Trace Elements in Calves Persistently Infected With Bovine Virus Diarrhoea Virus

Infections with bovine virus diarrhoea virus (BVDV) cause a wide spectrum of clinical syndromes throughout the world (1). The outcome of a transplacental infection includes foetal death, teratogenic effects and the birth of persistently infected (PI) calves (9) which are immunotolerant to the non-cytopathic strain of BVDV they harbour. Due to the tolerance such calves have no, or only a low level of, antibodies to BVDV. Persistently infected cattle may perform normally but they are often recognized as beeing small at birth, having a poor growth rate and an unthrifty appearance. They also seem to have an increased susceptibility to other infections (2) and are the cattle population at risk of developing the fatal condition mucosal disease (11). It is far from understood why PI cattle usually are small and have a retarded growth. Obviously, in some cases, this can be explained by the presence of chronic bacterial infections, which in turn may be attributed to a immunosuppressive state of the calves since BVDV infects the cells of the immune system. However, there are PI calves without signs of bacterial infections that are small. Since Srinivas et al (10) report that human patients with viral infections have altered concentrations of trace elements it is tempting to speculate that also a persistent BVDV infection can interfere with the body metabolism. The aim of this study was to examine the serum concentrations of copper, zinc and iron during persistent infection with BVDV in calves. Further, the levels of these trace elements levels were related to the heart girth of the calves.