52 Types and Market Classes of Live Stock 



"marbling." Practically no fat is deposited in the muscles which do 

 much work, hence we find the round steak coming from the thigh to 

 be almost completely free from fat. The muscles of the loin and back, 

 having little work to do, take on the marbling feature quite easily if 

 the animal is well bred and properly handled. This largely explains 

 why the cuts from the loin and back are most tender, although in these 

 muscles there is not the stimulus to the growth of connective tissue 

 such as is the case in working muscles, and this is undoubtedly another 

 reason why the loin and back yield cuts of superior terderness. 



As stated in the preceding chapter, the feeding of mature cattle 

 is essentially a fattening process. This is clearly shown by results at 

 the Missouri Station, ' where muscle fibers and fat cells extracted from 

 steers at different periods during the fattening process were examined 

 and measured under the microscope and it was found that while there 

 was very little or no increase in the diameter of the muscle fibers, the 

 fat cells increased enormously both in number and size. 



Thus we understand why cattle diff"er widely in the kind of car- 

 casses they yield, depending upon their inherited tendencies and upon 

 their feed and care. The effects of inheritance are discussed in more 

 detail in Chapter IV. 



Variations in carcasses. — A study of the carcasses in any cooler 

 brings out striking differences. Some are large, being from 1,500- to 

 1,600-pound animals; others are from younger beeves that weighed 800 

 to 1,100 pounds. Some are compact and wide, others are long and 

 narrow. Some are well developed in the regions of high-priced cuts, 

 while others are deficient in this respect. Some carry heavy fleshing, 

 others are very poorly covered indeed. The layer of outside fat is 

 very thick in some, these being highly finished cattle fed on grain. 

 Others show practically no covering of fat. These are from grass-fed 

 cattle — poor pasture too, for a steer puts on some fat on grass if the 

 pasture is good. Some show a nice intermixing of fat and lean, called 

 "marbling/' while others exhibit this feature very slightly, or none at 

 all. The lean meat of some carcasses has a pale red color; in others it 

 is very dark. Some carry snow-white fat, others carry fat of a yellow 

 color. Some beef is fine grained, and some is very coarse and fibrous. 

 Some carcasses have soft bones, somewhat cartilaginous in character; 

 others have hard flinty bones. Size of bones varies a great deal in 

 different carcasses. 



Demands of the butcher and consumer. — The questions which 

 now come before us are: 1. What kinds of lean meat and fat does 

 the butcher want? 2. How much lean meat does he want, and how 



^H. J. Waters: Influence of Nutrition Upon the Animal Form, paper presented 

 at Thirtieth Meeting of Society for Promotion of Agricultural Science. 



