XIV 
PIGS, CATTLE, OSTRICHES 
1 37 
averaging over a cow a year, but pure-bred importa¬ 
tions will probably only average four to five years. 
The bull should be kept in good condition ; the extra 
cost will be many times repaid in the improvement of 
calves. Overhead protection in yards is desirable, 
though not absolutely essential; otherwise the greater 
the freedom and absence of pampering given to the 
animals the better for their general health. 
Three diseases in particular have, up to the present, 
militated against the success of stock-breeders : 
rinderpest, East Coast fever and gastro-enteritis. Of 
these rinderpest is the most virulent. In countries 
where it has not previously existed the mortality on 
its introduction reaches 90 or 95 per cent. Where, 
however, the disease is endemic it sometimes falls as 
low as 10 per cent. Rinderpest first visited British 
East Africa in 1892, and for the next two or three 
years caused enormous damage, not only to cattle, but 
also to wild game. Rinderpest is an inoculable 
disease, which happy circumstance we owe to the 
discoveries of Koch in 1897. In 1910-11 rinderpest 
reappeared in the Protectorate, and was met at once 
by the introduction of serum, of which nearly 24,000 
doses were issued. Generally speaking, such inocula¬ 
tions were successful, but in some cases large mortality 
ensued. There is little doubt that this latter result 
was due to the depreciation of the serum. It may 
be stated nowadays with some confidence that settlers 
need no longer look on this disease with excessive 
dread. 
East Coast fever is a tick-born disease, being carried 
by two or more varieties of tick, the chief offender 
being the common brown variety. The difference 
of mortality is very great, but in the more serious 
