FEEDS 419 



Table 16-7 shows the ajjproxiinate chemical composition of some 

 ol the more important products made from milk. 



Packing-house By-products 



By-products ol the meat-packing industry have been used extensively 

 as protein supplements in rations for domestic livestock, and, in spite 

 of the present high cost of these materials, they are still considered 

 essential for successful feeding of swine and poidtry. Concentrates 

 of this type (Table 16-8), which are most commonly used, include 



TABLE 16—8. Per Cent Composition of Some Typical Packing-house 



By-products 



Dry Crude Crude Crude N-free 



Feeding Stuff Matter Ash Protein Fiber Lipide Extract 



tankage, meat meal, meat scraps, blood meal, and pork cracklings. 

 During the past few years the prices of tallows and greases have been 

 depressed to the point where their inclusion in the animal ration has 

 become economically feasible. Such fats reduce dustiness and in many 

 cases improve the texture and palatability of the feed. In beef-feeding 

 trials incorporation of stabilized fat up to 5 per cent produced efficient 

 gains. Addition of 5 to 10 per cent fat to poultry rations produced 

 good gains and superior finish in broilers. Such fats must be stabilized 

 with antioxidants to prevent the development of rancidity. 



Fish meal and ground dried fish are made from waste materials 

 from fish-packing plants or from types of fish that are not acceptable 

 as human food. Fish products are valuable as protein supplements in 

 many types of livestock rations and as sources of easily available 

 calcium and phosphorus because they contain appreciable amounts 

 of ground fish bone. Marine fish are also rich in iodine. 



Packing-house by-products and fish meals are valued primarily for 

 the biological value of the animal protein they contain. Animal 

 proteins are biologically superior to plant proteins because they con- 

 tain better combinations of the essential amino acids required by 

 animals for normal growth and reproduction. 



Packing-house by-products are generally used only for poultry and 

 swine. There is no advantage in using such i^rotein supplements in 



