Narrative Relation between Low Milk Somatic Cell Count and Mastitis Susceptibility in Dairy Animals

Abstract

Background: Somatic cell count in milk is closely associated with the incidences of intramammary infections
(IMI) in milch animals, and is regarded as a reliable marker of the mammary gland (MG) infection. The contradicting school of thought exist about the interpretation and consequences of SCC; most authors reported the
reduced incidences of IMI in dairy cows with lower milk SCC, but some research findings clearly explained the
elevated risks linked with lower SCC, and defended in ground of compromised immune status of the focus cows.
Areas Covered: The question of whether low SCC is correlated to increased susceptibility to IMI has aroused
the logical and rational debate. However, to date, SCC is considered a key measure in selecting dairy animals
that show reduced susceptibility to IMI. As selection indexes prioritize animals with lower SCC, it could enhance
the defense mechanisms of the MG concerns that has arisen about the potential long-term increase in susceptibility to IMI. The debate surrounding this issue persists, despite seemingly contradictory findings from previous
studies investigating the relationship between SCC and IMI susceptibility in dairy animals. A comprehensive
understanding of the leukocyte- dynamics in milk and immune-physiology of mammary cells, along with their
functions in combatting infections, can help reconcile these conflicting results. Recent studies focusing on SCCbased selection of dairy animals also contribute to resolving the matter.
Expert Opinion: It becomes apparent that the long-debated issues of susceptibility to IMI associated with
SCC is more likely a phenotypic trait linked to immunomodulation rather than a consequence of selection.