- Email: [email protected]
Evaluation of alfalfa type as a roughage source in feedlot adaptation and finishing diets containing different corn types
Animal Feed Science and Technology, 42 ( 1993 ) 109-119
109
0377-8401/93/$06.00 © 1993 - Elsevier Science Publishers B.V. All rights reserved
Evaluation of alfalfa type as a roughage source in feedlot adaptation and finishing diets containing different corn types 1 T.L. Mader*'a, G.L. Poppertb, R.A.
Stock c
aDepartment of Animal Science, Universityof Nebraska, NortheastResearch and Extension Center, Concord, NE 68728, USA b1545 B Street, Lincoln, NE 68502, USA CDepartment of Animal Science, Universityof Nebraska, Lincoln, NE 68583, USA (Received 5 February 1992; accepted 29 December 1992)
Abstract
In high grain diets, effects of roughage type or source may depend on diet (adaptation vs. finishing) and grain type fed. In four feedlot trials, alfalfa hay (AH) and alfalfa silage (AS) were compared as roughage types during grain adaptation and finishing phases of production. Roughage types were compared in dry whole corn (DWC), dry rolled corn (DRC), whole high moisture corn (WHMC), and ground high moisture corn (GHMC) diets. Common diets were fed during periods in which direct comparisons of alfalfa or corn types were not made. In adaptation trials, a roughage by corn type interaction (P< 0.10 ) was observed for intake when dry corn was fed; steers fed AS with DWC ate more (10.0 kg) than steers fed AS with DRC (9.5 kg), while steers fed AH had similar intakes when fed with DRC (9.7 kg) or DWC (9.6 kg). When high moisture corn diets were fed, greater intakes (P< 0.05 ) and gains ( P < 0.10) were observed for steers fed AS than for steers fed AH. Effects of roughage fed in the adaptation period were not carried over into the finishing period, in which high energy diets were fed. In finishing phase trials, effects of roughage type were not observed in steer performance or carcass traits. The data suggest that differences in effects of roughage types are observed only in adaptation diets. Observed performance differences are primarily attributed to differences in quality and/or fiber content between AH and AS.
Introduction Inclusion of roughage or fiber in feedlot diets aids in maintaining ruminal activity and adapting feedlot cattle to high energy diets. Mader et al. ( 1991 ) found that the effects of roughage depend on the roughage type (hay vs. silage) and corn type fed. Wattiaux et al. ( 1991 ) found that fractional rates of digestion differ depending on forage particle specific gravity, although overall *Corresponding author. lJournal article number 9344 of the University of Nebraska Agricultural Research Division, Lincoln, NE.
1 10
7~L. Mader et al. ~Animal Feed Science and Technology 42 (1993) 109-119
rates of digestion were similar between alfalfa hay and alfalfa silage. The effects of different roughage types may vary in finishing (fattening) diets owing to variations in particle size as well as density among roughage types. Goetsch et al. (1987) and Owens (1987) suggested that interactions between roughage (source and/or level) and grain type may exist. Relative differences in the digestibility of roughages are known to change as grain levels increase in mixed diets (Goetsch et al., 1987; Moore et al., 1990). In an effort to identify possible interactions between roughage and grain type and associated effects on animal performance, the evaluation of roughage type under both adaptation and finishing phases of production is warranted. During the feedlot feeding period, the percentage of roughage in diets is greatest during the adaptation or step-up phase; as much as 50% of the total roughage consumed during the finishing period may be consumed during this phase. Typically, the adaptation phase is short but is critical for adaptation or changing the ruminal microbial population from predominantly fiber to starch utilizers. The objectives of this study were to evaluate the effects of alfalfa hay and alfalfa silage as roughage sources in finishing diets, on cattle performance during the grain adaptation phase and subsequent finishing phase of a feedlot feeding program when different types of corn are fed. Materials and methods
Four trials were conducted utilizing either dry or high moisture corn. Two trials (Trials 1 and 3 ) examined treatment differences during a 28 day adaptation period with a common diet fed during finishing, while the other two trials (Trials 2 and 4) measured differences during the finishing phase in which only the highest energy diet was fed (Table 1 ). Treatment diets in all trials consisted of alfalfa as silage or hay fed in combination with whole or processed corn in a 2 × 2 factorial arrangement of treatments. In Trials 1 and 2, dry whole corn (DWC) or dry rolled corn (DRC) was used in treatment TABLE1 Experimental design ~ Trial
Corn type
Feeding phase treatments imposed
1 2 3 4
Dry Dry High moisture High moisture
Adaptation 2 Finishing 3 Adaptation 2 Finishing 3
'Within a trial, alfalfa in the form of hay or silage was fed with whole or processed corn in a 2>(2 factorial arrangement of treatments. 2Common finishing diets were fed following the 28 day adaptation phase. 3Common adaptation diets were fed prior to the finishing phase.
T.L. Mader et aL/Animal Feed Science and Technology 42 (1993) 109-119
111
diets, while in Trials 3 and 4, whole high moisture corn (WHMC) or ground high moisture corn (GHMC) was used. The WHMC was preserved and stored in an oxygen-limiting bin, whereas the GHMC was stored in a bunker silo. The bunker silo and oxygen-limiting bin were filled simultaneously with 76% dry matter (DM) corn. For Trials 1 and 2 and Trials 3 and 4, alfalfa hay (AH) and alfalfa silage (AS) were harvested from the same field. Alternate windrows were chopped and ensiled. The remaining windrows were allowed to field dry to about 85% DM, harvested and stored in loaf-type stacks. The AH was ground in a tub grinder prior to feeding. In Trials 1 and 3, five adaptation diets (roughage levels 39.6, 29.4, 18.7, 12.5, and 6.3% DM), typical of those fed in commercial feedlots, were fed with changes occurring every 5 days. The final diet to be fed (6.3% DM) was fed for 8 days during the 28 day adaptation period (Table 2). A common finishing diet, composed of a mixture of each roughage type (AH and AS, 1 : 1 ) and corn grain (whole and processed, 1 : 1 ), was fed to all animals durTABLE 2 Ingredient and nutrient composition (dry matter basis) of diets Adaptation diet
Final diet
1
2
3
4
59.27 39.62
69.36 29.41
78.75 18.65
0.94
0.94 0.17 0.12
1.87 0.57 0.08 0.08
83.79 12.51 1.26 1.87 0.41 0.02 0.14
88.84 6.32 2.56 1.87 0.21
1.37 11.50 0.50 0.30 0.60 0.17 0.16
1.41 11.50 0.50 0.30 0.60 0.15 0.15
1.46 I 1.50 0.50 0.30 0.60 0.14 0.15
Ingredient (%)
Corn type ~ (IFN 4-02-931 ) Alfalfa source 2 (IFN 1-00-630) Liquid supplement 3 Dry supplement 4 Limestone (IFN 6-01-069) Dicalcium phosphate (IFN 6-01-080) Potassium chloride (IFN 6-03-755 )
0.17
0.20
Calculated nutrient analysis
Net energy gain 5 (Mcal kg- ~) Crude protein s (%) Calcium 5 (%) Phosphorus 5 (%) Potassium 5 (%) Magnesium 5 (%) Sulfur 5 (%)
1.19 13.35 0.58 0.30 0.85 0.22 0.19
1.28 12.47 0.50 0.30 0.71 0.19 0.18
~Corn type varied with trial; on a dry matter basis, content was constant within respective diets across trials. 2Alfalfa type was either dry hay and/or silage depending on treatment. 3Molasses, urea supplement containing 49.2% crude protein equivalent, 12.31% Ca, 0.77% P, 4.62% K, 0.05% Mg, 0.26% S, 6.15% NaC1, 101 750 IU kg- ~vitamin A, and 20 350 IU kg- ~vitamin D. 4Ground corn 96.8%, fat 2.1% and monensin (60 g per 0.454 kg) 1.1%. 5Based upon National Research Council (1984) analysis, 6Based on feed analysis.
1 12
T.L. Mader et al./AnimalFeed Science and Technology 42 (1993) 109-119
ing the finishing periods (Day 29 to end of trials) of Trials 1 and 3. Two day consecutive weights were taken at the start of each trial and at Days 27 and 28 of Trials 1 and 3. In an attempt to further evaluate roughage effects during the adaptation trials (Trials 1 and 3), correction of fill differences was attempted by feeding the common diet for 7 days with weights measured again at Days 34 and 35. Feed remaining in bunks on Day 28 and Day 35 (Trials 1 and 3 ) was weighed and discarded. In Trials 2 and 4, cattle were adapted to high energy diets by feeding common adaptation diets. Cattle were allotted to treatment prior to the adaptation period; however, treatment diets were not imposed until cattle were on the highest energy diet. Two day consecutive weights were taken prior to starting the trials and feeding designated finishing treatment diets. Each trial consisted of 16 (four pens per treatment) pens containing seven or eight crossbred (predominantly crosses of Hereford and Angus breeds) yearling steers per pen. Mean initial steer weights were 422 kg, 431 kg, 399 kg and 445 kg for Trials 1, 2, 3, and 4, respectively. Prior to slaughter all cattle were weighed; final weights were determined from actual weights and from hot carcass weights adjusted to a dressing percentage of 62. Gains and feed conversions were based on the adjusted values. At slaughter time, back fat thickness, USDA quality grade and liver abscess scores were obtained. Abscess scores were based on a scale of 0 (no abscess) to 4 (adherence of liver to body of carcass or digestive tract). Grain and roughage types were sampled biweekly for analysis. Dry matter analysis was determined by placing duplicate samples in a forced air oven at 60 °C for 48 h. Geometric mean diameter (GMD; American Society of Agricultural Engineers (ASAE), 1969) was calculated for both grain types based on the average of duplicate samples ( 100 g) of dry sieved material. Corn samples were freeze-ground through a 1 mm screen. Starch content of the grain types was measured as alpha-linked glucose polymers via the enzymatic digestion method of MacRae and Armstrong (1968) and modified using Trisglucose oxidase (Dahlquist, 1964) in a Technicon Auto Analyzer II colorimeter (Technicon Instruments, Tarrytown, NY). In vitro rate of starch disappearance was determined for the grains using a modified version of the Tilley and Terry (1963) technique. Corn samples were weighed into 0.5 g portions and placed in duplicate 50 ml tubes. Ruminal fluid was obtained from a steer fed an 80% concentrate diet, squeezed through four layers of cheesecloth and allowed to settle in a water bath (39 ° C). The liquid fraction was then mixed with McDougaU's buffer (McDougall, 1948) in a ratio of 40% ruminal fluid, 60% McDougall's buffer. Urea (1 g 1-1 ) was added to the buffer before the addition of strained ruminal fluid. The mixture of ruminal fluid and buffer was used as the inoculum: 25 ml were added to the tube and mixed with the tube contents. The tubes were rinsed
T.L. Mader et al./Animal Feed Science and Technology 42 (1993) 109-119
1 13
TABLE 3 Composition (% DM ) and geometric mean diameter ( G M D ) of alfalfa fed as hay or silage
Dry matter (%) Crude protein 2 (%) IVDMD 2,3 (%) Neutral detergent fiber 4 (%) Acid detergent fiber 4 (%) Geometric mean diameter 4 (mm)
Trials 1 and 2
Trials 3 and 4
Hay
Silage
Hay
Silage
86.4 16.8 58.3 55.1 39.3 4.1
41.3 17.8 61.0 44.4 36.7 5.3
82.7 16.4 55.2 58.1 43.7 3.5
37.3 18.9 61.3 43.7 36.8 5. l
SE 1
1.9 0.4 1.3 1.4 0.9 0.1
~Pooled standard error of mean. 2Hay differs from silage ( P < 0.05 ) in Trials 3 and 4. 3In vitro dry matter digestibility. 4Hay differs from silage (P< 0.05 ).
with 7 ml of buffer, gassed with CO2, stoppered and placed in a 39 °C water bath. Microbial fermentation was stopped by the addition of 1.5 ml of 3.6 N aqueous HC1. Fermentation times were 9, 12, 15, 24 and 48 h. Starch disappearance was calculated from the regression of a logarithmic function of starch remaining vs. time. The compositions of the different types of alfalfa are shown in Table 3. In vitro DM disappearance (IVDMD) was determined using techniques described by Tilley and Terry (1963). Crude protein was determined by the Kjeldahl method (Association of Official Analytical Chemists (AOAC), 1980 ). Neutral detergent fiber (NDF) of AH and AS was determined by the procedure of Van Soest and Marcus (1964) and acid detergent fiber (ADF) was determined by the procedure of Van Soest (1963). Samples of each roughage type (AH and AS) were wet sieved for GMD determinations. Wet sieving consisted of sieving samples while submerged under water. After sieving, the water level was gradually lowered from the top to the bottom of the sieve stack to allow wet panicles to flow through respective screens. Steer performance data from each trial were analyzed (Statistical Analysis Systems Institute (SAS), 1985) as a 2 × 2 factorial experiment for a fixed model (Steel and Torrie, 1980). In Trial 1, experimental units (pens)were assigned at random within an 18 pen feeding facility (only 16 pens used), while in Trials 2, 3 and 4, pens of cattle were blocked among feeding facilities. All facilities contained outside dirt pens but the degree of shelter varied. Differences between AH and AS analysis were determined from variation (pooled) among sample replicates. Results and discussion
The compositions of the alfalfa types (Table 3 ) fed in these trials display the same trends and are similar to those of AH and AS reported by Mader et
114
T.L. Mader et al./Animal Feed Science and Technology 4 2 (1993) 109-119
TABLE 4 Effect of alfalfa source (hay or silage ) for adapting steers to dry corn finishing diets t (Trial 1 )
Initial wt. (kg)
Alfalfa hay ( AH )
Alfalfa silage (AS)
SE 2
DRC
DWC
DRC
DWC
421
421
422
422
4.5
Daily gain (kg) 0-28 days 0-35 days 0-86 days
1.43 1.56 1.41
1.41 1.46 1.47
1.59 1.50 1.50
1.57 1.55 1.53
0.13 0.15 0.07
Daily feed intake (kg) 0-28 days 3 0-35 days 0-86 days
9.7 9.8 10.0
9.6 9.5 9.9
9.5 9.7 10.0
10.0 10.0 9.9
0.2 0.2 0.2
Feed/gain ratio 0-28 days 0-35 days 0-86 days
6.79 6.33 7.04
6.84 6.54 6.71
5.95 6.45 6.62
6.42 6.45 6.54
0.58 0.58 0.26
Final wt. (kg) Adjusted 4 Actual
543 559
548 557
551 561
554 561
6.5 7.6
Carcass traits Quality grade 3'5 Back fat e (cm) Liver abscess score7
7.13 0.76 0.32
7.04 0.91 0.50
7.11 0.97 0.57
7.26 0.94 0.54
0.05 0.06 0.19
IDRC, dry rolled shelled corn; DWC, dry whole shelled corn. All steers were fed a common diet after 28 days. 2Standard error of the mean. 3Roughage by corn type interaction ( P < 0.10 ). 4Final weight based on hot carcass weight adjusted to a dressing percentage of 62. s6.83, high select; 7.17, low choice. 6AH vs. AS are different ( P < 0.10). 7Scoring system: 0, no abscess; 1, one or two small abscesses; 2, three or more small abscesses; 3, one or more large abscesses; 4, adherence of liver to body or digestive tract.
al. (1986) for alfalfa harvested with the same equipment under similar conditions. Even though AS and AH were windrowed at the same time, differences in quality were evident and may be attributed to additional leaf loss and weathering of alfalfa harvested as hay. Although AH contained a greater quantity of fiber, particle size ( G M D ) was lower when compared with AS. With regard to particle size and digestion rates (data not shown in the tables) of the corn fed in these trials, G M D were 4.98, 6.92, 3.40 and 7.03, respectively, for DRC, DWC, GHMC and WHMC, while rates of starch digestion were 5.26% h -1, 5.43% h -~, 6.05% h -1 and 5.30% h -~, respectively. Rates of starch digestion for DRC and WHMC are similar to those
115
T.L. Mader et al./Aniraal Feed Science and Technology 42 (1993) 109-119
TABLE 5 Effect of alfalfa source when used in dry corn finishing diets ~ (Trial 2)
Initial wt. (kg) Daily gain (kg) Daily feed intake (kg) Feed/gain ratio
SE 2
Alfalfa hay (AH)
Alfalfa silage (AS)
DRC
DWC
DRC
DWC
429 1.35 10.0 7.30
434 1.35 10.2 7.52
432 1.45 10.1 6.94
428 1.42 9.7 6.80
4.1 0.08 0.2 0.46
505 525
509 535
513 529
507 518
3.4 5.7
Final wt. (kg)
Adjusted 3 ActuaP Carcass traits
Quality grade 5 Back fat (cm) Liver abscess score 6
7.14 0.94 0.91
7.11 1.07 0.25
7.10 0.97 0.81
7.06 0.97 0.69
0.04 0.05 0.25
~DRC, dry rolled shelled corn; DWC, dry whole shelled corn. 2Standard error of the mean. 3Final weight based on a dressing percentage of 62. 4Roughage by corn type interaction (P< 0.10 ). 36.83, high select; 7.17, low choice. 6For scoring system see footnote 7 of Table 4.
reported by Stock et al. ( 1991 ), while the rate of starch digestion for GHMC is lower. The DRC tended to have a lower rate of digestion relative to GMD when compared with the other corn types, although GHMC had the lowest GMD and fastest digestion rate. In dry corn studies (Trial 1 ), during the diet adaptation period (0-28 days; Table 4), gains and feed to gain ratios of steers fed AH or AS were similar. A roughage by corn type interaction ( P < 0.10) was observed for intakes during the 28 day adaptation period; steers fed AS with DWC tended to consume more feed than steers fed other diets. However, after steers were fed a common diet for 7 days (0-35 days) and over the entire feeding period (0-86 days), no differences in intake or performance were found. Steers initially fed AS had more external fat ( P < 0.10 ) and over the entire feeding period tended to have greater gains and lower feed to gain ratios compared with steers fed AH during the adaptation period. In the finishing phase trial (Table 5 ) conducted with dry corn (Trial 2 ), performance and carcass traits were similar among steers fed the different diets, although a roughage by corn type interaction was observed ( P < 0.10) for final weight. Steers fed AH-DWC and AS-DRC diets had greater actual final weights (lower dressing percentage) than steers fed AH-DRC and ASDWC diets. Steers fed AH-DWC and AS-DRC diets also tended to have greater
116
7zL. Mader et al./A nimal Feed Science and Technology 42 (1993) 109-119
TABLE 6 Effect of alfalfa source for adapting steers to high moisture corn finishing diets ~ (Trial 3)
Initial wt. (kg)
Alfalfa hay (AH)
Alfalfa silage (AS)
SE /
GHMC
WHMC
GHMC
WHMC
400
398
401
396
2.3
Daily gain (kg) 0-28 days 3 0-35 days 0-104 days
1.64 1.64 1.27
1.48 1.59 1.28
1.71 1.69 1.23
1.75 1.73 1.26
0.09 0.06 0.06
Daily feed intake (kg) 0-28 days 4 0-35 days 3 0-104 days
10.1 10.0 9.9
9.6 9.1 9.8
10.5 10.2 9.8
10.5 10.3 10.1
0.2 0.2 0.2
Feed~gain ratio 0-28 days 0-35 days 0-104 days Final wt. 5 (kg)
6.17 6.06 7.75 533
6.45 5.92 7.63 533
6.14 6.02 7.87 529
6.04 5.99 8.00 526
0.30 0.29 0.38 6.6
Carcass traits Quality grade 6 Back fat (cm) Liver abscess score 7
7.14 0.99 0.88
7.18 0.94 0.75
7.13 0,99 1,45
7.14 0.89 1.00
0.04 0.02 0.24
IGHMC, ground high moisture corn; WHMC, whole high moisture corn. All steers were fed a common diet after 28 days. ZStandard error of the mean. 3AH vs. AS are different ( P < 0.10). 4AH vs. AS are different ( P < 0.05 ). 5Final weight based on hot carcass weight adjusted to a dressing percentage of 62. Actual final liveweights were not obtained. 66.83, high select; 7.17, low choice. 7For scoring system see footnote 7 of Table 4.
intakes than steers fed AH-DRC and AS-DWC diets, which would partially explain the greater actual final weights. Steers fed AS as the roughage source in high moisture corn diets (Table 6 ) during the adaptation period (0-28 days ) had greater gains ( P < 0 . 1 0 ) a n d intakes ( P < 0.05 ) than steers fed AH as the roughage source. The lower fiber ( N D F and ADF) content of AS may contribute to the greater intake of adaptation diets. In previous trials (Mader et al., 1991 ) increased intakes were observed for steers fed AS in processed corn (DRC and GHMC) diets compared with intakes of steers fed corn silage as the roughage source; however, reduced intakes were observed for steers fed AS in whole corn diets, during the early portion of the feedlot feeding period.
117
T.L. Mader et al. ~Animal Feed Science and Technology 42 (1993) 109-119
TABLE 7 Effect of alfalfa source when used in high moisture corn finishing diets I (Trial 4 )
Initial wt. (kg) Daily gain (kg) Daily feed intake (kg) Feed/gain ratio
SE z
Alfalfa hay (AH)
Alfalfa silage (AS)
GHMC
WHMC
GHMC
WHMC
446 0.99 9.5 9.52
446 1.09 9.5 8.77
444 1.03 9.8 9.43
444 1.11 9.7 8.70
4.6 0.06 0.2 0.45
520 536
526 545
523 543
526 549
3.3 5.0
Final wt. (kg)
Adjusted 3 Actual Carcass traits
Quality grade 4 Back fat (cm) Liver abscess score 5
7.08 1.02 1.34
7.11 0.99 1.09
7.15 0.94 0.91
7.06 1.02 0.93
0.08 0.08 0.19
IGHMC, ground high moisture corn; WHMC, whole high moisture corn. 2Standard error of the mean. 3Final weight based on a dressing percentage of 62. 46.83, high select; 7.17, low choice. 5For scoring system see footnote 7 of Table 4.
In Trial 4 (Table 7 ), the performance of steers and carcass traits were similar during the finishing phase of production. Steers fed AH tended to have greater liver abscess scores than steers fed AS. In previous studies (Mader et al., 1991 ), steers fed AH in WHMC diets also had greater liver abscess scores than steers fed AS or corn silage with WHMC. Increased feed sorting in diets containing dry roughage (vs. wet roughages) possibly contributed to digestive disturbances and subsequent liver abscesses. Although not analyzed, visible differences were not observed in orts among treatment diets. Wattiaux et al. ( 1991 ) found little difference in digestion rates between AH and AS. The differences in physical attributes between the two roughage types may influence the rate of diet consumption and rnminal fermentation pattern. These data suggest that during the adaptation period, feeding AS as the roughage type enhanced intake in steers compared with feeding AH. In addition to differences in moisture and physical attributes, differences in quality and/or fiber content between AS and AH would contribute to performance differences observed during the adaptation period. Weichenthal et al. ( 1989 ) found greater gains ( P < 0.10) and lower feed to gain ratios ( P < 0.10) in steers fed AS as the roughage source in dry rolled corn finishing diets, compared with steers fed AH as the roughage source, where dry supplement (4.67% of diet D M ) was fed; no differences were found when a liquid supplement was fed. In previous studies (Mader et al., 1991 ), data supported the use of silages
1 18
7~L. Mader et al./Animal FeedScience and Technology 42 (1993) 109-119
particularly in high moisture corn finishing diets. Data reported herein suggest that AS improves gains (Trial 3 ), and depending on corn types, enhances intakes (Trial 1 and 3 ) during the adaptation period but over the entire feeding period similar performance was found between steers fed AS and steers fed AH as a source of roughage in feedlot diets. Although the moisture content of AS could enhance intake, the greater particle size of AS would tend to contribute to decreased intakes. Conclusion
During the adaptation phase, where a greater portion of the diet is roughage compared with the finishing phase of production, feeding AS tends to increase gains and intakes compared with feeding AH, particularly in high moisture corn diets. Differences in forage quality between AS and AH, due to differences in the harvest and storage methods used, possibly contribute to the gain and intake response observed with AS diets. Once cattle are on feed, the effects of adaptation diets appear to be lessened. Roughage quality (energy value) is important only in adaptation diets. Fiber quantity (NDF or ADF) and physical characteristics of that fiber may be more important in high energy finishing diets, although when fed in high energy finishing diets AH and AS tend to behave similarly as roughage sources. Differences in diet consumption and ruminal fermentation pattern due to roughage type does not appear to affect overall performance.
References American Society of Agricultural Engineers, 1969. Method of determining and expressing fineness of feed materials by sieving. ASAE Standard: $319, ASAE, St. Joseph, MI, pp. 346-347 Association of Official Analytical Chemists, 1984. Official Methods of Analysis, 14th edn, AOAC, Washington, DC, pp. 152-157. Dahlquist, A., 1964. Method for assay of intestinal disaccharides. Anal. Biochem., 7: 18-25. Goetsch, A.L., Owens, F.N., Funk, M.A. and Doran, B.E,, 1987. Effects of whole or ground corn with different forms of hay in 85% concentrate diets on digestion and passage rate in beef heifers. Anita. Feed Sci. Technol,, 18:151-164. MacRae, J.C. and Armstrong, D.G., 1968. Enzyme method for determination of alpha-linked glucose polymers in biological materials. J. Sci. Food Agric., 19:578-581. Mader, T.L., Pankaskie, D.E., Klopfenstein, T.J., Britton, R.A. and Krause, V.W., 1986. Utilization of alfalfa hay and alfalfa silage. 1. Protein sources in corn silage-based diets. J. Dairy Sci., 69: 2334-2341. Mader, T.L., Dahlquist, J.M. and Schmidt, L.D., 1991. Roughage sources in beef cattle finishing diets. J. Anita. Sci., 69:462-471. McDougall, E.I., 1948. Studies in ruminant saliva. I. The composition and output of sheeps saliva. Biochem. J., 43: 99-109. Moore, J.A., Poore, M.H. and Swingle, R.S., 1990. Influence of roughage source on kinetics of
T.L. Mader et al. /Animal Feed Science and Technology 42 (1993) 109-119
1 19
digestion and passage and on calculated extents of ruminal digestion in beef steers fed 65% concentrate diets. J. Anim. Sci., 68: 3412-3420. National Research Council, 1984. Nutrient Requirements of Beef Cattle, 6th edn. National Academy Press, Washington, DC, pp. 48-63. Owens, F.N., 1987. Roughage sources and levels in finishing diets for feedlot cattle. Proc. Great Plains Cattle Feeders Conference and SW Kansas Experiment Station Feeders Day, Kansas State University, 13-14 May 1987, Garden City, KS, Agricultural Experiment Station, Manhattan, KS, pp. 68-80. Statistical Analysis Systems Institute, 1985. SAS User's Guide. SAS Institute, Cary, NC, pp. 434-506. Steel, R.G. and Torrie, J.H., 1980. Principles and Procedures of Statistics, 2nd edn. McGrawHill, New York, pp. 336-360. Stock, R.A., Sindt, M.H., Cleale, R.M. and Britton, R.A., 1991. High-moisture corn utilization in finishing cattle. J. Anita. Sci., 69:1645-1656. Tilley, J.M.A. and Terry, R.A., 1963. A two-stage technique for the in vitro digestion of forage crops. J. Br. Grassl. Soc., 18:104-111. Van Soest, P.J., 1963. Use of detergents in the analysis of fibrous feeds. II. A rapid method for the determination of fiber and lignin. J. Assoc. Off. Anal. Chem., 46: 829-835. Van Soest, P.J. and Marcus, W.C., 1964. Methods of the determination of cell wall constituents in forages using detergents and the relationship between this fraction and voluntary intake and digestibility. J. Dairy Sci., 47: 704-705. Wattiaux, M.A., Mertens, D.R. and Satter, L.D., 1991. Effect of source and amount of fiber on kinetics of digestions and specific gravity of forage particles in the rumen. J. Dairy Sci., 74: 3872-3883. Weichenthal, B., Rush, I. and van Pelt, B., 1989. Roughage and supplement sources for finishing cattle. Nebraska Agricultural Research Division, Institute of Agriculture and Natural Resources, Lincoln, NE. Miscellaneous Publication No. 54, pp. 47-48.
109
0377-8401/93/$06.00 © 1993 - Elsevier Science Publishers B.V. All rights reserved
Evaluation of alfalfa type as a roughage source in feedlot adaptation and finishing diets containing different corn types 1 T.L. Mader*'a, G.L. Poppertb, R.A.
Stock c
aDepartment of Animal Science, Universityof Nebraska, NortheastResearch and Extension Center, Concord, NE 68728, USA b1545 B Street, Lincoln, NE 68502, USA CDepartment of Animal Science, Universityof Nebraska, Lincoln, NE 68583, USA (Received 5 February 1992; accepted 29 December 1992)
Abstract
In high grain diets, effects of roughage type or source may depend on diet (adaptation vs. finishing) and grain type fed. In four feedlot trials, alfalfa hay (AH) and alfalfa silage (AS) were compared as roughage types during grain adaptation and finishing phases of production. Roughage types were compared in dry whole corn (DWC), dry rolled corn (DRC), whole high moisture corn (WHMC), and ground high moisture corn (GHMC) diets. Common diets were fed during periods in which direct comparisons of alfalfa or corn types were not made. In adaptation trials, a roughage by corn type interaction (P< 0.10 ) was observed for intake when dry corn was fed; steers fed AS with DWC ate more (10.0 kg) than steers fed AS with DRC (9.5 kg), while steers fed AH had similar intakes when fed with DRC (9.7 kg) or DWC (9.6 kg). When high moisture corn diets were fed, greater intakes (P< 0.05 ) and gains ( P < 0.10) were observed for steers fed AS than for steers fed AH. Effects of roughage fed in the adaptation period were not carried over into the finishing period, in which high energy diets were fed. In finishing phase trials, effects of roughage type were not observed in steer performance or carcass traits. The data suggest that differences in effects of roughage types are observed only in adaptation diets. Observed performance differences are primarily attributed to differences in quality and/or fiber content between AH and AS.
Introduction Inclusion of roughage or fiber in feedlot diets aids in maintaining ruminal activity and adapting feedlot cattle to high energy diets. Mader et al. ( 1991 ) found that the effects of roughage depend on the roughage type (hay vs. silage) and corn type fed. Wattiaux et al. ( 1991 ) found that fractional rates of digestion differ depending on forage particle specific gravity, although overall *Corresponding author. lJournal article number 9344 of the University of Nebraska Agricultural Research Division, Lincoln, NE.
1 10
7~L. Mader et al. ~Animal Feed Science and Technology 42 (1993) 109-119
rates of digestion were similar between alfalfa hay and alfalfa silage. The effects of different roughage types may vary in finishing (fattening) diets owing to variations in particle size as well as density among roughage types. Goetsch et al. (1987) and Owens (1987) suggested that interactions between roughage (source and/or level) and grain type may exist. Relative differences in the digestibility of roughages are known to change as grain levels increase in mixed diets (Goetsch et al., 1987; Moore et al., 1990). In an effort to identify possible interactions between roughage and grain type and associated effects on animal performance, the evaluation of roughage type under both adaptation and finishing phases of production is warranted. During the feedlot feeding period, the percentage of roughage in diets is greatest during the adaptation or step-up phase; as much as 50% of the total roughage consumed during the finishing period may be consumed during this phase. Typically, the adaptation phase is short but is critical for adaptation or changing the ruminal microbial population from predominantly fiber to starch utilizers. The objectives of this study were to evaluate the effects of alfalfa hay and alfalfa silage as roughage sources in finishing diets, on cattle performance during the grain adaptation phase and subsequent finishing phase of a feedlot feeding program when different types of corn are fed. Materials and methods
Four trials were conducted utilizing either dry or high moisture corn. Two trials (Trials 1 and 3 ) examined treatment differences during a 28 day adaptation period with a common diet fed during finishing, while the other two trials (Trials 2 and 4) measured differences during the finishing phase in which only the highest energy diet was fed (Table 1 ). Treatment diets in all trials consisted of alfalfa as silage or hay fed in combination with whole or processed corn in a 2 × 2 factorial arrangement of treatments. In Trials 1 and 2, dry whole corn (DWC) or dry rolled corn (DRC) was used in treatment TABLE1 Experimental design ~ Trial
Corn type
Feeding phase treatments imposed
1 2 3 4
Dry Dry High moisture High moisture
Adaptation 2 Finishing 3 Adaptation 2 Finishing 3
'Within a trial, alfalfa in the form of hay or silage was fed with whole or processed corn in a 2>(2 factorial arrangement of treatments. 2Common finishing diets were fed following the 28 day adaptation phase. 3Common adaptation diets were fed prior to the finishing phase.
T.L. Mader et aL/Animal Feed Science and Technology 42 (1993) 109-119
111
diets, while in Trials 3 and 4, whole high moisture corn (WHMC) or ground high moisture corn (GHMC) was used. The WHMC was preserved and stored in an oxygen-limiting bin, whereas the GHMC was stored in a bunker silo. The bunker silo and oxygen-limiting bin were filled simultaneously with 76% dry matter (DM) corn. For Trials 1 and 2 and Trials 3 and 4, alfalfa hay (AH) and alfalfa silage (AS) were harvested from the same field. Alternate windrows were chopped and ensiled. The remaining windrows were allowed to field dry to about 85% DM, harvested and stored in loaf-type stacks. The AH was ground in a tub grinder prior to feeding. In Trials 1 and 3, five adaptation diets (roughage levels 39.6, 29.4, 18.7, 12.5, and 6.3% DM), typical of those fed in commercial feedlots, were fed with changes occurring every 5 days. The final diet to be fed (6.3% DM) was fed for 8 days during the 28 day adaptation period (Table 2). A common finishing diet, composed of a mixture of each roughage type (AH and AS, 1 : 1 ) and corn grain (whole and processed, 1 : 1 ), was fed to all animals durTABLE 2 Ingredient and nutrient composition (dry matter basis) of diets Adaptation diet
Final diet
1
2
3
4
59.27 39.62
69.36 29.41
78.75 18.65
0.94
0.94 0.17 0.12
1.87 0.57 0.08 0.08
83.79 12.51 1.26 1.87 0.41 0.02 0.14
88.84 6.32 2.56 1.87 0.21
1.37 11.50 0.50 0.30 0.60 0.17 0.16
1.41 11.50 0.50 0.30 0.60 0.15 0.15
1.46 I 1.50 0.50 0.30 0.60 0.14 0.15
Ingredient (%)
Corn type ~ (IFN 4-02-931 ) Alfalfa source 2 (IFN 1-00-630) Liquid supplement 3 Dry supplement 4 Limestone (IFN 6-01-069) Dicalcium phosphate (IFN 6-01-080) Potassium chloride (IFN 6-03-755 )
0.17
0.20
Calculated nutrient analysis
Net energy gain 5 (Mcal kg- ~) Crude protein s (%) Calcium 5 (%) Phosphorus 5 (%) Potassium 5 (%) Magnesium 5 (%) Sulfur 5 (%)
1.19 13.35 0.58 0.30 0.85 0.22 0.19
1.28 12.47 0.50 0.30 0.71 0.19 0.18
~Corn type varied with trial; on a dry matter basis, content was constant within respective diets across trials. 2Alfalfa type was either dry hay and/or silage depending on treatment. 3Molasses, urea supplement containing 49.2% crude protein equivalent, 12.31% Ca, 0.77% P, 4.62% K, 0.05% Mg, 0.26% S, 6.15% NaC1, 101 750 IU kg- ~vitamin A, and 20 350 IU kg- ~vitamin D. 4Ground corn 96.8%, fat 2.1% and monensin (60 g per 0.454 kg) 1.1%. 5Based upon National Research Council (1984) analysis, 6Based on feed analysis.
1 12
T.L. Mader et al./AnimalFeed Science and Technology 42 (1993) 109-119
ing the finishing periods (Day 29 to end of trials) of Trials 1 and 3. Two day consecutive weights were taken at the start of each trial and at Days 27 and 28 of Trials 1 and 3. In an attempt to further evaluate roughage effects during the adaptation trials (Trials 1 and 3), correction of fill differences was attempted by feeding the common diet for 7 days with weights measured again at Days 34 and 35. Feed remaining in bunks on Day 28 and Day 35 (Trials 1 and 3 ) was weighed and discarded. In Trials 2 and 4, cattle were adapted to high energy diets by feeding common adaptation diets. Cattle were allotted to treatment prior to the adaptation period; however, treatment diets were not imposed until cattle were on the highest energy diet. Two day consecutive weights were taken prior to starting the trials and feeding designated finishing treatment diets. Each trial consisted of 16 (four pens per treatment) pens containing seven or eight crossbred (predominantly crosses of Hereford and Angus breeds) yearling steers per pen. Mean initial steer weights were 422 kg, 431 kg, 399 kg and 445 kg for Trials 1, 2, 3, and 4, respectively. Prior to slaughter all cattle were weighed; final weights were determined from actual weights and from hot carcass weights adjusted to a dressing percentage of 62. Gains and feed conversions were based on the adjusted values. At slaughter time, back fat thickness, USDA quality grade and liver abscess scores were obtained. Abscess scores were based on a scale of 0 (no abscess) to 4 (adherence of liver to body of carcass or digestive tract). Grain and roughage types were sampled biweekly for analysis. Dry matter analysis was determined by placing duplicate samples in a forced air oven at 60 °C for 48 h. Geometric mean diameter (GMD; American Society of Agricultural Engineers (ASAE), 1969) was calculated for both grain types based on the average of duplicate samples ( 100 g) of dry sieved material. Corn samples were freeze-ground through a 1 mm screen. Starch content of the grain types was measured as alpha-linked glucose polymers via the enzymatic digestion method of MacRae and Armstrong (1968) and modified using Trisglucose oxidase (Dahlquist, 1964) in a Technicon Auto Analyzer II colorimeter (Technicon Instruments, Tarrytown, NY). In vitro rate of starch disappearance was determined for the grains using a modified version of the Tilley and Terry (1963) technique. Corn samples were weighed into 0.5 g portions and placed in duplicate 50 ml tubes. Ruminal fluid was obtained from a steer fed an 80% concentrate diet, squeezed through four layers of cheesecloth and allowed to settle in a water bath (39 ° C). The liquid fraction was then mixed with McDougaU's buffer (McDougall, 1948) in a ratio of 40% ruminal fluid, 60% McDougall's buffer. Urea (1 g 1-1 ) was added to the buffer before the addition of strained ruminal fluid. The mixture of ruminal fluid and buffer was used as the inoculum: 25 ml were added to the tube and mixed with the tube contents. The tubes were rinsed
T.L. Mader et al./Animal Feed Science and Technology 42 (1993) 109-119
1 13
TABLE 3 Composition (% DM ) and geometric mean diameter ( G M D ) of alfalfa fed as hay or silage
Dry matter (%) Crude protein 2 (%) IVDMD 2,3 (%) Neutral detergent fiber 4 (%) Acid detergent fiber 4 (%) Geometric mean diameter 4 (mm)
Trials 1 and 2
Trials 3 and 4
Hay
Silage
Hay
Silage
86.4 16.8 58.3 55.1 39.3 4.1
41.3 17.8 61.0 44.4 36.7 5.3
82.7 16.4 55.2 58.1 43.7 3.5
37.3 18.9 61.3 43.7 36.8 5. l
SE 1
1.9 0.4 1.3 1.4 0.9 0.1
~Pooled standard error of mean. 2Hay differs from silage ( P < 0.05 ) in Trials 3 and 4. 3In vitro dry matter digestibility. 4Hay differs from silage (P< 0.05 ).
with 7 ml of buffer, gassed with CO2, stoppered and placed in a 39 °C water bath. Microbial fermentation was stopped by the addition of 1.5 ml of 3.6 N aqueous HC1. Fermentation times were 9, 12, 15, 24 and 48 h. Starch disappearance was calculated from the regression of a logarithmic function of starch remaining vs. time. The compositions of the different types of alfalfa are shown in Table 3. In vitro DM disappearance (IVDMD) was determined using techniques described by Tilley and Terry (1963). Crude protein was determined by the Kjeldahl method (Association of Official Analytical Chemists (AOAC), 1980 ). Neutral detergent fiber (NDF) of AH and AS was determined by the procedure of Van Soest and Marcus (1964) and acid detergent fiber (ADF) was determined by the procedure of Van Soest (1963). Samples of each roughage type (AH and AS) were wet sieved for GMD determinations. Wet sieving consisted of sieving samples while submerged under water. After sieving, the water level was gradually lowered from the top to the bottom of the sieve stack to allow wet panicles to flow through respective screens. Steer performance data from each trial were analyzed (Statistical Analysis Systems Institute (SAS), 1985) as a 2 × 2 factorial experiment for a fixed model (Steel and Torrie, 1980). In Trial 1, experimental units (pens)were assigned at random within an 18 pen feeding facility (only 16 pens used), while in Trials 2, 3 and 4, pens of cattle were blocked among feeding facilities. All facilities contained outside dirt pens but the degree of shelter varied. Differences between AH and AS analysis were determined from variation (pooled) among sample replicates. Results and discussion
The compositions of the alfalfa types (Table 3 ) fed in these trials display the same trends and are similar to those of AH and AS reported by Mader et
114
T.L. Mader et al./Animal Feed Science and Technology 4 2 (1993) 109-119
TABLE 4 Effect of alfalfa source (hay or silage ) for adapting steers to dry corn finishing diets t (Trial 1 )
Initial wt. (kg)
Alfalfa hay ( AH )
Alfalfa silage (AS)
SE 2
DRC
DWC
DRC
DWC
421
421
422
422
4.5
Daily gain (kg) 0-28 days 0-35 days 0-86 days
1.43 1.56 1.41
1.41 1.46 1.47
1.59 1.50 1.50
1.57 1.55 1.53
0.13 0.15 0.07
Daily feed intake (kg) 0-28 days 3 0-35 days 0-86 days
9.7 9.8 10.0
9.6 9.5 9.9
9.5 9.7 10.0
10.0 10.0 9.9
0.2 0.2 0.2
Feed/gain ratio 0-28 days 0-35 days 0-86 days
6.79 6.33 7.04
6.84 6.54 6.71
5.95 6.45 6.62
6.42 6.45 6.54
0.58 0.58 0.26
Final wt. (kg) Adjusted 4 Actual
543 559
548 557
551 561
554 561
6.5 7.6
Carcass traits Quality grade 3'5 Back fat e (cm) Liver abscess score7
7.13 0.76 0.32
7.04 0.91 0.50
7.11 0.97 0.57
7.26 0.94 0.54
0.05 0.06 0.19
IDRC, dry rolled shelled corn; DWC, dry whole shelled corn. All steers were fed a common diet after 28 days. 2Standard error of the mean. 3Roughage by corn type interaction ( P < 0.10 ). 4Final weight based on hot carcass weight adjusted to a dressing percentage of 62. s6.83, high select; 7.17, low choice. 6AH vs. AS are different ( P < 0.10). 7Scoring system: 0, no abscess; 1, one or two small abscesses; 2, three or more small abscesses; 3, one or more large abscesses; 4, adherence of liver to body or digestive tract.
al. (1986) for alfalfa harvested with the same equipment under similar conditions. Even though AS and AH were windrowed at the same time, differences in quality were evident and may be attributed to additional leaf loss and weathering of alfalfa harvested as hay. Although AH contained a greater quantity of fiber, particle size ( G M D ) was lower when compared with AS. With regard to particle size and digestion rates (data not shown in the tables) of the corn fed in these trials, G M D were 4.98, 6.92, 3.40 and 7.03, respectively, for DRC, DWC, GHMC and WHMC, while rates of starch digestion were 5.26% h -1, 5.43% h -~, 6.05% h -1 and 5.30% h -~, respectively. Rates of starch digestion for DRC and WHMC are similar to those
115
T.L. Mader et al./Aniraal Feed Science and Technology 42 (1993) 109-119
TABLE 5 Effect of alfalfa source when used in dry corn finishing diets ~ (Trial 2)
Initial wt. (kg) Daily gain (kg) Daily feed intake (kg) Feed/gain ratio
SE 2
Alfalfa hay (AH)
Alfalfa silage (AS)
DRC
DWC
DRC
DWC
429 1.35 10.0 7.30
434 1.35 10.2 7.52
432 1.45 10.1 6.94
428 1.42 9.7 6.80
4.1 0.08 0.2 0.46
505 525
509 535
513 529
507 518
3.4 5.7
Final wt. (kg)
Adjusted 3 ActuaP Carcass traits
Quality grade 5 Back fat (cm) Liver abscess score 6
7.14 0.94 0.91
7.11 1.07 0.25
7.10 0.97 0.81
7.06 0.97 0.69
0.04 0.05 0.25
~DRC, dry rolled shelled corn; DWC, dry whole shelled corn. 2Standard error of the mean. 3Final weight based on a dressing percentage of 62. 4Roughage by corn type interaction (P< 0.10 ). 36.83, high select; 7.17, low choice. 6For scoring system see footnote 7 of Table 4.
reported by Stock et al. ( 1991 ), while the rate of starch digestion for GHMC is lower. The DRC tended to have a lower rate of digestion relative to GMD when compared with the other corn types, although GHMC had the lowest GMD and fastest digestion rate. In dry corn studies (Trial 1 ), during the diet adaptation period (0-28 days; Table 4), gains and feed to gain ratios of steers fed AH or AS were similar. A roughage by corn type interaction ( P < 0.10) was observed for intakes during the 28 day adaptation period; steers fed AS with DWC tended to consume more feed than steers fed other diets. However, after steers were fed a common diet for 7 days (0-35 days) and over the entire feeding period (0-86 days), no differences in intake or performance were found. Steers initially fed AS had more external fat ( P < 0.10 ) and over the entire feeding period tended to have greater gains and lower feed to gain ratios compared with steers fed AH during the adaptation period. In the finishing phase trial (Table 5 ) conducted with dry corn (Trial 2 ), performance and carcass traits were similar among steers fed the different diets, although a roughage by corn type interaction was observed ( P < 0.10) for final weight. Steers fed AH-DWC and AS-DRC diets had greater actual final weights (lower dressing percentage) than steers fed AH-DRC and ASDWC diets. Steers fed AH-DWC and AS-DRC diets also tended to have greater
116
7zL. Mader et al./A nimal Feed Science and Technology 42 (1993) 109-119
TABLE 6 Effect of alfalfa source for adapting steers to high moisture corn finishing diets ~ (Trial 3)
Initial wt. (kg)
Alfalfa hay (AH)
Alfalfa silage (AS)
SE /
GHMC
WHMC
GHMC
WHMC
400
398
401
396
2.3
Daily gain (kg) 0-28 days 3 0-35 days 0-104 days
1.64 1.64 1.27
1.48 1.59 1.28
1.71 1.69 1.23
1.75 1.73 1.26
0.09 0.06 0.06
Daily feed intake (kg) 0-28 days 4 0-35 days 3 0-104 days
10.1 10.0 9.9
9.6 9.1 9.8
10.5 10.2 9.8
10.5 10.3 10.1
0.2 0.2 0.2
Feed~gain ratio 0-28 days 0-35 days 0-104 days Final wt. 5 (kg)
6.17 6.06 7.75 533
6.45 5.92 7.63 533
6.14 6.02 7.87 529
6.04 5.99 8.00 526
0.30 0.29 0.38 6.6
Carcass traits Quality grade 6 Back fat (cm) Liver abscess score 7
7.14 0.99 0.88
7.18 0.94 0.75
7.13 0,99 1,45
7.14 0.89 1.00
0.04 0.02 0.24
IGHMC, ground high moisture corn; WHMC, whole high moisture corn. All steers were fed a common diet after 28 days. ZStandard error of the mean. 3AH vs. AS are different ( P < 0.10). 4AH vs. AS are different ( P < 0.05 ). 5Final weight based on hot carcass weight adjusted to a dressing percentage of 62. Actual final liveweights were not obtained. 66.83, high select; 7.17, low choice. 7For scoring system see footnote 7 of Table 4.
intakes than steers fed AH-DRC and AS-DWC diets, which would partially explain the greater actual final weights. Steers fed AS as the roughage source in high moisture corn diets (Table 6 ) during the adaptation period (0-28 days ) had greater gains ( P < 0 . 1 0 ) a n d intakes ( P < 0.05 ) than steers fed AH as the roughage source. The lower fiber ( N D F and ADF) content of AS may contribute to the greater intake of adaptation diets. In previous trials (Mader et al., 1991 ) increased intakes were observed for steers fed AS in processed corn (DRC and GHMC) diets compared with intakes of steers fed corn silage as the roughage source; however, reduced intakes were observed for steers fed AS in whole corn diets, during the early portion of the feedlot feeding period.
117
T.L. Mader et al. ~Animal Feed Science and Technology 42 (1993) 109-119
TABLE 7 Effect of alfalfa source when used in high moisture corn finishing diets I (Trial 4 )
Initial wt. (kg) Daily gain (kg) Daily feed intake (kg) Feed/gain ratio
SE z
Alfalfa hay (AH)
Alfalfa silage (AS)
GHMC
WHMC
GHMC
WHMC
446 0.99 9.5 9.52
446 1.09 9.5 8.77
444 1.03 9.8 9.43
444 1.11 9.7 8.70
4.6 0.06 0.2 0.45
520 536
526 545
523 543
526 549
3.3 5.0
Final wt. (kg)
Adjusted 3 Actual Carcass traits
Quality grade 4 Back fat (cm) Liver abscess score 5
7.08 1.02 1.34
7.11 0.99 1.09
7.15 0.94 0.91
7.06 1.02 0.93
0.08 0.08 0.19
IGHMC, ground high moisture corn; WHMC, whole high moisture corn. 2Standard error of the mean. 3Final weight based on a dressing percentage of 62. 46.83, high select; 7.17, low choice. 5For scoring system see footnote 7 of Table 4.
In Trial 4 (Table 7 ), the performance of steers and carcass traits were similar during the finishing phase of production. Steers fed AH tended to have greater liver abscess scores than steers fed AS. In previous studies (Mader et al., 1991 ), steers fed AH in WHMC diets also had greater liver abscess scores than steers fed AS or corn silage with WHMC. Increased feed sorting in diets containing dry roughage (vs. wet roughages) possibly contributed to digestive disturbances and subsequent liver abscesses. Although not analyzed, visible differences were not observed in orts among treatment diets. Wattiaux et al. ( 1991 ) found little difference in digestion rates between AH and AS. The differences in physical attributes between the two roughage types may influence the rate of diet consumption and rnminal fermentation pattern. These data suggest that during the adaptation period, feeding AS as the roughage type enhanced intake in steers compared with feeding AH. In addition to differences in moisture and physical attributes, differences in quality and/or fiber content between AS and AH would contribute to performance differences observed during the adaptation period. Weichenthal et al. ( 1989 ) found greater gains ( P < 0.10) and lower feed to gain ratios ( P < 0.10) in steers fed AS as the roughage source in dry rolled corn finishing diets, compared with steers fed AH as the roughage source, where dry supplement (4.67% of diet D M ) was fed; no differences were found when a liquid supplement was fed. In previous studies (Mader et al., 1991 ), data supported the use of silages
1 18
7~L. Mader et al./Animal FeedScience and Technology 42 (1993) 109-119
particularly in high moisture corn finishing diets. Data reported herein suggest that AS improves gains (Trial 3 ), and depending on corn types, enhances intakes (Trial 1 and 3 ) during the adaptation period but over the entire feeding period similar performance was found between steers fed AS and steers fed AH as a source of roughage in feedlot diets. Although the moisture content of AS could enhance intake, the greater particle size of AS would tend to contribute to decreased intakes. Conclusion
During the adaptation phase, where a greater portion of the diet is roughage compared with the finishing phase of production, feeding AS tends to increase gains and intakes compared with feeding AH, particularly in high moisture corn diets. Differences in forage quality between AS and AH, due to differences in the harvest and storage methods used, possibly contribute to the gain and intake response observed with AS diets. Once cattle are on feed, the effects of adaptation diets appear to be lessened. Roughage quality (energy value) is important only in adaptation diets. Fiber quantity (NDF or ADF) and physical characteristics of that fiber may be more important in high energy finishing diets, although when fed in high energy finishing diets AH and AS tend to behave similarly as roughage sources. Differences in diet consumption and ruminal fermentation pattern due to roughage type does not appear to affect overall performance.
References American Society of Agricultural Engineers, 1969. Method of determining and expressing fineness of feed materials by sieving. ASAE Standard: $319, ASAE, St. Joseph, MI, pp. 346-347 Association of Official Analytical Chemists, 1984. Official Methods of Analysis, 14th edn, AOAC, Washington, DC, pp. 152-157. Dahlquist, A., 1964. Method for assay of intestinal disaccharides. Anal. Biochem., 7: 18-25. Goetsch, A.L., Owens, F.N., Funk, M.A. and Doran, B.E,, 1987. Effects of whole or ground corn with different forms of hay in 85% concentrate diets on digestion and passage rate in beef heifers. Anita. Feed Sci. Technol,, 18:151-164. MacRae, J.C. and Armstrong, D.G., 1968. Enzyme method for determination of alpha-linked glucose polymers in biological materials. J. Sci. Food Agric., 19:578-581. Mader, T.L., Pankaskie, D.E., Klopfenstein, T.J., Britton, R.A. and Krause, V.W., 1986. Utilization of alfalfa hay and alfalfa silage. 1. Protein sources in corn silage-based diets. J. Dairy Sci., 69: 2334-2341. Mader, T.L., Dahlquist, J.M. and Schmidt, L.D., 1991. Roughage sources in beef cattle finishing diets. J. Anita. Sci., 69:462-471. McDougall, E.I., 1948. Studies in ruminant saliva. I. The composition and output of sheeps saliva. Biochem. J., 43: 99-109. Moore, J.A., Poore, M.H. and Swingle, R.S., 1990. Influence of roughage source on kinetics of
T.L. Mader et al. /Animal Feed Science and Technology 42 (1993) 109-119
1 19
digestion and passage and on calculated extents of ruminal digestion in beef steers fed 65% concentrate diets. J. Anim. Sci., 68: 3412-3420. National Research Council, 1984. Nutrient Requirements of Beef Cattle, 6th edn. National Academy Press, Washington, DC, pp. 48-63. Owens, F.N., 1987. Roughage sources and levels in finishing diets for feedlot cattle. Proc. Great Plains Cattle Feeders Conference and SW Kansas Experiment Station Feeders Day, Kansas State University, 13-14 May 1987, Garden City, KS, Agricultural Experiment Station, Manhattan, KS, pp. 68-80. Statistical Analysis Systems Institute, 1985. SAS User's Guide. SAS Institute, Cary, NC, pp. 434-506. Steel, R.G. and Torrie, J.H., 1980. Principles and Procedures of Statistics, 2nd edn. McGrawHill, New York, pp. 336-360. Stock, R.A., Sindt, M.H., Cleale, R.M. and Britton, R.A., 1991. High-moisture corn utilization in finishing cattle. J. Anita. Sci., 69:1645-1656. Tilley, J.M.A. and Terry, R.A., 1963. A two-stage technique for the in vitro digestion of forage crops. J. Br. Grassl. Soc., 18:104-111. Van Soest, P.J., 1963. Use of detergents in the analysis of fibrous feeds. II. A rapid method for the determination of fiber and lignin. J. Assoc. Off. Anal. Chem., 46: 829-835. Van Soest, P.J. and Marcus, W.C., 1964. Methods of the determination of cell wall constituents in forages using detergents and the relationship between this fraction and voluntary intake and digestibility. J. Dairy Sci., 47: 704-705. Wattiaux, M.A., Mertens, D.R. and Satter, L.D., 1991. Effect of source and amount of fiber on kinetics of digestions and specific gravity of forage particles in the rumen. J. Dairy Sci., 74: 3872-3883. Weichenthal, B., Rush, I. and van Pelt, B., 1989. Roughage and supplement sources for finishing cattle. Nebraska Agricultural Research Division, Institute of Agriculture and Natural Resources, Lincoln, NE. Miscellaneous Publication No. 54, pp. 47-48.