps to make sure that cows do not lie too far forwards so that they do not dirty the back of the beds. If the cubicle dividers are too high and cows lie crossways, they can dirty the back of the beds.
There is a choice of bedding surfaces and that includes deep sand, mattresses, or concrete with a range of bedding materials on top. Cows will lie down for up to 14 hours a day if cubicles are well designed. This can reduce to 8 or 9 hours if cows are uncomfortable and lameness will increase.
Wide passageways keep cows cleaner and help reduce lameness from diseases like digital dermatitis. Every time that cows go for milking the beds should be cleaned off and passageways scraped clean. Most operators will bed up their cows daily and, in some cases, twice a day.
The exception is with deep sand which is often topped up weekly and then pulled back over the beds during the week. Sand should be deep raked weekly at the back of the beds to ensure there is adequate drainage. If sand gets black or dirty it needs to be dug out and replaced.
Always use plenty of clean dry bedding. Bedding has two functions, firstly to create a barrier between the bed and the cow to maximise cow comfort and secondly, to absorb moisture. There are many types of bedding that can be used including sand, straw, wood products (like sawdust or
... To read this complete article you need a Premium or Digital subscription Subscribe & login and you will be able to continue your reading * M2-premium – digital + print (€ 90 /year) * M2 – digital (€ 40 /year)