EN
Milk neutrophils and macrophages from mastitic sows were examined for membrane receptors for Fc portion of immunoglobulin G and complement. Also the spontaneous and stimulated reduction of nitroblue tetrazolium (NBT) by these cells was determined. The percentage of neutrophils but not macrophages with immunoglobulin receptor significantly decreased during mastitis. Percentage of both neutrophils and macrophoges carrying complement receptor was lower in mastitic milk. However, absolute numbers of neutrophils and macrophages with those receptors were similar in normal and mastitic milk. Milk phagocytes from mastitic sows showed diminished ability for NBT reduction. Consequences of observed alterations in papulation of milk phagocytes during mastitis in sows is discussed.