1019] ANIMAL PRODUCTION". 70!) 



;i period of 136 days gained <>n an average -.1 lbs. per head per day, while a 

 comparable lot receiving corn silage and hay gained 2.24 lbs. The silage ration 

 di' the sin nd lot was m lbs. less per day than the Bwede ration of the Brat. Tli«* 

 second lot made most of its greater gain during the early pari <>f the Feeding 

 period. The grain ration was the same In both cases, crushed oats, bran, cot- 

 tonseed meal, and corn meal (2:2:2:1). 



Mineral requirements of sheep, (i. S. FSAPS (T< DOS Sin. Hut. .'..LI il'.llK\, pp. 

 ■'< 10, fig. I).— For each component of the ash of rations t"« •* 1 sheep In I s - diges- 

 tion experiments, this bulletin furnishes data as to the amount fed per day. t lie 

 amount not recovered In the frees, and for 10 of the experiments the amount 

 found in the urine. Eighteen <>f the digestion trials were made In triplicate, 

 and 'J!) in duplicate, while 1 ration was fed to a single animal only. The digesti- 

 bility Of the organic nutrients and total ash <>f the rations of 43 of the experi- 

 ments (numbered 1 37, 24a, ~(*>, 78, 7'.>. 81, and 82) have i n given in three 



previous bulletins (E. s. R., :;7. p. 865), while the details of g (numbered 88-02) 

 are unpublished. In most of the experiments, the ration consisted of a single 

 roughage; in (he others, of alfalfa plus a supplement. The roughages fed 

 were accuff sorgo fodder, alfalfa hay. Bermuda hay, bur clover hay, buffalo 

 grass hay, corn fodder, cowpea hay, Guam grass hay. Johnson f. r rass hay, Kafir 



corn fodder, millet, oat hay, peanut hay, Para grass hay, prairie hay, RhodQS 

 grass hay. rice hay. rice straw, sorghum and cowpea silage, BOrghum hay. Ta- 

 bosa grass hay. and vetch hay. The supplements to alfalfa were corn bran, COld- 

 pressed cottonseed cake, cottonseed meal, a mixture of cottonseed meal and 

 bulls, Kafir corn chop. Kafir corn head chop, peanut hulls, rice bran, rice hulls, 

 and rice polish. A table gives the percentages of silica (insoluble ash), lime, 

 magnesia, phosphoric acid, anil potash found in the samples used of all these 

 feeding stuffs except Guam u'rass hay. 



The author points out that the rectum is a recognized path of excretion from 

 the body of some mineral elements, but tinds it convenient to speak of difference 

 between the intake and the fecal content sis the amount digested ami also 



to 'all the percentage of the intake that is "digested" the coefficient of digesti- 

 bility. He publishes a table showing the digestibility of tin- several constituents 

 of the ash for each of the rations except that no mention is made of Guam grass. 

 This omission and the combination of I ertain of the alfalfa experiments reduces 

 the number of items in Hie table to 44. In 14 of the silica entries, 10 of the 

 lime, and 12 of the phosphoric acid, the digestibility was zero, that is the 

 amount in the feces exceeded the amount in the feed. There were no cases of 

 "negative digestion " of magnesia and potash. The averages of such of the 44 

 determinations of the coefficient of digestibility as were not zero are given by 

 the author as: Silica 22.2, lime '.',-.:'., magnesia 323, phosphoric acid -'_'."», and 

 potash 83.2. Grouping the determinations by the amounts ingested shows, in 

 the case of lime and phosphoric acid at least, that the coefficient of digestibility 

 increases with an increase in the amount consumed, negative digestion timires 

 occurring as a rule only when this amount was small. This condition indicates 

 that fairly constant amounts of each tire eliminated daily in the solid excrement. 

 For lime the daily elimination is held lo be about 0.6 gm, and the corrected 

 digestibility to he about ■_'."> per cent For phosphoric acid the elimination is 

 0.8 .urn. and the approximate true digestibility is 60 per cent. The data also 

 indicate that an Increased digestion of 1 gm. of lime is accompanied by an 

 increased retention of 0.74 gm. of phosphoric acid. This ratio suggests to the 

 author the formation of tricalcium phosphate. 



Analyses of the urine collected in the balance experiments i those numbered 

 from 70 to 92) show that the mineral constituents appear in the urine in fairly 

 120653°— J9 6 



