HIGH-MOISTURE CORN UTILIZATION IN FINISHING CATTLE’

University of Nebraska, Lincoln 68583-0908 ABSTRACT

Two finishing trials, one laboratory trial and one metabolism trial were conducted with the following objectives: 1) to determine the associative effects of feeding high-moisture corn (HMC!) with either dry-rolled grain sorghum (DRGS) or dry-rolled corn (DRC) and 2) to evaluate HMC when harvested at different moisture levels, stored in different structures, or fed as whole or rolled HMC. In Trial 1, yearling steers (BW, 328 kg) were fed diets containing mixtures of HMC and DRGS. As level (0,33, loo%,as percentage of grain DM) of DRGS increased, ADG (P < .03) and gain/feed (P e .001) decreased linearly; gain/ feed tended to be affected quadratically (P = .14). In Trial 2, yearling steers (BW, 382 kg) fed HMC, stored whole in an upright, oxygen-limiting silo and rolled coarsely before feeding, gained faster (1.46 vs 1.36 kg/d) and more efficiently (.142 vs .131 gain/feed) than steers fed whole HMC (P e .01). In Trial 3, as length of storage of bunker HMC increased, in vitro rate of starch digestion and soluble N content increased (20.4 and 36.8%, respectively) and grain pH decreased (10.9%). In Trial 4, steers fed HMC or a mixture of 75%HMC with 25% DRGS had similar ruminal pH throughout a grain adaptation period, but total ruminal VFA were greater (P e .005) for steers fed HMC alone. These data are interpreted to suggest that feeding a mixture of HMC, ground and stored in a bunker or silo bag, with DRGS will result in a 3.2% associative effect. However, no associative effects were measured when a mixture of HMC, stored whole and fed whole or rolled, and DRC were fed. Key Words: Maize, Sorghum, Starch, Grain Processing, Cattle, Acidosis J. Anim. Sci. 1991. 69:16451656

In addition, other factors may influence the feeding value of HMC. The moisture content Early-harvested, high-moisture corn of H M C has been shown to affect cattle ADG (HMC), ground and stored in a bunker, is and feed efficiency (Goodrich and Meiske, degraded rapidly in the rumen (Stock et al., 1976; Teeter et al., 1979). The method of 1987b). Replacing a portion of the HMC with processing and storing HMC may also influa more slowly degrading grain such as dry- ence its feeding value. High-moisture corn rolled corn (DRC; Stock et al., 1987a) or dry- stored in upright, oxygen-limiting silos underrolled grain sorghum (DRGS; Stock et al., goes less fermentation (Goodrich et al., 1975) 1987b) can be complementary in improving and has a slower in vitro rate of digestion than feed efficiency, HMC ground and stored in a bunker (Britton and Krause, 1985). Cattle fed HMC stored whole and fed whole have been shown to be at least as efficient as cattle fed HMC stored whole and fed rolled (Tolman and Guyer, ‘Published as Papea Number 9188, J o d Series, 1973, 1975; Mader et al., 1983). Nebraska Agric. Res.Div. Ihe authors gratefully acknowlThe objectives of the trials reported herein edge the assistance of Laurie Dubrovin in sample colle43ioIL were 1) to determine main effects and interacb p t . of ~ n i m .sci. tions between HMC and dry grain mixtures h e s e n t address: American Cyanamid Co.. Princeton, when HMC was fed at various moisture levels, NJ. stored in different structures, or fed as whole Received May 3, 1990. Accepted October 4, 1990. or rolled graiq 2) to evaluate changes in grain Introduction

1645

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

R. A. Stock2, M. H. Sindt2, R. M. Cleale IV3 and R. A. Britton2

1646

STOCK ET AL.

Experimental Procedure

Trial I Trial 1 was conducted to study the main effects of HMC harvested at different moisture levels and stored in different structures and to determine possible interactions when HMC is mixed with DRGS. Two hundred sixteen British-Continental crossbred yearling steers (BW= 328 f 39 kg) were blocked by weight into three replications and fed for 129 d (February 6, 1985 to June 14, 1985). Two blocks of steers were housed in an open-front bam (pen size = 3.7 m x 6.2 m) with a flushflume waste disposal system, and one block was housed in outside pens (pen size = 15.4 m x 35.4 m) with bare soil and mounds. We assumed no treatment x facility interaction would occur or be biologically important. We have not observed treatment x facility interactions in any previous feedlot studies. Steers were allotted randomly within weight block to eight treatments (three penshreatment; nine steedpen). Three types of HMC were fed as either the only grain source or in combination with DRGS (67% HMC, 33% DRGS, as percentage of grain DM). Previous work (Stock et al., 1987b) indicated that the optimum mixture level was approximately 67 to 75% HMC and 25 to 33% DRGS. The higher level of DRGS was selected to minimize the use of HMC and maximize the use of DRGS in this trial. Two additional treatments were 100% DRGS (determination of complementary effects between HMC and DRGS) and 100% DRC (control). High-moisture corn treatments were prepared as follows: 1) 27.2% moisture, stored ground in a bunker; 2) 27.6% moisture, stored ground in a silo bag; 3) 36.3% moisture, stored ground in a silo bag. Each HMC source was stored in one type of storage facility and was ground through a tub grinder equipped with a 2.54cm screen. Steers were adjusted to their final diet in 15 and 30% d using three adaptation diets (70,50, corn silage; DM basis); each diet was fed for 5 d. The final diets consisted (DM basis) of 80%

grain, 12% corn silage, and 8% supplement (Table 1) and were formulated to contain 11.5% CP (based on a chemical analysis of dietary ingredients), .70% Ca, .35% P, .70% K, 27.5 mg/kg monensin, and 11 m a g of tylosin. Steers were implanted in the ear with 24 mg of estradiol-l7p and had ad libitum access to feed, with fresh feed added once daily. Bunks were cleaned at least every 28 d or when feed accumulated in the bunks. O r t s were weighed, sampled for DM analysis, and subtracted from feed fed to calculate DMI. Initial weights (water and feed not withheld), taken before the morning feeding, were the average of weights taken on two consecutive days. One final weight (water and feed not withheld) was taken before morning feeding and the experimental mean dressing percentage was 62.5%. Average daily gain was calculated by dividing hot carcass weight by .625. Cattle were slaughtered at a commercial, federally inspected slaughtering facility using a captive bolt stunning system and then were bled. Carcass weight was recorded at slaughter; fat thichess (over the 12th rib) and quality grade were recorded after a 48-h cooler chill. Fecal grab samples were taken from each steer 5 , 21, and 63 d after the 1st d of feeding the fial diet. Samples were freeze-dried, ground to pass through a 1-mm screen, and composited by pen. Feeds were sampled on the day of fecal sampling and processed in a manner similar to processing of fecal samples. Dry matter intake was recorded for a 5-d period before sampling. Starch content of feed and feces was measured as alpha-linked glucose polymers by the enzymatic digestion method of MacRae and Armstrong (1968) and modified using Tris-glucose oxidase (Dahlquist, 1964) in an automated procedure. Acidinsoluble ash was used as an internal marker and was determined by the procedure outlined by Van Keulen and Young (1977). Total tract starch digestion for each pen was calculated as a ratio of AIA and starch. Analysis of variance procedures (feedlot performance) for a randomized complete block design were performed as outlined by Steel and Tome (1980). Pen was used as the experimental unit. Main effects were grain treatment and block. Least squares means were computed, and preplanned comparisons were made using the GLM procedures of SAS (1982). Preplanned comparisons included the following: 1) interaction of HMC type and

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

pH and rate of digestion that occur as HMC is stored in bunker silos; and 3) to determine the effect of ground HMC stored in a bunker silo on ruminal measurements during adaptation of finishing cattle to high-grain diets.

1647

HIGH-MOISTURE CORN UTILIZATION

TABLE

1. COMPOSlTION

OF DIETS FED IN TRIAL I HMCDRGS~

1m:o

67:33

0 100

DRC~

orain

80.0 12.0 2.83 5.17 1.06 1.80 1.45

80.0 12.0 2.83 5.17 1.66 1.21 1.47 .23 .37 .20 .02 .01

80.0 12.0 2.83 5.17 2.91

80.0 12.0 2.83 5.17

Corn silage M O ~ ~ S Ssupplementb ~S Dry supplement Finely ground corn Soybean meal Limestone Dicalcium phosphate Potassium chloride Animal fat Monensin premix' Tylosin premixd

.a .39 .20

.a2 .01

-

1.50 .20 .33 .20 .02

.Ol

-

2.93 1.46 .2 1 .34 .20 .02 .o 1

%JMC = high-moisture corn, ground and stored in either a bunker silo at 27.2% moisture or in a silo bag at 27.6 or 36.3% moisture; DRGS = dry-roUed grain sorghum; DRC = dry-rolled corn.

%rea-based molasses supplement containing 50.6% CP,vitamins (78,925 IU vitamin A&g, 15,789 lU vitamin D&, and 20 iu vitamin mg), and trace m i n e d (.37% of supplement DM; 2.25% Fe, 1.0% Za, 54% Mn, .20% Cu, .18% Mg, ,1696 Co, and 5 5 % I). '132 g moneoslnjkg premix, dS8 g tylosin/kg premix.

mixture combination; when there was no ling steers were blocked by weight into four interaction (P >.15), the following main effects replications (BW= 392 f 44 kg). Two blocks were cornpard, 2) HMC (27.2% moisture) were housed in an open-front confinement barn from the bunker vs HMC (27.6% moisture) and two blocks were housed in outside lots. from the bag; 3) HMC (27.6% moisture) from Pen sizes were the same as in Trial 1. As the bag vs HMC (36.3% moisture) from the previously stated in Trial 1, we assumed no bag; 4) linear effect of feeding DRGS; 5) block (facility and weight) x treatment interacquadratic effect of feeding DRGS; 6) DRC vs tion would exist. Steers were allotted randomly average of mixtures of HMC:DRGS; 7) DRC within block to one of six treatments. Grain vs DRGS. The error term was the residual treatments were as follows: 1) whole shelled error (treatment x block). The total tract starch HMC (WHMC); 2) rolled HMC (RHMC); 3) and DM digestibility data were analyzed as a DRC; 4) 50% WHMC:50% RHMC; 5 ) 50% split-plot design. The main plot contained WHMC:50% DRC; and 6) 50% RHMC:50% block and grain treatments with block x DRC. Because limited data exist on feeding treatment as the error term. The subplot mixtures of rolled and whole HMC with DRC, contained day of sampling and day x treatment we selected an equal mixture of these grains. interaction with residual as the error term. High-moisture corn was stored (225 d) whole Least squares means were computed, and mean in upright, oxygen-limiting silos at 28% comparisons were made as previously outlined moisture and rolled coarsely each day before for feedlot performance. feeding. The final diet contained 80.4% corn, 5% corn silage, 5% alfalfa hay, and 9.6% supplement (DM basis, Table 2). Steers were Trial 2 adapted to the final diet during a 2 5 d period Trial 2 was designed to evaluate the effects using four adaptation diets consisting of 48 (3 of storing HMC as whole grain (stored in an d), 37 (4 d), 26 (11 d), and 15% (7 d) roughage upright, oxygen-limiting structure4) and fed as (DM basis). The final diet formulation, implant whole or rolled HMC and interactions when program, and method of feeding were the same mixed with DRC at feeding. One hundred as previously indicated in Trial 1. Blocks of sixty-eight British-Continental crossbred year- cattle (heaviest to lightest) were fed for 113, 85, 113, and 85 d, respectively (May 15 to 4A.0. Smith Harvestore Systems,Arlington Heights, September 5, 1985). Initial weights, taken IL. before the morning feeding, were the average

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

Ingredient

1648

STOCK ET AL. TABLE 2. COMPOSlTION OF DIETS FED IN TRIAL 2 Treatment'

~~~~

Grain

Corn silage Alfalfa bay M O ~ ~ S Ssupplementb ~S

Dry supplement Limestone Soybean meal Corn gluten meal Finely ground corn Salt

Dicalcium phosphate Potassium chloride Animal fat Monensin premix' Tylosin premixd

~

~

RHMC

DRC

50WHMC: 50WHMC 5-C: 50RHMC 5ODRC 5ODRC

80.4

80.4 5 .o 5.0 4.56 5 .04 1.30 1.19 .89 .87

80.4 5.0 5 .O 456 5.04 1.30 1.19 .89 .87

30

.30

.21 .ll .10

.21

~

80.4 5.0 5 .O 4.56 5.04 1.30 1.19 .89 .87 .30 .21 .ll .10

.a? .01

5 .O 5.0 4.56 5.04 1.30 1.19

.89 .87

30 .2 1 .ll

.10 .02 .o 1

.a? .01

80.4 5.0 5.0 4.56 5.04 1.30 1.19

80.4 5 .O 5.0 456 5.04 1.30 1.19

.89

.89 .87 .30 .2 1 .ll .10

.I1

.87 .30 21 .ll

.IO

.IO

.M

.02 .o 1

.01

.a2 .01

m C = high-moisture corn stored whole in oxygen-limiting structure and fed whole; RHMC = high-moisture corn stored similarly and fed rolled; DRC = dry-rolled corn. %rea-based molasses supplement containing 50.6% CP,vitamins (78,925 N vitamin A/kg, 15,789 IU vitamin D&, and 20 Tu v i e E!/kg), and trace minerals (.37% of supplement DM; 2.25%Fe, 1.0% Zn, 64% Mn, 20% Cu, .18% Mg, .16% Co, and .55% I). '132 g monensmkg premix. ds8 g tylosin/kg premix.

of weights taken on two consecutive days. For the three heavy blocks, final weight was calculated from hot carcass weight assuming that dressing percentage was 62%. For the light block, final weight was the average of weights (water and feed not withheld) taken on two consecutive days. Slaughter procedures and carcass data were collected as previously described in Trial 1. Livers were scored based on the procedure developed by Elanco Products Company (1974), which was modified to include a fourth category for liver abscesses adhering to either the diaphragm or digestive tract (Stock et al., 1990). Grain samples were collected weekly, composited, and h z e d r i e d at the end of the trial. Dry matter and starch content were analyzed as previously described in Trial 1. In vitro rate of starch disappearance was measured using a modification (Stock et al., 1990) of the Tilley and Terry (1963) technique. Three in vitro runs with duplicate tubes at each hour were conducted. The geometric mean diameter (GMD) of the individual grains fed in the trial was determined by the procedure of Ehsor et al. (1970). In addition, a 100-g sample (in duplicate) of each grain was sorted and whole kernels were weighed to determine the percentage of whole grain.

Analysis of variance for steer performance and carcass data was performed as outlined by Steel and Torrie (1980) for a randomized complete block design. Means were computed and statistical comparisons were made using GLM procedures outlined by SAS (1982). Contrasts made were WHMC vs RHMC; RHMC vs DRC; SOWHMCSORHMC vs the mean of treatments WHMC and RHMC; 5OWHMC.SODRC vs the mean of treatments WHMC and DRC; and 5ORHMC:SODRC vs the mean of treatments RHMC and DRC. The error term was the residual error (treatment x block). Rate of starch disappearance was analyzed as a completely randomized design with in vitro run, treatment (HMC vs DRC), and residual error as components of the model. Trial 3

Trial 3 was conducted to evaluate changes in HMC with time of storage. Early-harvested HMC was ground through a tub grinder equipped with a 2.54screen and ensiled in a concrete bunker covered with polyethylene as indicated in Trial 1. Samples of HMC were collected weekly during four finishing studies fed throughout the following year. Samples of HMC were collected across the surface of the

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

WHMC

Imredient

1649

HIGH-MOISlWRE CORN UTILIZATION

Trial 4

Trial 4 was conducted to study the effects of HMC:DRGS mixtures on ruminal measurements. Six mature, hereford-Angus steers (BW = 600 f 68 kg), which had been previously ruminally fistulated, were allotted randomly to two treatments: 100% HMC or 75% HMC, 25% DRGS (as percentage of grain DM) in a completely randomized design. Ruminal fluid was collected throughout the adaptation period. Four grain adaptation diets were evaluated 0, 25, 50, and 75% grain (DM basis; Table 3). Nutrient composition of diets was similar to that of diets in Trial 1. Each diet was fed for 7

TABLE 3. COMPOSITION OF DIETS FEDINTRIAL4 Adaptation diet, % grain @M basis) Ineredient

0

25

50

75

Graina

-

Alfalfa hay Com silage Molasses supplementb Drysupp~ementc

85 5

25 60 5

50 35 5

75 10 5

5 5

5 5

5

5 5

5

%rain was either 100% high-moisture corn or 75% high-moisture com:25% dry-rolled grain sorghum. %rea based molasses supplement containing 50.6% CP, vitamins (78,925 IU vitamin A/kg, 15,789 IU vitamin Dkg, and 20 IU vitamin J3kg), and trace minerals (.37% of supplement DW 2.25% Fe, 1.0% Zn, 64% Mn, . 2 W Cu, .18% Mg, .16% Co, and 3 5 % I). ‘Corn-based supplement containing limestone, d i d cium phosphate, potassium chloride, salt, monensinpremix (132 g/kg premix), and tylosin premix (88 g/kg premix).

d and ruminal fluid was collected on d 1 , 3 , 5 , and 7 of each adaptation period. Within each sampling day, ruminal samples were collected at 0, 3, 6, 9, 12, 18, and 24 h after feeding (0630). Steers were prepared for fistulation by removing feed and water 12 h before surgery and hair was clipped from a 60-cm x 60-cm area. Before surgery, steers were administered 5 mg of xylazine i.m. and lidocaine locally to effect. Penicillin was administered i.m. for 3 d after surgery. The surgical preparation and postsurgical procedures were reviewed and accepted by the University of Nebraska Institutional Animal Care Program. Steers had ad libitum access to feed, with fresh feed added twice daily (0630 and 1830). Steers were fed and sampled in a random order each day with 10 min allotted between sampling each steer. Polyethylene glycol (PEG; molecular weight = 4,000) was used as a fluid flow and volume marker and was pulsedosed (100 g) immediately before the 0630 feeding. Ruminal fluid was sampled from three to five different areas in the rumen using the suction strainer technique (Raw and Burroughs, 1962), with the strainer weighted and the suction tubing passing out through the ruminal cannula. Ruminal fluid pH was measured immediately using a combination electrode, 1 ml of 5% (HgC12) was added to stop microbial fermentation, and samples were frozen for later analyses. Ruminal fluid for VFA analysis was prepared as described by Erwin et al. (1961).

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

bunker to obtain a sample of HMC that represented corn fed that day from the bunker. Samples of HMC were composited within each finishing study and represented a mean sampling day of 120, 195, 290, and 365 d after initial ensiling. The composite-HMC samples were freeze-dried and ground to pass through a l-mm screen. Starch content was analyzed and the in vitro rate of starch disappearance was measured as previously described in Trial 1. For lactic acid and acetic acid analyses, a 5-g as-is grain sample was weighed into a 125-ml Erlenmyer flask, 15 ml of .5 N sulfuric acid was added, and the mixture was refrigerated overnight. After refrigeration, the mixture was filtered through #40 fiter paper. Filtrate was treated with meta-phosphoric acid at a rate of 1 ml of acid to 4 ml of sample and centrifuged (3,000 x g) for 10 min, the supernatant was then analyzed for lactic acid and acetic acid. Total lactic acid content of the HMC grain was measured by procedures of Barker and Summerson (1941). Acetic acid was measured by gas liquid chromatography (Erwin et al., 1%1), and .15 M sodium chloride soluble N was measured by the procedures of Waldo and Goering (1979). The pH of the HMC grain was measured by mixing 100 ml distilled water with 5 g of HMC (DM basis) and refrigerating it overnight. After the solution was allowed to adjust to room temperature, pH was measured on duplicate samples using a combination electrode. Length of time in storage was correlated to grain fermentation characteristics using procedures outlined by SAS (1982). Because grain samples were composited within the finishing study, correlations were the only statistical methods employed.

1650

STOCK ET AL. Results and Discusslon

Trial I There was an interaction (P < .05) between type of HMC and level of DRGS for DMI (Table 4). Dry matter intake was similar for steers fed bunker-27.2% HMC either alone or in Combination with DRGS. Steers fed bag27.6% HMC and DRGS consumed less DM than steers fed bag-27.6% HMC alone, whereas cattle fed bag-36.3% HMC and DRGS consumed more DM than steers fed bag-36.3% HMC alone. The differences between bag27.6% HMC and bag-36.3% HMC may be confounded with moisture level and method of storage because storage structures were not replicated. No interactions (P> .15) were observed for ADG, gain/feed (Table 4), or carcass measure ments (data not shown). As level of DRGS increased (0 to loo%), ADG (P < .03) and gain/feed (P c: .001) decreased linearly. Gain/ feed showed a trend toward a quadratic

T A B U 4. FINISHING STEERS FED HIGH-MOISI’URE CORN OR DRY-ROLLED GRAIN SORGHUM ALONE OR IN COMBINATION IN TRIAL 1

EiMc cyp.” Bunlrer-27.2

Bag-27.6

Bag-36.3

HMCDRGS~ Item

1oO:O

67:33

Feedlot erformance DMF kg/d 9.23 9.49 ADGe, kg 1.50 1.45 ADG/DMIf@ .164 .155 Starch in&, kg, and digestibility, % Intake d 5‘ 5.55 5.64 Intake d 21‘ 4.20 4.57 Intake d 63‘ 6.76 6.36 Dimxtibilitvf@ 97.8 94.3

8

~

~

~~

~

1OO:O 9.81 1.60 .164 5.64 4.26 6.54 94.9 ~

67:33 9.13 1.51 .166 5.39 4.26 6.11 93.0 ~

1oO:O

67:33

DRGS

8.42 1.49 .178

9.10 158 .174

9.80 1.39 .142

4.96 3.82

5.84 4.58

6.36 5.19 6.30

5.06

97.6

5.80 94.1

85.4

DRC~ 9.26 1.59 .172 6.54 4.64 6.14 92.8

SE 24 .05

,004 1.57 1.57 1.57 1.2

~

%ulcer-272 = stored in a buuker at 27.2% moisture;Bag-27.6 = stored in a silo bag at 27.6% moisture; Bag-36.3 = stored in a silo bag at 36.3% moisture. ~ H M c= high-moisture corn; DRGS = d r y - r ~ ~ egrain d sorghum; DRC = dry-roned corn. CHMC type x DRGS level interaction (P < .05). %RGS vs DRC (P = . n ) . ‘%vel of DRGS, linear (P < .03). vs DRC (P c .oil. gLevel of DRGS, hear (P .20) by feeding HMC in either the whole or rolled form. Daily gain (P c .lo) and gaidfeed (P c .lo) were improved 7 and 8%, respectively, when HMC was fed rolled compared with feeding HMC whole (Table 5). Total tract starch digestibility was 9.1% greater (P c .01) for RHMC than for WHMC, which explains the increased feed efficiency observed with the RHMC. Previous research comparing HMC stored whole and fed either whole or rolled has been variable. A positive response to processing WHMC was found by Burkhardt et al. (1970b); however, several reports have indicated that steers fed HMC stored and fed whole had feedlot performance superior or equal to that of steers fed HMC stored whole and fed rolled (Burkhardt et al., 1970a; Burkhardt and Embry, 1971; Tolman and Guyer, 1973, 1975). In a summary of Midwestern studies, Weichenthal(l973) reported a

TABLE 5. E m OF HIGH-MOISTURE CORN FED WHOLE, ROLLED, OR IN COMBINATION WITH DRY-ROLLED CORN ON FEEDLOT PERFORMANCE AND CARCASS CHARACTERISTICS IN TRIAL, 2 'habnen? Item

RWMC

RHMC

DRC

No. of severe liver abscesses' ~uality gradec@

10.55 1.36 .131 1.02 0 of 21 6.96

10.37 1.46 .142 .91 1 of 21 7.07

10.24 1.43 .140 .94 0 of 21 7.07

SOWHMC 50WHh4C 50RHMC 50RHMC 5ODRC SODRC

10.55 1.37 .130 .%

1 of 20 6.90

10.06 1.40 f140 .82 3 of 21 6.80

10.00 1.42 .143 1.07 1 of 21 7.04

a\KHMC = whole high-moisture corn; RHMC = rolled high-moisture corn; DRC = dry-rolled corn bwHMc vs RHMC (P < .lo). 'WHMC and DRC vs 5OWHMC:SODRC (P < .OS). dRHMC and DRC vs SORHMC:50DRC (P < .OS). %umber of abscesses scored as 3 OT 4. W t y grade: 6.75 = Cd+; 7.15 = Ch-; 7.45 = ch'. g W C and RHMC vs SOWHMCSORHMC (P = .12).

SE

.22 .04 .004

.05

-

.06

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

response (P = .14), with the mixture of HMC and DRGS being 3.2% more efficient than predicted (associative effect) using the averages for 100% HMC and 100% DRGS, which are slightly lower than the 5 to 7% reported by Stock et al. (1987a,b). Steers fed bag-36.3% HMC were more efficient (P c .02)than steers fed bag-27.6% HMC as a result of a lower DMI and similar ADG. Gaidfeed responses agree with the results of Gill et al. (1982) comparing HMC harvest at 24% or 31% moisture. Corn harvested at a higher moisture content may undergo a greater extent of fermentation during ensiling (Goodrich et al., 1975), resulting in more solubilization of nutrients and, thereby, greater digestibility. Steers fed DRC tended (P = .13) to consume less feed,gained faster (P c .Ol), and were more efficient (P < .01) than steers fed DRGS (Table 4). The DRGS was used 17.4% less efficiently than DRC, and total tract starch digestion was less for DRGS than for DRC. The magnitude of difference in feed efficiency between DRC and DRGS was greater than that reported in summaries (Hale and Prouty, 1980; Brethour, 1984; Riley, 1984). A grain treatment x day of fecal sampling interaction (P c .OOO4) was observed for starch intake (Table 4). However, there was no consistent difference in intake pattern among the treatments. This interaction as well as the HMC type x DRGS level interaction (Pc .05) observed at each sampling day was probably a

1652

STOCX ET AL.

TABLE 6. GEOMETRIC MEAN DIAMETER, PERCENTAGE OF WHOLE KERNELS AND IN VITRO RATE OP STARCH DIGESTION OF WHOLE AND ROLLED HIGH-MOISTURE CORN AND DRY-ROLLED CORN IN TRIAL 2 ~~~~

WHMC RHMC DRC

~

~

Pan

.25

Sieve ske, mm 50 1.00 2.00 4.00 6.30

-

-

-

-Retained on sieve,

Iof total weight

-

-

.32 1.97 97.71 .83 1.66 2.06 3.65 7.68 9.20 74.92 1.28 1.91 3.91 8.58 42.14 33.91 827

Rate of starch digestion

Whole kemels,%

GMDbSD

92.9 312 2.4

7.03 5.21 2.98

%/hc SE

.001 7.36 .28 .002 .002 6.28 -

WHMC = high-moisture corn stored and fed whole; RHMC = high-moisture corn stared whole and fed rolled; DRC = dry-rolled corn b~~ = geometric mean diameter in millimeters. Wgh-moisture corn vs dry-rolled corn (f‘ = .11).

1.3 to 2.5% improvement in feed efficiency when HMC was rolled before feeding. However, storage in upright, oxygen-limiting S ~ I U C tures may elicit different results. With the same storage structures used in this trial, Mader et al. (1983) reported a 9.9% advantage in rolling HMC before feeding versus feeding whole HMC. Although BW was not reported in the work of Mader et al. (1983), DMI in Trial 2 was 21% higher than in Mader’s trial, which suggests that steers in Trial 2 were heavier and(or) older. Owens and Hicks (1987) suggested that the need for grain processing was much greater for more mature cattle because younger cattle with lower intakes tend to chew their feed more thoroughly. Particle size of the HMC may also be a factor. Particle size of HMC was reduced 25.9% by rolling (Table 6); however, rolled HMC still contained 31.2% whole kernels compared with 2.4% for DRC. Thus, under the conditions of upright, oxygen-limiting storage used in the present trial, the feeding value of stored HMC was improved by rolling the grain. Combinations of whole, rolled, or DRC did not affect (P > .15) feedlot performance (Table 5). These results disagree with the results of Stock et al. (1987a,b), who found a 5 to 7% improvement in feed efficiency when combinations of bunker HMC were fed with dry whole or rolled corn or DRGS. The response to grain mixtures was attributed to a potential reduced subacute acidosis and an improvement in ruminal digestion of the more slowly digesting grain. In the studies by Stock et al. (1987a,b), HMC was ground and stored in concrete bunkers. Thus, storage structure may be the major reason for the difference in the results. High-moisture corn stored whole in upright,

oxygen-limiting silos undergoes less fermentation (Goodrich et al., 1975) and has a slower in vitro rate of digestion than HMC ground and stored in a concrete bunker (Sritton and Krause, 1985). In vitro rate of starch digestion (Table 6) tended to be slightly faster (P = .l1) for the HMC than for DRC. Steers fed SOWHMC:5ODRC (Table 5 ) had less fat thickness (P < .05), lower quality grades (P < .OS), and tended to have a greater number of severe liver abscesses than steers fed the grains individually. Steers fed SORHMC:50DRC had greater fat thickness (P c .OS) and steers fed SOWHMC:5ORHMC tended to have lower quality grades (P = .12) than the average of the steers fed WHMC, RHMC, or DRC alone. However, carcass differences were small and probably not biologically important.

Trial 3 As bunker HMC storage length increased from an average of 120 d to an average of 365 d (Table 7), in vitro rate of starch digestion and soluble N content increased (20.4 and 36.8%, respectively) and pH decreased 10.9%. Thomton (1976) summarized HMC data collected from bunker silos. Our values for grain pH, soluble N, lactic acid, and acetic acid agree well with those of Thornton’s, although our DM tended to be lower. Our data suggest that increased fermentation and protein solubility may increase availability of starch in the rumen; therefore, less starch will escape ruminal degradation. This agrees with the conclusion of Thomton (1976). Similar results were found by Aguirre et al. (1983) and by Britton and Krause (1985). Grain starch

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

Graina

~

1653

HIGH-MOISTURE CORN UTILIZATION TABLE 7. EFFFiCT OF LENGTH OF STORAGE ON ENSILED CORN GRAIN CHARACTERISTICS IN TRIAL 3 ~~

starch Length of storage, d

DM,%

120 195 290 365 Dry corn control

70.3 68.9 67.0 62.3 88.0

%ofDM

digestion, %/h

682 68.0 6s.7 69.7 67.7

10.8 11.0 11.4 13.0 7.1

Starch,

content and acetic acid content were not affected by length of storage. Dry matter content decreased (11.4%) with length of storage, which reflects one or more of the following: 1) corn moisture content declined during filling of the bunker, which resulted in dryer corn being fed earlier; 2) there was moisture contamination from the environment; 3) fermentation increased, resulting in increased DM losses; and 4) VFA formation increased but were volatilized and lost during oven DM procedures. Length of storage (Table 8) was correlated positively with rate of starch digestion (r = .91; P < .lo) and lactic acid content (r = .96; P < .05) and correlated negatively with DM content (r = -.95; P < .05) and pH (r = -.97; P < .05). Dry matter content was positively corre lated with pH (r = 9; P < .01) and negatively correlated with rate of starch digestion (r = -9; P < .01) and lactic acid content (r = -.98; P < .05), which agrees with the data of Thornton (1976). These data suggest that storing bunker HMC for longer periods of time or at higher moisture levels will result in

PH

Lactic acid, %ofDM

Acetic acid, %ofDM

Soluble nitrogen, %oftotal

422 4.16 3.99 3.76 6.02

1.06 1.14 1.78 2.40 .01

.43 .27 .43 .49

43.7 42.6 60.0 59.8 14.3

.In

greater fermentation and an increased rate of starch digestion, which may contribute to greater acidosis problems when the grain is fed to cattle. Trial 4

There were no grain x adaptation diet interactions (P > .15) for any ruminal measurement (Tables 9 and 10). Thus, data were pooled across grain diet and adaptation diet. Grain Diet. Steers fed the mixture of HMC and DRGS (Table 9) tended to consume less feed and consumed more of their feed from 0630 to 1830 than from 1830 to 0630 (P < .0005) compared with the steers fed H M C alone. The steers fed HMC alone may have partitioned their intake more uniformly throughout the day. Cattle experiencing subacute acidosis consume smaller quantities of feed at any one time but distribute their consumption more evenly throughout the day (Fulton et aL, 1979). The consumption of smaller meals may increase ruminal pH or slow the rate of a declining ruminal pH and

TABLE 8. CORRELATION COEFFICIENTS BETWEEN CHARACTERISTICS OP ENSILED CORN GRAIN IN TRIAL,3 Rate of Item

Dry matter Starch

Rate of starch digestion PH Lactic acid Acetic acid Soluble nitrogen

***P < .01. **P < .a. *P < .lo.

Length of storage

DM

-.9s** .14 .91* -.97** .96** .49 .90

-.42 -.99*** .99*** -.98** -58 -.81

Starch

Starch

digestion

.53 -.32 .27

-.97**

.20

-.15

.96** .59 .74

pH

-.99*** -.63 -.87

Lactic acid

Acetic acid

.68

.90*

.70

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

Rate of

1654

STOCK ET

AL.

TABLE 9. JPFECT OF GEWN DIET ON RUMINAL pH, VFA CONCENTRATION, AND LIQUID VOLUME AND PLOW IN TRlAL 4

Item ~~

~

~

1mo

75:25

SE

13.0 7.9 60.8 5.1 39.2

12.2 8.3 68.0 3.9 32.0

.2 .2

~

Daily DM intake, lcg Intake 0630 to 1830, kg Intake 0630 to 1830, % Intake 1830 to 06308, kg Intake 1830 to 0630, %

Ruminal characteristics PHb Acetate", mM Propionate", mhf Butyrate. mM Isobutyratec, mM Isovalerate, mM Valerate, mM Total WAf, mM Liquid volume, liter Liquid flow, %jh

5.84 67.5 34.9 11.9 1.6 2.0 2.5 120.4 80.6 9.6

(56.0)d (29.0) (9.9) (1.3) (1.7) (2.1)

5.83 59.0 32.4 10.9 1.3 2.1 2.9 108.6 76.3 9.1

.1 (54.4)d (29.8) (10.0) (12) (1.9) (2.7)

.03 .6 .3 .1 .03 .03

.04 1.0 3.9 .5

aP < .ooo5.

bRuminal pH CP
.15) between grain diets. Dry matter intake, VFA concentrations, and liquid flow rate did

not differ (P > .15) among the steers; hence, no covariance adjustment was made for these variables. Adaptation Diet. As level of grain in the diet increased (Table lo), DMI increased linearly (P e .005). Steers consumed more feed between 0630 and 1830 when fed 25 or 50% grain compared with steers fed 75% grain, which agrees with the data of Fulton et al. (1979). As level of grain increased, propionate concentration increased (P < .001). However, acetate (P < .001), butyrate (P e .Ol), isobutyrate (P < .05), total VFA (P e .001) concentrations, and ruminal pH (P < .01) decreased with increasing concentrate levels. Ruminal liquid volume was affected quadratically (P < .005), with the largest volume at 50% grain and the smallest volume at 75% grain; 0 and 25% grain were intermediate. Almost all ruminal measurements indicated a sigmficant adaptation diet x day of sampling interaction. However, there were no consistent patterns within diets except with 75% grain. Ruminal pH decreased and VFA concentration

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

High-moisturecomdry-rolled grain sorghum

1655

HIGH-MOISTURE CORN UTLJZATION TABLE 10. IWFZT OF ADA€TATION DIET ON RUMINAL pH, VFA CONCENTRATION, AND LIQUID VOLUME AND FLOW IN TRIAL 4

Daily DMI*, kg Intake 0630 to 1830b,kg Intake 0630 to 1830.46 Intake 1830 to 063Cf, kg Intake 1830 to 0630.46 Rumiaal characteristics PHd" Acetate', mM Propionate', mbf Butyrate', mM IsobutyrateB,mM Isovalerate, mM Valerate, mM Total WAC,mM Liquid v o l d , liter Liquid flow,%/I

11.2 7.8 59.6 3.4 30.4 6.21 74.7 27.8 12.0 1.8 2.2 2.4 120.9 80.1 9.4

12.2 8.1 66.4 4.1 33.6

(61.84 (23.0) (9.9) (1.5) (1.8) (2.0)

5.80 70.3 34.8 13.2 1.6 2.3 2.7 124.9 81.0 9.4

13.3 92 69.2 4.1 30.8

(56.24 (27.9) (10.6) (1.3) (1.8) (2.2)

SE

75

50

25

13.9 7.2 51.8 6.7 48.2

5.75 5.59 58.2 (53.4)f 49.8 33.8 (31.0) 38.0 10.8 (9.9) 9.6 1.3 (1.2) 1.2 2.1 (1.9) 1.5 2.8 (2.6) 3.1 109.0 1032 90.9 61.8 10.1 8.6

.3 .3

-

2 -

(482Jf (36.8) (9.3) (1.2) (15) (3.0)

.02 .8 5 2 .04 .04 .06 1A 55

.6

T i (P < .005). bQuadratic (P < .IO). cLinear (P < .001). dRuminal pH are adjusted by covariance with pH on a common dry-rolled corn diet used as a covariate. Tinear (P < .01). fNumber in parentheses represent molar proportions. BLinear (P < .05). *tic (P < .005).

increased each day the 75% grain diet was fed. The adaptation diet x sampling diet interactions were primarily indicating 1) typical dayto-day variation; 2) animal variation; and 3) large number of samples collected per diet (4 d, five sampling animals/d). The HMC fed in this trial was the same grain source used in Trials 1 and 3 and also used in a cattle intestinal fistulation trial reported by Stock et al. (1987b). This HMC had a fast rate of in vitro starch digestion and was 90% digested in the rumen (Stock et al., 1987b). However, in this trial, the effects of the HMC were minimal and did not result in any grain type x adaptation diet interaction, as hypothesized. implications

High-moisture corn is not a consistent grain and should be characterized as much as possible before it is fed to finishing cattle. Important characteristics are moisture level, particle size, method and length of storage, and rate of digestion. High-moisture corn stored

ground in either a bunker or silo bag seems to be similar in rate of starch digestion and affects cattle gain and efficiency similarly. A 3.2% positive associative effect was observed in gain/feed when high-moisture corn and dryrolled grain sorghum were fed together. No associative effects in gain/feed were measured when a mixture of high-moisture corn (stored whole and fed as whole or rolled) and dryrolled corn were f e d Literature Cited

Aquirre, E., F. N. Owens. D. R. Gill and J. H. Thorton. 1983. Effect of moisture addition on fermentation of high moisture corn. Anim. Sci. Res. Rep. Okla. Agric. Jbp. sta. M p 11290. Barker, S. B. and W. H. Summason. 1941. The colorimetric determination of lactic acid in biological material. J. Biol. Chem. 138535. Brethour, J. R. 1984. Processing grains for maximum utilization-comparison of dry processing methods. In: Roc.Feed Grains Utilization Symposium.pp 85-89. Texas Tech Univ., Lubbock Britton, R. and V. Krause. 1985.Efects of typeand length of storage on high moisture corn. Nebraska Beef Cattle Rep. MP 48:28.

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

Adatation diet. 46 grain 0

Item

1656

STOCK ET AL.

Ram, N. S. and W. Burroughs. 1962. Suction strainer techuiqueinobtainingrumenfluid samplesfrom intact lambs. J. Anim. Sci. 21:454. Riley, J. G. 1984.Cornparalivefeedlot performance of corn, wheat, milo and barley. In: Proc. Feed Grains Utilization Symposium. pp 9-18. Texas Tech Univ., Lubbock SAS. 1982. SAS User’s Guide: Statistics. SAS Inst., Inc., Gary, NC. Steel, RGB. and J. H. Tome. 1980. Principles and Procedures of Statistics: A Biometrical Approach (2nd Ed.). McGraw-Hill Book Co.. New York. Stock,R A., D. R. Brink, R. T. Brandt, J. K. M W and K. K. Smith. 1987a. Feeding combinations of high moisture corn and dry corn to finishingcattle. J. Anim. Sci. 65:282. Stock, R. A., D. R.Brink, R. A. Britton, P.K.Goedeken, M. H.Sindt,K. K. Kreikemeier, M. L.Bauer and K. K. Smith. 1987b. Feediog combinationsof high moisture corn and dry-rolled grain sorghum to finishing steers. J. Anim. Sci. 65:290. Stock, R A., M. H.Sindt, J. C. Parrotl and F. K. Goedeken. 1990. Effects of grain type, roughage level and mon& level on hishing cattle performance. J. Anim. Sci. 683441. Teeter, R. G., F. N. Owens, D. R. Gill and J. J. Martin. 1979. Corn moisture level for feedlot steers. Anim. Sci. Res. Rep. Okla. Agric. Exp. Sta. MP 104x52. Thornton, J. H. 1976. Chemical indices of quality of ensiled high moisture corn grain. In: High Moisture Grains Symposium. pp 15&160. Oklahoma State Univ., Stillwater. Tilley. J.M.A. and R A. Terry.1963.A two-stage technique for the in vitro digestion of forage crops. J. Br. GrassL SOC. 18104. Tolman, W. and P. Q. Guyer. 1973. Acid treated corn: finishing rations. Nebraska Beef Cattle Rep. EC73218. p 16. Tolman,W. and P. Q. Guyer. 1975.Feed highmoisture corn. Nebraska Beef Cattle Rep. EC75-218. pp 4-5. Ulyatt, M.J. 1964. The use of polyethylene glycol as a markerfor measuring m e n water volume and the rate of flow of water from the rumen of grazing sheep.N. Z. J. Agric. Res. 7713. Van Keulen. J. and B. A. Young. 1977. Evaluation of acidinsoluble ash as a natural marker in ruminant digestibfity studies. J. Anim. Sci. M282. Waldo, D. R. and H. K. Goering. 1979. Insolubility of proteins in ruminant feeds by four methods. J. Anim. Sci. 491560. Weichenthal, B. A. 1973. Recent midwestern studies on high-moisture corn. Illinois Beef Cattle Rep. pp 7-10.

Downloaded from https://academic.oup.com/jas/article-abstract/69/4/1645/4705635 by Iowa State University user on 17 January 2019

Burkhardt, J. D. and L. B. Embry. 1971. Dry and high moisturegrain fed whole or rolled with hay or haylage in cattle finishing diets. Cattle Feeders Day. pp 5-8. South Dakota State Umv., Brookings. Burkhardt, J. D., L. B. Embry and R M.Luther. 197Oa Dry and high-moisture corn fed whole or rolled with two levels of haylage in cattlefinishiog rations. Beef Cattle Field Day. pp 23-26. South Dakota State Univ., Bmkings. Burkbardt, J. D., L. B. b b r y and R M. Luther. 197Ob.Dry and high-moisturecorn fed whole or rolled with hay or haylage in cattle growing-finishingrations. Beef Cattle Field Day. pp 29-32. South Dakota State Univ., Bmkings. Dahlquist, A. 1964. Method for assay of intestinal disaccharides. Anal. Biochem. 7:18. Elanco Products Company. 1974. Tyhn premix for beef cattle: Technical B Manual. pp 4-5. Indianapolis,IN. Ensor, W. L., H. H. Olsonand V.F.Colenbrander. 1970. A report Committee on classifcation of particle size in feedstuffs. J. Dairy Sci. 53:689. Erwin, E. S.. C. J. Marc0 and E. M. Emery. 1961. Volatile fatty acid analyses of blood and m e n fluid by gas chromatography. J. Dairy Sci. M1768. Fulton, W. R.. T. J. Klopfenstein and R. A. Brinon. 1979. Adaptation to high concentrate diets by beef cattle. I. Adaptation to corn and wheat diets. J. Anim. Sci. 49: 775. Gill, D. R, F. N. Owens and J. J. Martin. 1982. Corn moisture and processing for iiaishing steers. J. Anim. Sci. 55(Suppl. 1):423. Goodrich, R D., F. M. B y m and J. C. Meiske. 1975. Influence of moisturecontent, processingand reconstitution on the fermentation of corn grain J. Anim. Sci. 41:876. Goodrich, R. D. and J. C. Meiske. 1976. Influence of maturity and moisture content on the fermentation of high moisture corn. In: High Moisture Grains Symposium. pp 5140. O h . State Univ., Stillwater. Hale, W. H. and F. L. Prouty. 1980. Grain processing systems for milo and corn. Arizona Cattle Feedas Day. pp 5.1-5.4. MacRae, J. C. and D. G. h t r o n g . 1968. Enzyme method for determinationof alpha-linkedglucose polymers in biological materials. J. Sci. Food Agric. 19578. Mader, T.. D. Brink, D. Paokaskieand I. Merrill. 1983.Corn storap and processing methods for finirhinP cattle. Nebraska Beef Cattle Rep. M P 44:13. Owens, F. and B. Hicks. 1987. Variables affecting value of processed grain in ruminant diets. In: Proc.Southwest Nutrition and Management Conference. pp 61-78. Univ. of Arizona, Tempe.