Acute phase protein response in cows with staphylococcus aureus subclinical mastitis

Abstract

Inflammation at a local and systemic level is a complex process that involves the synthesis of acute phase proteins (APPs) with multiple functions in the regulation of the inflammatory process itself. The aim of this work was to define local and systemic APPs response induced by natural Staph. aureus subclinical infection of the mammary gland in dairy cows with a different number of quarters involved. Midlactation dairy cows (n=30) were devided into three groups. First group were cows with bacteriologically negative milk samples (BN group), second group were cows with one quarter infected with Staph. aureus (SaQ1) and third group were cows with two quarters infected (SaQ2). Milk samples were analyzed for inflammation indicators: serum amyloid A (SAA) and somatic cell count (SCC). Serum samples where analyzed for SAA, haptoglobin (Hp), ceruloplasmin (Cp) and albumin concentration. Also, complete blood count (CBC) was done. SCC and SAA increased in quarter milk samples, being lowest in the BN group and highest in the SaQ2 group. In serum samples, SAA, Hp, Cp and albumin concentrations were significantly higher only in the SaQ2 group comparing with BN group. The leukocyte number, as well as hemoglobin concentration were in the physiological range in all three groups of cows. These results confirm that the magnitude of tissue injury has an impact on APPs concentration. They also demonstrate that cows having Staph. aureus sublinical infections of two mammary quarters have a more pronounced systemic APP response than cows with only one quarter involved.