Mastitis in Beef Cows - Frequently Asked Questions

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 What is mastitis?
Mastitis is the inflammation of the mammary gland. This disease and resulting infection can significantly reduce milk production.

Are there different forms of mastitis?
Two types of mastitis (infectious and non-infectious) can occur. Approximately 1% of mastitis cases are non-infectious, which can be a result of a physical injury. The vast majority of the cases are infectious, which are a result of an infection - like streptococcus.

Are beef and dairy operations at risk?
Mastitis is most commonly found in dairy herds. It is now recognized as a growing problem in beef herds. This is a growing problem in beef herds, and can result in weaning weights being reduced by 7% to 12.5%.

Is the entire udder infected at the same time?
Most mastitis cases involve one quarter (one teat) of the udder, with normal milk production from the other three quarters. Overall milk yield is lower, reducing weaning weights, reducing profitability of the operation.

What are the signs/symptoms of mastitis?
Mastitis can be broken down into four categories dependent upon the signs and symptoms, Peracute, Acute, Subacute and Subclinical mastitis.

A bag that is swollen, hot, and red can detect Peracute mastitis. The cow may flinch or kick when the bag is touched because the bag is sensitive. Milk production is reduced. A general fever may be present, depression, shivering, rapid weight loss, and appetite loss occurs in many cases. In very severe cases death may occur.

Severe inflammation, and some signs of fever and mild depression also detect acute mastitis.

With subacute mastitis, symptoms on the bag are much less pronounced, and there are no signs of fever or depression or any other systemic signs.

Subclinical mastitis is the inflammation of the mammary gland without showing any signs or symptoms.

Does mastitis have other effects on the cow herd?
Mastitis can reduce fertility (first service conception rates) and delay the onset of heat cycles in cattle.

Are there cows that are more susceptible to mastitis?
Cattle held in confined areas, with high fly populations, can increase the incidence of mastitis. Infections rates can be as high as 25%.

Older cows, are at greater risk of getting mastitis. Older cows typically have larger bags than younger cows. The chance of physical injury by being stepped on is greater, and in early lactation the bag often contacts the ground, allowing the entry of bacteria into the teats.

Size and shape of the teats influence infection rates. Generally the larger the diameter of the teat, the faster the milk flow, increasing the risk of pathogens entering the teat. Cows with pointed teat ends (rarely seen) will have a greater resistance to mastitis than the most common round teat ends, which have some resistance. Flat teat ends have the least resistance to mastitis.

How does infectious mastitis spread throughout the herd?
Flies are a large factor in the spread of the disease. Flies carry the disease, moving bacteria from the skin surface into the tissue by biting at the teat ends and exposing live tissue. This is the entry point of the pathogen, allowing the bacteria into the bag infecting the specific quarter.

Calves can also spread the infection from quarter to quarter, infecting the entire bag. If cross suckling occurs, bacteria can be spread to other cows

When are cows at greatest risk to infection?
Mastitis can occur at any stage of lactation. Cows are at risk to bacteria and microorganisms entering the udder, as long as the teat ends are not sealed off or there is potential for injury to the udder. Most cases occur in the first month of lactation.

Higher instances of mastitis can also occur when the weather changes from hot and humid, to wet and muddy conditions.

What can you do to prevent mastitis?
  • Managing the environment is more important that using medications. Environmental management is key in preventing mastitis.
  • Avoid keeping cows in confinement areas as much as possible.
  • Clean grass is always better than even the cleanest barn. Ensure that cows are receiving proper nutrition throughout the entire dry period to maintain a proper immune system.
  • If you have a severe problem with mastitis, consider treatment at weaning time to clean up infections
  • If there is a history of mastitis in the herd, heifers they should be treated one month prior to calving.
  • When treating active cases, ensure the treatment area is clean, as more problems can occur with poor sanitation.
  • Consult with your nutritionist to develop a sound nutrition plan.
  • Consult your veterinarian for a proper treatment plan.

To treat or not treat mastitis?
Winter Feeding Programs for Cows and Calves
Does Lime Stop mastitis?
Mastitis in Beef Cows Merck Vet Manual

Prepared by Nanita Blomquist, Alberta Ag-Info Centre, Alberta Agriculture and Rural Development

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For more information about the content of this document, contact Hernan Ortegon.
This document is maintained by Kathy Andersen.
This information published to the web on February 13, 2004.
Last Reviewed/Revised on December 14, 2017.