Mastitis: Diagnosis, Treatment and Prevention Measures

Poor hygiene and handling are the number one accelerator for most cases of mastitis at the farm. This is because mastitis is a bacterial infection and bacteria tend to thrive in unhygienic conditions.

Mastitis in cows is manifested as the inflammation of the cow's mammary gland and udder tissue. This disease/condition is a major endemic disease of dairy cattle but can affect all other lactating mammals as well (including humans).

When the bacteria gain entry into the udder through the teat canal, they find nutrients in the udder and multiply rapidly. Their metabolic byproducts cause poisoning of the udder tissues resulting into an inflammation. The inflammation is due to the cow’s autoimmune response to the toxic metabolites released by the bacteria.

Predisposing factors for the development of mastitis in cows

In this post, we highlighted some sources of bacteria that you may need to check if you have to control bacterial infection at the farm level. It is important to take note that mastitis can also occur due chemical, mechanical, or thermal injury to the cow's udder.

The bacterial metabolites released in the udder tissue can damage the milk-secreting tissues and ducts throughout the udder. In some situations, the damage is permanent and the udder loses its functionality. Acute cases can lead to fatalities while cows that recover will be incapacitated for the rest of their lactation lives.

Mastitis in cows can be a very complex illness since the farmer may not be able to detect it during its subclinical phases. This is to say that the herd may have mastitis without showing any signs and symptoms. At this stage, the disease can spread very fast to the rest of the herd if proper handling is lacking in the farm.

To manage the situation, you should consider paying a very close attention to the milking hygiene to avoid cross contamination. You should couple this with good housing and proper nutrition to promote general good health of the animals. In extreme cases, you may need to cull the severely infected cows.

The losses a farmer is likely to incur due to mastitis:

  • Farmers will throw away milk contaminated by medication for being unfit for consumption.
  • The cows will produce less during the illness. A permanent udder tissue injury will negatively affect the yields.
  • The farmer will have to spend more in extra labor required to tend to the sick cows.
  • Medication and veterinary services for treating the sick cows tend to be high.
  • Sick cows will have a reduced productive lifespan due to the injured udders. You may have to cull them before exploiting their full potential.
  • Cross contamination in the farm can lead to loss of the entire herd due to culling

Given the gravity of the effects of mastitis in cows, it is important to take precautions to ensure that you do not end up with mastitis in your farm. Dairy cows have many predisposing factors to mastitic infections such as the risk of contamination from the milking equipment, hygiene of the milking equipment handlers, and cleanliness of the cleaning water.

Since farmers tend to milk their animals at predetermined hours, their udder sphincters tend to be under stress than beef cows whose calves nurse regularly. The stress may lead to loosening of the teat canal through which the bacteria will gain entry into the udder to cause mastitis.

Public health concerns

There are occasions when incidences of mastitis may qualify to be a public health concern. When this is the case, farmers must do all they have to do to ensure that their animals are not infected. At the same time, they must manage the already infected animals to prevent any further spread of the disease.

Consequently, it is not uncommon to see the farmers to procure intramammary antibiotics due to its low risk of administration.

Organic dairy farmers on the other hand prefer to use limited antibiotics and prefer to use alternative therapies, e.g. homeopathy, to treat mastitis. Such farmers also prefer to take a more holistic approach in their farms to prevent mastitis.

Avoid prescription abuse when treating mastitis in cows

While applying any treatment method you prefer to use, you must be sure that you know what you are doing. If in doubt, consult your veterinarian or animal health care expert. There have been incidences of prescription abuse, which puts us on the precipice of losing the war against bacteria.

When the bacteria have developed sufficient resistance to the antibiotics, you will be forced to look for a more potent alternative, which could be very expensive or non-existent. Whenever you treat a bacterial infection in your herd, it is important not to go for the strongest medication first because if it fails to deliver, you will not have an alternative.

Important terms on mastitis in cows

i) Severe clinical mastitis

Characterized by an extremely ill cow that may die if untreated. The udder becomes gangrenous and the milk may look normal even the though the cow is sick in the early stages. Soon enough, the milk becomes abnormal.

ii) Acute clinical mastitis

Here, the cow may not necessarily be sick but the udder is visibly swollen, painful, and hot. The cow produces abnormal milk with clots and blood.

iii) Clinical mastitis

The cow looks indifferent and the udder does not show any observable changes. You will notice abnormalities in the milk.

iv) Mild clinical mastitis

The cow looks fine and the udder does not have any abnormalities. You will notice a few clots or flakes in the milk.

v) Chronic mastitis

The cow looks very fine but you may feel lumps in the udder tissue. You will also observe changes in milk e.g. the milk can be very watery. This could be the reason why your milk is always rejected at the dairy despite feeding your cow well and treating it from all diseases.

vi) Subclinical mastitis

Your cow looks fine and the udder is well. You may not make out any observable changes in the milk but a chemical analysis of the milk will show significant changes in the milk composition.

How to test for mastitis in cows

There are many scientific methods for testing and confirming mastitis in cows. Some of the tests are straight out simple while others are complicated and require sophisticated equipment, e.g. DNA testing method.

The most common method for mastitis testing is the California Mastitis Test (CMT). This cow-side testing method works by disrupting the cell membranes of the somatic cells present in the milk sample and exposing the DNA of the cells to the reagent.

Upon touching the reagent, the mixture turns into a gelatinous mass, which confirms the presence of mastitis in cows.

To perform this test, you will need the CMT test kit. You can get one from Amazon at a reasonable price and it will be shipped to you.

Here is the CMT procedure:

  1. First, begin by cleaning the teats then strip a few squirts of milk onto the ground. After stripping the teats, milk several milliliters from each quarter into the corresponding well/compartment of the paddle.
  2. Tilt the plate to get a better estimate of the volume you collected and then add an approximately equal volume of the CMT solution into each well.
  3. Swirl the paddle gently to get a uniform mixture of the CMT solution and milk.
  4. Observe the results. A purple gelatinous mass will indicate a positive reaction.

You can have a look at this short video to see how it actually works.

(Source: NBC Field Service).

Some pathogens that cause mastitis in cows

Where found

Manifestation

Management

Pseudomonas aeruginosa – Causes subclinical mastitis

   

Found in soil-water environments in dairy farms.  

May cause infection from contaminated water, teat cup liners or intramammary treatments

Severe mastitis with toxaemia and high mortality results in some herds. May also lead to subclinical infections.

The bacteria can persist in the glands for up to five lactations. Spontaneous recovery may occur

Ensure clean feeds and water for the cows. Clean the milking equipment and aseptically clean the udders.

Therapy may not work for the affected cows. Cull the sick animals.

Mycoplasma spp. Causes severe mastitis that spreads quickly

   

M bovis is the most common cause. Other species include M. californicumM. canadense, and M. bovigenitalium  

Carrier animals do not show symptoms.

Common in growing farms that have brought more animals into the farm.

Carriers are asymptomatic. Shed the bacteria through the intrammamary or respiratory disease transmissions.  

The disease is very severe when it breaks out.

Leads to a dramatic drop in productivity. You may observe a granular flaky substance in the secretion.

Take a lot of care when introducing animals into the farm because carriers do not show symptoms.  

Maintain high levels of hygiene at the farm.

Segregate cows during active outbreaks.

Routinely check bulk milk to identify infected cows.

Do not feed calves on milk from sick cows; may lead to respiratory or inner ear infections.

Cull cows with signs of systemic infections

Trueperella pyogenes. Causes characteristic mastitis in heifers and dry cows

   

Common in dry cows/heifers that graze in the pastures and access water from the ponds.  

Carrier fly for this pathogen is Hydrotaea irritans.

Produces an inflammation with a foul-smelling exudate.
 
May occur in lactating cows with injured teats, as the pathogen takes the opportunity as a secondary invader to cause infection.

Therapy is rarely successful; do not milk infected quarters.

Avoid grazing cows in pastures where they have to stand udder-deep.

Treat susceptible cows with long-acting penicillin to reduce infections.

Cull cows with abscesses.

Nocardia asteroids. Causes destructive mastitis

   

Characterized by high fever, loss of appetite, loss of weight, udder inflammation.

The udder inflammation exhibits extensive fibrosis with palpable nodules.

Practice aseptic intrammamary treatment to prevent infections.
 
Cull infected cows by slaughtering them.

Serratia spp.

   

Infections arise from contaminated cleaning water, dirty hoses, contaminated teat dips and other milking equipment.

The bacteria are resistant to disinfectants but infected cows show clinical signs of mastitis.

Cull cows that continue to show clinical signs of mastitis.

Yeasts and molds

   

Common in cows with prolonged antibiotic/penicillin treatment. These fungi are introduced during preparation of infusions.

However, even heifers that have never received intrammamry infusions may also develop yeast mastitis

Severe infection, high fever.

The animals may heal on their own after 1 – 2 weeks.

Cows that fail to heal may develop destructive mastitis.

Certain strains of yeasts cause only limited inflammation.

Reduce contact between the teat dip container and the teats when treating the cows

Prototheca spp

   

These bacteria tend to inhabit wet and humid environments.

Muddy environments in dairy farms is prime for their survival.

There are carriers of the pathogen that occasionally shed it leading to spontaneous infections.

Chronic and asymptomatic.

Sporadic severe infections may occur in subsequent lactations.

Hard to predict and therapy does not work with this pathogen.

Farmers must, therefore, manage the disease as it comes.
 
Cull cows with chronic mastitis

Common methods for treating mastitis in cows

a) Antibiotic applications

Milk the cow dry and apply an intrammamary antibiotic. Do not add the affected cow’s milk into the batch tank until the drug clears from the cow’s system. You can only use such milk to feed the calves, otherwise, just drain the milk.

It is illegal and unethical to sell milk with antibiotics in it. You can use a physical marker (e.g. leg bands) to mark out sick cows in a large herd. Keep health records of the herd.

b) Intrammamary infusions

Clean the teat and disinfect with ethanol, after which you allow it to dry for a few seconds. Partially insert the cannula containing the infusion onto the teats to reduce contact, which can introduce fungi that will cause a different form mastitis.

Once the teat comes into contact with the antibiotic infusion, streak the teats by pinching and palpate a little bit to make sure that the antibiotic treatment enters the mammary gland.

c) Oxytocin treatment

Effective treatment of mastitic cows depends on complete removal of milk from the teat cisterns. You can achieve this by increasing the intervals of milking.

Bacteria thrives in milk because it gets nourishment from the milk. When you empty the teat canal, the bacteria will not find nourishment and the antibacterial drugs will be more effective.

If the cow is a high producer, you may need to streak it in between the milking times. You can inject the cows with oxytocin to increase milk let down so that you can achieve complete milking.

In some instances, the bacteria may fail to go away despite regular streaking and application of the antibacterial drugs. This will lead to chronic infections, which is associated with Staphyloccocus aureus, bacteria that naturally exist on the skin.

In such cases, the cow will remain a constant source of contamination for the rest of the herd. You will have no option but to cull such a cow if you must protect the herd.

How do you prevent mastitis in cows?

Given the magnitude of the effect of mastitis in a dairy enterprise, it is important to look for ways to prevent the spread of this disease in the farm.

Having a firsthand knowledge of mammary anatomy and physiology, the defense mechanisms, microbial behaviors, aetiology and manifestations, farm and equipment hygiene, and antibiotics/germicides will be very helpful in controlling the spread of mastitis.

There are several intervention methods that can help a farmer to achieve this and they include:

i) Vaccination methods

Researchers have been able to develop bacterins from E. coli and Salmonella that can help reduce the severity of mastitis caused by coliforms. They also observed that repeated application of these vaccines during the dry period can significantly reduce clinical coliform mastitis in the early lactation.

The effectiveness of these vaccines reduces after 50 days; therefore, large herds may warrant extended immunizations.

Sadly, the researchers have not yet developed an effective vaccine for Staphyloccocus aureus, which is a big pathogen for mastitis in cows.

ii) Controlling the environmental and contagious factors that promote mastitis in cows

Environmental pathogens pose a special challenge to the farmer in terms of control. They are not specific to the cow or the farm; therefore, the farmer must find the source/habitat and control it from the source. Usually, one can achieve an effective control of the pathogens by eliminating their habitat.

You can also reduce their effectiveness by implementing the following:

  1. Dip the teats in a germicide after every milking to decrease incidences of the disease
  2. Treat each quarter separately with antibiotics to avoid disease prevalence
  3. Milk infected cows last and use separate milk handling equipment for their products to avoid cross contamination
  4. Use individual disposable towels for cleaning the udders. If you have to use a cloth towel, each cow should have a separate towel. Clean the towel thoroughly with hot water after milking and air dry.
  5. The milkers should be clean and preferably wear latex gloves while milking
  6. Isolate new additions into the herd and culture their milk to find out if they have the pathogens that cause mastitis.
  7. Cull chronically ill animals
  8. Give your heifers dry-cow antibiotic treatment if you notice that they have Staphyloccocus aureus infection
  9. Clip the udders to reduce dirt dangling around the teats
  10. Pre-dip the teats in a germicide before milking and ensure you only milk clean dry teats.
  11. Keep the cows standing after milking to ensure that their teat canals close to avoid entry by bacteria. You can achieve this by giving the cow some feed.
  12. Use single-dose infusions to avoid cross contamination when performing udder cleaning and sterilization.
  13. Maintain high levels of hygiene by keeping the milking parlor very clean, using clean milking equipment, and using sterile teat dippers.
  14. Clean the pipes regularly to avoid buildup of bacteria. In case of Pseudomonas spp. Invasion, you may be forced to replace the heating and piping systems.

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MSc. Food Science | Interested in Data Science for Quality Management - learning python | Agribusiness consultant with special interest in food processing and quality management. | Solve this if you can - if a ship had 26 goats and 10 sheep onboard, how old is the ship's captain?