94 



Feeds and Feeding. 



The strength of the thigh bones was determined in the following 

 manner: The two rounded, iron supporting edges of a machine 

 used for testing the breaking strength of materials were set four 

 inches apart. On these a thigh bone was placed, the rounded edge 

 of the breaking-bar pressing down on the bone from above, mid- 

 way of its length. The downward pressure was gradually in- 

 creased, being measured by the tilting beam of the machine. Under 

 the steadily increasing pressure the bone finally broke, its resist- 

 ance at the time of breaking being recorded. The trials showed 

 that the pigs fed the ration rich in crude protein had the strongest 

 bones. In the first "Wisconsin trial, as the table shows, the bones 

 of the corn-fed pigs broke at an average pressure of 380 lbs. for 

 each 100 lbs. of carcass, while those of the pigs fed milk, dried 

 blood, and middlings broke at about 500 lbs.— a difference of 32 per 

 ct. in favor of the pigs getting the ration rich in crude protein. 

 Analyses of the organs and parts of the pigs used in the second 

 Wisconsin trial showed further that the corn-fed pigs had propor- 

 tionately less dry matter in their blood and kidneys and a smaller 

 amount of dry lean-meat tissue than those on the narrow ration. 



Later investigations show that the differences produced by the 

 exclusive corn rations and those rich in crude protein were not en- 

 tirely due to the dift'erence in the supply of crude protein. In each 

 case the ration rich in crude protein was also the richer in mineral 

 matter, for corn is not only rather low in crude protein but it also 

 lacks mineral matter. 



116. Effect on tenderloins of exclusive corn feeding.— At the Mis- 

 souri Station^ Forbes fed 6 lots, each of five 120-lb. pigs, on un- 

 limited rations for 60 days. One lot was fed corn only, while the 

 others received corn supplemented with the various by-feeds shown 

 below. All rations but the one exclusively of corn had the same 

 nutritive ratio. On slaughtering the pigs, portions of the tender- 

 loin muscles were analyzed, with the results shown below: 



Bui. 81. 



