GENERAL PROBLEMS IN SWINE HUSBANDRY 605 



(1) Equal parts by weight of ground limestone and salt ; or equal parts 

 wood ashes and salt. These supply calcium but no appreciable amounts 

 of phosphorus. 



(2) Equal parts of ground limestone, salt, and either bone meal or 

 ground rock phosphate. This furnishes both calcium and phosphorus. 



(3) Nine parts of either bone meal or ground rock phosphate and one 

 part tankage for flavoring. These mixtures also furnish both calcium and 

 phosphorus. 



If one desires to use a more complicated mixture than these, he might 

 use the following, which was suggested by Eward. 7 He, himself, how- 

 ever, states that after comparisons of simple mineral mixtures with more 

 complex combinations, he is inclined to leave out such ingredients as 

 copperas and Epsom salts, until such time as they have been proved to be 

 useful : 



Salt, common, flake form 30. Ibs. 



Spent bone blackj or bone meal, finely ground, or bone flour . . 25 . Ibs. 



Commercial kainit, or potassium chloride, or wood ashes .... 12 . Ibs. 



Sulfur, flowers of 10. Ibs. 



Air-slaked lime, or limestone, finely ground 10.0 Ibs. 



Glauber's salts or sodium sulfate 5.7 Ibs. 



Epsom salts or magnesium sulfate 5.0 Ibs. 



Copperas, or iron sulfate 2.0 Ibs. 



Potassium iodide 0.3 Ib. 



Total 100.0 Ibs. 



As yet, it is impossible to state definitely just what mineral mixtures 

 will give the best results. However, this matter is now being investigated 

 at several different experiment stations, and soon there should be much 

 further knowledge gained on this important question. 



917. Hairless pigs. In some sections, especially in certain districts 

 of the Northwest, heavy losses have been experienced in recent years 

 from "hairlessness" or goitre in new born pigs. Pigs so affected are 

 practically hairless or have very light coats of hair at birth, and have 

 large necks and thick pulpy skin. In severe cases, if the pigs are born 

 alive, they are generally so weak that they live but a few hours. It has 

 been pointed out previously that this trouble is due to the thyroid gland 

 in the neck being diseased and enlarged, just as in the case of humans 

 suffering from ordinary goitre. This is apparently brought about by a 

 lack of iodine in the feed or a failure of the body to absorb and use the 

 traces of iodine usually present in the feed. As has been shown else- 

 where, the disease may be prevented or cured by administering iodine in 

 the form of potassium iodide to the sows while they are pregnant. ( 101 ) 



Hairless pigs are most apt to be produced in spring after a severe win- 

 ter with a heavy snowfall, when the sows do not take much exercise. In 

 most districts goitre or hairlessness is rare if brood sows are fed well- 

 balanced rations, neither too low nor too rich in protein, and if they get 

 plenty of legume hay and secure ample exercise. Therefore it is usually 



7 Iowa Cir. 70. 



