of the SAVA
to the carriers used in the injectable multimineral
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.
Figure 2: Antelope liver cut surface accentuating the mottling
due to extensive hepatic necrosis with haemorrhage.
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)