192 



BETTER DAIRY FARMING 



of lime and phosphorus. Of course common salt must be provided 

 for all animals at all times in a suitable way. (12, 13) 



There is one other mineral that may be lacking in the diet 

 in certain areas. This mineral, iodine, is the one connected with 

 the development of the most common type of goitre. Its lack is 

 also responsible for the hairless pig. In the goitre area, cows are 



Pearl's Dot 57445 

 Yearly record 19,602. 5 pounds of milk, 965.8 pounds of butter fat. Owned 

 by D. D. Tenney, Crystal Bay, Minn. 



sometimes affected. It has been recommended that cows in these 

 areas receive one-tenth of one pound of potassium or sodium iodide 

 per thousand pounds of grain. 



321. Measuring the value of feeds. — The first thing we want 

 to know about a feed, in estimating its value, is its chemical anal- 

 ysis, — that is, its content of the nutrients we have just mentioned, 

 namely, protein, fat, carbohydrates, etc. However, chemical anal- 



