Mastitis is an inflammation of the udder. Most mastitis cases are caused by intramammary infections. In rare cases, mastitis might be caused by trauma (e.g. kick of another cow on the udder) or irritation (e.g. contact with a chemical product). 

In our e-learning M&M Boost training "Mastitis, an intriguing disease - science into practice", we elaborate on the causes of mastitis in dairy cows in an interactive and practical way. Click here for more information.

Most intramammary infections are caused by bacteria present in the environment of the cow that penetrate via the teat orifice into the udder. Exceptions are intramammary infections caused by Mycoplasma species. Dairy cows may already be colonised by Mycoplasma bovis in the respiratory tract. A stress stimulus (e.g. calving, moving to another barn) can cause a haematogenic (= via the blood) spread of the Mycoplasma bacteria from the respiratory system to the udder.  Because of this haematogenic spread, several quarters are often affected simultaneously in case of Mycoplasma mastitis. Another exception are the iatrogenic infections caused by yeasts or moulds. Iatrogenic infection means that during the introduction of an intramammary tube (e.g. one containing antibiotics) for the treatment of a primary mastitis case or at dry-off, yeasts or moulds are introduced from the teat skin into the teat canal and the udder. Primary cases of mastitis caused by yeasts or moulds also occur but are rather rare.

In our e-learning M&M Boost training "Mastitis, an intriguing disease - science into practice" we elaborate on the different types of mastitis causing pathogens. Click here for more information.

Mastitis occurs after that the invading germs in the udder are recognised by the resident inflammatory cells (neutrophils, macrophages, natural killer cells) in the milk and the mammary epithelial cells. The receptors on the cell wall of the inflammatory cells (Pathogen Recognition Receptor or PRR) recognise the molecules in the cell wall of the bacteria (Pathogen Associated Molecular Patterns or PAMP). After the identification of the invading bacteria, the inflammatory cells in turn produce pro-inflammatory cytokines (IL-8, TNF-alpha), attracting masses of neutrophils from the blood to the milk. Together with the other inflammatory cells, these neutrophils will phagocytose (= eat) the bacteria and eliminate them from the udder. In our e-learning M&M Boost training "Mastitis, an intriguing disease - science into practice" we go deeper into the pathogenesis of mastitis in dairy cows. Click here for more information.

As indicated earlier, in case of mastitis, a large number of immune cells migrate from the bloodstream to the milk. Based on the presence or absence of visible symptoms, 2 forms of mastitis are distinguished: clinical mastitis and subclinical mastitis. In case of clinical mastitis, the milk (flakes, blood in the milk, watery) and/or the udder (hard, swollen, painful, red or warm) show visible abnormalities and the cow might be generally ill (fever, loss of appetite, deep lying eyes, sluggish). Cows with clinical mastitis can therefore be easily identified.

In case of subclinical mastitis, neither the milk nor the udder show visible abnormalities. The cow is not generally ill. Cows with subclinical mastitis can best be detected by regularly determining the individual somatic cell count of all cows in the barn. Cows with a somatic cell count of more than 200 000 cells/ml are most likely infected in one or more quarters.

Our virtual assistant Keno-M™ calculates with one mouse click the percentage of subclinical mastitis on a dairy herd and provides support in the interpretation of results. Click here for more info.

No, not all cows with clinical mastitis have fever. Based on the clinical symptoms, 3 types of clinical mastitis can be distinguished: mild (Grade A), moderate (Grade B) and severe (Grade C). 
 

In a cow with mild clinical mastitis, the milk is abnormal (flakes, lumps, blood admixture), but the cow is not generally ill. The cow has a normal appetite and has no fever. 
 

In case of moderate clinical mastitis, besides the abnormal aspect of the milk, the udder might be hard, swollen, painful, red, or feeling warm, there may be a slight rise in temperature (between 39.5° and 40° C) and there might be a slight fall in milk production.

A cow with severe clinical mastitis has strongly abnormal (sometimes watery) milk, is languid, has a moderately to poorly filled rumen, deep-lying eyes, has a severe body temperature increase (more than 40°C) or just a very low body temperature (= shock) and produces hardly any milk. 

In our e-learning M&M Boost training "Mastitis, an intriguing disease - science into practice", the different types of clinical mastitis and their approach are explained in detail. Click here for more info.

The severity of the inflammatory reaction is determined by 3 factors: 

1. The infection pressure: indication for the number of bacteria to which the cow is exposed. The more bacteria that can enter the udder, the more severe the cow's reaction and the more pronounced the symptoms will be. The infection pressure is mainly determined by the mastitis management on the dairy farm (hygiene during milking and between milkings, milking technique, functioning of the milking machine, hygiene and ventilation of the housing). 

    

2. The type of mastitis causing pathogen: intramammary infections caused by major pathogens such as Escherichia coli, Streptococcus uberis and Staphylococcus aureus result more often in clinical mastitis and cause a higher rise in the somatic cell count compared to intramammary infections caused by minor pathogens such as Corynebacterium bovis and non-aureus staphylococci. Differences between major pathogens also exist. Gram-negative bacteria such as Escherichia coli often provoke a more severe inflammatory reaction than gram-positive mastitis causing pathogens such as Staphylococcus aureus. 

    

3. The immunity of the cows: cows with a suppressed immunity will often experience a more severe mastitis than cows with an optimal immunity. After all, cows with a reduced immunity react too slowly, which gives bacteria the chance to grow and colonise the udder. In case of an intramammary infection with Escherichia coli, the number of colonies doubles every 20 minutes.

In our e-learning M&M Boost training "Mastitis, an intriguing disease - science into practice", we elaborate on the 3 important factors that determine the severity of the inflammation reaction and the different types of mastitis causing pathogens. Click here for more info.

A dairy farm has good udder health when the bulk milk somatic cell count is lower than 200 000 cells/ml and the average percentage of clinical mastitis is lower than 2% per month. Please note that a good udder health today does not mean that the udder health will still be good tomorrow, next week or next year. On many dairy herds, there is a constant risk of mastitis. There are few dairy herds with a perfect mastitis management. Therefore, it is recommended to make the mastitis management visible on every dairy herd at least once a year. If the risk of mastitis is high, action needs to be taken to prevent an outbreak. If the risk is low, then the dairy producer does not have to keep worrying unnecessarily. To measure is to know. 

Our virtual assistant U-Scan visualises the strengths and weaknesses of mastitis management on every dairy herd in a simple, results-oriented and scientifically substantiated way. Click here for more info.

A bulk milk somatic cell count lower than 50 000 cells/ml may increase the risk of clinical mastitis. With such a low bulk milk somatic cell count, there will be several quarters with a cell count lower than 20 000 cells/ml. Scientific research has shown that quarters with a somatic cell count lower than 20 000 cells/ml are more susceptible to develop clinical mastitis. After all, there are not enough resident inflammatory cells present to react decisively and quickly against invading germs. Most clinical mastitis cases on such herds are caused by environmental germs such as Streptococcus uberis and Escherichia coli. On such herds, it is therefore very important that the mastitis management is perfect and that cows are exposed to as few mastitis causing pathogens as possible during milking and in between two milkings.

Our virtual assistant U-Scan helps to determine the risk of environmental mastitis during milking and in between two milkings in a simple, objective and scientifically sound way and formulates, based on all the information, herd-specific recommendations to further reduce the infection pressure. Click here for more information.
 

Most intramammary infections are caused by bacteria. In rare cases, intramammary infections are caused by yeasts, fungi or algae. Viruses do not directly cause intramammary infections. However, they can make the udder more susceptible to mastitis. For example, Bovine Viral Diarrhoea (BVD) suppresses the immunity of animals, making them more sensitive to the development of mastitis. Bovine Herpes Mammillitis Virus 2 (BHV-2) can damage the teat skin, making it easier for germs to attach to and colonise the teat skin, after which they can cause new intramammary infections.

In our e-learning M&M Boost training "Mastitis, an intriguing disease - science into practice", we elaborate on the different types of mastitis causing pathogens that can be found on dairy herds and how to best prevent new intramammary infections with each of these mastitis pathogens. Click here for more information.

Yes, a reduced immunity of cows can definitely result in an outbreak of clinical mastitis. However, it is important not to draw any premature conclusions in case of an outbreak of clinical mastitis. Currently, there is no method available to directly determine a cow's immunity. In research settings, however, this is possible. For example, one can measure the activity and viability of neutrophils in blood and milk. A reduced immunity is the most probable cause of an outbreak of clinical mastitis on dairy herds where the infection pressure during milking and in between two milkings is well-managed and the teat ends are in good condition (= indication of good functioning of the milking equipment).

Our virtual assistant U-Scan helps to make the infection pressure during milking and in between two milkings visible in a simple, objective and scientifically sound way. Click here for more info.

The best approach differs from herd to herd and strongly depends on the type of mastitis pathogen causing the intramammary infections. Many risk factors have been associated with udder health on a dairy farm. However, certain measures are especially effective in the prevention of new intramammary infections caused by contagious mastitis pathogens (e.g. most Staphylococcus aureus and Streptococcus agalactiae), while other measures are especially effective in the prevention of new intramammary infections caused by so-called environmental pathogens (e.g. most Streptococcus uberis and Escherichia coli).

Intramammary infections caused by contagious mastitis pathogens can best be prevented by minimising transmission of germs from infected to non-infected animals during milking. Transmission usually occurs via the hands, teat liners or cloths used during teat preparation.

Intramammary infections with environmental mastitis pathogens can best be prevented by reducing the infection pressure to which the cows are exposed and by further optimising the cow's immunity. After all, on every dairy herd worldwide, dairy cows are exposed to environmental pathogens. However, not every dairy herd has a problem with environmental mastitis. A difference in infection pressure and immunity of the animals can explain this.

With the help of our virtual assistant U-Scan, the risk of contagious and environmental mastitis in lactating animals can be determined in a simple, objective and scientifically sound way with a focus on results. Click here for more information.

Yes, freshly calved heifers can have both clinical and subclinical mastitis. The intramammary infections are, just like with lactating animals, caused by contagious (e.g. Staphylococcus aureus) or environmental (e.g. Streptococcus uberis) mastitis pathogens. Heifer mastitis can be prevented by, among other things, providing clean and dry housing in the last months of pregnancy, effective fly control during pasture season and avoiding vitamin and mineral deficiencies.

The risks of contagious and environmental heifer mastitis on a dairy farm can be made visible in a simple, objective and scientifically sound way with our virtual assistant U-Scan. Click here for more information.

Yes, it is possible to vaccinate against mastitis nowadays. Of course, it is important to always keep in mind the 3 typical characteristics of vaccination:

• specific
• time-related and
• preventive

Currently, vaccination is available against Staphylococcus aureus, Streptococcus uberis and Escherchia coli. Depending on the type of vaccine, the animals are less susceptible to new infections, recover more quickly after being infected, the symptoms are less severe and they recover more quickly, resulting in lower milk production losses.

In our media library "Vaccination against mastitis" of our e-learning M&M Boost training "Mastitis, an intriguing disease - science into practice", the 3 typical characteristics, the effect and the efficacy of vaccination against mastitis are explained. Click here for more information.

The most appropriate recommendation for cows with a high somatic cell count depends on various factors. Animals that still have a high likelihood of cure and which are not expected to recover spontaneously (= without antibiotics) can be treated with antibiotics during lactation, based on the results of bacteriological culturing and corresponding antimicrobial sensitivity tests. If the animals can be dried off soon, it is preferable to wait until dry period. After all, the likelihood of cure is always higher during dry period than during lactation. Animals with a low likelihood of cure are best culled or separated from the other animals so that they cannot infect other animals (older animals, multiple infected quarters, chronic infection). The likelihood of (spontaneous) cure depends on: 

1. Type of mastitis causing pathogen
2. Age of the cow
3. Stage of lactation
4. History (= number of months of elevated somatic cell count/clinical cases)  
5. Number of infected quarters 
6. Quarter position

Our virtual assistant Keno-M™ generates with one mouse click the most suitable recommendation for each cow with an elevated somatic cell count, taking the above parameters into account. Click here for more info.

The best way to solve an udder health problem on a dairy herd is to first identify the problem (e.g. clinical mastitis) and the cause of the problem (e.g. too many first cases of clinical mastitis during lactation). Other causes of an outbreak of clinical mastitis may be, e.g. too many first cases of clinical mastitis in the freshly calved cows or too many repeated cases. The problem and the cause of an outbreak of clinical mastitis may best be identified by means of the key performance indicators for clinical mastitis. After that, the reason (e.g. too high infection pressure in the lactating animals between two milkings) for the problem (e.g. too high incidence of clinical mastitis) and its cause (e.g. too many first cases of clinical mastitis in the lactating cows) should be determined. This is best done based on the observations collected during a herd audit. Finally, a list of herd-specific action points should be presented to the dairy producer.

By proceeding in this structured manner, the number of action points can be limited and only those solutions can be proposed which are most effective in addressing the herd-specific problem. In this way, results are achieved quickly and the dairy producer also remains motivated. If no clinical mastitis data are available on the dairy farm and, therefore, the clinical mastitis indices cannot be calculated, one may immediately proceed to step 3, where first the most probable reason for the problem is determined by determining the risk of mastitis in the various elements of mastitis management (milking technique, milking machine, dry cows, ...).

Our virtual assistant Keno-M™ calculates and interprets the 5 key performance indicators of clinical mastitis with one mouse click. Click here for more info.

With the help of our virtual assistant U-Scan, the weaknesses and strengths in various elements of mastitis management on a dairy farm are made visible in a simple, objective and scientifically sound way. Click here for more info.