420 SCIENCE IN AFRICA 



bulls it is easy to alienate native opinion, since the small bull is 

 often active, and if only large lazy bulls are left in a herd, many 

 COWS may remain infertile for long periods, a result which, though 

 desirable for reducing the head of stock, is unsatisfactory from the 

 native's point of view. Moreover, before embarking on wide-scale 

 castration of this kind, it is necessary to decide whether the stock 

 is to be selected for beef, milk, or draught, since a breed poten- 

 tially useful for one of these purposes may be spoiled by faulty 

 selection. Different policies may be desirable in different parts of 

 a single territory. In the tropical parts of Africa it appears desir- 

 able to breed local stocks selected for qualities appropriate to 

 varying economic conditions, and for resistance to different dis- 

 eases. In some parts of the continent where reduction in numbers 

 is desired it might even pay to breed for sterility and to aim at 

 having a certain proportion of sterile animals in every herd. In 

 order to indicate the scope of the problem and the possible methods 

 of attack, the work done in some of the territories may be described. 



In Northern Rhodesia the cattle industry has been built up under 

 protection from outside competition as an incidental result of 

 disease restrictions. The recent development in copper mining has 

 created a large market, but restrictions, especially in connection 

 with foot-and-mouth disease, hamper the sale of stock. Consider- 

 able doubt is expressed, moreover, whether the industry could 

 hold its own if free imports from Southern Rhodesia and else- 

 where were permitted. Meanwhile, opportunity is being taken to 

 improve stock by breeding, partly on the lines described above in 

 connection with Southern Rhodesia. There is a government herd 

 organized into subherds for experiments in grading with bulls of 

 English breeds, the progeny being compared for rate of maturing, 

 weight increase, milk yield, and resistance to diseases. Surplus 

 stock either pure-bred or graded is sold to stock-owners. 



In Tanganyika the chief problem is the redistribution of native 

 herds to avoid overgrazing, which is discussed later. Although 

 breeding naturally enters into this work, the nutritional aspects 

 have been especially stressed by the Department of Veterinary 

 Science and Animal Husbandry. Breeding experiments have been 

 carried out by the department particularly with a view to pro- 

 ducing a good type of dairy cow primarily for non-natives 



