PARASITIC DISEASES I77 



not be used for ihogs. The pastures and pens should 

 be well drained and all ponds filled in. More atten- 

 tion S'hould be given the methods used in feeding 

 hogs. Feeding in muddy yards that have been in 

 use for years and on feeding floors that are not kept 

 clean, should not be practised. The drinking^-water 

 should come from a deep well, and we should try to 

 keep it pure by using clean troughs in which the 

 hogs cannot wallow and fill with filth. 



In young hogs the feeding of a ration that will 

 meet the needs of the system and keep them in a 

 healthy condition, is an important preventive measure. 

 Because of the healthy, active condition of the in- 

 testines and other organs as well, the parasites are 

 unable to live and multiply, and most of them perish 

 and are thrown off. In the average herd, freedom 

 from this class of disease does not depend so much 

 on the surroundings, but on the vigor of the hogs 

 themselves. 



In order to prevent infection from thorn-headed 

 worms, hogs should not be allowed to run around old 

 straw stacks and manure heaps, or in places where 

 white grubs are common. Qld hog lots and pastures 

 can be largely freed from grubs by plowing and 

 sowing them to some forage crop. 



Medicinal Treatment. — The average herd of pigs 

 is kept under such conditions that it is necessary 

 to dose them at least once during the year with 

 some remedy that will destroy the worms, or drive 

 them out of the intestines. Drugs belonging to 

 this class are called vermicides and vermifuges. 



