Interrelationship of milk acute-phase proteins and casein percentage in cows and buffaloes subclinical mastitis

A total number of 62 clinically healthy dairy animals of three farms located in Kafr El Sheikh governorate, Egypt, were subjected to field screening surveys of subclinical mastitis (SCM) using California mastitis test (CMT). The obtained results revealed that 38.80% of quarter milk samples were positive to CMT. The most frequently major causative agents isolated from the positive CMT samples were Escherichia coli, Staphylococcus aureus, and environmental streptococcus spp. Acute-phase proteins (APPs), as immunological biomarkers for SCM, including milk serum amyloid A (mSAA) and haptoglobin (Hp) were measured using ELISA. A significant positive correlation was found between the severity of the mammary infection of cow's quarter milk samples represented in somatic cell count (SCC) and each of APPs and pH values. The correlation coefficient (R) between SCC and mSAA, Hp and pH were 0.54, 0.38 and 0.73, respectively. On the other hand, there was a significant negative correlation between casein percentage in milk of SCM cases, and each of APPs, pH and the presence of bacterial pathogens in the milk samples. The obtained results threw light on the inter-relationship between SCC, mSAA, pH value and casein percentage in milk of cows and buffalo suffered from SCM. The percentage of casein in milk is considered a significant accurate tool for diagnosis of SCM and this finding offers the farmers a cheap and fast selection for diagnosis of such disease. These results presented a specific structured view on the efficacy of different diagnostic tools of SCM in dairy herds.