Analysis of factors influencing the transfer of passive immunity in the donkey foal

Abstract

An inadequate colostrum intake results in Failure of Passive Transfer, a condition that makes foals more susceptible to potentially fatal infectious diseases. The aim of the study was to evaluate the transfer of passive immunity in the donkey, using electrophoresis as main diagnostic tool. A group of 20 Ragusana crossbreed jennies (age 3–19 years) and their foals were enrolled. The γ-globulin content of colostrum and dams’ and foals’ sera was measured, then the effects of foals’ season of birth and age and parity of the jennies on γ-globulin concentration and on the efficiency of the immune transfer were evaluated. Influence of season factor was analysed by grouping the data on the basis of foaling season (spring, summer or autumn). For the evaluation of age and parity the jennies were divided into two categories: younger/older and primiparous/pluriparous, respectively. Finally, the possible association of these factors with the efficiency of the immune transfer was investigated. According to the horse reference range, 70% of donkey foals showed complete transfer of passive immunity (γ-globulin >8 g/L; 13.15 ± 4.60 g/L) and 30% had a partial Failure of Passive Transfer (γ-globulin 4–8 g/L; 5.78 ± 1.29 g/L), but without showing clinical signs. Age and parity did not significantly affect passive immunity transfer, nor did the season. Total Protein values measured through refractometer were positively correlated to the γ-globulin content (r = 0.69; p < .01), confirming the possibility to use this diagnostic tool in the field as a first, inexpensive approach for colostrum evaluation. Highlights The transfer of passive immunity in the donkey is still poorly investigated. We investigated the transfer of passive immunity in donkeys using electrophoresis. Influence of age, parity and season on the immune transfer has been evaluated.