606 FEEDS AND FEEDING 



not advisable, except perhaps with very valuable brood sows, to go to 

 the expense of the iodine treatment unless there has actually been pre- 

 vious trouble from the disease. 



Experiments at the Montana, Washington, and Wisconsin Stations 8 

 show that hairless pigs can be prevented by giving iodine to the sows 

 during pregnancy. Tincture of iodine may be injected under the skin or 

 a suitable dose may be poured on the pregnant animal's back every 2 

 weeks during pregnancy. The most common method, and probably the 

 simplest with swine, is to give iodine in the form of potassium iodide in 

 the feed. (Sodium iodide may be used if it is cheaper.) It has been found 

 that 2 grains of potassium iodide given to each sow daily during the ges- 

 tation period will be sufficient to prevent the disease. A convenient way 

 of administering the potassium iodide is to dissolve one ounce in a gallon 

 of water. One tablespoonful of such a solution contains approximately 

 2 grains of the drug and is therefore a daily dose for a sow. The proper 

 amount of this solution for the number of sows to be fed may be readily 

 mixed with the feed each day. If more convenient, about 320 grains 

 (two-thirds ounce, troy weight) of the dry potassium iodide may be 

 mixed thoroly in each 1,000 Ibs. of the concentrate mixture fed the preg- 

 nant sows. 



918. Maintenance requirements of swine. In experiments at the Wis- 

 consin and Illinois Stations 9 Dietrich found that pigs could be maintained 

 on 0.10 Ib. digestible crude protein and 0.42 to 0.57 Ib. total digestible 

 nutrients per 100 Ibs. live weight. This is 4.2 to 5.7 Ibs. total digestible 

 nutrients per 1,000 Ibs. live weight, somewhat less than the amount re- 

 quired by the dairy cow or the steer, as is shown in Appendix Table V. 

 This is probably due to the fact, previously pointed out (90), that main- 

 tenance requirements depend upon body surface, and since the pig is 

 built more compactly than the steer or cow, he has less body surface per 

 100 Ibs. live weight. 



Faville of the Wyoming Station 10 found that brood sows weighing 314 

 Ibs. at the beginning of the trial and 376 Ibs. at the close made average 

 daily gains of 0.4 Ib. on a daily allowance of 4.6 Ibs. of concentrates 

 (2 parts corn and 1 part mill feed). This ration supplied only 57 per 

 ct. of the nutrients called for by the Wolff -Lehmann standard. 



919. Vitamine requirements; rickets. Recent investigations have shown 

 that there is much more chance of swine suffering from a lack of the fat- 

 soluble vitamine than there is in the case of horses, cattle, or sheep. This 

 is due to the fact that swine which are not on pasture are fed chiefly on 

 grain and grain by-products, and nearly all the cereals, with the excep- 

 tion of yellow corn, contain little of this vitamine. (104) It is pointed 

 out in the following chapter that young pigs fed such rations as white 

 corn and skim milk without pasture usually fail to thrive after a time 

 and many die from rickets or pneumonia. (929) These troubles may 



8 Mont. Bui. 119; Wash. Bui. 156, Pop. Bui. 117; Wis. Bui. 297. 

 'Wis. Rpt. 1899; 111. Bui. 163. 10 Wyo. Bui. 96. 



