Abstract

The aim of this study was to examine the changes in milk constituents of Awassi ewes due to experimental infection with Staphylococcus aureus which was isolated from milk sample of clinically infected ewe with mastitis. We examined the relationship between somatic cell count (SCC) and total bacterial count (TBC) in normal and infected milk and to detect the changes in fractions of whey proteins before and after infection. A total of 240 samples of normal and infected milk from both left and right halves of udder of 6 Awassi sheep before and after infection were collected from tested healthy ewes. Milk samples were collected through 10 days before and after infection. Inoculum with Staph. aureus was done with effective dose (150 colony forming unit). Ten days later, samples were taken for 10 successive days to estimate TBC, SCC and milk constituents. The results showed that the samples collected from the left infected half of ewe udder, there was a significant increase in TBC, which followed by a significant increase in SCC. There was a significantly positive relationship between the TBC and SCC. The right half of udder after experimental infection of bacteria also showed the same significant results such as those in the left mastitic half due to transmission of the infection between the two halves, after inoculation of the left half.