Evaluation of some milk enzymes as biomarkers in detection of bovine subclinical mastitis

Abstract

The present study was carried out on One hundred and fifity , one day old chicks to evaluate the immunogenicity of multivalent pilus vaccine containing pili from the three common pathogenic serotypes of E. coli (O1, O2 and O78). Nienty vaccinated birds at 14 days & 28 days of age by 0.5ml s/c of pilus vaccine at base of neck and 60 unvaccinated were divided to 4 subgroups (30 vaccinated & 20 unvaccinated) were used for challenge two weeks after second dose . Each group was challenged each with one type of E.coli strains O1 , O2 and O78. Blood samples were collected during the experiment from the flocks one week before vaccination and weekly for 7th week after the first dose of vaccination for evaluation of immune response by using ELISA test. The prepared multivalent E.coil pilivaccine from combination of O₁, O₂ and O₇₈ E.coli strains were seemed to cover good range of protection and has been elicited a protective immune response against virulent E.coli challenge with homologous and heterologous strains. Strong correlation was found between antibody response vaccinated groups and low lesions score that indicated a good protection.