125 Seekles: Trace Elements in Pastures and Animals 



elements) in the blood is often considered in connection with 

 "deficiency." However, when doing so many problems arise. 

 We, therefore, carried out balance trials in which copper sulfate 

 (and salts of other trace elements) were administered orally and 

 experiments in which copper, with different types of chemical 

 binding, was injected intravenously. Attempts have been made 

 to obtain a picture of the extent of saturation of body tissues 

 before and after treatment. Figure 24 shows the results of a 

 balance trial in which copper sulfate was added to normal food 

 (hay and concentrates). This experiment was carried out with a 

 normal heifer. 



In the period previous to the administration of copper sulfate 

 the intake of copper was shown to be almost equal to the excretion 

 of copper in the faeces. Only traces of copper left the body 

 through the kidneys. 



As might be expected, the excretion of copper in the faeces 

 increased during the period of copper addition as all added copper 

 was not absorbed. The (alkaline) urine was shown to contain 

 only traces of copper. No increase of the copper level in the 

 blood occurred. This indicates a condition of non-saturation of 

 the body tissues. 



Over a fortnight, previous to the administration of copper 

 sulfate, a retention of 40 mg of copper was calculated. However, 

 it seems to be doubtful whether this is a real retention as the 

 traces of copper leaving the body by the kidneys had not been 

 taken into account. For the three week period of copper sulfate 

 addition, together with the six day period following this addition, 

 a retention of 1590 mg of copper was found, i.e., about 17 per 

 cent of the quantity of copper added. For three days no records 

 were kept. For the next period of seven days a retention of 77 

 mg of copper was recorded. Apparently about 50 mg may be 

 considered to be the real retention for this period. 



To obtain an idea of the extent of saturation of the animal 

 body with copper, determinations of copper have been carried out 

 in 55 samples of liver originating from normal cattle aged P/i 

 years and older. These samples were collected in wartime. The 

 content of copper ranged from 5 to 194 mg per kg (dry matter 

 basis). A classification of the results is presented in Table 23. 



We learn from this table that about 60 per cent of the livers 

 of normal cattle had a copper content ranging from 5 to 15 mg 



