TDK conference 2016

There are believed to be two main causes of the exertional rhabdomyolysis in horses. Those two are incorrect nutrition and genetic. In our research, we have been looking at the nutritional factors with an emphasis on the impact of selenium (Se) and vitamin E deficiency, electrolyte imbalances and lack of sufficient energy. The symptoms of different myopathies are quite similar to each other, they often include muscle rigidity and myoglobinuria. A form of exertional rhabdomyolysis occurs endemically in the district of Hargita, Transylvania. In two villages that are located at the highest points of the region the prevalence of the disease is about 17-23%, while it remains under 2% at the villages nearby. The goal of our study is to reveal the cause of the high occurance of the disease in that given high altitude area. Horses were randomly selected from four villages of that geographic area but then allocated into groups A and B based on their location. In group “A” 20 horses were included from the two

high altitude villages and in group “B” horses were from the surrounding lower altitude

settlements. Their forage consisted of local hay, and in periods of hard work additional barley or oats. No minerals, vitamins or other supplements were added. At the time of sampling none of them showed clinical signs. Blood samples were collected from the jugular vein, in order to be analyzed for Se and vitamin E levels. Samples of hay, grains and soil had also been collected in order to check the mineral contents. Mineral content analysis was completed by spectrophotometry. In the past year, 7 horses from group A, and 1 horse from group B showed clinical signs of the disease. There was a significant difference between the two groups in their blood Se levels and the mineral contents of the hay they were fed.

In group A all horses affected by the disease had relatively low Se levels, however in group B there was one horse showing sings of rhabdomyolysis with adequate blood Se level. The cause of low blood Se could be high levels of Zn, Pb, Fe, Mn in the hay, which can reduce the intestinal absorption of the Se by complexation. Also, the levels of Na and K in the hay were also noticed to be low, and this can contribute to developing rhabdomyolysis as well. 65 % of horses in group A did not show any clinical signs despite of low Se levels. Afterall, it could be stated that low selenium levels could affect the frequency of clinical manifestations, and the severeness of the symptoms, but other non-nutrition related factors, like genetic disorders have to be considered as well.