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Udderly Important: A Guide to Preventing Mastitis Through a Thoughtful Milking Routine…

Mastitis is a common disease on dairy farms. From a disease perspective, mastitis has the second largest economic impact to dairy farmers.


Mastitis is the inflammation of the mammary gland (udder). The most common cause is a bacterial infection, although trauma can also be involved.


Mastitis develops from microorganisms invading the udder through the teat canal. They migrate up the teat canal and colonise the secretory cells. The colonised organisms produce toxic substances harmful to the milk producing cells.

Historically, the most common way mastitis spread was between cows through the milking process, known as 'contagious mastitis'. The most common way to spread it now is the 'environment mastitis' from housing and environment.

In the UK the average cost per mastitis case is £250-£300. More severe cases can result in much higher costs such as E-coli infections.



Milking Routine


The aim is to remove milk efficiently from the cow with minimal risk to udder health. The routine must be practical and labour efficient with the milker understanding the scientific reasoning for each step in the process to achieve this aim. Routine must include practices that limit the spread of contagious mastitis in the parlour.


Ideal Milking Routine...


  • Foremilk cows

  • Dry wipe clean teats

  • Wash and dry dirty teats

  • Pre-dip, allowing a 30 second contact time and wipe off

  • Attach the milking unit within one minute of teat preparation

  • Check machine sits squarely on the udder

  • When milked out, shut off vacuum and remove cluster

  • Teat dip once cluster is removed

  • Cows to remain standing for 30 minutes


Why Foremilk?

  • Early detection of mastitis

  • Stimulates the milk let down reflex

  • Removes bacteria that may have entered the teat canal since the last milking


Teat Preparation

  • Goal is for clean dry teats

  • Dry wipe clean teats

  • Wash and dry dirty teats

  • Avoid communal udder cloth

  • Predipping is the gold standard


If water is used to wash teats it should be sanitised as contaminated water can be a source of Pseudomonas and Nocardia mastitis infections.


Ensure only teats are washed and not the udder. When the udder gets wet, water drains back down onto the teats after they have been dried (magic water).


This increases the risk of liner slip and if sucked in through the top of the liner can contaminate milk or create impact forces which will increase the risk of new environmental infections.


Disinfection with 60ppm Iodine or 200ppm sodium hypochlorite is beneficial. In no circumstances should a communal udder cloth be used as this spreads infection from cow to cow.


Disinfectant in water for washing and dried with paper towels will keep total bacteria count lower than washing alone.



Milkers Hands


Milkers hands can spread mastitis bacteria from cow to cow. Hands cannot be disinfected so it is advisable to wear gloves.


  • 50% of milkers hands infected before milking

  • 100% of hands infected during milking

  • Gloves reduce the risk of transferring infection

  • Gloves must be rinsed throughout milking


Predipping

  • Disinfects the teat

  • Reducing the number of bacteria in bulk milk

  • Reduces the incidence of environmental mastitis

  • Minimum contact of 20-30 seconds is allowed

  • Thoroughly wipe off the teat before the milking unit is applied to avoid any chemical contamination of milk


Mastitis Detection

  • Foremilking

  • Change in the behaviour of the cow

  • Palpation of the udder

  • Observation of quarter swelling

  • In-line mastitis detectors

  • Checking the milk sock or filter at the end of milking

Udder examination is one way to check for subclinical mastitis cases.


Palpation of the udder

  • Palpate the udder immediately after milking when it is soft

Skin

  • Grasp the skin between the thumb and forefinger - it should be pliable and easily separated from the underlying tissue. If not, it suggests there is an oedema of the udder associated with infection or recent calving.

Udder Tissue

  • Palpate each quarter with both hands, one either side of the quarter. The udder should have a fine grain feel, if there are lumps, coarse grain or hard udder then it suggests a sub-clinical case.

Lymph Nodes

  • The mammary lymph nodes lie in-between the hind quarter known as the perineal region. Normally the lymph nodes are inapparent but will enlarge and feel nodular when infected.

In all cases of clinical mastitis, it is advisable to collect sterile pre-treatment milk samples for bacterial identification. This will allow the identification of pathogens causing clinical mastitis so that specific control measures can be implemented. It is preferable to process fresh samples, but they can be stored in the fridge for up to 5 days or frozen before going to the lab.


Mastitis Cows


Ideally, mastitis cows should be milked last to avoid the risk of residues entering bulk supply and eliminating any spread of infection. Often there are no facilities to separate, so if milked during the milking process, they should be milked into a dump bucket or dump line. Cluster used for dump line should be disinfected between use.


Post Milking


Post milking teat disinfection:

  • Kills bacteria on teat after milking

  • Reduces new infection rate

  • Allows for inadequacy in the milking routine

  • Improves teat skin condition

  • No effect on existing udder infections

  • Must be carried out after every milking


Dipping - fully immerse in the solution using 10ml per cow per milking


Spraying - need 2 rotations around the udder, one clockwise and the other anti-clockwise, 15ml solution used.


Automatic teat spray systems - can be unreliable and provide poor coverage of the teat and use high volumes of teat dip.


Milking Order


Preferable milking order:

  • Fresh calvers

  • High yielders

  • Medium yielders

  • Low yielders

  • High cell count cows

  • Mastitis and other treated cows

Bactoscan


Bactoscan and Total Bacteria Count (TBC):


Bactoscan is more accurate and faster, with results 3-4 times higher than the TBC Psychrotrophs are bacteria which grows under refrigerated conditions and are picked up by Bactoscan but not TBC. These are dust organisms and can be associated with poor or damp bedding.


Sources of bacteria in milk are: mastitis organisms from the udder, environmental contamination and dirty milking plant.


Environmental contamination can be measured with the Coliform count, >20/ml requires better udder preparation.


Milking Equipment


If not washed and disinfected correctly, milk films may build up inside the system. This allows thermoduric bacteria to multiply. These bacteria withstand pasteurisation, i.e. temperatures over 63°C. Levels over 175/ml suggest a wash-out problem.



If you would like more advise or are worried about mastitis within your herd, contact your DN Sales Specialist for more information.






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