Somatic cell count can be an indicator of animal performance and milk quality. As somatic cell count increases, milk yield and quality will decrease.
When a cow is dealing with any inflammatory response, including a response caused by mastitis, they will utilize nutrients and energy — close to 2 kg of glucose per day — to fuel that response, leaving fewer nutrients available for milk production. This results in a lower milk yield by that cow. The immune cells that rush to the mammary gland to fight the infection will show up in the milk. This can lower milk quality by changing the flavor and the color.
Management is the best defense against mastitis-causing pathogens, but at the same time, pathogens are always present in barns. Supplementing your dairy cow nutrition program with performance trace minerals, particularly zinc, can reduce the incidence and severity of mastitis, reduce somatic cell counts and help cows produce high-quality milk.
Mastitis and Somatic Cell Counts: How Are They Related?
If a cow becomes infected with mastitis, the inflammation can damage to the epithelial tissue, resulting in white blood cells invading the mammary gland and causing a high somatic cell count. If a cow is dealing with inflammation due to some other stressor – heat and humidity, for example – the inflammation can open the door for mastitis to occur as well.
Mastitis and Somatic Cell Count During Transition and Dry-Off
A cow is also susceptible to mastitis during dry-off. During the dry period, infectious bacteria are not being flushed from the mammary gland on a regular basis. Additionally, shortly after dry-off, cows may be moved away from the herd and observed less often. Furthermore, dry cow pens are usually cleaned less often, causing those cows to be more susceptible to infection. If a cow gets mastitis during the dry period, she will calve and start lactation with an elevated somatic cell count. Dry cow treatments and teat sealants are excellent ways to reduce mastitis during the dry period, if used properly
Additionally, improving milk quality in transition cows starts with improving mammary health and preventing the spread of infectious bacteria. With proper nutrition strategies, your dairy cows can produce high-quality milk when they come into lactation.
An Outside-In Approach to Controlling Mastitis in Dairy Cows with Performance Trace Minerals
Mastitis in dairy cows and the resulting increase in somatic cell count can be caused by environmental pathogens — like E. coli or contagious pathogens like staph aureus — that are passed from cow to cow. Contagious mastitis can be passed from cow to cow if a milker is using the same towel to clean off multiple cows’ udders, is not wearing gloves or is not properly cleaning the equipment.
Whether those pathogens are picked up from the environment or are passed from cow to cow, the mode of entry is the same: through the teat end.
There are two kinds of protection to stop pathogens from damaging the mammary gland and causing mastitis: the teat keratin just inside the opening of the mammary gland (external) and the epithelial tissue on the inside (internal).
The teat keratin is the plug on the outside of the udder that prevents pathogens from entering the mammary gland. It has bactericidal properties that can kill bacteria on contact as they try to invade the gland.
The epithelial tissue on the inside of the mammary gland is much like other epithelial tissues in the body. Epithelial cells are “bound” or “stitched” together by complex protein structures called tight junctions. Epithelial tissue must be constantly repaired and replaced, and the integrity of tight junctions maintained in order to protect against pathogens such as mastitis.
If pathogens are able to get past the keratin plug, then it is up to the inner epithelial tissue to be strong enough to hold off the infection until the immune cells arrive and kill the infection.
Zinc Helps Prevent Mastitis in Dairy Cows, Lower Somatic Cell Counts
Zinc is involved in over 300 enzyme functions and is critical to improving immune function. It plays a key role in keratin formation, including teat keratin — the mammary gland’s first line of defense from the outside. It is also critical for the integrity of the epithelial tissue on the inside, so that if the pathogens do get through the keratin, the epithelial barrier can minimize the damage.
Supplementing zinc from performance trace minerals can improve the production of keratin within the teat end to help keep pathogens out of the mammary gland and can produce an extra milligram of teat keratin over the course of a day.
Supplementing your dairy cow nutrition program with zinc from performance trace minerals at the start of the dry period can reduce somatic cell counts by 30,000, which can be equal to regaining about 1% of a cow’s milk yield. When you feed performance trace minerals as a part of your dairy nutrition program, pathogens have a much harder time penetrating the teat keratin and entering the mammary gland.
That said, there’s nothing that will stop every pathogen. Epithelial tissues and the tight junctions that hold them together are the animals first defense when dealing with pathogens that have invaded. Thus, nutritional solutions that strengthen the epithelial barrier on the inside can help keep the pathogens out until the immune cells take care of them, even if they get past the teat keratin.
Overall, supplementing dairy cattle nutrition programs with performance trace minerals can strengthen the immune system of the cow to help dairy cattle mount a rapid and robust inflammatory response to immune challenges. This will ensure they have adequate energy and nutrients to improve milk production and milk quality.