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Passive immunity transfer in Holstein cows immunized and not immunized against rotavirus: hematological parameters, immunoglobulins, acute phase proteins and serum and mucosal immune responses of calves

Abstract

Bovine rotaviruses (BRV) are the main etiologic agents of calf enteritis, comprising one of the most important causes of economic losses in cattle-raising all over the world. Once the main strategy of protection against diarrhea caused by BRV consists in the vaccination of the pregnant cow and the intake of a colostrum containing high levels of specific anti-rotavirus immunoglobulins by the calves along the first week of life, the knowledge of the effectiveness of available vaccines against stirps found under field conditions is ultimately important. In the face of controversial information verified in the literature, the aim of the present study is to evaluate the humoral immune response of cows immunized against rotavirus with inactivated commercial vaccine by immunonzymatic assay (EIE), and for this purpose, two groups and four subgroups will be formed: Group V1: 24 cows immunized with inactivated commercial vaccine against BRV, with two subgroups - V1n (12 first parturition heifers) e V1v (12 second and on parturition cows) and Group V2: 24 cows non-immunized against BRV, with two subgroups - V2n (12 first parturition heifers) and V2v (12 second and on parturition cows). The female calves will also be allotted into groups and subgroups according to the mother's distribution, for the evaluation of humoral immunity in serum and mucosa after colostrum intake, the kinetics of hematologic, biochemical and blood gas analysis parameters and the acute phase proteins response, and also the monitoring of rotavirus excretion in the feces along the first 4 months of life. The data will be evaluated by variance analysis and the contrast between mean values will be evaluated using the Tukey's test, considering the results significantly different when P<0,05. (AU)