148 FEEDS AND FEEDING, ABRIDGED 



milk, buttermilk, and whey are thoroly pasteurized at a temperature 

 of 180° F. before being taken back to the farms, bovine tuberculosis 

 and other diseases may be widely spread from possibly a single diseased 

 herd. The pasteurized product also keeps better and is less likely to 

 produce scours. 



A trial at the Iowa Station ^ shows how readily tuberculosis may be 

 spread thru skim milk. Forty pigs, supposedly free from tuberculosis, 

 were divided into 4 lots. Two lots were kept on separate pastures and 

 two in dry lots. Corn and pasteurized skim milk were fed to all. How- 

 ever, the germs of tuberculosis were put into the milk of one lot on 

 pasture and one lot in the yard, just before feeding. After 196 days 

 the pigs were slaughtered. It was found that every animal in the 2 lots 

 receiving infected milk, 20 in all, was tuberculous, while of those not 

 given infected milk, 2 were tuberculous and 18 free from the disease. 



II. Packing House By-Products 



The packing house by-products, tankage or meat meal, meat scrap, 

 dried blood, and meat-and-bone meal, are extremely rich in highly 

 digestible, well-balanced protein. Most of them are also rich in cal- 

 cium and phosphorus, since they contain more or less bone. As they 

 are high in price, the feeder should understand their nature and eco- 

 nomical use. 



Tankage or meat meal. — At the packing plants waste meat, scrap 

 bones, and fat trimmings are thoroly steam-cooked under high pressure. 

 The fat, while yet liquid, is drawn off and the residue is then dried and 

 ground to a fine meal. The resulting tankage, also called meat meal, 

 contains from 40 to 60 per ct. protein and from 1 to 10 per ct. fat. 

 The variation in protein is due chiefly to the amount of bone present. 

 On account of the wide range between different grades, tankage should 

 always be purchased on guarantee of composition, for the value 

 depends primarily on the protein content. Being thoroly cooked under 

 pressure, tankage is sterilized, so that it cannot carry disease to animals 

 fed on it. In the manufacture of the best grades of tankage, carcasses 

 condemned because of disease are not used. 



Tankage or meat meal is generally fed to pigs and poultry, ranking 

 next to skim milk as a supplement for corn and other carbonaceous 

 grains. Owing to its richness in protein, 10 per ct. of tankage fed with 

 90 per ct. of corn or other cereals is sufficient to balance the ration 

 for pigs over 100 lbs. in weight, but younger ones need somewhat more. 

 Mixed with other feeds, it may be fed to cattle, sheep, and horses, 



2 Iowa Bui. 92. 



