GROWTH AND FATTENING 89 



cattle, 1 :4.5 to 1 :5.4 for fattening sheep, and 1 :5.9 to 1 :7.0 for fattening 

 swine, numerous experiments have shown that mature animals of all 

 classes can be successfully fattened on much less crude protein. 



It has been found that mature fattening animals may make satis- 

 factory gains where the nutritive ratio is as wide as 1 :16. 32 How- 

 ever, as shown previously (84), supplying as little protein as this is not 

 usually economical, because it decreases the digestibility of the ration. 

 Kellner accordingly advised that for mature fattening cattle the nutri- 

 tive ratio should never be wider than 1 :10 or 1 :12. 



On the other hand, in regions where alfalfa hay, cottonseed meal, or 

 other nitrogenous feeds are abundant and low in price compared with 

 those rich in carbohydrates it may be most profitable to feed a much 

 narrower ration, even to mature fattening animals. (750) Those in 

 thin flesh should at first be liberally supplied with protein in order that 

 their muscular tissues may develop. For such animals Kellner held 

 that the nutritive ratio should be about 1 :6, with from 12 to 15 Ibs. of 

 digestible nutrients daily per 1,000 Ibs. of live weight. 



Owing to the greater economy of gains by young animals, in this 

 country the larger part of our meat-producing animals are fattened and 

 marketed before maturity. Such animals are adding not only fat, but 

 also considerable lean meat to their bodies as they fatten, and therefore 

 require a more liberal supply of protein than mature animals. Skinner, 

 Cochel, and King 33 in extensive trials at the Indiana Station have found 

 that 2-year-old steers make larger gains and require less feed per 100 

 Ibs. gain when fed rations with a nutritive ratio of 1 :7 to 1 :7.8 than 

 when the ration has a wider nutritive ratio. For fattening lambs rations 

 having an average nutritive ratio of 1 : 6.8 proved better than when the 

 nutritive ratio was 1 :8.8. The results of these trials and other investi- 

 gations have been taken into consideration in the recommendations given 

 in the Morrison feeding standards. (Appendix Table V.) 



It is important to bear in mind that since protein-rich feeds are usual- 

 ly high in price, the most profitable ration may not be the one producing 

 the largest gains, as the ration containing an abundance of protein may 

 be considerably more expensive. (197) Rations for fattening each kind 

 and age of animals are discussed in detail in Part III. 



130. Factors influencing fattening. The deposition of fat in an animal 

 depends primarily upon the quantity of food consumed in excess of main- 

 tenance and growth requirements. Fattening may take place at any 

 age, tho the tendency of young animals to grow greatly reduces the pro- 

 portion of food usually available for fattening. Supplying an abundance 

 of feeds that are palatable, concentrated, and largely digestible tends 

 to rapid fattening because a large surplus of nutrients then remains 

 after supplying the body needs, which surplus may go to form fat. 



32 Ernahr. landw. Nutztiere, 1907, pp. 418-420. 

 ""Ind. Buls. 153, 162, 167, 168, 178, 179. 



