A94-1030-5,000-L180 TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS BULLETIN NO. 418 NOVEMBER, 1930 DIVISION OF CHEMISTRY Digestibility by Sheep 0f the Con- stituents 0f the Nitrogen-Free Extract 0f Feeds AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. O. WALTON, President STATION STAFFt ADMINISTRATION: A. B. CONNER, M. S., Director R. E. KARPER, M. S., Vice-Director CLARIcE MIxsoN, B. A., Secretary M. P. HOLLEMAN, JR., Chief Clerk J. K. FRANOKLOW, Assistant Chief Clerk CHESTER HIGGS, Executive Assistant C..B’. NEBLETTE, Technical Assistant CHEMISTRY: - G. S. FRAPS, Ph. D., Chief; State Chemist S. E. ASBURY, M. S.. Chemist J. F. FUDGE, Ph. D.,~Chemist E. C. CARLYLE, B. S., Assistant Chemist WALDO H. WALKER, Assistant Chemist VELMA GRAHAM, Assistant Chemist T. L. OGIER, B. S., Assistant Chemist ATHAN J. STERGES, B. S., Assistant Chemist JEANNE M. FUEGAS, Assistant Chemist RAY TREICHLER, M. S., Assistant Chemist RALPH L. ScHwARTz, B. S., Assistant Chemist C. M. POUNDERS, B. S., Assistant Chemist HORTICULTURE: S. H. YARNELL, Sc. D., Chief ——i—~————, Horticulturist RANGE ANIMAL HUSBANDRY: J. M. JONES, A. M., Chief B. L. WARwIcK, Ph. D., Breeding Investigatio_ns STANLEY P. DAVIS, Wool Grader ENTOMOLOGY: F. L. THOMAS. Ph. D., Chief; State Entomologist . J. REINHARD, B. S., Entomologist . K. FLETOHER, Ph. D., Entomologist . L. OWEN, JR., M. S.. Entomologist . N. RONEY, M. S., Entomologist . C. GAINES, JR., M. S., Entomologist . E. JONES, M, S., Entomologist . F. BIBBY, B. S., Entomologist ~CEcIL E. HEARD. B. S., Chief Inspector OTTO MAcKENsEN, B. S. Foulbrood Inspector . B. WHITNEY, Foulbrood Inspector AGRONOMY: E. B. REYNOLDS, Ph. D., Chief R. E. KARPER, S , Agronomist P. C. MANGELSDORP, Sc. D., Agronomist g. T. KILLOUGH, M. S., Agronomist B. mmuuéwm é E. REA, B. S., Agronomist -————-——-—-——, Agronomist C. LANGLEY, B. S., Assistant in Soils PUBLICATIONS: A. D. JAcKsoN, Chief VETERINARY SCIENCE: *M. FRANcIS, D. V. M., Chief H. ScHMIDT, D. V. M., Veterinarian F. P. MATHEWS, D. V. M., M. S., Veterinarian W. T. HARDY, D. V. M., Veterinarian F. E. CARROLL. D. V. M., Veterinarian PLANT PATHOLOGY AND PHYSIOLOGY: J. J. TAUBENHAUS, Ph. D., Chief W. N. EzEKIEL, Ph. D., Plant Pathologist W. J. BAcH, M. S., Plant Pathologist B. F. DANA, M. S., Plant Pathologist FARM AND RANCH ECONOMICS: L. P. GABBARD, M. S., Chief W. E. PAULSON, Ph. D., Marketing C. A. BONNEN, M. S., Farm Management ————————, Assistant -———————, Assistant RURAL HOME RESEARCH: JESSIE WHITAcRE, Ph. D., Chief MARY ANNA GRIMES, M. S.. Textiles ELIZABETH D. TERRILL, M. A., Nutrition - SOIL SURVEY: **W. T. CARTER, B. S., Chief E. H. TEMPLIN, B. S., Soil Surveyor T. C. REITcH. B. S., Soil Surveyor A. H. BEAN, B. S., Soil Surveyor BOTANY: V. L. CORY, M. S., Act. Chief SIMON E. WOLFF, M. S., Botanist SWINE HUSBANDRY: FRED HALE, M. S., Chief DAIRY HUSBANDRY: O. C. COPELAND, M. S., Dairy Husbandman POULTRY HUSBANDRY: R. M. SHERWOOD, M. S., Chief AGRICULTURAL ENGINEERING: H. P. SMITH, M. S., Chief MAIN STATION FARM: (i. T. McNESS, Superintendent APICULTURE (San Antonio): II. B. PARKS, B. S., Chief A. H. ALEX, B. S., Queen Breeder FEED CONTROL SERVICE: F. D. FULLER. M. S., Chief S. I). PEAROE, Secretary J. H. ROGERS. Feed Inspector K. L. KIRKLAND, B. S., Feed Inspector W. D. NORTIIOUTT, JR., B. S., Feed Inspector SIDNEY D. REYNOLDS, JR., Feed Inspector P. A. MOORE, Feed Inspector E. J. WILSON, B. S., Feed Inspector _ SUBSTATIONS No. 1, Beeville, Bee County: R. A. HALL, B. S., Superintendent N0. 2, Troup, Smith County: _ P. R. JOHNSON, M. S., Superintendent No. 3, Angleton, Brazoria County: . H. STANSEL, M. S., Superintendent No. 4, Beaumont, Jefierson County: R. H. WYcHE, B. S., Superintendent No. 5. Temple, Bell County: _ HENRY DUNLAvY, M. S., Superintendent . B. F. DANA, M. S., Plant Pathologist H. E. REA, B._S., Agronomist; Cotton Root Rot Investigations _ SIMON E. WOLPF, S., Botanist; Cotton Root Rot Investigations No. 6, Denton, Denton County; P..B. DUNKLE, B. S., Superintendent No. 7, Spur, Dickens County: _ R. E. DIcKS0N, B. S., Superintendent -——————-———, Agronomist No. 8, Lubbock, Lubbock County: D. L. JONES, Superint ndent FRANK GAINES, Irriga ionist and Forest Nurseryman No. 9, Balmorhea, Reeves County: J. J. BAYLES, B. S., Superintendent No. 10, College Station, Brazos County: R. IVI. SHERWOOD, M. S., In charge L. J. McCALL, Farm Superintendent No. 11, Nacogdoches, Nacogdoches County: I H. F. MORRIS, M. S., Superintendent **No. 12, Chillicothe, Hardeman County: J. R. QUINBY, B. S., Superintendent **J. C. STEPHENS, M. A.. Assistant Agronomist No. l4, Sonora, Sutton-Edwards Counties: W. H. DAMERON, B. S., Superintendent ————i—~, Veterinarian W. T. HARDY, D. V. M., Veterinarian **O. G. BABCOCK, B. S., Entomologist O. L. CARPENTER, Shepherd No. 15, Weslaco, Hidalgo County W. H. FRIEND, B. S., Superintendent SHERMAN W. CLARK, B. S.. Entomologist W. J. BAcH, M. S., Plant Pathologist No. 16, Iowa Park, Wichita County: C. H. McDOwELL, B. S., Superintendent No. 17, -———-—+—— ——————————, Superintendent No. 18, — —— ———-———————, Superintendent No. 19, Winterhaven, Dimmit County: E. MORTENsEN, B. S., Superintendent ——————-———, Horticulturist No. 20, , Superintendent Tefixchersiin the School of Agriculture Carrying Cooperative’ Projecté on the Station: W. ADRIANcE, Ph. D., Horticulture W. BILSING, Ph. D., Entomology _ P. LEE, Ph. D., Marketing and Finance ScOATEs, A. E., Agricultural Engineering . K. MAcKEY, M. S., Animal Husbandry *Dean School of Veterinary Medicine. J. S. MOGFORD, M. S., Agronomy F. R. BRIsoN, B. S., Horticulture y. R. HORLAcHER, Ph. D., Genetics H. KNOX, M. S., Animal Husbandry TAs of November 1, IQSO. **In cooperation with U. S. Department of Agriculture. The sugars, starch, and other constituents of feeding stulfs were studied by means of chemical analyses and digestion experiments with sheep, for the purpose of ascertaining if there was any relation between the content in these materials and their feeding values, and also in order to secure more definite information regarding the composition of the feeds and the digestibility of their chemical constituents. In general, feeds of high feeding value have a high content either of starch, or of sugars and starch combined, or a high content of protein. Analyses and about 40 digestion experiments are reported. Analyses and digestion experiments on 56 feeds are averaged. The occurrence and the digestibility are briefly discussed for the sugars, starches, total pentosans, pentosans in nitrogen-free extract, pentosans in crude fiber, and the residual nitrogen-free extract. CONTENTS Page Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Method of Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Composition of feeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . '. . . . . . . . 7 Coefficients of digestibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Nature of the residual nitrogen-free extract . . . . . . . . . . . . . . . 13 Relation of nitrogen-free constituents to feeding value . . . . . . 13 Summary . . I‘! . . . . . . .1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 BULLETIN NO. 418 NOVEMBER, 1930 DIGESTIBILITY BY SHEEP OF THE CONSTITUENTS OF THE NITROGEN-FREE EXTRACT OF FEEDS G. S. FRAPS The ordinary chemical analysis of feeds deals With groups of compounds. The protein, fat, crude fiber, and ash are each mixtures of definite chemical substances, which vary both in character and in relative proportions from one feed to another. The individual substances vary in digestibility, in value to the animal organism, and in other properties. The consequence is that the same groups of constituents in different feeds have different nutritive values. The differences may result in differ- ent degrees of digestibility, and in different values of the same quantity of digested material, for the purposes of production of flesh, fat, or milk, or for maintenance of the animal body. While considerable Work has been done on the constituents of protein and fats, the investigations on the constituents of the nitrogen-free extract of feeds, With the exception of pentosans, have been more limited in number. These include the Work of Frear on timothy hay (6), and Headden (7) on various Colorado feeds. Street and Bailey (9) have reported on the carbohydrates of the soy bean and Peterson and Churchill (10) on those of the navy bean (10). The Work here reported Was done in connec- tion With ordinary digestion experiments on sheep, and is in- tended to supplement the Work already reported, and is a con- tinuation of that published in Bulletin No. 172 of the North Carolina Agricultural Experiment Station and Bulletins Nos. 104, 175, 196, and 290 of the Texas Agricultural Experiment Station (1, 2, 3, 4, 5). The great differences in the productive values of feeding stuffs depend not only upon differences in digestibility, but no doubt also upon differences in chemical composition. A pound of digestible nitrogen-free extract in hays and fodders is much less valuable to the animal than a pound digested from feeds such as corn. This is no doubt caused by differences in the chemical constituents. Starch, being easily digested, has a higher value t0 the animal than other less soluble compounds which yield hexoses by hydrolysis. These studies of the composition and digestibility of the nitrogen-free extract of feeds were undertaken in the hope that they would throw some light on the reasons for the differ- ences in the feeding values of some of these feeds. 6 BULLETIN NO. 418, TEXAS AGRICULTURAL EXPERIMENT STATION Table 1.—Average percentage composition o_f feeds U) c: l‘ g C! 1"» 22 . E 2m 2i a - Q o ° u; 2 cw: "c: ' o T,» . ._ on‘ E > .5,’ s >=.c: 3 ‘t’ ' ~52 f3 E“ ' 5 c: q, w —o~ o 3 52 o. o 0U Z 0'1 1'11 U) Q4 U: F‘ Q4 Alfalfa hay . . . . . . . . . . . . . . . . . . .. 9 -1.92 1.65 1.90 9.21 22 44 14 O0 4.91 Alfalfa meal . . . . . . . . . . . . . . . . . .. 4 2.33 1.45 1.23 10.13 24.07 14 70 4.59 Alfalfa hay and meal . . . . . . . . . . .. 13 2.05 1.58 1.69 9.49 22.94 14.21 4.81 Beans, Jack . . . . . . . . . . . . . . . . . . .. 1 0.07 1.86 32.59 8.36 .13 .86 0.50 Beans, pinto . . . . . . . . . . . . . . . . . . . 1 0.12 5.77 22.22 7.30 22.80 7.53 0.44 Bermuda hay . . . . . . . . . . . . . . . . .. 2 . 1.39 1.57 4.01 18.60 24.07 22.53 3.89 Broom corn seed, ground . . . . . . .. 1 1.14 0.24 25.40 13.70 19.27 15.83 2.13 Corngram . . . . . . . . . . . . . 1 0.44 0.72 62.82 5.61 1.82 5.81 0.20. Corn bran . . . . . . . . . . . . . . . . . . . .. 1 1.14 1.92 26.79 19.09 15.69 23.09 4.00 Corn cobs (ground) . . . . . . . . . . . . . 1 0.49 0.34 2.39 26.31 23. 18 33.07 6.76 ' Corn silage (dried) . . . . . . . . . . . . . . 1 2. 41 0.13 6. 02 16. 96 23.52 20.96 4.00 Cottonseed, Whole pressed . . . . . . . 3 0. 06 3.73 0.00 11.14 12. 51 14.40 2. 99 Cottonseed hulls . . . . . . . . . . . . . .. 3 0.10 0.18’ 1.14 18.74 14.87 23.68 4.71 Cottonseed meal . . . . . . . . . . . . . . . 5 0.26 5.60 0.04 7.96 10.59 9.42 1.46 DOlIChOS lablab hay . . . . . . . . . . . . . 1 0. 65 0. 54 6. 63 8.29 17. 5O 13.29 5.00 Darso seed . . . . . . . . . . . . . . . . . . . .. 1 0.76 0.30 56.24 3.14 10.31 3.36 0.22 Feterita forage . . . . . . . . . ..~ . . . . .. 1 0. 58 0.19 3. 72 17.12 20.28 22.46 5. 34 Feterita seed . . . . . . . . .._. . . . . . . .. 1 0.35 0.77 60.05 3.19 5.66 3.39 0.20 Flax plant by-product . . . . . . . . . . . 1 0.25 0.20 1.66 12.50 18. 27 20.37 7. 87 Goose rass . . . . . . . . .... . . . . . . .. 1 0.39 0.14 0.25 19.74 25.24 24.55 4.81 Kafirc ops . . . . . . . . . . . . . . . . . . .. 1 0.58 0.34 65.14 4.25 0.22 4.45 0.20 Kafir forage . . . . . . . . . . . . . . . . . .. 1 1.01 0.55 2.36 17.94 23.89 23.26 5.32 Kafir head chops . . . . . . . . . . . . . .. 1 0.48 0.90 54.18 6.75 5.11 8.75 2.00 Kafir head stems. .; . . . . . . . . . . .. 1 1.69 0.25 8. 91 22. 67 23.23 26.01 3.34 Linseed meal . . . . . . . . . . . . . . . 2 0.35 2.75 3.17 9.70 20.06 11.11 1.42 Mesquite beans (in pods) . . . . . . .. 1 1.55 13.73 4. 65 10. 85 16.77 16.18 5.34 Mesquite grass . . . . . . . . . . . . . . . .. 1 0.58 0.10 1.23 18.23 22.12 21.53 3.30 Miloc ops . . . . . . . . . . . . . . . . . . .. 1 0.57 0.63 54.21 10.06 3.75 10.56 0.50 Milo forage . . . . . . . . . . . . . . . . . . .. 1 0.55 0.37 1.64 18.65 23.77 23.73 5.08 Milo (grain) . . . . . . . . . . . . . . . . . .. 4 1.18 0.32 59.01 4.12 6.79 4.32 0.20 Moth beanhay................. 1 0.66 0.29 4.55 6.76 22.01 11.76 5.00 Oak leaves, live . . . . . . . . . . . . . . .. 1 1.07 0.04 0.61 9.11 34.48 13.22 4.11 Oats, rolled (oat groats) . . . . . . . . . 1 0.19 1.13 52.43 3. 63 8. 00 3.66 0.04 Oats, whole, 12% fibre . . . . . . . . .. 1 1.00 0.79 36.55 10.32 9.41 11.65 1.33 Oats, whole, low grade (17% fibre) 1 1.27 0. 65 27. 87 15. 95 9.23 18.15 2.20 Oat hull clipping . . . . . . . . . . . . ..- 3 1.04 0.21 7.36 18.46 18.06 21.45 3.31 Oat meal mill by-product . . . . . . . . 2 1.03 0. 60 10.91 23.17 15.33 26. 93 3.89 Peanut ha . . . . . . . . . . . . . . . . . . .. 4 1.89 2.78 4.29 8.27 26.92 11.80 3.53 Peanut huls . . . . . . . . . . . . . . . . . .. 3 0.93 1.41 1.99 4.56 11.25 16.12 11.56 Peanut kernels . . . . . . . . . . . . . . . .. 1 0.19 5.11 4.56 2.33 1.16 2.69 0.36 Peanut vines . . . . . . . . . . . . . . . . . .. 2 4.97 1.91 5.97 7.07 28.78 11.07 4.00 Peat . . . . . . . . . . . . . . . . . . . . . . . . .. 1 0.09 0.03 0.53 2.25 32.00 2.62 0.37 Prairie hay . . . . . . . . . . . . . . . . . . .. 5 1.89 0.76 2.12 16.68 25.11 13.99 10.74 Rhodes grass hay . . . . . . . . . . . . . .. 2 1.67 0.93 1.01 19.15 19.94 23.46 4.31 Ricebran . . . . . . . . . . . . . . . . . . . .. 2 1.25 5.54 17.52 8.04 9.17 9.92 1.90 Rice ha . . . . . . . . . . . . . . . . . . . . .. 1 1.17 0.82 6.80 15.30 15.82 18.91 3.61 Rice hu ls . . . . . . . . . . . . . . . . . . . .. 2 0.20 0.27 2.63 9.53 15.36 16.26 6.74 Rice polish . . . . . . . . . . . . . . . . . . .. 3 1.77 4.04 41.15 4.94 . . . . .. 5.14 0.20 Rice, rough... 3 0.36 0.56 60.01 5.15 0.02 5.65 0.50 Shallu forage . . . . . . . . . . . . . . . . . . 1 0. 63 0.39 1.47 20.64 22.44 26.07 5.43 Sorgo forage (accuff) . .. . . . . . . .. 1 0.17 0.39 1.50 19.75 22.05 25 14 5.39 Sorghum hayp . . . . . . . . . . . . . . . .. 2 8.50 0.48 3.55 13.92 21.86 18 92 5.00 Sorghum seed (red top) . . . . . . . . . 1 0. 86 1.17 49.90 3.96 16.89 4.31 0.35 Sorghum silage (dried) . . . . . . . . . . 1 3.79 0.03 23.56 10.26 20.39 15.26 . . . . . . Silage (dried) sorghum and cow- pea...., . . . . . . . . . . . . . . . . . .. 1 2.61 1.82 15.70 11 59 21.57 16.59 . . . . .. Sudan grass hay . . . . . . . . . . . . . . .. 5 3.15 0. 89 .23 15 29 20. 98 19.72 4.43 Tabosa grass......... 2 p 1.53 0.97 2.50 17 88 22.98 22.88 5.00 Velvet beans . . . . . . . . . . . . . . . . . . . 1 3.26 2.58 25.58 6 28 12.25 7.15 0.87 Velvet beans, pods..... . . . . . . . .. ~ 1 0.49 -0.02 0.86 12 82 33.90 15.99 3.34 Wheat, whole . . . . . . . . . . . . . . . . . . 1 0.82 2.38 51.64 7 33 8.36 7.83 0.50 Wheat bran . . . . . . . . . . . . . . . . . . . . 1 0. 79 4. 89 15.53 20 24 12.92 20.94 0. 70 Wheat gray shorts . . . . . . . . . . . . .. 2 1.21 5.11 28.92 13 63 8.25 14.07 0.45. Wheat white shorts . . . . . . . . . . . . . 1 0.62 1.80 52. 15 6 65 6.03 6.75 0.10 DIGESTIBILITY BY SHEEP OF CONSTITUENTS OF N.-F. EXTRACT OF FEEDS 7 METHOD OF WORK The materials used Were secured in the digestion experiments with sheep, discussed in Bulletins Nos. 291, 315, and 402 of this Experiment Station. The feeds were fed alone or in combina- tion, as there described. The sugars were extracted with 50 per cent alcohol, and esti- mated by the Munsen and Walker method. Starch was made soluble by diastase, on material previously extracted with ether .and alcohol, and the analysis was completed in the usual way. Some gums, if present, Would be included in the starch. Total pentosans were determined in the usual way, by conversion into furfural followed by precipitation with phloroglucinol. Pen- tosans in crude fiber were estimated in the crude fiber prepared from a 3-gram sample. The total pentosans less that in the crude fiber gives the pentosans in the nitrogen-free extract. The reducing sugars, non-reducing sugars, starch and pentosans in ‘the nitrogen-free extract, were added together and the sum sub- tracted from the total nitrogen-free extract. The difference is here called the residual nitrogen-free extract. The residual nitrogen-free extract is the amount of total nitrogen-free extract remaining after the sugars, starches, and pentosans in the nitrogen-free extract have been deducted. COMPOSITION OF FEEDS The ordinary analysis of the feeds is‘ given in Bulletins Nos. 1291, 315, and 402. Table 1 contains the sugars, starch, and other constituents of the feeds used in the experiments here ' "reported. It also includes those used in previous experiments, already reported, for purposes of comparison, together with some additional analyses. The feeds known to be of high feeding value are characterized by a high content of sugars and starch, or, if the starch content is not high, by a high percentage of protein. The residual nitrogen-free extract, while appreciable, is low compared with ‘the other classes of feed. The roughages or feeds of low feeding value are generally characterized by a high content of pentosans and of residual nitrogen-free extract. The nature of the residual nitrogen-free extract of these feeds is a good subject for further study. h With respect to sugar, the feeds studied may be grouped as follows: ~ Less than 2 per cent sugar—broom corn seed, corn cobs, cot- tonseed hulls, cottonseed meal from heated seed, darso seed, flax plant by-product, ‘goose grass, kafir head stems, live oak 8 BULLETIN NO. 418, TEXAS AGRICULTURAL EXPERIMENT STATION leaves, milo seed, oat groats, Whole oats, oat hull clippings, oat meal mill by-product, peanut shells, rice hulls. From 2 per cent to 5 per cent sugar—alfalfa, cottonseed feed, cottonseed meal, linseed meal, sacchuista grass, sorgo seed, Wheat White shorts. Over 5 per cent sugar—mesquite beans in pods (15.28 per cent of sugar), rice bran, rice polish, velvet beans in pod, velvet beans, whole wheat, Whole bran, Wheat gray shorts. With respect to starch, the feeds studied may be grouped as follows: Less than 2.5 per cent starch—alfalfa, corn cobs, cottonseed feed, cottonseed hulls, goose grass, live oak leaves, mesquite beans, peanut hulls, rice hulls. From 2.5 per cent to 25 per cent starch—commercia1 kafir head stems, linseed meal, mesquite beans in pod, oat hull clippings, oat meal mill by-product, pinto beans, velvet beans in pods, rice bran, Wheat bran. From 25 per cent to 50 per cent starch—broom-corn seed, Whole oats, rice polish, sorghum seeds, velvet beans, Wheat gray shorts. l Uver 50 per cent starch——darso seed, milo seed, oat groats, Whole Wheat, Wheat White shorts. Pentosans are low in the concentrated feeds and high in hays and fodders. Feeds containing less than 6 per cent of total pentosans include corn, darso seed, feterita seed, kafir seed, milo seed, oat groats, peanut kernels, rice polish, rough rice, and sorghum seed. Feeds With 6 to 11 per cent pentosans include beans, cottonseed meal, kafir head chops, milo head chops, rice bran, velvet beans, Whole Wheat, and Wheat White shorts. Alfalfa, dolichos lablab, linseed meal, moth bean hay, Whole oats, peanut hay, and vvheat-gray shorts contain 11 to 14 per cent of pentosans. Cereal hays and other roughages in general contain over 20 per cent of pentosans. COEFFICIENTS OF DIGESTIBILITY The coeflicients of digestibility secured are given in Table 3. Average coefficients of digestibility for the work given in this and previous bulletins, are given in Table 2. Single experiments (usually with two sheep) are also given, so that the table presents a complete summary of the digestion coefiicients secured with sheep. Sugars and starches have almost invariably a high diges- tibility. In a few cases, the digestibility appears to be loW, but this is in feeds which have a low content of sugar or starch. It is also questioned if the reducing substances found in the excre- ment really consists of sugar. As pointed out previously (1), DIGESTIBILITY BY SHEEP OF CONSTITUENTS OF N.-F. EXTRACT OF FEEDS 9‘ Table 2.-—Averag_e digestion coefficients, with sheep. Each experiment usually with two sheep (h a 5 ‘H $1, .5 8 .5 ° E a w» 2a J1 ‘E 2 $11 as 5 '5 é o cw - w - a as - Q 3 5 8 5 ‘J3 ‘<8 5 .5“. é“? T‘, 35' 5 § g 8 5 "Z5 E EZ T32 s’ 5° Z m m u: m m: P m Alfalfa hay . . . . . . . . . . . . . . . . . . . . 16 97 98 86 56 69 53 41 Alfalfa meal . . . . . . . . . . . . . . . . . . . 4 95 96 81 60 70 58 52 Cottonseed hulls . . . . . . . . . . . . . . . 7 52 69 44 78 24 76 57 Cottonseed meal . . . . . . . . . . . . . . . . 5 73 99 . . . . . . 95 53 94 79 Cold pressed cottonseed . . . . . . . . . 3 72 99 . . . . . . 86 41 82 13 Bermuda hay . . . . . . . . _ . . . . . . . . . 2 97 99 9O 44 48 4,4 43 Broomcorn seed, ground . . . . . . . . . 1 77 100 84 37 2O 32 5 Corn bran . . . . . . . . . . . . . . . . . . . . . 1 99 1OO 99 93 65 90 . . . . . . Corn, Argentine . . . . . . . . . . . . . . . . 1 1OO 1OO 93 97 50 91 23 Corn cobs . . . . . . . . . . . . . . . . . . . . . 1 84 79 83 53 34 55 65 Corn silage . . . . . . . . . . . . . . . . . . . . 1 99 94 97 77 68 56 72 Dalochos lablab hay . . . . . . . . . . . . . 1 94 1OO 92 49 63 56 68 Feterita forage . . . . . . . . . . . . . . . . . 1 94 97 89 64 54 63 71 F eterita seed . . . . . . . . . . . . . . . . . . . 1 1OO 1OO 99 91 73 85 50 Flax plant by-product . . . . . . . . . . . 2 30 69 . . . . . . 2 . . . . . . 3 5 Goose grass. . . . . . . . . . . . . . . . . . . . 1 79 1OO 1OO 44 22 42 33 Jack beans . . . . . . . . . . . . . . . . . . . . . 1 1OO 1OO 100 97 78 95 . . . . . . Kafir chops . . . . . . . . . . . . . . . . . . . . 1 95 1OO 97 89 O 75 . . . . . . Kafir head chops . . . . . . . . . . . . . . . 1 1OO 88 88 64 3 57 . . . . . . Kafir head stems . . . . . . . . . . . . . . . 1 91 95 94 51 23 48 32 Kafir forage . . . . . . . . . . . . . . . . . . . 1 94 97 95 43 42 54 46 Linseed meal . . . . . . . . . . . . . . . . . . 1 78 99 97 84 79 78 44 Live oak leaves. . . . . . . . . . . . . . . . 1 1OO 1OO 1OO 1 28 13 38 Mesquite beans . . . . . . . . . . . . . . . . 2 87 79 97 58 48 52 43 Milo head chops . . . . . . . . . . . . . . . . 1 1OO 1OO 99 92 3 7O . . . . . . Milo forage . . . . . . . . . . . . . . . . . . . . 1 81 79 6O 57 41 62 68 Moth bean fodder . . . . . . . . . . . . . . 1 85 94 93 47 63 59 74 Milo . . . . . . . . . . . . . . . . . . . . . . . . . . 4 90 64 99 9O 77 79 33 Oats . . . . . . . . . . . . . . . . . . . . . . . . . . 2 89 98 1OO 74 54‘ 68 46 Oat hull clippings . . . . . . . . . . . . . . . 2 47 53 93 65 29 64 54 Oat meal mill by-product . . . . . . . . 2 96 94 1OO 35 22 33 20 Peanuts, whole . . . . . . . . . . . . . . . . . 1 84 1OO 1OO 5O . . . . . . 4O 28 Peanut hay . . . . . . . . . . . . . . . . , . . . 4 98 1OO 91 66 62 6O 58 Peanut vines . . . . . . . . . . . . . . . . . . . 1 52 88 92 64 76 . . . . . . 66 Peanut hay with nuts . . . . . . . . . . . 1 84 1OO 1OO 5O O 4O 28 Peanut hulls . . . . . . . . . . . . . . . . . . . 2 97 1OO 88 1O 64 24 4O Pinto beans . . . . . . . . . . . . . . . . . . . . 1 97 1OO 99 9O 86 85 35 Prairie hay . . . . . . . . . . . . . . . . . . . . 6 97 94 77 52 35 5O 43 Rhodes grass hay . . . . . . . . . . . . . . . 2 97 97 61 62 63 62 64 Rice bran . . . . . . . . . . . . . . . . . . . . . 2 95 1OO 1OO 6O 38 47 2 Rice hay . . . . . . . . . . . . . . . . . . . . . . 1 94 95 86 46 26 46 5O Rice polish . . . . . . . . . . . . . . . . . . . . 3 98 99 1OO 88 44 76 19 Rice hulls . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . 81 88 43 24 49 43 Rough rice . . . . . . . . . . . . . . . . . . . . . 3 88 1OO 99 34 . . . . . . 52 . . . . - .- Shallu forage . . . . . . . . . . . . . . . . . . . 1 94 1OO 73 56 41 58 65 Sprgo forage accuif . . . . . . . . . . . . . 1 74 96 67 57 32 74 55 Sorghum hay . . . . . . . . . . . . . . . . . . 2 99 93 83 49 48 65 55 Silage, sorghum, and cowpeas. . . . 1 95 97 9O 28 32 36 - - . - - - Sorghum silage . . . . . . . . . . . . . . . . . 1 98 1OO 92 40 46 49 . . . . . . Sudan grass . . . . . . . . . . . . . . . . . . . . 5 99 84 77 53 38 55 58 Tabosa grass . . . . . . . . . . . . . . . . . . . 2 98 99 79 48 36 49 53 Velvet beans, cracked and pods. . . 1 98 98 96 97 90 95 87 Wheat, whole . . . . . . . . . . . . . . . . . . 1 98 1OO 99 96 95 95 86 Wheat bran. . .- . . . . , . . . . . . . . . . . . . 1 91 15 26 22 79 26 1OO Wheat gray shorts . . . . . . . . . . . . . . 2 96 99 1OO 85 4O 85 46 Wheat white shorts . . . . . . . . . . . . . 1 95 99 1OO 95 74 93 1OO IO. TBULLETIN NO. 418, TEXAS AGRICULTURAL EXPERIMENT STATION other materials may give rise to the small amount of reduction "which occurs. The digestibility of the pentosans in the nitrogen-free extract waries according to the nature of the feed in which it is con- "tained. The digestibility is especially loW with oatmeal mill by- product. As a rule, the pentosans in the nitrogen-free extract are digested to a greater extent than the total pentosans or the pentosans in the crude fiber. The total pentosans in hays and fodders are generally digested to the extent of around 50 to 60 per cent. Corn silage, corn cobs, kafir-head chops, kafir-head stems, rice bran, rice hulls, and rough rice come in the same group. The pentosans of certain feeds have a high digestibility; ithis group includes cottonseed meal, cottonseed hulls, corn bran, _jack beans, linseed meal, milo, pinto beans, rice polish, velvet ‘beans in pods, Whole Wheat, Wheat gray shorts, and Wheat White shorts. The pentosans of some feeds have a lOW digestibility; "these include broom-corn seed, flax plant by-product, live oak ileaves, and peanut hulls. The pentosans in the crude fiber are generally digested to a less extent than the total pentosans, and the pentosans in the nitrogen-free extract to a greater extent. This is exactly What one Would expect. The pentosans in the nitrogen-free extract have a high digestibility in cottonseed meal, corn bran, corn, ffeterita seed, jack beans, kafir, cold-pressed cottonseed, linseed rmeal, milo head chops, milo, pinto beans, rice polish, velvet beans pod, whole Wheat, Wheat gray shorts, and Wheat white shorts. The residual nitrogen-free extract in hays and fodders is generally digested to a greater extent than the pentosans, in which the pentosans have a digestibility around 50 to 60 per cent. The digestibility of the residual nitrogen-free extract is generally lower than that of the pentosans in such feeds as have high digestion coefficients for pentosans. Corn cobs Was the (only exception to this rule; the pentosans in the crude fiber were digested to a greater extent than those in the nitrogen-free ex- tract. There is a possibility that fermentation in the animal umay change crude fiber so as to be partly soluble in 1i per cent acid or alkali, thereby causing it to appear in the nitrogen-free extract. This change may have occurred with the corn cobs. The residual nitrogen-free extract has a low ‘digestibility in nzottonseed hulls, broom-corn seed, corn cobs, goose grass, kafir ‘chops, kafir head chops, kafir head stems, live oak leaves, milo head chop, oatmeal mill by-product, peanut hay with nuts, rice liay, rice hulls, and rough rice. wflwO-HMB . . . . 300:0 0E» 0H0 . ...........0wHmH0H 0002 H0 0H0 0 .02 . .. . 0 00.20 0005 00000 0:0 . . H0 .00 H.w0 0.00 H .02 002m 1.1.1.02 .0 Q A 0 0050002 0x02 m w w» we... HmmmmH W00 MHHHWWH 0ww MH mm 0000M. 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O - . . - - - . . % . . . . . . . . . . - . . . . . . . . . . . . . m . . . . . . . . . . . . . . . . . - . . - . ‘m .Q 0.00M 0.00M 0.00M 0.00M v.00 0.00M 0.00 0M 02 000:0 . 0.00M 0.00M M.0v 0.00M 0.v0 0.00M 0.v0 0 .02 000:0 . . . . . . . . . . . . . . . . . . . . . .0vM .0M 0M 202020 :::30 0M:M>: 00M00 MM .0 0000 am 4.: .2 E0000 .02 0: 0:00 -3000 .mM .0M .2 0: 0000 :0:0:0 0000005. 0:: 201M 10:00AM :0.:0.H M0:M.:00MM. 10000.0 009202 0000M v0:0:::0n0|0:00:0:2000 00200020 Q2361? DIGESTIBILITY BY SHEEP OF CONSTITUENTS OF N.-F. EXTRACT OF FEEDS 13 NATURE OF THE RESIDUAL NITROGEN-FREE EXTRACT The nitrogen-free extract of feeds is quite generally assumed to consist of sugars, starches, pentosans, and other carbohy- drates. This assumption is not strictly correct. It is known that phytin (inosite phosphoric acid) may be present in cotton- seed meal or wheat bran to the extent of 3 to 6 per cent and the organic part of phytin is part of the nitrogen-free extract. Chlorophyll, organic acids, and ligno-cellulose are also known to be present. Carbohydrates no doubt make up most of the nitrogen-free extract in concentrates such as corn, Wheat, or milo. It is different, however, with roughages and by-products which consist partly of the woody or fibrous material of the plant. According to unpublished work of the writer, .the nitrogen-free extract of these materials may contain large per- centages of substances which it is not possible to hydrolize to sugars. The low digestibility of the residual nitrogen-free ex- tract in some feeds is further evidence of its non-carbohydrate nature. RELATION OF NITROGEN-FREE CONSTITUENTS TO FEEDING VALUE It is known from the work of Kellner, Armsby, and others, that the value for energy purposes of the digested nutrients of roughages is much less than the value of concentrates. While a portion of this loss may be due to the work of chewing and digestion, a portion may also be due to the lower value of the chemical constituents of the hays and fodders, involving losses of energy both in digestion and in utilization of the digested nutrients. As has been pointed out in the preceding pages, the concentrates usually contain high percentages of starches, which can be readily digested and utilized. The roughages contain low percentages of starches, together with pentosans, and other car- bohydrates, together with non-carbohydrate material, possibly, in relatively high percentages. The low value of the digested material of roughages as com- pared with concentrates is thus associated‘ with radical differ- ences in chemical constituents. The nature of the constituents of the nitrogen-free extract of roughages offers a field for ex- tensive study. Additional work will be reported by the Texas Agricultural Experiment Station. SUMMARY The percentages of sugars, starches, pentosans, and residual nitrogen-free extract were determined in a number of feeds. The digestibility, by sheep, of the sugars, starches, pentosans, perimeint-Sltation, Bulletin No.290.- » r ~ a 14 BULLETIN NO. 418, TEXAS AGRICULTURAL EXPERIMENT STATION and residual nitrogen-free extract, was determined on a number of feeds and average figures given for 56 feeds. _ jilgeds-known to be of high feeding value are characterized by a high content of starch, 0r sugar and starch combined, or, if the starch content is not high, by a high contentrof protein...- \The nitrogen-free extract of feeds of low feeding "value con- tains high percentages of pentosans and of residual nitrogen- free extract. The nitrogen-free extract of some feeds contains-appreciable percentages of compounds which are not carbohydrates. Sugars and starches have a high digestibility. . The digestibility of pentosans varies according to the kind of feed, being around 50 to 6O per cent with. a number of feeds. The pentosans in crude fiber are usually digested to a less. > extent than the total pentosans, or the pentosans in the nitrogen- free extract. . . The residual nitrogen-free extract in hays and fodders is gen- erally digested to a greater extent than are the pentosans. ‘ACKNOWLEDGMENT Analytical and other work involved in the preparation of this Bulletin has been done by J. K. Blum, .K. Kitsuta, J. B. Smith, Waldo Walker, and other members of the staff. REFERENCES 1. Fraps, G. S. (1900) The Digestibility of Some Non-Nitrogenous Constituents of Certain Feeding Stuffs, North Carolina Agricultural ' Experiment Station Department, Bulletin No. 172. -2. Fraps, G. S. (1908) ' Digestion Experiments, Texas Agricultural Experiment ' Station, Bulletin No. 104. ‘ ~ 3. Fraps, G. S. (1915) I " Distribution and Digestibility of the Pentosans of Feeds, Texas Agricultural Experiment Station, Bulletin No. 175. ' 4. Fraps, G. S. (1916) - ' ’ ? " _'Digestibility' of Sugars, Starches, and Pentosans of ~ ' Roughages, Texas Agricultural Experiment Station, Bul- r "letin No.“ 196. ' I A _ " s ' 5. Fraps, G. S. (1922) ' ’ - ' ‘ Digestibility of the Sugars, Starches, Pentosans, and Protein of some Feeding Stufis, Texas Agricultural Ex- ,6; .,."Frear,.Wm., etial. ~ (1904) a , a . s a .;,,.Studies upon the Composition of Timothy Hay, Pennsyl- vania Station Report, 1904, p. 40. DIGESTIBILITY BY SHEEP OF CONSTITUENTS OF N.-F. EXTRACT OF FEEDS 1S 7. 10. Headden, W. P. (1907) Colorado Fodders, Colorado Agricultural Experiment Station, Bulletin No. 124. . McCollum, E. V. and Brannon, W. A. (1909) The Disappearance of Pentosans from the Digestive Tract of the Cow, The Journal of American Chemical Society, 31 :1252. Street, J. P. and Bailey, E. M. (1915) The Carbohydrates and the Enzymes of the Soy Bean, The Journal of Industrial and Engineering Chemistry, 7:853. Peterson, W. H., and Churchill, H. (1920) The Carbohydrate Content of the Navy Bean, Journal of the American Chemical Society, 43:1180.