Intramammary infections (IMI) are highly prevalent in dairy cows. Mastitis is often described as the most important disease for the modern dairy industry, due to reduced milk production, discarded milk, treatment cost, antibiotic usage, impaired reproduction, and premature culling. Clinical mastitis is also a welfare issue, as it is often associated with severe systemic signs of illness, leading to pain and discomfort. Somatic cells are mostly cells of the immune system and are a reflection of the inflammatory response to IMI. Somatic cell count (SCC), or a parameter derived from this count (e. g. linear scores, used by DHIA) is often used to distinguish infected and uninfected quarters. Thresholds of 200,000 and 250,000 cells have been systematically used to define subclinical mastitis. Somatic cell count is largely used to monitor the level of IMI and milk quality in individual cows, and bulk milk SCC are used as an overall barometer of milk quality. Although the primary reason for dairy producers to reduce SCC is because high SCC is associated with impaired milk yield, it is important to highlight that federal law allows milk to be sold only if the bulk tank has a SCC of less than 750,000. Additionally, marketing agencies pay premiums for milk with low SCC because it reflects in increased milk quality and increased cheese yield. Therefore, improved udder health by decreasing SCC has great economic importance for a dairy enterprise.