When consistently high bulk tank SCC persists due to *Streptococcus agalactiaeinfections, what precise culling and segregation strategy, beyond targeted antibiotic therapy, provides the most rapid and sustained herd-level reduction?

When consistently high bulk tank Somatic Cell Count (SCC) persists due to *Streptococcus agalactiaeinfections, the most rapid and sustained herd-level reduction is achieved through a precise culling and segregation strategy focused on eliminating the primary reservoir: the infected mammary gland. *Streptococcus agalactiaeis an obligate intramammary pathogen, meaning it lives almost exclusively within the udder of infected cows and is highly contagious, spreading primarily during milking. The initial critical step is the definitive identification of all infected animals. This is best accomplished through individual cow milk culture, which involves collecting milk samples from each quarter of suspected cows (those with high individual SCC records or positive California Mastitis Test results) and culturing them in a laboratory to specifically identify the pres....