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ANIMAL PRODUCTION |
* Department of Animal Sciences, The Ohio State University, Wooster 44691 and
and
Archer Daniels Midland, Inc., Decatur, IN 46733
Abstract
One hundred eighty-four Angus x Simmental steers (initial BW 161.7 ± 3.4 kg) were used to determine whether different sources and amounts of energy in the growing phase could extend the growth curve and maintain high amounts of intramuscular fat deposition in early-weaned steers. Steers were allotted by source, age, and BW to one of four growing-phase (119 to 259 d of age) regimens. For three regimens, steers were weaned at 119 d of age and either 1) fed (DM basis) a 50% grain diet ad libitum (ALC); 2) limit-fed a 70% grain diet to achieve a gain of 0.8 kg/d from 119 to 192 d of age, and 1.2 kg/d from 193 to 259 d of age (LFC); or 3) fed a 60% haylage diet ad libitum from 119 to 192 d of age, and a 25% haylage diet ad libitum from 193 to 259 d of age (ALF). For the fourth regimen, steers were normal-weaned at 204 d of age and fed a silage diet from 205 to 259 d of age (NW). From 260 d of age to slaughter, all steers consumed a 70% grain (DM basis) diet. Limit-fed and ALF steers spent the most, and NW the least amount of time (P < 0.01) in the feedlot to achieve a target fat depth of 1.27 cm. Ad libitum-fed steers were the youngest (331 d), and NW the oldest (383 d) at slaughter (P < 0.01). Overall ADG was greatest for ALC and least for NW steers (P < 0.01). Overall, ALF steers consumed the most DM (P < 0.01). While in the feedlot, LFC and ALC steers were more efficient in converting feed to BW gain (P < 0.01) than ALF and NW steers. Normal-weaned had the least and ALC the greatest (P < 0.01) fat depth at 260 d of age. Consequently, NW steers produced the heaviest, and ALC the lightest (P < 0.01) carcasses at slaughter. Normal-weaned steers had the largest, and ALC and LFC steers had the smallest longissimus muscle area (P < 0.06). Growing phase dietary treatments did not affect (P > 0.20) yield grade. Marbling score did not differ (P > 0.35), but laboratory analysis revealed that ALC steers had the lowest percentage of fat (P < 0.02) in the longissimus muscle. Shear force was greatest (P < 0.08) for steaks from ALC and LFC steers, and least for steaks from ALF and NW steers. Feeding steers the ALC diet from 119 to 260 d of age hastened physiological maturity, decreased marbling scores, and decreased muscle tenderness compared with forage feeding (ALF, NW). Limit-feeding a high-grain diet also hastened physiological maturity and decreased muscle tenderness but did not decrease marbling scores. Source and amount of energy affected partitioning of fat deposition.
Key Words: Beef Cattle • Early Weaning • Limit-Feeding • Marbling
Introduction
Accelerated finishing systems for early-weaned bulls and steers can result in carcasses with consistently high marbling scores, but physiological maturity can be hastened and excessively fat or lightweight carcasses can also result (Myers et al., 1999
; Schoonmaker et al., 2001, 2002). Restricting intake at various times during growing periods increases carcass leanness, decreases rate of gain, and increases the time required for cattle to reach market weight and body condition (Plegge, 1987; Hicks et al., 1990; Murphy and Loerch, 1994). Controlling growth rate by limit-feeding grain-based diets or feeding a high-fiber diet to early-weaned cattle from 119 to 218 d of age decreased gains, and increased time on feed, but did not allow their growth curve to be extended compared to early-weaned steers whose intake was not restricted (Schoonmaker et al., 2003). Feeding high-concentrate diets ad libitum increased intramuscular fat deposition in early-weaned steers during the growing phase, but differences were diminished when they were placed on the same diet in the finishing phase (Schoonmaker et al., 2003).
Cattle exhibiting compensatory growth have been reported to possess a greater potential for lean tissue accretion (Fox et al., 1972; Rompala et al., 1985). A feeding program to achieve stepwise increases in intake can result in multiple compensatory growth responses that offset periods when growth rates are reduced, and can result in increased carcass leanness (Knoblich et al., 1997; Loerch and Fluharty, 1998). Phase feeding has not been investigated in early-weaned cattle, and it may be a strategy to maximize growth rate and optimize intramuscular fat deposition. Thus, our objective was to investigate the potential to extend the growth curve of feedlot steers by using a 140-d two-phase growing period, consisting of a stepwise increase in energy intake before providing a high-grain diet ad libitum. Three early weaning systems were compared to a normal weaned positive "control."
Materials and Methods
One hundred eighty-four Angus x Simmental steers (initial BW 161.7 ± 3.4 kg) from five locations in Ohio (Caldwell, n = 27; Columbus, n = 12; Coshocton, n = 37; Jackson, n = 64; Wellston, n = 44) were allotted by source, age, and weight to one of four growing-phase (119 to 259 d of age) treatments: 1) weaned at 119 d of age and fed an intermediate-concentrate diet (50% high moisture corn, 30% corn silage; DM basis) ad libitum from 119 to 259 d of age (ad libitum concentrate-fed); 2) weaned at 119 d of age and limit-fed a high-concentrate diet (70% high moisture corn, 15% corn silage; DM basis) to achieve a gain of 0.8 kg/d from 119 to 192 d of age, and 1.2 kg/d from 193 to 259 d of age (limit-fed concentrate); 3) weaned at 119 d of age and fed a high-forage diet (60% orchardgrass haylage, 25% soybean hull; DM basis) ad libitum from 119 to 192 d of age, and an intermediate-forage diet (25% orchardgrass haylage, 60% soybean hull; DM basis) ad libitum from 193 to 259 d of age (forage-fed); or 4) weaned at 204 d of age and fed a 70% corn silage diet (DM basis) from 205 to 259 d of age (normal-weaned). Intake of limit-fed concentrate diets was regulated to achieve target gains according to NRC net energy equations for medium-framed steers (NRC, 1984). The forage-fed and limit-fed concentrate diets were formulated and fed to achieve similar gains. Diets for steers weaned at 119 d of age (ad libitum concentrate-fed, limit-fed concentrate, and forage-fed) contained 16% CP for the first 31 d (receiving diets—Table 1), and 14% CP until 259 d of age (intermediate diets—Table 2). Diets for normal-weaned steers contained 16% CP for the first 14 d (receiving diets), and 14% CP until 259 d of age (intermediate diets). From 260 d of age to slaughter (finishing phase) all steers consumed a 70% high-moisture corn, 15% corn silage diet (DM basis), containing 14% CP (finishing diet—Table 2). Steers were divided among 24 pens (six to nine steers/pen), with six pens per treatment. Steers were fed in a totally enclosed feedlot barn (slatted concrete floor; metal gates). Pens were 5.4 x 5.4 m, and each steer had a minimum of 0.6 m of bunk space.
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).
Limit-fed concentrate steers were weighed every 14 d and intakes were adjusted to meet the increasing energy needs for maintenance as the steers grew (NRC, 1984). Steers on the remaining treatments were weighed every 28 d. To determine weight gain from 119 to 259 d of age, initial weight was calculated as an average of weights taken on two consecutive days, and all cattle were fed the 70% concentrate diet at 2.0% of BW for 5 d before final weighing at the end of the first phase (259 d of age). Feed was delivered once daily at 0900, and feed refusals were recorded daily for each pen. Feed samples were taken every 7 d throughout the trial and were composited for analysis of DM and N (AOAC, 1996). Crude protein was calculated as N x 6.25.
Steers were implanted with Compudose (25.7 mg of estradiol; provided courtesy of VetLife) at 150 d of age, and with Component TE-S (24 mg of estradiol, 120 mg trenbolone acetate; provided courtesy of VetLife) when steers within each treatment were estimated to be 100 d from slaughter. Ad libitum concentrate-fed steers were implanted with Component TE-S at an average age of 248 d, forage-fed, limit-fed concentrate, and normal-weaned steers were implanted at an average age of 262 d.
Steers were scanned by ultrasound (Classic Ultrasound Equipment, Classic Medical Supply, Tequesta, FL) at 119 and 260 d of age by a trained ultrasound technician for fat thickness, longissimus muscle area, and percentage of intramuscular fat. Due to large variation in weight and fat cover within pens, cattle were slaughtered in two stages (half a pen) based on a target ultrasound fat thickness of 1.27 cm. Hot carcass weight; fat thickness; percentage of kidney, pelvic, and heart fat; longissimus muscle area; and USDA quality and yield grades were determined by qualified Ohio State University personnel 48 h after slaughter. Steaks were dissected from the 13th rib, frozen after 24 h and stored at -20°C until determination of tenderness. Steaks were thawed and cooked to an average internal temperature of 71.7°C, and peak Warner-Bratzler shear force was used as a measure of tenderness according to AMSA (1995) recommendations. The longissimus dorsi muscle from the 11th to 12th ribs was removed from the right side of each carcass, trimmed of external fat, ground three times and subsampled for determination of moisture and ether extractable lipid (AOAC, 1996).
Performance and carcass data were analyzed using the GLM procedures of SAS (SAS Inst. Inc., Cary, NC) for a completely randomized design comparing four treatments. Performance and carcass data were measured and means were calculated for each pen for statistical analysis. The model included effects due to growing phase treatment. Residual mean square was the error term, and pen was the experimental unit for all analyses. Treatment means were compared using the PDIFF statement of SAS when protected by a significant (P < 0.10) F-value.
Results and Discussion
Eighteen steers were removed from the trial for various reasons (8.5% loss) not associated with experimental treatments (pneumonia, bloat, lameness). The reason for such an abnormally high amount of loss is unknown. Cattle were placed in groups and were brought in from five locations, possibly contributing to increased respiratory problems, and perhaps contributing to social aggressiveness, which may have led to the lameness. Early-weaned cattle used in the past at this facility were fed on an individual basis and were predominantly from one source.
Performance data are presented in Table 3 and carcass data are presented in Table 4. Early-weaned steers, led by limit-fed concentrate and forage-fed treatments, spent the most amount of time (P < 0.01) in the feedlot. Ad libitum concentrate-fed steers were the youngest (P < 0.01) at slaughter (331 d of age), spent an intermediate amount of time in the feedlot (P < 0.01) to achieve a target fat thickness of 1.25 cm, and the fewest (P < 0.01) days (86 d) elapsed from last implant to slaughter (P < 0.01) among treatments. Limit-fed concentrate and forage-fed steers were approximately 360 d of age at slaughter, they spent the most amount of time in the feedlot to achieve 1.25 cm of fat thickness, and approximately 100 d elapsed from last implant to slaughter. Normal-weaned steers were 383 d of age at slaughter, they spent the least amount of time in the feedlot to achieve 1.25 cm of fat thickness, and 124 d elapsed from last implant to slaughter. Schoonmaker et al. (2003) also observed that, when early-weaned steers were slaughtered at a constant fat thickness, limit-feeding extended the days on feed and increased slaughter age compared to ad libitum feeding. However, Knoblich et al. (1997), Loerch and Fluharty (1998), and Rossi et al. (2001) demonstrated that, for cattle weaned at 205 d of age and programmed to achieve stepwise increases in gain, no difference existed for days on feed when steers were slaughtered at a constant body weight. Differences in slaughter end point (constant body weight vs. constant fat thickness), and age at feedlot entry (119 vs. 205 d) may account for performance and time on feed differences among these studies.
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equations for medium-framed steers predicted for the growing phase, due to compensatory gain. Loerch and Fluharty (1998) demonstrated that the actual growth rate of limit-fed concentrate steers is 3 to 19% higher than predictions based on net energy equations (NRC, 1984).
During the finishing phase of the present trial, early-weaned steers limit-fed concentrate, or forage-fed in the growing phase, or steers that were normal-weaned gained 14.5, 13.9, and 9.1% faster (P < 0.02), respectively, than steers fed a concentrate diet ad libitum in the growing phase. The inverse relationship in growth that develops upon realimentation of previously limit-fed steers compared to steers that have never had their growth restricted has been demonstrated previously (Knoblich et al., 1997; Loerch and Fluharty, 1998; Rossi et al., 2001), as has the inverse relationship in growth that develops upon feedlot entry of normal-weaned steers compared to early-weaned steers that have been in the feedlot for some time (Myers et al., 1999; Schoonmaker et al. 2001, 2002). However, these results are in contrast to Schoonmaker et al. (2003), where early-weaned steers limit-fed concentrate in a 99-d growing phase exhibited no compensatory growth response upon ad libitum feeding in the finishing phase. Steers in Schoonmaker et al. (2003) were also slaughtered at a common fat end point. Type (one level vs. stepwise) and period (99 vs. 140 d) of growth restriction, and timing of initial implant (119 vs. 150 d of age) differed in Schoonmaker et al. (2003) compared to this trial and may have affected the growth response. Age of the animal at the time of growth restriction may play an important role in a compensatory growth response. Tudor and O’Rourke (1980) weaned steers at 4 d of age, and restricted their energy intake until 200 d of age, and observed no compensatory growth upon realimentation at 200 d of age. Morgan (1972) studied age effects of intake restriction on subsequent growth by restricting calves from birth to 16 wk or from 16 to 32 wk of age. Calves were not weaned. Calves restricted from birth to 16 wk of age had rates of gain similar to ad libitum-fed control calves upon realimentation and underwent no compensatory growth. However, calves restricted from 16 to 32 wk of age had increased rates of gain and exhibited compensatory growth upon diet realimentation. Steers in the present trial were early-weaned at 17 wk of age and could have fallen into either of these two categories.
Despite increased finishing phase gains by limit-fed concentrate, forage-fed, and normal-weaned steers in the present trial, gain when measured from 119 d of age to slaughter was greatest for ad libitum concentrate-fed steers (P < 0.01), intermediate for limit-fed concentrate and forage-fed steers, and least for normal-weaned steers. Feeding a concentrate diet ad libitum to early-weaned steers increases gains but causes an appreciable amount of energy to be partitioned to subcutaneous fat, thereby accelerating physiological maturity, as indicated by a lower (P < 0.01) slaughter weight at the same fat thickness. Feeding steers an ad libitum forage diet from 119 to 260 d of age, as well as normal weaning, extended the growth curve as indicated by 21- and 45-kg heavier (P < 0.01) slaughter weights. Limit-feeding a high-concentrate diet did not extend the growth curve, indicating that source of energy may affect partitioning of fat deposition.
Daily DMI during the growing phase did not differ (P > 0.10) among normal-weaned, ad libitum concentrate-fed, and forage-fed steers, but, due to intake restriction, daily DMI from 119 to 259 d of age was lowest (P < 0.01) for limit-fed concentrate steers. Total DMI during the growing phase was greatest (P < 0.01) for ad libitum concentrate-fed and forage-fed steers, and, due to intake restriction, total DMI among early-weaned steers was least for those limit-fed concentrate. Because normal-weaned steers did not enter the feedlot until 204 d of age, total DMI during the growing phase was lowest (P < 0.01) for normal-weaned steers. Gain/feed before 260 d of age was 14, 24, and 45% greater (P < 0.01) for limit-fed concentrate compared to ad libitum concentrate-fed, normal-weaned, and forage-fed steers, respectively. In agreement, Schoonmaker et al. (2003) demonstrated that when in the growing phase, early-weaned cattle that were limit-fed concentrate were the most efficient. However, Loerch and Fluharty (1998) demonstrated that when in the growing phase, no difference existed for the feed efficiency of normal-weaned cattle that were limit-fed concentrate compared to those that were full-fed. In the current trial, steers fed a forage-based diet in the growing phase (forage-fed and normal-weaned) consumed the most daily and total DM from 260 d of age to slaughter, indicating that they may have had more digestive capacity. From 260 d of age to slaughter, daily DMI was similar (P > 0.10) between steers fed high-forage diets in the growing phase (forage-fed and normal-weaned), but, because it took a longer amount of time (23 d more) in the finishing phase to achieve a similar fat thickness, normal-weaned steers consumed the most (P < 0.01) total DM in the finishing phase. Between grain-fed treatments, ad libitum concentrate-fed steers consumed the least (P < 0.01) amount of DM per day and the least (P < 0.01) total DM, due in part to their smaller mature weight and shorter stay in the feedlot. Steers that were limit-fed concentrate in the growing phase were the most efficient (P < 0.01) in the finishing phase. Hicks et al. (1990), Knoblich et al. (1997), and Rossi et al. (2001) also observed that feed efficiency was improved after periods of restriction in limit-fed cattle. In contrast, Schoonmaker et al. (2003) demonstrated that early-weaned cattle were not more efficient after periods of restriction compared to early-weaned cattle that were not restricted. Improvements in efficiency after realimentation have been attributed to a reduced visceral organ mass, and a resultant lowering of maintenance energy requirements (Fluharty and McClure, 1997). However, Schoonmaker et al. (2001) observed that reduced visceral organ mass may not have significant influences on feed efficiency in early-weaned cattle fed high-energy diets. Because intestinal weights at 254 kg were increased by implantation (Schoonmaker et al., 2001), it was suggested that implants may affect organ function or efficiency of highly metabolically active tissues in early-weaned cattle. Steers in Schoonmaker et al. (2003) were implanted at 119 d of age, compared with 150 d of age for the present trial.
As a result of growing and finishing phase differences in intake, daily DMI when measured while cattle were in the feedlot was greatest (P < 0.01) for normal-weaned, followed by forage-fed steers. Ad libitum concentrate-fed steers consumed 0.7 kg/d less than forage-fed steers, and limit-fed concentrate steers consumed the least per day. However, due to the difference in days on feed in the present trial, total DMI in the feedlot was not different (P > 0.10) among ad libitum concentrate-fed, limit-fed concentrate, and normal-weaned steers; forage-fed steers consumed 336 to 379 more kg of DM (P < 0.01) compared to ad libitum concentrate-fed, limit-fed concentrate, and normal-weaned steers. Because early-weaned cattle consume more feed when their maintenance energy requirements are low (NRC, 1996), feed efficiency is generally improved for early-weaned compared to normal-weaned steers (Myers et al., 1999; Story et al., 2000, Schoonmaker et al., 2001). While in the feedlot, the gain-to-feed ratio, when compared with normal-weaned steers, was 20.1% and 15.5% greater (P < 0.01) for early-weaned cattle that consumed high-concentrate diets in the growing phase (limit-fed concentrate followed by ad libitum concentrate-fed steers); it was not greater for early-weaned cattle that were forage-fed in the growing phase. Feeding high-forage diets in the growing phase offsets the improvements in feed efficiency generally seen in early-weaned cattle.
Differences in body composition can result from restricting feed intake, and are affected by severity and duration of the feed restriction period as well as age of the animal at restriction. Butterfield (1966), Mader et al. (1989), and Carstens et al. (1991) demonstrated that restricting feed intake for a portion of the feeding period in cattle that were 6 mo of age or older has been shown to decrease fat and increase lean deposition at the end of the finishing period. When growth was restricted in cattle less than 2 mo of age (while calves were still with their dams), increased fat deposition occurred upon realimentation (Stuedemann et al., 1968; Tudor et al., 1980). In the present trial, fat thickness and intramuscular fat percentage as measured by ultrasound did not differ (P > 0.45) among early-weaned treatments at 119 d of age (Table 4
). Limit-fed steers had a smaller (P < 0.01) longissimus muscle area at 119 d of age. By 260 d of age, ad libitum concentrate-fed steers had 48 to 94% more fat depth over the rib (P < 0.01), and a 10 to 16% larger longissimus muscle area (P < 0.01) compared to forage-fed, limit-fed concentrate, and normal-weaned steers. Steers fed the high-forage and limit-fed concentrate diets in the growing phase had an intermediate fat depth over the rib, and normal-weaned steers had the least fat depth over the rib. Longissimus muscle area at 260 d of age was not different among forage-fed, limit-fed concentrate, and normal-weaned steers. Percentage of intramuscular fat at 260 d of age did not differ among treatments. Steers with the lowest fat depth at 260 d of age (normal-weaned) produced the heaviest (P < 0.01) carcasses at slaughter, followed by forage-fed and limit-fed concentrate steers; ad libitum concentrate-fed steers produced the smallest carcasses at slaughter. As planned, fat thickness at slaughter did not differ among treatments (P > 0.56). Normal-weaned cattle had a larger longissimus muscle area at slaughter compared to ad libitum concentrate-fed and limit-fed concentrate steers (P < 0.06). Steers fed the high-forage diet had an intermediate longissimus muscle area that did not differ from normal-weaned, ad libitum concentrate-fed, and limit-fed concentrate steers. Greater weights for normal-weaned steers at slaughter likely contributed to increased longissimus muscle area. Dressing percent, percentage of KPH, yield grade, and yield grade distributions did not differ (P > 0.20) due to treatment at slaughter.
Despite a lack of difference (P > 0.35) for marbling score and quality grade distribution, source of energy and rate of gain affected (P < 0.04) longissimus dorsi composition. Steers fed a high-concentrate diet ad libitum in the growing phase had the lowest percentage of fat (P < 0.02) and the highest percentage of moisture (P < 0.04) in the longissimus muscle at slaughter, indicating that feeding early-weaned steers a high-concentrate diet ad libitum from the time of early weaning until slaughter was not the best option for maximizing intramuscular fat deposition. This is in contrast to the results of Schoonmaker et al. (2003), where source of energy and rate of gain did not affect longissimus muscle composition. Smith and Crouse (1984) demonstrated that glucose provides 50 to 75% of the acetyl units for intramuscular fat deposition, whereas it provides only 1 to 10% of the acetyl units for subcutaneous fat deposition. Schoonmaker et al. (2003) observed that insulin, which regulates blood glucose, was increased in steers fed a high-concentrate diet compared with steers fed a high-forage diet in the growing phase. This may suggest that there was an increased uptake of glucose by peripheral tissues. Even though intramuscular fat may be deposited at a faster rate in cattle fed a high-grain diet ad libitum from 119 to 218 d of age compared to limit-fed concentrate or forage-fed steers (Schoonmaker et al., 2003), subcutaneous fat is also deposited at a faster rate. Because the subcutaneous fat depot is the second-largest fat depot (Cianzio et al., 1985), it may consume more total glucose than the intramuscular fat depot, still causing subcutaneous fat to be deposited at a faster rate than intramuscular fat. Thus, differences at 218 d of age did not translate into differences at slaughter because a high level of subcutaneous fat was achieved too quickly for early-weaned steers fed a high-grain diet ad libitum (Schoonmaker et al., 2003). In the present trial, ad libitum concentrate-fed steers achieved the target fat thickness quickly, but, because limit-fed concentrate and forage-fed steers were restricted in energy intake for a longer period of time compared to Schoonmaker et al. (2003), it took them a longer period of time to achieve the same level of subcutaneous fat; meanwhile, a higher level of intramuscular fat was also achieved.
Shear force was greatest (P < 0.08) for steers fed a high-concentrate diet in the growing phase (ad libitum and limit-fed) and least for steers fed a high-forage diet in the growing phase (forage-fed and normal-weaned steers). It is unclear whether source or amount of energy caused this difference in muscle tenderness. Previous reports have indicated that shear force was greater for longissimus muscle from cattle and sheep that had been finished on grass or forage than for those that received supplemental grain or fed concentrate diets (Bowling et al., 1977; Harrison et al., 1978; Hedrick et al., 1983). However, these differences may have been due to differences in physiological maturity, because when fed to similar body weights and ages, differences in tenderness between forage-fed and concentrate-fed ruminants decrease (Xiong et al., 1996; Mandell et al., 1998). Rate of growth may also affect muscle tenderness. Owens and Gardner (1999) reported that faster gaining cattle produced steaks with greater shear force values, but, when these authors calculated a correlation using data from numerous published studies, slower gaining cattle produced steaks with greater shear force values. Calkins et al. (1987), using various levels of intake restriction to cause weight loss or gain of young bulls, detected no relationship between ADG and either shear force or sensory panel estimates of tenderness. Age is a factor that can affect tenderness (Wulf et al., 1996), with younger cattle generally producing steaks with greater tenderness, but the youngest cattle in this trial produced the toughest steaks. In addition, differences existed in tenderness between limit-fed and forage-fed cattle, despite a similar slaughter age.
Implications
Feeding high-concentrate diets ad libitum to young steers caused an appreciable amount of energy to be partitioned to subcutaneous fat, thereby accelerating physiological maturity. As a result, when steers were slaughtered at a constant age or fat thickness, smaller carcasses with smaller longissimus muscles and less intramuscular fat were produced. Limit-feeding a high-concentrate diet from 119 to 260 d of age increased days on feed, but did not extend the growth curve; however, it increased final intramuscular fat content. Feeding steers an ad libitum forage diet from 119 to 260 d of age, as well as normal weaning, extended the growth curve and increased final intramuscular fat content; however, extending the growth curve by feeding a high-forage diet or normal weaning was less efficient and may increase age at slaughter.
Footnotes
1 Salaries and research support provided by state and federal funds appropriated to the Ohio Agric. Res. and Dev. Center, The Ohio State Univ. Manuscript No. 9-03 AS. 
2 Correspondence: 114 Gerlaugh Hall, OARDC, 1680 Madison Ave. (phone: 330-263-3900; fax: 330-263-3949; e-mail: loerch.1{at}osu.edu.
Received for publication May 22, 2003. Accepted for publication September 22, 2003.
Literature Cited
AMSA. 1995. Research Guidelines for Cookery, Sensory Evaluation, and Instrumental Tenderness Measurements of Fresh Meat. Am. Meat Sci. Assoc., Chicago, IL.
AOAC. 1996. Official Methods of Analysis. 16th ed. Assoc. Offic. Anal. Chem., Arlington, VA.
Bowling, R. A., G. C. Smith, Z. L. Carpenter, T. R. Dutson, and W. M. Oliver. 1977. Comparison of forage-finished and grain-finished beef carcasses. J. Anim. Sci. 45:209–215.
Butterfield, R. M. 1966. The effect of nutritional stress and recovery on the body composition of cattle. Res. Vet. Sci. 7:168–177.[Medline]
Carstens, G. E., D. E. Johnson, M. A. Ellenberger, and J. D. Tatum. 1991. Physical and chemical components of the empty body during compensatory growth in beef steers. J. Anim. Sci. 69:3251–3264.[Abstract]
Cianzio, D. S., D. G. Topel, G. B. Whitehurst, D. C. Beitz, and H. L. Self. 1985. Adipose tissue growth and cellularity: Changes in bovine adipocyte size and number. J. Anim. Sci. 60:970–976.
FASS. 1998. Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Consortium for Developing a Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. Champaign, IL.
Fluharty, F. L., and K. E. McClure. 1997. Effects of dietary energy intake and protein concentration on performance and visceral organ mass in lambs. J. Anim. Sci. 75:604–610.
Fox, D. G., R. R. Johnson, R. L. Preston, T. R. Dockerty, and E. W. Klosterman. 1972. Protein and energy utilization during compensatory growth in beef cattle. J. Anim. Sci. 34:310–318.
Harrison, A. R., M. E. Smith, D. M. Allen, M. C. Hunt, C. L. Kastner, and D. H. Kropf. 1978. Nutritional regime effects on quality and yield characteristics of beef. J. Anim. Sci. 47:383–388.
Hedrick, H. B., J. A. Paterson, A. G. Matches, J. D. Thomas, R. E. Morrow, W. C. Stringer, and R. J. Lipsey. 1983. Carcass and palatability characteristics of beef produced on pasture, corn silage, and corn grain. J. Anim. Sci. 57:791–801.
Hicks, R. B., F. N. Owens, D. R. Gill, J. J. Martin, and C. A. Strasia. 1990. Effects of controlled feed intake on performance and carcass characteristics of feedlot steers and heifers. J. Anim. Sci. 68:233–244.
Knoblich, H. V., F. L. Fluharty, and S. C. Loerch. 1997. Effects of programmed gain strategies on performance and carcass characteristics of steers. J. Anim. Sci. 75:3094–3102.
Loerch, S. C., and F. L. Fluharty. 1998. Effects of programming intake on performance and carcass characteristics of feedlot cattle. J. Anim. Sci. 76:371–377.
Mader, T. L., O. A. Turgeon, Jr., T. J. Klopfenstein, D. R. Brink, and R. R. Oltjen. 1989. Effects of previous nutrition, feedlot regimen and protein level on feedlot performance of beef cattle. J. Anim. Sci. 67:318–328.
Mandell, I. B., J. G. Buchanan-Smith, and C. P. Campbell. 1998. Effects of forage vs. grain feeding on carcass characteristics, fatty acid composition, and beef quality in Limousin-cross steers when time on feed is controlled. J. Anim. Sci. 76:2619–2630.
Morgan, J. H. L. 1972. Effect of plane of nutrition in early life on subsequent live-weight gain, carcass and muscle characteristics and eating quality of meat in cattle. J. Agric. Sci. (Camb.) 78:417–423.
Murphy, T. A., and S. C. Loerch. 1994. Effects of restricted feeding of growing steers on performance, carcass characteristics, and composition. J. Anim. Sci. 72:2497–2507.[Abstract]
Myers, S. E., D. B. Faulkner, F. A. Ireland, L. L. Berger, and D. F. Parrett. 1999. Production systems comparing early weaning to normal weaning with or without creep feeding for beef steers. J. Anim. Sci. 77:300–310.
NRC. 1984. Nutrient Requirements of Beef Cattle. 6th ed. National Academy Press, Washington, DC.
NRC. 1996. Nutrient Requirements of Beef Cattle. 7th ed. National Academy Press, Washington, DC.
Owens, F. N., and B. A. Gardner. 1999. Effects of nutrition on meat quality: Ruminant nutrition and meat quality. Proc. Recip. Meat Conf. 52:25–36.
Plegge, S. D. 1987. Restricting intake of feedlot cattle. Pages 297–301 in Feed Intake by Beef Cattle. Oklahoma Agric. Exp. Stn., MP 121, Stillwater.
Rompala, R. E., S. D. M. Jones, J. G. Buchanan-Smith, and H. S. Bayley. 1985. Feedlot performance and composition of gain in late-maturing steers exhibiting normal and compensatory growth. J. Anim. Sci. 61:637–646.
Rossi, J. E., S. C. Loerch, S. J. Moeller, and J. P. Schoonmaker. 2001. Effects of programmed growth rate and days fed on performance and carcass characteristics of feedlot steers. J. Anim. Sci. 79:1394–1401.
Schoonmaker, J. P., F. L. Fluharty, S. C. Loerch, T. B. Turner, S. J. Moeller, and D. M. Wulf. 2001. Effects of weaning status and implant regimen on growth, performance, and carcass characteristics of steers. J. Anim. Sci. 79:1074–1084.
Schoonmaker, J. P., S. C. Loerch, F. L. Fluharty, H. N. Zerby, and T. B. Turner. 2002. Effect of age at feedlot entry on performance and carcass characteristics of bulls and steers. J. Anim. Sci. 80:2247–2254.
Schoonmaker, J. P., M. J. Cecava, D. B. Faulkner, F. L. Fluharty, H. N. Zerby, and S. C. Loerch. 2003. Effect of source of energy and rate of growth on performance, carcass characteristics, ruminal fermentation, and serum glucose and insulin of early-weaned steers. J. Anim. Sci. 81:843–855.
Smith, S. B., and J. D. Crouse. 1984. Relative contributions of acetate, lactate and glucose to lipogenesis in bovine intramuscular and subcutaneous adipose tissue. J. Nutr. 114:792–800.
Story, C. E., R. J. Rasby, R. T. Clark, and C. T. Milton. 2000. Age of calf at weaning of spring-calving beef cows and the effect on cow and calf performance and production economics. J. Anim. Sci. 78:1403–1413.
Stuedemann, J. A., J. J. Guenther, S. A. Ewing, R. D. Morrison, and G. V. Odell. 1968. Effect of nutritional level imposed from birth to eight months of age on subsequent growth and development patterns of full-fed beef calves. J. Anim. Sci. 27:234–241.
Tudor, G. D., and P. K. O’Rourke. 1980. The effect of pre- and post-natal nutrition on the growth of beef cattle II. The effects of severe restriction in early post-natal life on growth and feed efficiency during recovery. Aust. J. Agric. Res. 31:179–189.
Tudor, G. D., D. W. Utting, and P. K. O’Rourke. 1980. The effect of pre- and post-natal nutrition on growth of beef cattle. III. The effect of severe restriction in early post-natal life on development of the body components and chemical composition. Aust. J. Agric. Res. 31:191–204.
Xiong, Y. L., W. G. Moody, S. P. Blanchard, G. Liu, and W. R. Burris. 1996. Postmortem proteolytic and organoleptic changes in hot-boned muscle from grass- and grain-fed and zeranol-implanted cattle. Food Res. Int. 29:27–34.
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