The Effects of High-Oil Corn or Typical Corn with or without Supplemental Fat on Diet Digestibility in Finishing Steers

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1 Beef Reserch Report, 2000 Animl Science Reserch Reports 2001 The Effects of High-Oil Corn or Typicl Corn with or without Supplementl Ft on Diet Digestibility in Finishing Steers Crig R. Belknp Iow Stte University Allen Trenkle Iow Stte University Follow this nd dditionl works t: Prt of the Animl Sciences Commons Extension Number: ASL R1719 Recommended Cittion Belknp, Crig R. nd Trenkle, Allen, "The Effects of High-Oil Corn or Typicl Corn with or without Supplementl Ft on Diet Digestibility in Finishing Steers" (2001). Beef Reserch Report, This report is brought to you for free nd open ccess by the Animl Science Reserch Reports t Iow Stte University Digitl Repository. It hs been ccepted for inclusion in Beef Reserch Report, 2000 by n uthorized dministrtor of Iow Stte University Digitl Repository. For more informtion, plese contct digirep@istte.edu.

2 The Effects of High-Oil Corn or Typicl Corn with or without Supplementl Ft on Diet Digestibility in Finishing Steers Abstrct Two 3 x 3 ltin squres were utilized in n 84-dy digestion tril with ruminlly- nd duodenllycnnulted steers. Diets consisted of 73 to 78% whole corn grin, 12.3% corn silge nd 2.0% N, with tretment differences being high-oil corn- (), isogenetic typicl-corn- (TC), or isogenetic typicl-corn + ft- (TC+F) bsed diets. The nd TC+F diets were formulted to provide the sme ether extrct (EE) content. All diets were fed t 90% of d libitum intke. Chromic oxide ws used s digestibility mrker. Totl trct dry mtter (DM) (P=.08), orgnic mtter (OM) (P=.08) nd nitrogen (N) (P=.06) digestibilities tended to be greter for TC thn diets, wheres strch neutrl detergent fiber (NDF), cid detergent fiber (ADF), nd ether extrct digestibilities were similr (P>.10). There were no differences (P>.10) in totl trct dry mtter, orgnic mtter, strch, NDF, ADF, ether extrct, or nitrogen digestibilities between TC+F nd diets or TC nd TC+F diets. Ruminl digestion of dry mtter, orgnic mtter, strch, NDF, ADF, nd feed nitrogen ws similr (P>.10) mong tretments. Microbil-nitrogen flow nd efficiencies were lso similr (P>.10) mong tretments. Results indicte finishing steer diets composed of primrily re eqully or less digestible thn similr diets composed of TC, nd dding ft to TC diets did not ffect the digestibility of the diet when fed to finishing steers. Keywords ASL R1719 Disciplines Animl Sciences This feedlot nutrition is vilble t Iow Stte University Digitl Repository:

3 The Effects of High-Oil Corn or Typicl Corn with or without Supplementl Ft on Diet Digestibility in Finishing Steers A.S. Leflet R1719 Crig R. Belknp, grdute reserch ssistnt Allen Trenkle, professor of niml science Summry Two 3 x 3 ltin squres were utilized in n 84-dy digestion tril with ruminlly- nd duodenllycnnulted steers. Diets consisted of 73 to 78% whole corn grin, 12.3% corn silge nd 2.0% N, with tretment differences being high-oil corn- (), isogenetic typicl-corn- (TC), or isogenetic typicl-corn + ft- (TC+F) bsed diets. The nd TC+F diets were formulted to provide the sme ether extrct (EE) content. All diets were fed t 90% of d libitum intke. Chromic oxide ws used s digestibility mrker. Totl trct dry mtter (DM) (P=.08), orgnic mtter (OM) (P=.08) nd nitrogen (N) (P=.06) digestibilities tended to be greter for TC thn diets, wheres strch neutrl detergent fiber (NDF), cid detergent fiber (ADF), nd ether extrct digestibilities were similr (P>.10). There were no differences (P>.10) in totl trct dry mtter, orgnic mtter, strch, NDF, ADF, ether extrct, or nitrogen digestibilities between TC+F nd diets or TC nd TC+F diets. Ruminl digestion of dry mtter, orgnic mtter, strch, NDF, ADF, nd feed nitrogen ws similr (P>.10) mong tretments. Microbil-nitrogen flow nd efficiencies were lso similr (P>.10) mong tretments. Results indicte finishing steer diets composed of primrily re eqully or less digestible thn similr diets composed of TC, nd dding ft to TC diets did not ffect the digestibility of the diet when fed to finishing steers. Introduction Ft is sometimes dded to finishing cttle diets to increse the cloric density of the feed in hopes of ultimtely improving verge dily gin nd feed efficiency. Recently, high-oil corn, which hs pproximtely twice the oil content of typicl corn, hs become more populr from n gronomic stndpoint due to dvncements in plnt breeding nd improvements in yields nd gronomic trits. Becuse corn is the primry source of energy used in mny finishing cttle diets, the use of high-oil corn is n lterntive wy to increse the dietry energy concentrtion. Previous reserch published in the 1999 A.S. Leflet R1631 discussed the effects of high-oil corn or supplementl niml/vegetble ft on finishing steer performnce nd crcss chrcteristics. In summry, yerling steers fed high-oil corn-bsed diets numericlly hd lower verge dily gin nd poorer feed efficiency thn steers fed typicl-corn- or typicl-corn + ft-bsed diets during the first 56 dys of the study. However, during the finl 50 dys of the feeding tril, steers fed the high-oil corn diet gined fster nd were more efficient thn steers consuming the typicl-corn-bsed diets with or without dded ft. Therefore, the objectives of this experiment were to compre the nutrient digestibilities of finishing steer diets contining primrily high-oil corn, isogenetic typicl-corn, nd isogenetic typicl-corn with supplementl niml/vegetble ft. Mterils nd Methods Three mture crossbred steers hd been fitted with rumen nd duodenl cnnules. The steers were used in two successive 42-dy, 3 x 3 ltin squre digestibility trils. Ech ltin squre consisted of three, 14-dy periods, with the initil 8 dys of ech period being for diet cclimtion, followed by 6-dy smpling period on the sme diet. The steers were rndomly ssigned to dietry tretments (Tble 1) consisting primrily of typicl-corn, typicl-corn with n dded niml/vegetble ft blend, or high-oil corn. All corn grin ws fed s unprocessed, whole kernel corn. Ft ws dded to the typicl-corn-bsed diet t level to supply dietry ether extrct in n mount (5.6%) equl to tht of the high-oil corn diet. The silge ws weighed seprtely nd dded to the concentrte mix t ech feeding to mintin freshness. All diets were formulted to be isonitrogenous (2.0%) nd contin the sme mount of both protein nd non-protein nitrogen. Additionl nutrient requirements were met or exceeded ccording to NRC recommendtions. The nutrient compositions of both types of corn re shown in Tble 2. The steers were fed monensin throughout the experiment nd were housed in individul 3 meter by 3 meter pens with rubber mtted flooring. These pens were locted in n environmentlly controlled room mintined t 25 o C with continuous rtificil lighting nd fresh supply of clen drinking wter. 25

4 Tble 1. Diet composition (% of dry mtter). Diet Ingredient Typicl Typicl + Ft High-Oil Corn Corn silge (ll non-high-oil) Soyben mel Molsses Blended ft Limestone Ure Sodium chloride Potssium chloride Vitmin A premix Elementl sulfur Trce minerls Monensin premix b Provided 3,080 IU/kg dry mtter. b Provided 34.3 mg/kg dry mtter. Tble 2. Nutrient composition of corn vrieties. Corn Vriety Composition (%) Typicl High-Oil Dry mtter Nutrient composition (% of dry mtter) Ether extrct Protein Strch Typicl nd high-oil corn were sourced by Optimum Qulity Grins, Des Moines, IA. Over 60 dys, steers were cclimted to the room nd whole corn-grin-bsed finishing diet similr to the diets used throughout the experiment to determine d libitum feed intke. Fourteen dys prior to the strt of the experiment, ll steers were poured with the recommended dosge of Ivermectin to control internl nd externl prsites, lthough no visul indictions of prsitic infesttion were pprent. Throughout the experiment, steers were fed t 0900 nd 2100 dily, t level of 10% below d libitum intke. A timeline depicting the feeding nd smpling schedule for ech 14-dy period is shown in Figure 1. Smples were frozen immeditely fter collection until the end of the experiment. Upon subsequent thwing, feed nd fecl smples were pooled for ech steer by period on n equl weight bsis nd dried. Duodenl smples nd rumen bcteril pellets were freeze-dried. After drying, smples of feed, dried duodenl contents, feces nd bcteril pellets were ground, nd duodenl smples were pooled on n equl weight dry mtter bsis to form one smple per steer per period. Approprite lbortory nlyses were conducted on feed, rumen fluid, duodenl digest, nd feces to determine ruminl, intestinl, nd totl trct nutrient digestibilities for the three diets. The mmoni-nitrogen (NH 3 -N) concentrtions of ruminl fluid nd duodenl digest were mesured. Chromium ws used s digestibility mrker nd purines were used s mrker for microbil flow. Anlysis of vrince ws used to nlyze the dt s two 3 x 3 ltin squres. Tukey s multiple rnge comprison ws used to test dietry tretments for significnce. Dt were considered sttisticlly significnt t P<.05, wheres trend or tendency ws indicted t P<.10. P-vlues greter thn.10 were considered not significnt (NS). The stndrd errors of the mens (SEM) re lso presented. 26

5 Results nd Discussion The pprent ruminl digestion of dry mtter, orgnic mtter, strch, NDF, ADF, ether extrct or feed nitrogen ws not significntly different mong typicl-corn, typiclcorn + ft, nd high-oil corn diets (Tbles 3, 4, nd 5). Although the rumen digestibility of dry mtter, orgnic mtter, ether extrct, nd nitrogen frctions of the high-oil corn diet were numericlly less thn either of the two typicl-corn-bsed diets, sttisticl significnce could not be reched due to lrge mount of vrition nd inconsistency in digestibility coefficients. On the contrry, the rumen digestion of the fibrous frction of the diet (NDF nd ADF) ws numericlly higher, lthough not significnt, for either of the diets with the dded energy source thn the unsupplemented typicl-corn diet. Prior reserch indictes supplementl ft will either not chnge or will decrese fiber digestion in the rumen, due to decrese in microbil ttchment to the ft-coted feed prticle. Nonetheless, it seems s though the ft in the present diet did not hve detrimentl effect on bcteril ttchment to feed fiber. For the high-oil corn diet this could hve been due to the fct tht the dditionl dietry oil ws within the corn kernel, where it hs very little opportunity to interfere with the fibrous frction of the feed. In the typicl-corn + ft diet, the fct tht dded ft did not ffect fiber digestion ws probbly due to combintion of two things. First, the ft ws dded to the grin portion of the diet t mixing wheres the silge ws mixed with the concentrte immeditely prior to feeding. Therefore, the ft never hd the opportunity to physiclly cot the silge, which is the portion of the diet contining the mjority of the fiber. Secondly, the ft included in the diet ws reltively smll mount tht pprently hd no effect on the popultion of fiber digesting bcteri in the rumen. This is further confirmed by very similr bcteril nitrogen flows reching the duodenum with ll three of the diets. Moreover, there ws no difference in the mount of ether extrct tht reched the duodenum beyond tht included in the diet, indicting similr microbil ft synthesis. All of this suggests the dded ft from either the ft supplemented diet, or the high-oil corn diet hd no detrimentl effect on the rumen microbil popultion. However, this is ll overshdowed by the fct tht the mount of dietry fiber in the rtion of finishing cttle is typiclly very low, which mkes smll differences in fiber digestion of little importnce in the overll efficiency of the niml to convert feed to gin. Figure 1. Feeding nd smpling schedule for ech period. Dys 1-6 Feed steers; dminister chromium gel-cp in rumen: 0900, Dys 7-8 Feed steers; dminister chromium gel-cp in rumen: 0900, Dy 9 Feed steers; dminister chromium gel-cp in rumen: 0900, Duodenl fluid collections: 0900, 1300, Fecl smple collections: 0900, 1300, Dy 10 Feed steers; dminister chromium gel-cp in rumen: 0900, Duodenl fluid collections: 1000, 1400, Fecl smple collections: 1000, 1400, Dy 11 Feed steers; dminister chromium gel-cp in rumen: 0900, Duodenl fluid collections: 1100, 1500, Fecl smple collections: 1100, 1500, Dy 12 Feed steers; dminister chromium gel-cp in rumen: 0900, Duodenl fluid collections: 1200, 1600, Fecl smple collections: 1200, 1600, Dy 13 Feed steers; dminister chromium gel-cp in rumen: 0900, Ruminl fluid collections: 0900, 1000, 1100, 1200, 1300, 1500, 1700, Dy 14 Feed steers; dminister chromium gel-cp in rumen: 0900, Ruminl fluid collections: 1200,

6 Tble 3. Effects of typicl-corn-, typicl-corn + ft-, nd high-oil corn-bsed diets on ruminl, intestinl, nd totl trct nutrient digestion in steers. Diet P-Vlue Typicl Typicl + Ft High-Oil SEM TC vs. TC+F TC vs. TC+F vs. Intke (g/d) DM OM Strch NDF ADF Apprent Ruminl Digestion (%) DM NS NS NS OM NS NS NS Feed OM NS NS NS Strch NS NS NS NDF NS NS NS ADF NS NS NS Apprent Intestinl Digestion (%) DM NS NS NS OM NS NS NS Strch NS NS NS NDF NS NS NS ADF NS NS NS Apprent Totl Trct Digestion (%) DM NS.08 NS OM NS.08 NS Strch NS NS NS NDF NS NS NS ADF NS NS NS Not significnt t P>.10. No difference ws observed in the intestinl or totl trct digestion of dry mtter or orgnic mtter between typicl-corn nd typicl-corn + ft diets. However, the high-oil corn diet tended to hve lower totl trct dry mtter nd orgnic mtter digestibility thn the typicl corn diet, nd ws numericlly less digestible (64.3 nd 65.7% versus 72.1 nd 73.5%), lthough not significntly, thn the typicl-corn + ft diet. It is difficult to ssess why the highoil corn diet ws less digestible in this study thn either of the two typicl-corn-bsed diets. Possibly the oil within the high-oil corn kernel ws inhibiting the enzymtic digestion of the feed in the smll intestine, becuse no significnt difference in ruminl digestion of these nutrients ws observed. For the sme contrst, sttisticl significnce ws not reched for intestinl digestibility, however, there did pper to be difference just by interpreting the rw numbers. In looking more specificlly t wht nutrient within the orgnic mtter of the feed ws more poorly digested in the high-oil corn diet, nitrogen is the only nutrient tht showed definite trend towrds lower intestinl nd totl trct digestibility. Both strch nd ether extrct, however, were numericlly less digestible, lthough not significntly, for the high-oil corn diet thn either of the two typicl-corn diets. With this in mind, both of the typicl-corn diets contined higher proportion of soyben mel in the diet in order to blnce the diets isonitrogenously. Becuse soyben mel composed lrge prt of the nitrogen constituent in the diets, it is possible, nd quite logicl, tht the nitrogen from the soyben mel ws more digestible thn the nitrogen contined within the corn kernel. Most of the nitrogen within the kernel is found in the germ, which is the innermost prt of the kernel. Becuse the corn ws not processed, thorough physicl mstiction of the feed would be necessry to expose the inner germ to microbil or enzymtic ctivity needed for nitrogen digestion. Similrly, the difference in ether extrct digestion cn be looked t the sme wy. Simply put, ft on the outside of the feed is more ccessible to digestion thn ft imbedded deep within the kernel. In relting these dt to those previously reported, in the feeding tril, during the first period, the increse in gin nd feed efficiency in steers fed both the supplemented nd unsupplemented typicl-corn-bsed diets coincides with the higher totl trct nitrogen digestibility observed in the digestion tril. Therefore, more nitrogen ws being digested in the typicl-corn-bsed diets, llowing for greter nitrogen retention, thereby incresing len tissue gin. Sometime within the finl 50 dys of the feeding tril, these steers 28

7 reched the point in their growth curve where len tissue deposition slows, nd ft deposition is incresed. At this time, verge dily gin nd feed efficiency typiclly declines. The steers consuming the high-oil corn diet, however, grew less rpidly during the initil 56 dys of the tril; thus, they were lighter. They lso experienced more dys of growth under which high proportion of len, nd little ft, ws being deposited. This explins the dvntge the high-oil corn fed steers hd in dily gin nd efficiency during the second phse of the feeding tril. It is possible tht the high-oil corn fed steers were responding to the dditionl energy during the finl dys of the tril, resulting in more rpid gins. However, the observtion tht the steers fed the ft-supplemented typicl-corn diet did not hve n dvntge from the stndpoint of dily gin or efficiency suggests dditionl energy is not the mjor fctor influencing gin during this period. Results from the digestion tril, lthough not sttisticlly significnt, suggest ether extrct from both of the typicl-corn diets to be more digestible thn tht from the high-oil corn diet. Therefore, the steers fed typicl-corn + ft were probbly digesting more ether extrct thn steers fed high-oil corn, yet this did not ffect feedlot performnce. Implictions This study suggests tht finishing steer diets composed of whole high-oil corn grin tend to be less digestible thn similr diets composed of trditionl corn without n dded ft source. Additionlly, blended ft dded to trditionl cornbsed finishing diets does not significntly differ from typicl-corn-bsed finishing diets or high-oil corn-bsed finishing diets from the stndpoint of nutrient digestion. However, digestion coefficients for typicl-corn-bsed diets with dded ft seem to more closely resemble those of typicl-corn diets without dded ft s opposed to high-oil corn diets. Acknowledgments This work ws supported in prt by grnts from Optimum Qulity Grins, L.L.C., nd the Iow Corn Promotion Bord, both of Des Moines, Iow. Tble 4. Effects of typicl-corn-, typicl-corn + ft-, nd high-oil corn-bsed diets on ether extrct flow nd the site nd extent of ether extrct digestion in steers. Diet P-Vlue Typicl Typicl + Ft High-Oil SEM TC vs. T+F TC vs. TC+F vs. Intke (g/d) EE Flow to Duodenum Above Intke EE (g/d) EE NS NS NS Apprent Intestinl Digestion (%) EE NS NS NS Apprent Totl Trct Digestion (%) EE NS NS NS Not significnt t P>

8 Tble 5. Effects of typicl-corn-, typicl-corn + ft-, nd high-oil corn-bsed diets on the site nd extent of nitrogen digestion nd microbil efficiency in steers. Diet P-Vlue Typicl Typicl + Ft High-Oil SEM TC vs. TC+F TC vs. TC+F vs. Intke (g/d) Totl N Protein N b Rumen Degrdtion (% of intke) Totl N NS c NS NS Protein N NS NS NS Flow to Duodenum (g/d) Totl N NS NS NS Feed N NS NS NS Bcteril N NS NS NS NH 3 -N NS NS NS Flow to Duodenum (% of totl N flow) Feed N NS NS NS Bcteril N NS NS NS NH 3 -N NS NS NS Microbil Efficiency OM d NS NS NS Strch e NS NS NS Apprent Intestinl Digestion (%) Totl N NS.08 NS Apprent Totl Trct Digestion (% of intke) Totl N NS.06 NS Includes ure N. b Does not include ure N. c Not significnt t P>.10. d g bcteril N/kg OM truly digested in the rumen. e g bcteril N/kg strch digested in the rumen. 30