Total and differential somatic cell counts in secretions from noninfected bovine mammary glands: the peripartum period.

In 3 cows, mean total somatic cell counts in mammary gland secretions were greater than 1 x 10(6)/ml from 25 days before parturition until parturition. Cell population decreased rapidly after parturition, and 10 days after parturition, all counts in foremilk were less than 1 x 10(5)/ml. Macrophages and lymphocytes in equal numbers were present in secretions before parturition. Starting approximately 5 days before parturition, lymphocytes decreased so thay they were absent at parturition. Nearly all cells in secretions after parturition were macrophages. Polymorphonuclear neutrophils were in low numbers or absent from all secretions.