668 FEEDS AND FEEDING 



close of the pasture season, for they are less apt to root than are hogs. 

 However, the pasture lots must be watched closely, and if the pigs start 

 rooting badly, it will be necessary to ring them at once, especially if 

 they are on a permanent pasture, such as alfalfa or blue grass. Even 

 if fed good rations, pigs are apt to begin rooting after hard summer or 

 fall rains, to get the angle worms which then come close to the surface 

 of the ground. This is not surprising, for in a state of nature, the hog 

 gained his living largely by rooting. On annual crops, such as rape, it is 

 not usually necessary to ring pigs if they are fed well-balanced rations. 



984. Feeding a supplement with corn on pasture. All forage crops, at 

 the immature stages when commonly used for pasture, are much richer 

 in protein than the same crops when nearly mature. (81, 310) It will be 

 noted in Appendix Table III that the common forage crops used for 

 swine all have as narrow a nutritive ratio as wheat middlings, and in 

 many cases the forage plants are even richer than middlings in protein 

 at the stages of growth when pastured. This is true with alfalfa, red 

 clover, rape, oats, rye, and even blue grass. 



Due to the richness of the common pasture crops in protein and also 

 because of their other virtues, young pigs fed only corn on good forage 

 will usually make fair gains. Especially when pigs are full fed on corn 

 they will not, however, eat enough of the bulky green forage to balance 

 their ration entirely. Hence they will make much more rapid gains if 

 some protein-rich concentrate is added to balance the ration. This is 

 shown clearly in the following table, which summarizes the results of 7 

 trials in each of which one lot of spring pigs, averaging 49 Ibs. in weight, 

 was fed only corn on rape pasture, while another lot was fed corn plus 

 a small amount of tankage : 



Adding a supplement to corn and good pasture 



Concentrates for 



Length Daily 100 Ibs. gain 



Average ration of trial gain Corn Tankage 



Days Lbs. Lbs. Lbs. 



Lot I,* Corn, 3.7 Ibs. Rape 142 0.88 427 



Lot II* Corn, 4.3 Ibs. 



Tankage, 0.24 Ib. Rape 120 1 . 25 344 20 



*Average of 5 trials by Robison (Ohio Buls. 343 and 349); and 2 by Eward (Am. Soc. Anim. Prod., 

 Proceedings, 1913, and information to the authors) . 



The pigs fed 0.24 Ib. of tankage a head daily in addition to corn on 

 rape pasture were more thrifty, ate more feed, and made much more 

 rapid and economical gains. In these trials each 100 Ibs. of tankage 

 saved 415 Ibs. of corn. 



It should be pointed out that in these trials only enough tankage was 

 fed to balance corn on good pasture. This requires only about half as 

 much as when the pigs are fed corn in dry lot. Several investigators 

 and many farmers have disregarded this fundamental fact that pasture 

 crops save expensive protein-rich feeds, and have fed as much tankage 

 or other protein-rich supplement to pigs on pasture as would have been 



