Rothamsted Symposium on Trace Elements 132 



turies. It is particularly common along the Oude Rijn river. 

 The soil in the affected area along the river is alluvial clay, at 

 some places mixed with sand or peat. 



A relation between the intake of manganese and the occur- 

 rence of grass tetany, as suggested by Blakemore et ah, could not 

 be established in the Netherlands (Table 27). 



Manganese in relation to steri/ity.— Sterility in rodents is often 

 considered as a result of a deficiency of manganese. In young 

 rats, kept on a manganese deficient diet, growth seems to be nor- 

 mal (7). The females showed a normal cycle and produced 

 normal young. However, the animals were unable to suckle the 

 newborn rats. In males, kept on a manganese deficient ration, a 



Table 27 : Manganese content of pasture grass in relation 

 to the occurrence of grass tetany: — 



Manganese content of pasture grass 

 mg p. 100 g, dry matter basis 



Grass tetany in spring (40 affected farms) 4.1 — 19.5 



Grass tetany in autumn (9 affected farms) 3-3 — 27.6 



No grass tetany (15 farms) 5-5 — 17.6 



"Lactation tetany" in Lincolnshire 



(Blakemore and assoc.) (11 affected 



farms) 54—132 



No grass tetany, in Lincolnshire (12 farms, 



24 samples) 1.6—9.2 



degeneration of the testes was observed, within 100 days, causing 

 complete sterility. According to recent experiments, rats showed 

 the features of manganese deficiency after feeding with a ration 

 rich in vitamin Bi (8). The Fi generation showed a reduced 

 fertility and disturbed lactation, moreover, some cannibalism. In 

 young mice, kept on a manganese deficient food, growth was 

 stunted, ovulation discontinued and heat seldom occurred (9). 



It remains to be seen whether the frequent occurrence of ster- 

 ility in male and female cattle (if not due to anatomical and 

 pathological disorders) may be connected with a relative manga- 

 nese deficiency (2, 10). It has already been shown that the 

 manganese content of pasture grass and hay, in the Netherlands, 

 will vary considerably depending on the condition of the soil (2). 

 Sometimes, the manganese values are as low as 2 mg in 100 g 

 (dry matter basis). These low values have been observed on 



