626 FEEDS AND FEEDING 



consist of this grain. However, good results have been secured in 

 numerous trials where corn has been the chief feed, but where the allow- 

 ance was restricted so that the sows did not become too fat and the ration 

 was properly balanced by furnishing such feeds as legume hay and 

 tankage or dairy by-products. (1019) 



In the corn belt corn is usually fed on the cob. This is a wise practice, 

 for, as we have seen in the previous chapter, there is no appreciable 

 advantage in shelling, grinding, or soaking corn for pigs under 150 Ibs. 

 in weight, and even for older ones the slight saving will not usually pay 

 for such preparation. (920) 



If pigs are to hog down immature corn in the fall or are to be fed 

 such grain in the yard, the change should always be made gradually; 

 otherwise digestive disturbances are apt to result. Immature corn, is 

 more fermentable than mature grain, and is apt to cause diarrhea unless 

 this precaution is taken. Contrary to a common belief, new corn does 

 not cause hog cholera. However, pigs which have become unthrifty due 

 to improper feeding of new corn, are more susceptible to the disease if 

 they are exposed to infection. 



On account of the great storage of nutrients in the corn grain during 

 the latter stages of growth, an acre of standing corn will make much 

 more pork if fed after the grain begins to dent than it will if fed off 

 when in the roasting ear stage. When the kernels have dented, little 

 trouble will be experienced in changing pigs to new corn, and in fact 

 they will appreciate a change from dry, hard old corn. If the pigs are 

 to be marketed within a week or so after new corn is ready, they had 

 best be continued on their former ration if there is still old corn on 

 hand, as a change might lessen the gains for a few days. 



939. Yellow versus white corn. Whether there is any difference in 

 the feeding value of yellow and white corn is a question which has often 

 been discussed by farmers and scientists alike. The general conclusion 

 until 1920 was that there was no difference whatsoever. Then Steenbock 

 discovered at the Wisconsin Station 1 that yellow corn contains con- 

 siderable of the mysterious fat-soluble vitamine, which is present in 

 butterfat, while white corn contains little or none. (104) As soon as 

 this was learned, experiments were begun by Morrison, Bohstedt. and 

 Fargo at the same station 2 to find what difference, if any, there was in 

 the feeding value of the two kinds of corn. 



Since it had already been discovered that the green-leaved parts of 

 plants contain large amounts of this same fat-soluble vitamine, it did 

 not appear probable that there could be any difference in the feeding 

 value of the two kinds of corn for animals which ate plenty of pasture 

 or good, green hay. Therefore, experiments were undertaken chiefly 

 with pigs fed in dry lots, where they had no fresh, green feed. 



Five trials have been conducted with pigs started at weights of 50 to 



'Jour. Biol. Chem., 41, 1920, pp. 81-96; Wis. Bui. 319, pp. 50-1. 

 2 Wis. Buls. 323, pp. 10-11; 339, pp. 125-9; unpublished data. 



