The Effect of Immunization against Theileriosis on the Reproductive Function of Boran/Friesian Cross Heifers Preliminary Study

Abstract

Bovine theileriosis, caused by Theileria parua is the most important disease of livestock in East and Central Africa. T parva infection is associated with high morbidity and mortality rates (Brocklesby et at., 1961). To date, the only method of immunization against T parua is by infection with sporozoite stabilates and treatment with oxytetracyclines (Purnell, 1977; Radley, 1978, 1981). This method has been adopted and is being used in several countries in the region where theileriosis is endemic. Currently, long-term programmes have been formulated in these countries with the aim of protecting a larger proportion of animals at risk. However, T parva infected animals have been shown to suffer from loss of reproductive function (Rumberia et at., 1993). In view of these findings and anecdotal reports linking theileriosis with abortions and long anoestrous periods (Oteng, 1977), this study was undertaken to determine if immunization has any adverse effect on reproductive function in cattle.