Hooo-Hooo Volume 11 Nr 3 - Page 10

WildLife Group of the SAVA to the carriers used in the injectable multimineral preparations. 1. Selenium Selenium deficiency is common in many parts of South Africa due to low soil and/or foliage levels and is usually associated with conditions such as white muscle disease, cardiomyopathy, stillbirths, retained placenta and infertility. Selenium is still commonly supplemented in wildlife using injectable multimineral preparations and incidents of toxicity most commonly occur in this situation, frequently associated with errors in dose calculation. The stand out features of selenium toxicity are usually myocardial necrosis and massive hepatic necrosis. There is a potential common mechanism of cell injury that results in myocardial necrosis with both Se deficiency as well as Se toxicity. Therefore, in cases of acute myocardial necrosis it is imperative that tissue Se concentrations are quantified before a diagnosis of selenium deficiency / toxicity is made. In this example in an antelope where an injectable selenium product was used at an over-estimated ten- fold dose is characterized by extensive centri-zonal to periacinar hepatic necrosis with haemorrhage (figures 1 and 2). Figure 1: Antelope liver with marked hepatomegaly (note rounded borders) and mottled red appearance due to haemorrhage and necrosis. 10 Figure 2: Antelope liver cut surface accentuating the mottling due to extensive hepatic necrosis with haemorrhage. 2. Copper The liver is the primary storage organ for copper and is considered the best indicator of copper status. A liver store of copper in the fetus is important to meet post-natal requirements as milk is poor source of copper in most species. In the perinatal period copper deficiency has been associated with immunodeficiency, anaemia, musculoskeletal degeneration, skeletal abnormalities (osteochondrosis, osteoporosis), in-utero growth retardation and hypomyelinogenesis. Coat color changes and cardiomyopathies are described with deficiencies in adult animals. A copper deficiency associated myocardial necrosis resembling falling disease in dairy cattle, has recently been documented in a roan antelope (figure 3). Figure 3: Roan antelope heart showing extensive endocardial and myocardial suggilation hemorrhages. On hitopathology there was severe myocardial necrosis. (Image courtesy of Champion Wildlife)