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Abstract
Although bovine ephemeral fever is a non-fatal disease, it is considered as one of the viral diseases which cause un-neglected economic losses due to the great sharp decline in milk production; trials of treatment and mortalities in complicated cases. Egypt still threatened by the disease till the last few years and vaccination remains the corner stone in the disease control. Many live attenuated and inactivated BEF vaccines were developed and attracted the attention toward its efficacy.
The present study was carried out in a trial to answer some questions about the best schedule to vaccination of cattle against bovine ephemeral fever and some factors affecting its successful or failure. The obtained experimental results showed that:
1- The best vaccination schedule is that one in which calves were vaccinated with the live attenuated BEF vaccine followed by a dose of the inactivated one with 2 weeks in between.
2-Vaccination of pregnant cows with the inactivated BEF cell culture vaccine showed that all vaccinated animals did not show any abnormal clinical signs post vaccination and exhibited high levels of specific BEF indicating the safety and potency of such vaccine.
3-Following up the maternal immunity in calves born to vaccinated dams; it was noticed that the newly born calves exhibited high levels of specific BEF antibodies by the I week of age and began to decline by the 3 month age to reach their lowest level by the 5th month.
4-Vaccination of calves under different age stages and general health condition indicated that the suitable animal age (neither early nor senile) and good health enable the animal to be well responded to BEF vaccine as shown in tables (5&6). 5-Vaccination of calves with the inactivated BEF vaccine under the effect of some dmgs revealed that both of Oxytetracyclin and Berinil has an immune suppressive effect on calves vaccinated with the inactivated BEF vaccine where they showed the lowest titers of BEF antibodies (16&8 by SNT and 0.88 and 0.95 by ELISA) respectively. On the other side each of Vitamin E; BCG and Levamisol induced an immune stimulant effect in vaccinated animals.