131 Seekles: Trace Elements in Pastures and Animals 



jection in quantities of 30 mg of copper, did not result in any per- 

 manent increase of the copper content of the blood serum. The 

 copper level of the blood serum seems to vary rather considerably. 

 Apparendy, the excess of copper injected is rapidly transferred to 

 the tissues (Table 25). 



In order to obtain an idea of the extent of saturation of the 

 liver, determinations of copper were carried out in samples of 

 liver originating from normal and nearly normal horses (Table 

 26). 



The copper content of the liver of normal, adult horses shows 

 considerably less variation than the copper values of cattle liver. 

 Values up to 10 mg of copper per kg of liver (dry matter basis), 

 which were observed in catde in 51 per cent of the cases ex- 

 amined, did not occur in horses. 



Evidence has been obtained from the examination of a small 

 number of livers, viz., 10 samples, originating from horses in foal, 

 or shordy after deliverance, that there is a tendency towards lower 

 copper values. In surgical cases there seems to be, however, a 

 tendency in the opposite direction. In a new-born foal the cop- 

 per content of the liver was shown to be 10 to 15 times as high 

 as in adult horses. 



Manganese in Relation to Grass Tetany and Sterility in 

 Cattle. The Occurrence of Manganese in Pasture Grass and 

 Hay in the Netherlands:— 



Manganese in relation to grass tetany.— The observations of 

 Blakemoke, Nicholson and Stewart, suggesting that in Lin- 

 colnshire "lactation tetany" in catde occurs under conditions in 

 which the manganese intake is likely to be at its maximum (6), 

 suggested an investigation concerning the possibility of a parallel- 

 ism between the occurrence of grass tetany and high manganese 

 content of certain pastures in the Netherlands. If a correlation 

 would be found, this would indicate a third disease among ani- 

 mals due to an excess of trace elements— alkali disease (Se) and 

 the scouring of cattle on the "teart lands" of Somerset (Mo) are 

 already known. 



Just as in England, most grass tetany cases occur, in the Neth- 

 erlands, when the cows are first turned out to pasture in the 

 spring. A second, though less severe outbreak of grass tetany 

 occurs in August and September. 



This kind of grass tetany has been known in Holland for cen- 



