Historically, the dairy industry has addressed common challenges, such as poor reproduction, decreased milk production and milk quality, as well as lameness, as singular issues. We now understand that there is a common root cause that links these production issues: chronic or imbalanced inflammation.
What is Inflammation?
Inflammation is necessary for life and is the first step in the healing or repair process that helps the body fight off bacteria, pathogens and their toxins, and repair damaged tissue. If you’ve ever twisted your ankle, been stung by an insect or cut your finger, you may have experienced firsthand the familiar sensations of pain, redness, swelling, and heat that result from an injury or infection. This is inflammation in action.
Acute inflammation is the first line of defense to a pathogen or injury. It’s a short-term process where the immune system sends white blood cells to the site of the injury or invasion of the pathogen to initiate the healing process. This response should be rapid and robust, appearing within minutes or hours following activation of an immune response.
Chronic inflammation occurs when the immune response fails to eliminate the cause of the immune response or acute inflammation. Chronic inflammation can utilize nutrients and energy and persist for weeks, months or longer.
What are the Risks or Costs Associated with Chronic Inflammation?
When an animal is sick, its feed intake will decrease. At the same time, the immune system redirects nutrients utilized for growth and/or production to protection during an acute inflammatory response.
When the immune response persists, and chronic inflammation occurs, nutrients and energy are diverted away from animal performance (including growth, reproduction, feed efficiency, and milk production), ultimately decreasing profitability.
The Immune System in Action
The immune system is comprised of a sophisticated network of cells, proteins and enzymes that are programmed to monitor animal wellness. This network of cells detects and responds to bacteria and pathogens that may invade the body, as well as responds to stressors, injury or environmental challenges. All of these can have a detrimental impact on animal wellness and performance.
When a pathogen or bacteria crosses one of the body’s barriers, such as the skin, mucous membrane, or blood vessel linings, the immune system will detect the invasion. The immune system then sends signals to cytokines — small pro-anti-inflammatory proteins that are important in cell signaling — indicating that help is needed. This initiates the movement of white blood cells toward the site of inflammation, infection or trauma.
The first responders to the site are white blood cells called phagocytes. These cells help protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. There are two forms of phagocytes:
- Neutrophils are small, granular leukocytes that quickly appear at the site of a wound and ingest bacteria.
- Monocytes are larger leukocytes that appear about three days after infection and scavenge for bacteria, foreign particles and dead cellular material left behind by the neutrophils.
The neutrophils appear at the site first and work to engulf and destroy the pathogen or bacteria. They then display pieces of the pathogens on their surface to signal the monocytes to help continue the attack on the invading pathogens.
There are also a group of anti-inflammatory cytokines that help control the pro-inflammatory cytokine response. However, if there is a lack of balance between the pro-inflammatory and anti-inflammatory proteins, the pro-inflammatory cytokines can send too many monocytes (white blood cells) to the site, damaging healthy cells and leading to chronic or prolonged inflammation. This is the point when an acute inflammatory response can potentially turn into a chronic inflammatory response.
Common Sources of Inflammation
There are several common inflammation sources that impact dairy performance and profitability. Two of the most common sources are poor gut integrity and heat stress.
Poor gut integrity: The gastrointestinal (GI) tract lining serves as an important barrier to prevent bacteria, pathogens and their toxins from passing through the intestinal lining and into the bloodstream. When a breakdown in the barrier occurs, this can lead to a condition called leaky gut. When a prolonged inflammatory response occurs in the GI tract, this decreases feed intake and animal performance.
Heat stress: When animals are under heat stress, blood flow is diverted away from the tissues that line the blood vessels within the digestive tract and other internal organs to the skin, which facilitates the heat dissipation process. However, the reduction in blood flow causes a decrease in the amount of nutrients available to the epithelial layer of cells lining the gastrointestinal tract, allowing pathogens and their toxins to enter the bloodstream, due to a condition termed leaky gut.
Production Challenges Link to Inflammation
A few common results or consequences of inflammation in dairy cattle include reduced milk production, lower milk quality, decreased reproductive performance, and increased lameness. These production challenges involve an immune response. Left uncontrolled, this immune response can lead to chronic inflammation.
Calving and Reproduction
Although in general, inflammation reduces reproductive performance, inflammation of reproductive tissue can also impact the animal. A dairy cow in transition has 60 to 70 days to successfully repair damage to the reproductive tract caused by calving and be ready to get pregnant again. If this remodeling process happens in a robust manner and the inflammation quickly goes away. However, if the process of moving through the inflammation processes is slowed down or prolonged, the cow may experience chronic inflammation which is energetically expensive and negatively impacts milk production and her ability to get pregnant efficiently.
Lameness is a significant dairy cow wellness and economic issue. Lameness not only impacts animal locomotion; it also is often caused by inflammation. Left uncontrolled, the results can be reduced milk yield, reduced fertility and increased risk of culling, leading to considerable economic costs.
Somatic cell count is a marker for chronic inflammation in the udder. By lowering chronic inflammation in the dairy cow, you can lower somatic cell count, allowing more energy and nutrients to be used for milk production versus fighting inflammation.
Role of Performance Trace Minerals
Performance trace minerals — when fed as part of a well-balanced dairy nutrition program — can help manage the effects of chronic inflammation by ensuring a robust and balanced immune response. Performance trace minerals play a vital role in building healthy first responder cells, as well as ensuring the pro-inflammatory proteins (cytokines) are in balance with the anti-inflammatory proteins. In addition, performance trace minerals are key to developing a strong epithelium, which will help reduce the involvement of the rest of the immune system in an inflammatory response.
It’s important to note that not all trace minerals are created equal. Peer-reviewed research demonstrates that performance trace minerals help fortify the immune system, providing a more robust and balanced immune response compared to feeding either inorganic or organic trace minerals. This helps animals recover faster, while minimizing economic losses.
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