| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ANIMAL NUTRITION |
Department of Animal Science, University of Missouri, Columbia 65211
Abstract
Two experiments were conducted to determine the efficacy of whole raw soybeans as a partial or whole replacement for soybean meal in a corn/soybean meal-based feedlot diet. In Exp. 1, 80 crossbred steers (average BW = 441.3 kg) and, in Exp. 2, 96 Angus-sired steers (average BW = 413.7 kg) were blocked by weight and assigned randomly to one of four dietary treatments. Treatments were 0, 8, 16, and 24% dietary inclusions of whole raw soybeans. Diets within experiments were isonitrogenous. Across experiments, diets were similar, differing only in amount of corn silage (8 vs. 15% DM) at the expense of whole, shelled corn for Exp. 1 and Exp. 2, respectively. No treatment differences were observed for ADG or final BW. Dry matter intake from d 0 to d 58 decreased linearly (P < 0.05) with increased inclusion of whole raw soybeans in Exp. 1, with no effect on feed efficiency. In Exp.2 from d 0 to 72, whole raw soybean inclusion had no effect on DMI or feed efficiency. There tended (P < 0.10) to be a linear reduction in hot carcass weight when whole raw soybeans were included in Exp. 1. Unexpectedly, longissimus muscle area tended (P < 0.10) to respond quadratically (P < 0.10) to the increased inclusion of whole raw soybeans in Exp.1. No differences were detected in marbling score, 10th-rib backfat, or yield grade for Exp. 1 and 2 steers. In Exp. 2, inclusion of whole raw soybeans had no effect on hot carcass weight or longissimus muscle area. Incrementally increasing the inclusion of whole raw soybeans in the diet of feedlot steers had little overall effect on weight gain, feed efficiency, or carcass quality in Exp. 1 and 2. There were subtle differences in the treatment responses observed for hot carcass weight and longissimus muscle area between Exp. 1 and Exp. 2 for the 24% inclusion level. These noted differences may indicate that inclusion levels above 24% might not be beneficial.
Key Words: Carcasses • Cattle • Performance • Soybeans • Steers
Introduction
Soybeans are high in protein and fat and when economically priced may be able to be used as an alternative protein/energy source for feedlot cattle in the Midwest, where farmer-feeders have ample supply of both soybeans and cattle. In the past, feeding whole raw soybeans (WRS) to feedlot cattle has not been readily practiced. Data on the effects of feeding WRS to feedlot cattle in regards to performance and carcass quality are limited.
In previous work with growing steers, the inclusion of WRS and other oilseeds as dietary sources of energy and protein were evaluated. The feeding of raw or extruded soybeans to steers receiving grass hay ad-libitum improved gain and gain efficiency over those of steers fed only hay (Albro et al., 1993
). Gain efficiency was greater for steers fed raw vs. extruded soybeans. Research with dairy calves has shown that WRS can be included in the diet as 16% of the dietary DM without detrimental effects on the digestibility of DM or fiber (Bunting et al., 1996). Others have reported no adverse effects on ruminal environmental conditions and energy or OM digestibility at levels of up to 16% dietary inclusion (Aldrich et al., 1995a,b). Dietary inclusion of WRS has been shown to lower the percentage of acetate produced in the rumen while increasing the percentage of propionate (Bunting et al., 1996). Increasing ruminal propionate could be beneficial in the feedlot setting, as propionate is a precursor for i.m. fat (Smith and Crouse, 1984). Based on this and other previously reported literature, it is our hypothesis that the inclusion of WRS into the diet of feedlot steers will have no detrimental effects on steer performance or carcass characteristics. The objectives of these studies were to determine the effects, if any, that the inclusion of WRS in the diet at increasing levels would have on feedlot steer performance and carcass characteristics.
Materials and Methods
Animals and Management
Experiment 1.
Eighty crossbreed yearling steers of mixed breeding were assigned to one of four experimental diets (T0, T8, T16, and T24). These diets contained 0, 8, 16, and 24% WRS, respectively. Steers were weighed on two consecutive days and sorted by average weight into one of four weight blocks (n = 20 per block; 400.5, 428.4, 450.8, and 485.0 kg). Steers within block were stratified to treatment, yielding five animals per pen per weight block. There was no replication of block within treatments. The five steers per weight block within treatment were randomly assigned to 1 of 16 pens after the second day weights were measured. Pens were of open construction and measured 7.3 x 24.4 m. A 9.8-m concrete feed bunk was split and shared between two pens (4.9 m/pen). Bunks were set on concrete slabs extending approximately 2.5 m into the pens. Frost-free waterers were shared between two pens. Feed bunks and slabs were located under sloped-roof shades.
Steers were fed and managed the same for a period of at least 28 d before initiation of the study. Steers were adapted over a period of 6 d from a moderate-energy diet (66% concentrate) to a high-grain ration (86% concentrate) before the study began. Steers were previously implanted (Revalor; Intervet, Millsboro, DE) with the expected payout expiring before initiation of treatments. Steers were not reimplanted. Treatment diets were fed once daily and were offered for the first time immediately after all steers returned to their respective pens on d 2 after measuring the second consecutive initial body weight. Treatment diets were fed for 58 d, at which time steers were slaughtered. Experimental procedures were conducted under an approved animal care and use protocol (ACUC #3278) as regulated by the University of Missouri Animal Care and Use Committee.
Experiment 2.
Ninety-six short-yearling Angus-sired steers out of percentage Angus dams were assigned to the same experimental treatments as in Exp. 1. In this study, there were 24 steers per weight block, with weight blocks averaging 374.8, 405.1, 428.2, and 446.9 kg, respectively. Steers were allotted to treatment diets, housed in the same pens and were started on treatment diets as described in Exp. 1. These steers were previously implanted (Synovex-S; Fort Dodge Animal Health, Overland Park, KS) with the payout expiring before initiation of treatments, and were not reimplanted. Similar to the aforementioned experimentation management protocol used in Exp.1, all steers were fed a corn silage-based diet for at least 60 d before administration of dietary treatments. Steers were fed dietary treatments for 72 d before slaughter.
Treatments
Experiment 1.
Steers were fed their respective treatment diets throughout the study utilizing clean-bunk management via a Harsh (Model 203T; Harsh International, Inc., Eaton CO) truck-mounted mixer. Diet composition is reported in Table 1. Treatment diets were created by replacing a portion of the corn and soybean meal with 8.0 (T8), 16.0 (T16), or 24.0% (T24) whole raw soybeans.
|
), compared with those in Exp. 1, contained a greater amount of corn silage (15 vs. 8% of diet DM) at the expense of whole shelled corn. Other dietary variables were similar to those in Exp. 1.
|
). The reported chemical analysis of diets is the average nutrient composition of weekly diet samples. One day after final BW determination, steers were fed 50% of the previous day’s recorded intake (as-fed basis). Late afternoon on the same day, steers were transported from Columbia, MO, to Emporia, KS, where they were slaughtered the following morning at a commercial processing facility (IBP Inc., Emporia, KS). Hot carcass weight (HCW) was recorded immediately before the carcass entered the cooler. Carcass measurements (marbling scores; backfat [BF]; longissimus muscle area [LMA]; percentage of kidney, pelvic, and heart fat [KPH]; and yield grade [YG]) were taken after the carcasses were allowed to chill for 72 h at 0°C by trained personnel (DaBulls Data Collection Service, Kansas State University, Manhattan). Marbling scores were coded so that 4.0 = slight00 (low Select), 5.0 = small00 (low Choice), 6.0 = modest00 (average Choice), and 7.0 = moderate00 (high Choice).
Experiment 2.
In addition to the analyses described for Exp. 1, ultrasonography was also performed. Steers were evaluated for marbling and backfat by the use of ultrasound on d 0, 31, 58, and 72 by trained personnel (Prime Ultrasound LLC, Shawnee, KS). Marbling and backfat were estimated by an image analysis procedure (Brethour, 1994). Marbling and backfat were estimated caudal to the last rib and hooks, approximately 8 cm distal to the back for longissimus and gluteus muscle readings, respectively. Measurements represented an average of at least three scans. Feeding, transportation, and carcass data collection were similar to those used in Exp. 1, except that carcasses were allowed to chill for only 48 h before collection of carcass data.
Statistical Analysis
Experiments 1 and 2.
In Exp. 1 and 2, pen was the experimental unit used for the analysis of all variables. Both experiments were analyzed as randomized block designs by the GLM procedures of SAS (SAS Inst. Inc., Cary, NC) using linear, quadratic, and cubic contrast statements to test for differences in least squares means. Block was used as pen replicate. The model included treatment, pen replicate, and treatment x replicate as the experimental error term. In response to detected differences in initial BW for Exp. 1, initial BW was used as a covariate. An 
-level of 0.05 was used for significance to minimize type-I errors, with -levels of 0.05 to 0.10 denoting a tendency for significance.
Results and Discussion
Dietary composition and chemical analysis are reported in Tables 1
and 2 for each experiment. Soybeans are high in PUFA; as WRS inclusion increased, the proportion of dietary PUFA (mainly cis-linoleic and -linolenic) should increase at the expense of saturated and monounsaturated fatty acids. When high levels of unprotected PUFA are fed, such as in the form of soybean oil, a depression in performance has been reported (Engle et al., 2000). The authors speculated that this may have been due to the high unsaturated fatty acid content of the oil in combination with both a relatively high basal diet ether extract level of 3.5% and a very low dietary fiber level. Particulate-lipid absorption may have reached saturation and caused greater microbial incorporation of dietary PUFA. It has been demonstrated that high microbial PUFA incorporation can be inhibitory to microbial function (Harfoot and Hazlewood, 1988).
Feedlot Performance
In Exp. 1 as the days on test progressed from d 0 to 29, ADG was depressed (P < 0.05) as the inclusion of WRS increased (Table 3). As the study progressed from d 29 to 58, an inverse situation was observed (P < 0.05). At the conclusion of Exp. 1, no treatment effects were noted for ADG (1.49 kg/d). In Exp. 2, as the days on test increased from d 0 to 31 and to d 72, no effects on ADG were detected as WRS inclusion increased (Table 4). Likewise, no differences were detected in ADG for the periods of d 31 to 58 or d 58 to 72.
|
|
. Conversely, in Exp. 2, there was no difference in overall DMI (9.98 kg/d) or feed efficiency (175.0 g/kg) as WRS inclusion level increased.
Carcass Performance
Two steers from the same pen and treatment (T16) in Exp. 1 were not slaughtered with the contemporary group. This exclusion was not a result of treatment administration but of steers escaping during loading for slaughter. Thus, carcass data for these two steers were not available and entered as missing observations. Carcass data for Exp. 1 and 2 are reported in Table 3 and 4, respectively. In Exp. 1, there was a tendency (P < 0.10) for HCW to decrease with the increasing inclusion of WRS, as was similar to previous results using roasted soybeans and soybean oil (Rumsey et al., 1999; Engle et al., 2000). The weight difference in these previous studies was partially attributed to a reduction in body fat without altering carcass merit. Others have reported no detrimental effects on HCW with the feeding of soybeans or soybean oil (Brandt and Anderson, 1990; Eweedah et al., 1997). Unlike HCW in Exp. 1, no effect on HCW (325.5 kg) in Exp. 2 was detected. Without potential explanation, a cubic relationship (P < 0.10) was observed for LMA of steers in Exp. 1. Longissimus muscle areas for steers in the T0, T16, and T24 treatments were not different (83.5, 83.7, and 83.2 cm2, respectively), but LMA for T8 steers averaged only 80.7 cm2. Similar to the results for HCW in Exp. 2, there were no treatment effects on LMA (79.6 cm2) or dressing percent (60.5%) for Exp. 2 steers.
In Exp. 1, there were no treatment effects on KPH (2.1%), marbling (5.1; small07 = low Choice), BF (1.1 cm), dressing percent (59.6%) or YG (2.5). Numerically, there were a greater number of steers in the average Choice or better quality grades with the increasing dietary inclusion of WRS (Figure 1). Others have reported increased marbling scores in feedlot animals with the addition of fat and/or oilseeds (Brandt and Anderson, 1990; Huerta-Leidenz et al., 1991). The amount of carcass measured BF (10.5 mm) was unaffected by WRS inclusion in Exp. 2. Likewise, there were no treatment effects on longissimus dorsi backfat measured by ultrasound initially (7.4 mm), at d 31 (9.1 mm), at d 58 (10.0 mm), or at d 72 (11.8 mm).
|
). This was later confirmed at slaughter with treatments averaging a small71 marbling score, placing these carcasses into the low Choice category of carcass quality.
|
demonstrated that ultrasound measurements did not correlate well to actual marbling scores when used before slaughter. Due to the relative similarities observed in measured carcass qualities in Exp. 2, the sensitivity required to detect differences by means of ultrasound may have been exceeded. However, the use of ultrasound did appear to follow the progression of fat deposition rather realistically and may have adequately ranked cattle in terms of carcass quality, which has been suggested previously (Brethour, 2000). In Exp. 2, the distribution of animals falling into each carcass quality grade was not different (data not reported) from one another, but, in general, steers used in Exp. 2 graded better than steers used in Exp. 1. Over 85% of the steers used in Exp. 2 graded low Choice or better with a Yield Grade 2 or 3 carcass, whereas only 50% achieved this in Exp. 1.
Feeding is the greatest single cost of producing livestock products for human consumption. Any time alternative feeds can be used to potentially lower production costs without negatively affecting production, a benefit can be realized. In these experiments, whole raw soybeans were fed at 0, 8, 16, and 24% of dietary DM to determine the effect on feedlot performance and carcass quality. The later stages of finishing were chosen in these experiments in an effort to study performance and carcass quality effects possibly induced by WRS. Specifically, this was attempted during the period of time when efficiency of gain is typically the poorest and i.m. fat deposition is the greatest. Previous data led us to hypothesize that high dietary fat might reduce animal performance. Because the 24% inclusion level resulted in higher than recommended levels of CP for steers of this size and maturity, this treatment served only to define the effect of excessive WRS inclusion. However, minimal negative effects were noted for this treatment. Thus, it would appear that feeding WRS at inclusion levels to meet required dietary protein levels (13 to 16% of the diet DM) should have no negative effects on feedlot cattle performance in the later stages of finishing.
In comparison of the carcass quality results between these two experiments, WRS inclusion clearly had no benefit on marbling scores for steers in Exp. 2. However, the same cannot be definitively stated for steers in Exp. 1. As noted earlier, there was a numerical increase in the number of animals achieving quality grades greater than low Choice as WRS inclusion increased. Steers in both experiments had similar management protocols before treatment initiation, including exposure to supplemental dietary fat. During an earlier stage of growth/development, steers used in Exp. 1 had been fed diets containing an animal-derived fat source, whereas steers used in Exp. 2 had previously been fed soybeans at 10% of dietary DM during a much earlier stage of growth. Due to the relatively high content of PUFA found in soybeans as compared to animal fat sources, and the fact that PUFA have been shown to be involved with the regulation of gene expression and sensitivity of adipose tissue to circulating blood metabolites (Okuno et al., 1997; Fickova et al., 1998; Sessler and Ntambi, 1998) responsible for adipocyte differentiation (Gregoire et al., 1998), any observable effect in Exp. 2 from WRS inclusion at the finishing stage may have been lost. Furthermore, steers used in Exp. 1 were of mixed breeding and from multiple sources with limited known background. Thus, the numerical increase may or may not have been an actual effect of dietary treatment. In contrast, all steers used in Exp. 2 were of similar genetics from the same herd. The herd from which steers used in Exp. 2 originated had significant selection pressure placed on them for carcass quality. Therefore, any improvement in marbling may have been negated as a result of earlier WRS exposure and/or genetic makeup. Our interpretation of these data was that marbling ability of the animal and/or previous dietary exposure might impact the potential of the finishing diet to enhance marbling score.
An interesting observation made in both experiments was the gain response in regard to the length of time the treatment diets were fed. When compared to soybean meal controls, gain was reduced for up to the first 30 d on feed. Interestingly, this effect was reversed for the last 30 to 40 d on feed. The reason for the gain differences among treatments at the different days on feed is obviously beyond the scope of these experiments. Typical finishing feeding periods are much longer than the feeding periods used in these studies. Thus, if steers were fed WRS for longer periods before slaughter than the periods used in these studies, results may have been different from those reported here. Thus, performance results of steers fed raw soybeans may depend on the length of time that soybeans are fed.
Implications
Whole raw soybeans can be used to meet the supplemental crude protein recommendations of feedlot cattle fed corn/silage-based feedlot diets, while supplying additional dietary energy in the form of vegetable oil. Negative performance effects at inclusion levels below 24% of dietary dry matter seem to be minimal; however, levels above 16% of dietary dry matter are not recommended due to potentially excessive amounts of dietary fat and protein. Thus, farmer-feeders in the U.S. Midwest should be able to use whole raw soybeans as an alternative feed source for finishing cattle when inclusion levels are below 16% of dietary dry matter.
Footnotes
1 This research was supported in part by the Missouri Soybean Merchandising Council. 
2 Current address: Dept. of Anim. and Vet. Sci., West Virginia Univ., Morgantown 26506.
3 Correspondence: 111A Animal Sciences Research Center, 920 E. Campus Dr. (phone: 573-882-0834; fax: 573-884-4606; e-mail: KerleyM{at}Missouri.edu).
Received for publication February 16, 2003. Accepted for publication November 10, 2003.
Literature Cited
Albro, J. D., D. W. Weber, and T. DelCurto. 1993. Comparison of whole, raw soybeans, extruded soybeans, or soybean meal and barley on digestive characteristics and performance of weaned beef steers consuming mature grass hay. J. Anim. Sci. 71:26–32.[Abstract]
Aldrich, C. G., N. R. Merchen, and J. K. Drackley. 1995a. The effect of roasting temperature applied to whole soybeans on site of digestion by steers: I. Organic matter, energy, fiber, and fatty acid digestion. J. Anim. Sci. 73:2120–2130.[Abstract]
Aldrich, C. G., N. R. Merchen, D. R. Nelson, and J. A. Barmore. 1995b. The effects of roasting temperature applied to whole soybeans on site of digestion by steers: II. Protein and amino acid digestion. J. Anim. Sci. 73:2131–2140.[Abstract]
AOAC. 1984. Official Methods of Analysis. 14th ed. Assoc. Offic. Anal. Chem. Washington, DC.
Brandt, R. T., and S. J. Anderson. 1990. Supplemental fat source affects feedlot performance and carcass traits of finishing yearling steers and estimated diet net energy value. J. Anim. Sci. 68:2208–2216.[Abstract]
Brethour, J. R. 1994. Estimating marbling score in live cattle from ultrasound images using pattern recognition and neural network procedures. J. Anim. Sci. 72:1425–1432.[Abstract]
Brethour, J. R. 2000. Using receiver operating characteristic analysis to evaluate the accuracy in predicting future quality grade from ultrasound marbling estimates on beef calves. J. Anim. Sci. 78:2263–2268.
Bunting, L. D., J. M. Fernandez, R. J. Fornea, T. W. White, M. A. Froetschel, J. D. Stone, and K. Ingawa. 1996. Seasonal effects of supplemental fat or undegradable protein on the growth and metabolism of Holstein calves. J. Dairy Sci. 79:1611–1620.[Abstract]
Carter, J. N., P. A. Ludden, M. S. Kerley, M. Ellersieck, W. O. Herring, and E. Berg. 2002. Intramuscular fat deposition in steers is accelerated at a set body weight. Prof. Anim. Sci. 18:135–140.
Engle, T. E., J. W. Spears, V. Fellner, and J. Odle. 2000. Effects of soybean oil and dietary copper on ruminal and tissue lipid metabolism in finishing steers. J. Anim. Sci. 78:2713–2721.
Eweedah, N., L. Rozsa, J. Gundel, and J. Varhegyi. 1997. Comparison of fullfat soybean, sunflower seed and protected fat as fat supplements for their effect on the performance of growing-finishing bulls and carcass fatty acid composition. Acta Vet. Hung. 45:151–163.[Medline]
Fickova, M., P. Hubert, G. Cremel, and C. Leray. 1998. Dietary (n-3) and (n-6) polyunsaturated fatty acids rapidly modify fatty acid composition and insulin effects in rat adipocytes. J. Nutr. 128:512–519.
Gregoire, F. M., C. M. Smas, and H. S. Sul. 1998. Understanding adipocyte differentiation. Physiol. Rev. 78:783–809.
Harfoot, C. G., and G. P. Hazlewood. 1988. Lipid metabolism in the rumen. Page 258 in the Rumen Microbial Ecosystem. P. N. Hobson, ed. Elsevier, New York.
Huerta-Leidenz, N. O., H. R. Cross, D. K. Lunt, L. S. Pelton, J. W. Savell, and S. B. Smith. 1991. Growth, carcass traits, and fatty acid profiles of adipose tissues from steers fed whole cottonseed. J. Anim. Sci. 69:3665–3672.[Abstract]
Okuno, M., K. Kajiwara, S. Imai, T. Kobayashi, N. Honma, T. Maki, K. Suruga, T. Goda, S. Takase, Y. Muto, and H. Moriwaki. 1997. Perilla oil prevents the excessive growth of visceral adipose tissue in rats by down-regulating adipocyte differentiation. J. Nutr. 127:1752–1757.
Rumsey, T. S., T. H. Elsasser, S. Kahl, and M. B. Solomon. 1999. The effect of roasted soybeans in the diet of feedlot steers and Synovex-S ear implants on carcass characteristics and estimated composition. J. Anim. Sci. 77:1726–1734.
Sessler, A. M., and J. M. Ntambi. 1998. Polyunsaturated fatty acid regulation of gene expression. J. Nutr. 128:923–926.
Smith, S. B., and J. D. Crouse. 1984. Relative contributions of acetate, lactate and glucose to lipogenisis in bovine intramuscular and subcutaneous adipose tissue. J. Nutr. 114:792–800.
This article has been cited by other articles:
|
|
 |
|
  B. W. Hess, G. E. Moss, and D. C. Rule A decade of developments in the area of fat supplementation research with beef cattle and sheep J Anim Sci, April 1, 2008; 86(14_suppl): E188 - E204. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Mach, M. Devant, I. Diaz, M. Font-Furnols, M. A. Oliver, J. A. Garcia, and A. Bach Increasing the amount of n-3 fatty acid in meat from young Holstein bulls through nutrition J Anim Sci, November 1, 2006; 84(11): 3039 - 3048. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. McPhee, J. W. Oltjen, T. R. Famula, and R. D. Sainz Meta-analysis of factors affecting carcass characteristics of feedlot steers J Anim Sci, November 1, 2006; 84(11): 3143 - 3154. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Jordan, D. Kenny, M. Hawkins, R. Malone, D. K. Lovett, and F. P. O'Mara Effect of refined soy oil or whole soybeans on intake, methane output, and performance of young bulls J Anim Sci, September 1, 2006; 84(9): 2418 - 2425. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. D. Maddock, M. L. Bauer, K. B. Koch, V. L. Anderson, R. J. Maddock, G. Barcelo-Coblijn, E. J. Murphy, and G. P. Lardy Effect of processing flax in beef feedlot diets on performance, carcass characteristics, and trained sensory panel ratings J Anim Sci, June 1, 2006; 84(6): 1544 - 1551. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Select, Choice minus, Choice, and 
Choice plus marbling scores, respectively. T0 = control diet, 0% whole raw soybeans (WRS); T8 = diet contains 8% WRS; T16 = diet contains 16% WRS; T24 = diet contains 24% WRS; n = 20 carcasses per treatment for T0, T8, and T24, and 18 carcasses for treatment T16.