MISCELLANEOUS CONCENTRATES 185 



which pigs fed milk from tubercular cows are infected with the disease 

 has been shown in a trial at the Iowa Station. 8 



Since the germs of tuberculosis are killed by pasteurizing the milk at 

 a temperature of 180 F., this simple precaution will remove danger 

 from this source. The pasteurized product also keeps better and is less 

 likely to produce scours. This practice is likewise advantageous to the 

 factories, for the milk cans may be more readily kept in good condition 

 and the quality of the milk delivered at the factory will thereby be im- 

 proved. Careful farmers should insist that skim milk, buttermilk, and 

 whey be thoroly pasteurized at the factory, a practice required by law in 

 Denmark and in certain states in this country. (957) 



II. PACKING HOUSE BY-PRODUCTS 



The pa-cking houses now furnish to the feeder great quantities of by- 

 products, including tankage or meat meal, meat scrap, dried blood, and 

 meat-and-bone meal. These are usually extremely rich in protein which 

 is well balanced in composition and highly digestible. Some of them are 

 also rich in lime and phosphoric acid, since they contain more or less 

 bone. When fed in proper combination with other feeds, animals rarely 

 object to these by-products. Owing to the high prices which these con- 

 centrated feeds command, the feeder should understand their nature and 

 how they must be fed to secure the best returns. 



270. Tankage or meat meal; meat s<*rap. At the packing plants the 

 fresh meat scraps, fat trimmings, and scrap bones are thoroly cooked in 

 steel tanks by steam under pressure, which separates the fat. In the 

 larger plants the residue is then pressed to remove the liquid ' ' soup. ' ' 

 This is then evaporated down separately to a syrup-like consistency, 

 when it is known as * ' stick. ' ' To the wet, solid meat residue, which has 

 been pressed, are added various proportions of " stick " and sometimes 

 of partly dried blood, and the whole mass is then dried and ground fine, 

 after being passed over powerful magnets to remove nails and other 

 metallic material. The resultant product, sold either as tankage or as 

 meat meal, contains from 40 to 60 per ct. or more of crude protein and 

 from 1 to 10 per ct. of fat. The variation in content of crude protein is 

 due principally to differences in the amount of bone present. Owing to 

 the wide range in crude protein and fat content, these feeds should 

 always be purchased on guarantee of composition. The value will depend 

 chiefly on the percentage of protein, for in case an additional supply of 

 lime and phosphoric acid is needed, it may be furnished cheaply in bone 

 meal or floats. (99) Even tho tankage may be produced in part from 

 the carcasses of diseased animals, there is no danger, of it carrying disease 

 to animals fed on it, for it is steam-cooked under pressure and therefore 

 thoroly sterilized. 4 



Meat scraps are a product similar to tankage, but not ground fine. 

 They are used chiefly for poultry. 



'Iowa Bui. 92. 4 U. S. Dept. Agr. Bur. Anim. Indus., Clr. 144. 



