VARIATION 201 



two years old ; " in 1773, five ; in 1774, two ; in 1775, 

 five; in 1776, two; and in 1777, two. The first nine 

 lambs were lambed within eleven months." l The 

 Country Gentleman reports the case of a sow that 

 produced twenty-three pigs at one birth. The above 

 examples are of Unusual cases of fertility and are so far 

 above the average fertility of the respective races of 

 animals that they represent a marked departure from 

 the established type. Other things being equal, those 

 races of domestic animals which are most fertile are most 

 profitable. One of the qualities of economic importance 

 which commends certain breeds to the practical farmer 

 is the quality of fertility. This is especially true among 

 swine and sheep. 



193. Variation in the milking function. The milk- 

 ing function in domesticated animals is of special interest 

 for the reason that it is probably the most valuable single 

 functional variation in the domestic animals. The im- 

 provement of the domestic cow in the direction of greater 

 functional efficiency in the production of milk and butter 

 has been little short of marvelous. This improvement 

 has not only resulted in developing an animal with a 

 capacity to produce enormous quantities of milk, but the 

 efficiency of the cow in the economic utilization of food 

 has been no less noteworthy. The highly improved 

 domestic cow is able to utilize the raw products of the 

 farm, consisting of grain, hay and grass, and produce 

 from these a larger amount of human food than any other 

 domestic animal. The high efficiency of the milk cow 

 as compared with the beef steer is clearly shown by the 

 records kept at the Missouri Experiment Station. 2 A 



1 Culley, "Live Stock," p. 123. 



2 Eckles, " Dairy Cattle," p. 6. 



