FEEDING THE HERD AND THE PIGS 201 



considerably impaired so that she will not produce as 

 large litters as she otherwise would, and she may even 

 become entirely barren and not produce at all. Again, 

 the milk-giving functions of such a sow are not as likely 

 to be well developed as would be the case if she were 

 bred earlier in life. 



Old Sows. As previously learned, the animal body 

 uses protein primarily to supply the protein metabolism 

 either for maintenance, for the factor of waste, or for the 

 production of new protein or lean meat tissue. Also, the 

 carbohydrate feeds are used most economically for the 

 production of energy, heat, and fat tissues. Thus an old 

 sow that has come to maturity and is adding no more 

 lean meat to its carcass, needs only sufficient protein to 

 supply what is needed for maintenance and for the factor 

 of waste. If the factor of waste was not established 

 previously or has been greatly reduced, such a sow will 

 need only sufficient for maintenance which, as previously 

 seen, is a comparatively small quantity. After such a 

 sow is bred, and during the period of lactation, she will 

 need enough in addition to develop the foetus as well as 

 to supply milk during the period of lactation. Thus a ma- 

 ture sow may be fed more economically than a young and 

 growing sow because carbohydrate feeds in general are 

 cheaper than protein feeds. 



FEEDING THE BOAR. 



This member of the breeding herd may be fed in gen- 

 eral the same as the sows. If he is young and growing, 

 he should have sufficient protein for this purpose, and if 

 he is mature, he needs only enough for maintenance, as- 

 suming that the factor of waste is a minus quantity, and 

 the remainder of his ration may be made up in the main 



