Abstract
Vaccines are the most effective method for animal immunization against infectious diseases. This work aimed to study the effect of some vaccines commonly, used in sheep, on some innate immunological and clinicopathological parameters. For this purpose, forty-five Barki ewes were housed at the sustainable development Centre of Matrouh resources farm. They were divided into: Pox group: fifteen ewes were injected with live-attenuated pox vaccine. FMD+RVF group: fifteen ewes were injected separately with two vaccines (polyvalent inactivated foot and mouth disease oil adjuvant vaccine and rift valley inactivated vaccine). Ultrabac group: fifteen ewes were injected with 2.5 ml bacterial toxoid (Ultrabac® 8, Zoetis). Blood samples were collected then immunological and clinicopathological parameters were estimated and statistically analyzed. The three studied groups showed a significant (P˂0.05) increase in the activity of pro-inflammatory cytokines, ceruloplasmin, and oxidative stress, associated with serious clinicopathological changes (anemia, leukocytosis, increased liver and kidney functions, hyperglobulinemia, hypoalbuminemia). These alterations peaked on the 14th day, and subsequently moved towards their baseline values. They were more prominent and sustained in the Ultrabac group (with selective hyperproteinemia) than in the other two groups. The FMD+RVF group displayed a higher degree of cytokines activity, APR, oxidative stress, leukocytosis, and AST values than the Pox group. Conclusion: Sheep vaccination evokes an innate immune response which results in clinicopathological changes. These alterations are more pronounced in bacterial and combined vaccines than viral and single vaccines. The first 14 days after vaccination is a critical period and needs proper management.

Key words: Sheep vaccines; Pox; FMD+RVF; Clostridium; Clinicopathological alterations.