122 THE MANAGEMENT AND FEEDING OF CATTLE 



They should be able to serve from 50 to 100 cows 

 in a year without injury to themselves, more especially 

 when the times of service are not too frequent. It is 

 usually impossible, however, to so arrange that the times 

 of service will cover all the year. The owners of herds 

 desire to have the bulk of the calves come within a few 

 months, and because of this the tax on the procreative 

 powers of the bull is overmuch at certain seasons and 

 none at all at other seasons. The aim should be so to 

 use males in service that are highly valuable, that 

 they shall not be overtaxed. The common practice, 

 therefore, of not allowing them to serve common cows or 

 cows that are simply to be renewed in milk production, 

 regardless of any value that the calf may possess, is to be 

 commended. Any excess in service tends to shorten 

 the period of generative power in bulls, and unnecessary 

 service should be avoided because of the drain which is 

 thus put on the vital powers. 



Ordinarily when bulls have passed the meridian of 

 vigor, they should be disposed of, for the reason, first, 

 that they are less able than formerly to transmit in the 

 same degree the most desirable qualities; second, that 

 they become too heavy and sluggish for some kinds of 

 service; third, because of the increased cost of feeding 

 them; and, fourth, because of the less price that will be 

 obtained for them when sold for meat when they become 

 aged. In the case of animals whose transmission has 

 been of a high order, it may be wise to retain them in 

 service as long as they retain sure begetting power. 

 Progeny from them may be more desirable than progeny 

 from younger sires, but without marked prepotency. 

 The age to which bulls are able to breed successfully 

 varies greatly. Instances are on record in which pure- 

 bred bulls have begotten progeny until beyond the age 

 of 15 years, but usually it is not profitable to retain them 

 in service beyond the age of eight or nine years. The 



