192 SIR ARNOLD THEILER 



lime. As soon as the animals were dosed ^tith calcium 

 phosphate (the chief component of bone meal), or phos- 

 phorus, pica again disappeared. 



In another experiment pica was produced by feeding 

 cattle with a ration deficient in phosphorus. A num- 

 ber of bone-cravers were despatched from Armoedsvlakte 

 to Onderstepoort and kept in a stable. After a short 

 time the craving for bone entirely disappeared. They 

 were then fed on chatf and fanko which hardly contain 

 any phosphorus and slowly pica reappeared until 90% 

 Avere affected. Again they were given phosphorus, and 

 within a few weeks pica totally disappeared. There can 

 not be the slightest doubt that pica was caused by a lack 

 of phosphorus in the food and that the craving can be 

 renft)ved by feeding the animals with this substance. 



The next point for consideration is the form in which 

 phosphorus should be administered. Hutcheon recom- 

 mended bone meal and it has been shown that bone meal 

 fed in a quantity of ^ to 1 lb. per day removed pica with- 

 in a few weeks. Whalebone meal gave the same result, 

 but it took somewhat longer since it contains less phos- 

 phorus. Bone oil is useless ; but dissolved bone meal or 

 calcinated bones (bone ash), given in a dry form or 

 dissolved, are all equally efficient in the elimination of 

 pica; bone ash is less efficient than the other substances 

 mentioned. 



The best way to administer the bone meal is to feed the 

 cattle at first with a larger quantity (4 or 1 lb. per day) 

 for 2 or 3 weeks, until pica has nearly disappeared and 

 then to continue with a smaller quantity' (^ lb. per day). 

 The pica will not reappear. At Armoedsvlakte 50 

 draught oxen were fed on bone meal in this way and not 

 a single one contracted lamziekte; the feeding with bone 

 meal must not be stopped too soon or the pica will re- 

 api>ear. 



It is not necessary to feed with bone meal all the 

 year round. During the winter pica is at its height, but 



