الفهرس 
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Abstract
The present work was subjected to study pasteurellosis in sheep with special regarding to studying epidemiological pattern of the disease, monitoring the causative agents and a trial for vaccination of ovine pasteurellosis by combined vaccine of Pasteurella multocida and Pasteurella hemolytica locally isolated strains and the out comes of the this study were as the following:
1-The clinical aspects of pasteurellosis with different signs of respiratory manifestations in addition to the postmortem examination were done.
2-The epidemiology of ovine pasteurellosis in different age system and different localities in Dakahlia Province and all round the year were studied with high infection rate in young sheep of age less than 8 months and in high percentage in winter season
3-The biochemical and serological tests were done to the isolated strains of both Pasteurella multocida and Pasteurella hemolytica.
4-The isolation rate of both nasal swabs and pneumonic lungs showed that Pasteurella multocida isolated from 34 out of 465 nasal swabs from sheep showing respiratory manifestations in a ratio of 7.3% from nasal swabs and from 13 out of 68 positive pasteurella infected pneumonic lungs of dead or emergency slaughtered sheep in ratio of 19.11% while Pasteurella hemolytica isolates were isolated only from pneumonic lungs from 55 out of 68 positive pasteurella infected pneumonic lungs of dead or emergency slaughtered sheep in ratio of 80.88%
5-The isolated Pasteurella multocida strains 47 strains 34 of them from nasal swabs and 13 from pneumonic lungs of dead or emergency slaughtered sheep were capsular typed into A from 32 out of 47 isolates in ratio of 68.08%, B from 2 out of 47 isolates in ratio of 4.25%, D from 9 out of 47 isolates in ratio of 19.14% and untypable 4 out of 47 isolates while Pasteurella hemolytica isolates were typed into biotypes A 34 out of 55 in ratio of 61.81% and biotype T 21out of 55 in ratio of 38.18%
6-The rate of isolation of ovine pasteurellosis from nasal swabs was highest in winter season followed by, autumn, spring and summer in a ratio of 8.44%, 7.05%, 6.08% and 5% respectively for Pasteurella multocida and 0%for Pasteurella hemolytica.
7-While the rate of isolation of Pasteurella multocida and Pasteurella hemolytica from pneumonic lungs of dead and emergency slaughtered sheep was highest in winter, spring, autumn and summer respectively
8-The age played a significant role in susceptibility to ovine pasteurellosis as it is cleared that the young age lambs showed higher isolation rate of pasteurellosis as out of 44 positive samples 37 were positive for Pasteurella hemolytica the ratio is 84.09% in lambs and 18 out of 24 samples 18 were positive for Pasteurella hemolytica in adult sheep in opposite to pasteurellosis due to Pasteurella multocida as it is cleared from the ratio of lambs is 7 out of 44 positive samples 7 were positive for Pasteurella multocida in ratio is 15.9% in lambs and 6 out of 24 samples were positive for Pasteurella multocida in adult sheep in ratio of 25%
9-The control and vaccination of ovine pasteurellosis in this study were achieved by vaccination both twenty lambs of 3-4 months of age and also twenty pregnant ewes at 2.5-3 months of pregnancy, the lambs vaccinated by injection of 2 ml subcutaneous, two doses in between 3 weeks and the pregnant ewes were injected 4 ml subcutaneous route two doses in between 3 weeks
10-The titer of antibodies in vaccinated lambs and ewes rises from the second week of first injection and reach its maximum level at the second month and decline at the fifth month from the first dose
11-On the other hand the lambs born to vaccinated dams showed titer of antibodies against both Pasteurella hemolytica and Pasteurella multocida was highest in the first week then decline at the 8th week of age
In summary and conclusion we concluded that
1.Climatic stress in winter season is one of the most predisposing factors for ovine pasteurellosis.
2.P. multocida as well as P. hemolytica can be isolated from diseased sheep in the field
3.The importance of polyvalent pasteurellosis vaccine in preventing
that disease.
4.Vaccination of dams at late pregnancy which protect both dams and the borne lambs during the first two months of age and the vaccination of lambs 3-4 months of age which protect them for at least five months later and the vaccination twice a year may be a practical goal to ensure year round immunity for all ages of sheep.