MODE OF ACTION AND OCCURRENCE OF TRACE 



ELEMENTS IN PASTURES AND IN THE BLOOD 



AND LIVER OF FARM ANIMALS 



hy L. Seekles, Ph.D., 



Laboratory for Veterinary Biochemistry, Urxiversity of Utrecht, Netherlands 



About the year 1930, Sjollema for the first time reported, 

 amongst the cattle on the North East diluvial part of Holland, 

 which is of Scandinavian origin, conditions of deficiency due to 

 a low copper content of the pastures (1). For the southern 

 diluvium these deficiences have not been reported, and it seems 

 doubtful whether they occur. This diluvial soil consists mainly 

 of slate and other material, originating from mountain areas along 

 the river Rhine and of the Ardennes, mixed with fine material 

 of Scandinavian origin. 



During recent years, disorders in cattle frequently occurred, 

 although there is no real shortage of trace elements, e.g., copper, 

 in the pasture (2). This may be called "conditioned deficiency" 

 and it suggests a combined influence of the absorption and the 

 metabolism of one or more trace elements. An interaction of 

 trace elements with various chemical substances in the food and 

 in the animal tissues may also play a part. The disorders are 

 found in the Netherlands, both on the North East diluvium and 

 on the alluvial parts, especially on peat. Presumably, they also 

 occur on the southern diluvium but definite data are not yet avail- 

 able. Recently, a similar kind of hypocupremia in catrie has been 

 reported for Great Britain by Allcroft (3). 



In order to establish the nature of these "conditional deficien- 

 cies" it is necessary to study the basic importance of the trace 

 elements and their function in the metabolic processes of the 

 animals concerned. This enquiry is primarily of a scientific 

 nature as its results will further our knowledge of the nature of 

 the above mentioned phenomena. The enquiry also has its 

 practical aspects as may be illustrated by the following example. 



