What is Mastitis in Cows?

What is mastitis in cows? What is the treatment for mastitis in cows? What are the symptoms of mastitis in cows?

Do you have cows that are milking or nursing?  If so, then you'll need to know what mastitis is, how to identify it and how to treat it.

A cow with mastitis will have pain and swelling; this can lead to a cow that avoids milking or nursing.  Keep reading to learn what mastitis is, how to identify it and how to treat it.

​🤚Before we dive in, I want to give you a FREE guide that will help you raise livestock for fresh meat, eggs and dairy! Grab your free copy of the Livestock Planning Guide here and start raising animals that will produce for you!

Do cows get mastitis?

Yes.  Mastitis is an illness that affects the milk producing tissues of the udder, so all mammals that produce milk are able to develop mastitis.  It's a prevalent disease in cattle and is one of the causes of lost income in cattle businesses.

​Beef cattle with mastitis may not want to nurse their calves, causing a decrease in calf growth.  Dairy cows with mastitis may produce milk that cannot be consumed.

Mastitis in Dairy Cattle

Mastitis is simply the inflammation of udder tissue.  This can be caused by an injury or from infections.  Usually, mastitis is caused by infection from bacteria.

​Mastitis is the most common disease that dairy cattle can get. It can also be an expensive disease; one case of mild mastitis may cost you around $200 to treat.  Preventative care is highly recommended to avoid mastitis in your cattle.

what is mastitis, mastitis in cows

A little known fact about mastitis is the effect that it can have on reproductive health.  The mammary tissue that is inflamed during a bout of mastitis can communicate to the reproductive system that it's not a good time to reproduce.

Cows that have mastitis often take longer to become pregnant.  In fact, research shows that it takes cows about 40 days longer to get pregnant after mastitis than cows that haven't had it!

​There are five main types of mastitis.  Each one has its own symptoms and problems that it causes.  Identifying the type of mastitis that your cow has can help you to choose the proper treatment for your cow.

Types of Mastitis and Associated Symptoms

There are five types of mastitis.  Don't let the names overwhelm you.  I've listed the types out so that you can hopefully learn and identify the type that your cow has.  Learning the type of mastitis can give you and your veterinarian clues as to which treatment option might work best for your cow.

Subclinical Mastitis

Subclinical mastitis is a type of mastitis that is sneaky and can hide from you easily.  It doesn't cause changes in the milk like the other types of mastitis.  It also doesn't cause pain or inflammation of the udder or teats.

Staphylococcus aureus (staph) and Streptococcus (strep) bacteria are the usual causes of subclinical mastitis.

​Subclinical mastitis can be thought of as the beginning stages of a developing infection.  The infection is present and causing problems inside of the udder but not enough for you to notice.

Clinical Mastitis

Clinical mastitis occurs after subclinical mastitis has gone untreated and is now noticeable.  In clinical mastitis, the udder and teats will be red, swollen and tender to the touch.  There may also be fever in the affected area.  It's not uncommon for the cow to have a high body temperature and appear depressed.

​Milk may also start to show signs of mastitis.  A common sign of clinical mastitis is the appearance of clots in the milk.  Milk can develop clots when too much serum or fibrin is in the milk.  Fibrin is a protein that helps blood to form clots.

Acute Mastitis

Acute mastitis is a more severe form of mastitis.  It's commonly caused by E. coli, Streptococcus and Klebsiella bacteria.

The udder and teats in acute mastitis are extremely tender and show signs of severe inflammation.  The udder and teats can become so swollen that they become hard to the touch.  Cows will appear depressed and can stop eating.

​Milk will also appear abnormal.  The milk can vary in appearance; some milk will become watery while some will appear clumpy.  There may be clots or flakes in the milk.  Sometimes pus will also be in the milk.

what is mastitis, mastitis in cows

Acute Gangrenous Mastitis

This is a very severe form of mastitis that can cause permanent damage to the udder.  Acute gangrenous mastitis is commonly caused by Clostridium perfringens, Staphylococcus aureus, and E. coli.

Acute gangrenous mastitis develops quickly, causing damage to the udder within a few hours.  At first, the udder will show typical signs of mastitis: redness, swelling and tenderness.  Cows will usually stop eating, appear depressed or lethargic and have a high body temperature.

A few hours after the udder shows signs of fever and redness, it will go cold.  Don't make the mistake of thinking that your cow is cured!  She will still show other symptoms that there is a problem.  Leaving acute gangrenous mastitis uncured can have serious negative effects.  The bacteria can start breaking down the tissues of the udder from the inside, causing the udder to essentially rot from the inside out.

The milk can give you some hints that your cow is dealing with acute gangrenous mastitis.  Milk will become watery and bloody.

​Cows with acute gangrenous mastitis can also develop toxemia.  Toxemia happens with the bacteria enter the blood and cause a widespread infection.  Toxemia can lead to death.

Chronic Mastitis

Chronic mastitis occurs in some cattle.  The underlying cause of mastitis could be due to a number of reasons, from genetic predisposition to a weak immune system.

Cows with chronic mastitis will have bouts of the illness from time to time and never really get over it.  If you were to do testing on these cows, they would show signs of mastitis more often than not.  They may appear healthy from the outside, produce fine and milk out ok, but there is always a slight infection going on in the background.

Chronic mastitis is usually caused by staph bacteria.

​They may have subclinical mastitis almost constantly with occasional cases of clinical mastitis.  Milk may occasionally contain clots, flakes or too much fibrin.

Diagnosis of Mastitis in Dairy Cows

There are a few different ways to diagnose mastitis in dairy cows.  Any time that you notice the udder is tender, red, swollen or has fever, you should suspect mastitis.  You can also test cows for mastitis when the udder appears normal to ensure that there is no underlying subclinical mastitis.

​It's important to understand some basic udder anatomy.  The cow's udder has four compartments.  Each compartment is separated from the others and has its own teat.  It's common for cows to develop mastitis in one compartment while the other three are healthy.

When testing for mastitis, you'll want to test all four compartments individually to pinpoint where the infection is.  This will allow you to treat the infection more effectively.

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The easiest way to test for mastitis is with the California mastitis test (CMT).  This test is cheap and very easy to use.  It can be used to test all four teats on a cow.

​The California mastitis test kit includes a paddle with four individual cups and a small bottle of reagent.  The reagent is a chemical that will change color if there is infection present.

To use the California mastitis test, collect milk from each teat into the cups.  Make sure that milk from each teat only goes into one cup so that you can determine which udder compartment(s) the infection is in.  Each cups should contain about 1/2 teaspoon of milk.  You can tilt the test to remove excess milk.

Add 1/2 teaspoon of the reagent into each cup.  Gently tilt and swirl the paddle to mix the reagent with the milk.  Changes in color or gelling of the milk are signs of mastitis.

Milk that isn't infected will not have color changes and will remain free-flowing.  Milk with mild infection will change color and have small clumps.  Milk with a severe infection will clump into a large mass that sticks to the side of the cup.

For more information about interpreting the results of a California mastitis test, check out this article from the University of Missouri.

Cattle can also be tested for the presence of somatic cells.  This is more commonly done on large commercial farms.  Somatic cells are cells that show up in milk.  There are many kinds of somatic cells; it's also normal for cells to be in milk.  Somatic cell testing will look at the total number of cells in the milk and determine how many of these are white blood cells.

White blood cells fight off infection.  Too many white blood cells in the milk can indicate that there is an infection present.

Commercial farmers must limit the amount of somatic cells that are in the milk so they routinely perform somatic cell tests.

​Somatic cell counts are the only way to detect subclinical cases of mastitis.

Treatment for Mastitis in Cows

The best way to treat mastitis is to treat the udder compartment(s) that is affected.  Determine which compartment(s) are infected.  It's helpful to know which bacteria is causing the infection.  Different antibiotics treat different types of bacteria better than others.  Knowing the type of bacteria causing the infection will help you or your veterinarian to choose the most effective antibiotic for the type of bacteria you're dealing with.

If you don't know the type of bacteria causing the infection, you can use a broad-spectrum antibiotic to treat the infection.

The most effective antibiotics are intramammary antibiotics.  These antibiotics are inserted into the compartments with mastitis tubes.  These tubes allow the antibiotic to go directly into the infected udder, putting it into direct contact with the bacteria.

Intramammary tubes can be used with normal systemic antibiotics.  This is useful when more than one udder compartment is infected and/or the cow shows overall signs of illness (depressed, not eating, fever, etc.)

​One of the best ways to treat mastitis is to prevent it.  The teat is an open door for bacteria to enter the udder and cause infection.  So, it's a good idea to try and keep the udder clean when handling it.

what is mastitis, mastitis in cows

Before you milk your cow, use an teat dip.  A teat dip is an iodine dip that is used to sanitize the teat and kill any unwanted bacteria.  A teat dip cup is easy to use and allows teat dips to be done quickly before milking.  Repeat the dip after milking to kill any bacteria that may have gotten onto the teat from your hands or milking equipment.

You may think that mastitis affects cows that are producing milk only, but it can also affect cows that are not lactating.  There are some things that you can do to make sure that your cow doesn't develop an infection during her dry period.

When you stop milk your cow (aka dry her off), you can seal her teats with an internal teat sealant.  Her teats are an opening for bacteria to enter.  She can get bacteria into her teats from laying on the ground or in soiled bedding, which can lead to an infection.  The sealant will prevent bacteria from entering the teat.

What if treatment doesn't work?

There are a few reasons that mastitis treatment may not work.

If you treat the infection with a broad spectrum antibiotic and the infection doesn't go away, have the cow tested.  Determine what kind of bacteria is responsible for the infection and then use a narrow-spectrum antibiotic that is effective for that bacteria.  Your veterinarian can determine the type of bacteria and the best antibiotic.

You may not be treating the infection long enough.  Let's say that you have a round of antibiotics that should be used for 10 days.  On day 7, your cow no longer shows signs of mastitis.  Her udder isn't swollen and her milk looks normal.  DON'T STOP TREATING HER NOW!  Remember, cows can have mastitis without showing signs of it.  If you stop giving the antibiotics before the 10 days (or whatever the treatment time is), then you aren't killing all of the bacteria.

Stopping treatment early leaves bacteria in the udder.  These bacteria reproduce and then cause 'another' case of mastitis.  Early treatment stopping can also cause bacteria that are resistant to antibiotics.  This is a problem that you don't want to cause.

If you don't stop treatment early but then the infection returns after a while, you're probably treating a new infection.  In this case, you might want to look into your milking process to see if you're accidentally introducing bacteria into the teat.

Make sure that you're:

-using a teat dip before and after each milking
-sanitizing milking equipment or milking with clean hands
-cleaning bedding frequently to prevent bacteria buildup in bedding

​If you've exhausted all of these options and you still have a cow that doesn't respond to treatment, then you may have cow with a case of chronic mastitis.  This is most often seen in older cows.  It may cost less money to get rid of the chronic cows than to continually treat them, especially when treatment doesn't work.

Mastitis in Dairy Cattle

Dairy cattle are susceptible to developing mastitis since their udders are handled frequently.  It's important to check the udders and milk at each milking to look for signs of mastitis.  Treating mastitis early is the most effective.  Putting off treatment can cause permanent damage or infections that are expensive to treat.

It's also important to determine the cause of infection.  Pinpointing the bacteria responsible for infection will allow you to choose the best antibiotic to treat it.  Don't stop treatment early even if your cow is showing signs of being mastitis-free.

​Always work clean around your cows.  The teat is an open door for bacteria to enter.  Use teat dips before and after each milking.  Also, consider preventative measures for dry cows to prevent mastitis.

​If you haven't yet, click here to grab your FREE copy of the Livestock Planning Guide and get instant access to my foolproof method for planning for livestock so you can start raising animals for delicious, homegrown meat, eggs and dairy!

Mastitis in Cows, Livestock Planning Guide

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Do you have problems with mastitis in cattle? How do you treat or prevent mastitis in dairy cattle?

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