868 EXPERIMENT STATION RF.COHD. 



"Corn is tlic (•li(',;ii)(.'st ralion fed. corn aiul sliorts Itcing socond, corn iuul 

 tankage third, corn and steamed j;ronnd bone fourth, and corn and skim milk 

 fifth in eo.st of production at the prices for feed used in tins bulletin. . . . 



'• n will be noted that where sui)plenientar,v foods were used, the hojjs j;en- 

 erally made niori^ rapid jxains and reached heavier weights in a jjiven lenjith of 

 time, so that they were ready for tlie market at an earlier a^e. This point is 

 a distinct advantage, since it shortens the period of risk and increases tlie 

 profit per (lay on each piK-" 



The effect of food on breaking strength of bones, 10. A. P.T'nxinr (Xrhrasl.d 

 8ta. Hill. 101, pp. U-39, fltjs. 9). — Usinj^ the piRs under test in the feeding trials 

 noted above, a test was made to determine the effect of different rations on the 

 breaking strength of Iwnes in growing pigs. The average breaking strength of 

 all the bones i)er 100 lbs. live VA'eight at the time of slaughter of the 10 pigs used 

 in the work of lt)()(>-7 was for lot 1 2S1 Ib.s., lot 2 ;ni.7.~> lbs., lot 3 41:5.75 lbs., 

 and lot 4 4(i7.7r» lbs. The average l)i-eaking strength of all bones per KM) 

 lbs, live weight for the 20 pigs used in l[)()7-8 was for lot 1 325 lbs., lot 2 3t)0 

 lbs., lot 3 50!) lbs., lot 4 ,580 lbs., and lot 5 (i81 lbs. 



"The laboratory examination of these bones reveals a marked dit'lorence in 

 fifth in cost of production at the prices for feed used in this bulletin. . . . 



" The laboratory tests have also shown that there is no apparent increase In 

 the external measurements of the bones resulting when protein or mineral 

 matter is added to the food nutrients, but that these additional nutrients, so far 

 as they are assimilated, have greatly added to the thickness of the bone walls 

 by accretion on the inner surface of these walls, thereby reducing the marrow 

 within the bones. 



" The thickness of the bone wall increased about 50 per cent in those fed 

 bone meal over those fed only corn. The percentage of mineral matter and the 

 specific gravity in the green bones increased in nearly the same proportion as 

 the thickness of the walls. 



" That foods rich in phosphates and mineral matter will increase the strength 

 of bone is conclusively proven. 



" There can be no doubt about the advantage of feeding a sufficient amount 

 of phosphates to build uj) strong, healthy bones, and a deficiency of phosphates 

 during the growing period may materially effect the development of the growing 

 animals. Bone meal and tankage may often be fed economically and the 

 additional cost, if any, can profitably be incurred in the production of high- 

 class breeding animals. 



"That an excess of mineral matter in the food may cause mineral matter 

 to be deposited in the bones in excess of that actually needed for the healthy 

 growth of the animal is also (piite possible, though not yet proven. 



" That such food will cause the animal to stand up scpiarely on his pasterns 

 is not yet proven. It would seem that the conformation of the pastern will 

 have most to do with this. Strong-boned pigs with short, ui»right pasterns will 

 be most likely to grow out with good feet, while pigs with long or oblique 

 jtasterns will generally go down. Excessive weight at early ages will affect 

 all pigs unfavorably, and lack of exercise is also detrimental." 



Weighings and measurements of a number of bones showed that the nature 

 of the feed has no distinct effect upon the length, circumference, or volume of 

 the bone. " The first two lots | in 1007-Sl, which were fed only corn or corn and 

 shorts, had bones of less weight, of lower sjjecific gravity, with thinner walls, 

 and with a much lower content of mineral matter than those of the three other 

 lots. These properties were characteristic of the entire bones as well as of the 

 portions of the shafts where the fractures appeared when the strength was 



