Milk Osteopontin Levels in Egyptian Baladi Goats with Mastitis Caused by S. aureus and E. coli

Mastitis in goats is responsible for serious consequences on milk composition and udder morphology. The present study aimed to determine the effect of mastitis on milk osteopontin (OPN) level and microbiological quality as well as morphological and pathological changes of the udder. Thirty dam's Baladi goats (15 apparently healthy and 15 having clinical signs of mastitis) were examined for detection of mastitis by clinical and laboratory examination including inspection, California mastitis test (CMT), bacteriological and pathological examination. The results revealed that all 15 apparently healthy goats were CMT negative, all udder measurements were significantly higher in goats suffered from mastitis than healthy goats (P<0.05), while the teat length were comparable between both groups (P>0.05). Nine isolates (60%) were E. coli and 6 isolates (40%) were S. aureus in clinical mastitis milk samples. All isolated S. aureus (n=6) were positive for 23S rRNA, and virulence genes sea, seb and coa. On the other hand, all E. coli strains (n=9) possessed virulence genes eaeA, stx1, and phoA and none of them possessed stx2. OPN level were significantly higher in both the S. aureus mastitis and E. coli mastitis than the healthy goats (P<0.05), while the OPN level were comparable between S. aureus mastitis and E. coli mastitis (P>0.05). Histopathological examination of tissue samples obtained by surgical biopsy technique showed severe tissue damage induced by bacterial infection, massive fibrosis of interstitial tissues, atrophy of milk acini, and infiltration with inflammatory cells.