Preparation of an Inactivated Polyvalent Vaccine Against Common Bacterial Pathogens Causing Bovine Mastitis and Evaluation of its’ Immunizing and Therapeutic Potentials
Preparation of an Inactivated Polyvalent Vaccine Against Common Bacterial Pathogens Causing Bovine Mastitis and Evaluation of its’ Immunizing and Therapeutic Potentials
Rafik Soliman1*, Rafik H. Sayed2, Hanan Mahmoud3, Heidy Abo El-Yazeed1, Marsell Saad1, Shaimaa Abdelall Elsaady2, Khalid Sh3
ABSTRACT
A total of 3608 quarter’s milk samples were aseptically collected form 902 Friesian cows, of which 68 (7.54%) suffered from clinical mastitis and 120 (13.3%) proved to suffer from subclinical form of mastitis. Bacteriological examination of the milk samples revealed the isolation of the following pathogens from clinical and subclinical mastitis cases, respectively; E. coli (29.41% and 29.2%), S. aureus (19.12% and 25%), Str. agalactiae (16.2% and 16.6%), Str. dysgalactiae (14.7% and 20%), Str. uberis (7.3% and 2.5%), K. pneumoniae (4.4% and 3.3%), Str. fecalis (4.4% and 0%), Str. pyogenes (2.9% and 0%) and Pseudomonas aeruginosa (1.5% and 3.3%). Among the recovered E. coli serotypes, the serotype O111:K58 (B4) was the most prevalent (38.2%). An inactivated polyvalent autogenous mastitis vaccine was prepared from the most encountered bacterial pathogens, namely, E. coli, S. aureus, Str. agalactiae and Str. dysgalactiae. The selected strains for vaccine preparation were inactivated with a predetermined minimal lethal dose of gamma radiation (4krad kGy/min) and the bacterial inactivation was assured using bacteriological examination. Two experiments were done; in experiment No.1, the immunizing efficacy of the prepared vaccine was evaluated in two groups of apparently normal lactating cows (4 cows /group). The first group was unvaccinated and kept as a control group all over the study while the animals in the second group were immunized with the prepared vaccine. Vaccinated cows received two vaccinal doses (5ml) at two week interval. The vaccine was injected subcutaneously in the brachiocephalic muscle. In experiment No. 2, the therapeutic potential of the prepared vaccine was tested in four groups of lactating cows suffering from subclinical mastitis. The first group was left untreated. The second group was treated only with antibiotics (neomycin and penicillin) and the third group was immunized with the prepared vaccine alone. The fourth group was treated simultaneously both with the antibiotics and the prepared vaccine. In both experiments blood and milk samples from cows in all groups were collected before and at 2 weeks intervals post immunization and/or antibiotic treatment. Vaccinated cows in the two experiments did not develop clinical mastitis during the whole observation period that extends up to 20 weeks post treatment. The total immunoglobulin concentration (g/dl) measured four weeks post immunization was significantly higher in the serum and milk whey of immunized cows as compared to the non-immunized cows (P<0.01). The highest ELISA titers against E. coli (O111), S. aureus, Str. agalactiae and Str. dysgalactiae were recorded 4 weeks post immunization in the serum and milk whey of immunized cows as compared to the non-immunized group. In cows suffering from subclinical mastitis the vaccination and /or antibiotic treatment induced significant decrease in the somatic cell counts (P<0.01). Also, significant reduction of the CFU/ml of the examined milk samples (P<0.01) and spontaneous recovery were recorded. No case proceeds to clinical mastitis for an observation period of 20 weeks. These finding showed that the prepared vaccine is potent and able to protect cow against mastitis and able to reduce the disease severity in infected cows.
To share on other social networks, click on any share button. What are these?
