Browsing by Subject "Soil eating"

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Geophagie bei Pferden : Ursachen und Hintergründe
(2016) Bauderer, Patricia; Hölzle, Ludwig
Geophagy, the ingestion of soil, is a behavior practiced by a lot of animals includ-ing birds, carnivores, elephants, and primates as well as humans. However, ge-ophagy in horses is poorly documented. In the present study reasons and back-grounds for geophagy in horses especially in terms of mineral feed intake were examined. A total of 36 horses were selected and assigned to three groups. Group G consisted of 24 horses that showed geophagy. Seven horses which never showed geophagy, although they had the possibility to eat soil on pasture were assigned to control group K I. The control group K II consisted of five stal-lions that had no ability to eat soil because of their groom. Blood samples of the horses were taken and minerals like calcium, phosphorus, magnesium, potassium, sodium, iron, copper, selenium and zinc were deter-mined. At the same time the licks of the horses were also physico-mineral-chemically analyzed for their contents of minerals. Horses of the groups G and K I showed significantly higher calcium levels in the blood samples than horses of Group K II. The investigated licks contained high calcium concentration. However, no significant correlation between the calcium contents in soil and blood samples could be found, because the horses of control group K I had also high blood values, even though no geophagy was obvious in these animals. Similar observations were made with the element phosphorus. Many horses showed low copper levels in blood serum irrespective of the group. . However, geophagy could only be observed in horses of group G, therefore cop-per deficiency is, thus, effectively excluded as reason for geophagy. This result was further supported by the low content of copper at the licks of the horses. Interstingly, most horses of group G, which showed geophagy, showed a low zinc contents in the blood serum. The reason for this could be that the horses of this group were not fed with oats or straw. All licks analyzed showed high amounts of zinc (above average or high). A relationship between zinc supply of horses and zinc contents of the licks were given here. However, the intake of soil could not improve zinc supply of the horses, because high levels of calcium and phosphorus make zinc absorption more difficult. The affected horses showed no clinical signs of deficiency. Nevertheless, it can be assumed that the horses are trying to improve their supply of minerals by ge-ophagy.