Klebsiella is a difficult bacteria to deal with because infections can come on quickly without warning and have the potential to be fatal. Understanding how it spreads and how to prevent it is important for protecting herd health.
Where are bacteria found?
Klebsiella species are commonly found in dirt, water and the intestinal tract or feces of animals and humans. Therefore, the organisms can be found from many different sources throughout the dairy farm. Bedding cows with sawdust can increase the chances of intramammary infection because Klebsiella is found in high levels on the forest floor. Klebsiella can also be spread during the milking process. Milk from an infected cow can contaminate the milking unit and infect the next cow being milked.
Which cows are most at risk?
Infections can occur at any time during lactation. Due to increased stress around calving, infection rates rise during the fresh period. Cows are also at a higher risk shortly after dry off because of the cessation of milk removal. Removing milk helps to eliminate bacteria from the gland.
Are there seasonal effects?
Infections can happen any time of year, but they are more common in the summer months. Klebsiella can grow at temperatures as low as about 40ºF but prefers a temperature range of 95ºF to 98ºF for optimal growth. Its ability to grow at higher temperatures and its presence in water may contribute to the higher infection rates during the warmer months of the year.
What is the severity of mastitis cases?
Most mastitis cases caused by Klebsiella are mild or moderate, with symptoms ranging from an increased somatic cell count to abnormal milk or swollen quarters. However, some cases can become systemic. As Klebsiella bacteria die, they release a toxin that is the primary cause of clinical and systemic signs of infection. Because the toxin is released upon cell death, antibiotic treatment for Klebsiella cases is not recommended. With veterinary consultation, antibiotics may be used to treat systemic cases of mastitis.
Klebsiella can also lead to chronic mastitis. Although the causes of chronic cases are not yet fully understood, research suggests it may be due to Klebsiella’s ability to penetrate deeply into the secretory tissue of the mammary gland.
How to prevent Klebsiella cases?
Because of its presence in the environment and the ineffectiveness of treatment, preventing new cases of mastitis is key. Bedding should be kept clean and dry, especially when using organic bedding materials like straw or sawdust. Organic bedding promotes the growth of bacteria.
Although sand is a preferred bedding material, it is not perfect. Recycled sand can contain high levels of organic material and moisture. Even fresh sand can be problematic. Sand should be stored in a dry place. Sand stored near groundwater can have high bacteria counts. Farms have successfully reduced bacteria levels by stirring their sand piles and moving sand from the bottom to the top, allowing it to dry.
Proper milking procedures should not be overlooked. Using a pre-milking teat disinfectant helps kill bacteria the cow brings in from her environment, while post-milking teat disinfectant helps eliminate bacteria acquired during milking.
What tools can be used?
Vaccines
Research results for Klebsiella vaccines have been inconsistent. Some of the most recent research shows promise. However, vaccines do not prevent mastitis cases; rather, they help decrease the severity. To prevent mastitis cases, focus should be on decreasing the bacteria in the environment. Moisture meters, organic matter tests and sieves can help assess how well bedding and the environment are being managed.
Moisture meters
Moisture meters measure the dry matter of bedding. Higher moisture levels can indicate increased bacteria counts and reduce the bedding’s ability to absorb urine and feces. Dry matter percentages above 65% are ideal. Sand with a dry matter above 95% is also ideal. Testing for dry matter in bedding uses the same procedures as in feed.
Organic matter tests
Organic matter provides a food source for bacteria to grow. These tests are done in a lab. To determine organic matter, bedding samples are incinerated by drying at 1,000ºF for 12 hours. The weight of the remaining content (ash) is subtracted from the initial weight. Organic matter should be less than 3%. Specific bacteria counts, such as Klebsiella, can also be collected in a lab. Ideally, Klebsiella counts should be zero cells per square centimeter.
Sand sieves
Not all sand is the same. Particle sizes in sand bedding affect its quality. The ideal particle size ranges from 0.1 to 0.2 millimeter. Larger particles can be problematic for cow comfort. However, too-fine sand can negatively impact milk quality. Fine sand doesn't allow water to filter to the bottom of the bed, which results in higher moisture content.
A positive outlook
Klebsiella mastitis is a serious challenge, but it is not insurmountable. Focusing on reducing bacteria counts in the cow’s environment will help prevent mastitis cases. Taking steps to ensure good bedding quality is essential. Collaborating with your veterinarian and a milk quality lab can provide all the necessary tools to help herds prevent or prepare for a Klebsiella issue.
