Abstract:
A study was carried out to detect subclinical mastitis by California
mastitis test, to compare the different mastitis indicators, to identify the
bacterial agents responsible and their antibiogram and to assess the efficacy of
different treatments adopted.
The occurrence of subclinical mastitis in organized farms and in and
around Thrissur was found to be 25.17 per cent, after examining 1053 quarter
milk samples by California mastitis test.
A total of 265 milk samples were subjected to somatic cell count,
modified Whiteside test and modified Aulendorfer mastitis probe test. These
tests showed a positive correlation with somatic cell count.
Staphylococcus aureus was found to be the chief etiological agent
followed by coagulase negative staphylococci, coliforms and Streptococcus
agalactiae.
Chloramphenicol and enrofloxacin were found to be the most effective
antibiotics against bacterial isolates from mastitis cases and sulphadiazine and
trimethoprim the least effective.
In vivo studies revealed that oxytetracycine is more effective followed
by enrofloxacin and amoxycillin-cloxacillin combination. But the
bacteriological cure was same for all the treatments.
The twenty four Staphylococcus aureus isolated from clinical mastitis
were grouped into seven different genotypes using RAPD analysis. The four
Escherichia coli isolates gave single RAPD pattern. S. aureus genotype a was
found to be more prevalent.
