FARM ANIMALS 225 



farmers from seven to ten weeks. It is ordinarily 

 best to take away two or three of the strongest 

 pigs and thus gradually remove them from the 

 sow so that no trouble arises in the way of inflam- 

 mation of the udder. 



The sow may be depended upon to carry her 

 pigs ten weeks, the actual time varying from 

 one hundred to one hundred and fifteen days. 

 The weight of pigs at birth varies from one and 

 one-half to three pounds with an average of 

 two and one-half pounds. The total weight of 

 litters from prolific sows is usually about 15 

 pounds. 



Age in Relation to Cost and Rate of Gain. It 

 is a general law which holds true for all domestic 

 animals that less food is required for a given 

 amount of gain in young animals than in adults. 

 The amount of food required for each pound of gain 

 increases uniformly with the increase in age. Con- 

 versely the rate of gain decreases as the age in- 

 creases and consequently the economy of gain de- 

 creases with the age of the animal. This fact should 

 not be surprising, since it is well-known that the 

 digestion is much more active in young animals 

 than in adult animals and, therefore, the food is 

 better utilized. Not only are the rate and economy 

 of gain decreased by the age of pigs, but they also 

 depend to a considerable extent on the length 

 of the fattening period. No animal can be suc- 

 cessfully fed beyond a certain period, which is usu- 

 ally quite limited. In cattle it may range from 

 four to six months, but in pigs it is considera- 

 bly shorter. As a rule, pigs make their best gains 

 during the first month of fattening and after that 

 considerable difficulty is experienced in producing 

 economic gains. In other words, they are more 



