Growth and body composition of dairy calves fed only milk replacer at 3 intakes.

Determination of energy requirements for growth depends on measuring the composition of BW gain. Previous studies have shown that the composition of gain can be altered in young dairy calves by the composition of the milk replacer diet. Here, our objective was to determine body composition and the composition of empty body gain in young calves fed increasing amounts of a milk replacer containing adequate CP. Male Holstein calves underwent an adjustment period of 14 d after birth in which they were fed whole-waste milk at 10% of BW. Calves were then stratified by BW and randomly assigned to either an initial slaughter group (n = 11) or to groups fed 1 of 3 milk replacer amounts and slaughtered after 35 d of growth. Calves in all treatments consumed the same milk replacer containing 24.8% CP (DM basis; from all milk proteins) and 18.9% fat, reconstituted to 12.5% solids. Treatments were milk replacer fed at 1.25% of BW (DM basis; n = 6), 1.75% of BW (n = 6), or 2.25% of BW (n = 8), adjusted weekly as calves grew. Calves fed at 1.25% or 1.75% of BW were fed twice daily and those fed 2.25% of BW were fed 3 times daily. No starter was offered. Postslaughter, the bodies of calves were separated into 4 fractions: carcass; total viscera minus digesta; head, hide, feet, and tail;, and blood. The sum of those 4 fractions was empty BW (EBW), which increased linearly as the amount of milk replacer increased. Final heart girth and body length, but not withers height, increased linearly as intake increased. Gain:feed increased linearly with increasing milk replacer. Feeding more milk replacer increased the amounts of lean tissue and fat in the body. The percentages of water and protein in the final body decreased linearly, whereas fat percentage and energy content increased linearly as intake increased. As gain increased, the percentage of protein in gain decreased and the percentage of fat increased, resulting in an increase of energy content of EBW gain. Efficiency of energy use (retained energy:gross energy intake) increased linearly but retained energy:ME available for growth was not different among treatments. Efficiency of protein use increased quadratically as feeding rate increased; there was no further increase at 2.25% of BW. Plasma insulin-like growth factor 1, insulin, and glucose increased linearly, whereas urea-N decreased linearly, as milk replacer intake increased. Our data document changes in body composition that affect estimates of retained energy in the bodies of calves slaughtered at a common age. These data are important for calculations of energy requirements for young calves.

Influence of starter crude protein content on growth and body composition of dairy calves in an enhanced early nutrition program.

Our objectives were to determine the effect of starter crude protein (CP) content on body composition of male Holstein calves from birth to 10 wk of age in an enhanced early nutrition program, and to compare the enhanced program to a conventional milk replacer program. Calves (n = 45) were purchased on the day of birth and assigned to a randomized block design. Eight calves were harvested at baseline and remaining calves were divided among the following 3 dietary treatments: (1) low rate of milk replacer [LMR; 20.6% CP, 21.7% fat; 1.25% of body weight (BW) as dry matter (DM)] plus conventional starter (CCS; 21.5% CP, DM basis); n = 11 calves; (2) high rate of milk replacer (HMR; 29.1% CP, 17.3% fat; 1.5% of BW as DM for wk 1, 2% of BW as DM wk 2-5, 1% of BW as DM wk 6) plus conventional starter; n = 12 calves; and (3) enhanced milk replacer (HMR) plus high-CP starter (HCS; 26% CP, DM basis); n = 14 calves. A subset of calves (n = 8) was harvested on d 2 to provide baseline data. Calves began treatments on d 2 or 3 of age. Calves were weaned at d 42. Starter was available ad libitum. Calves from each treatment were harvested at 5 (n = 18) and 10 (n = 19) wk of age and divided into 4 fractions: carcass; viscera; blood; and head, hide, feet, and tail. Fractions were analyzed for energy, CP, lipid, and ash. Average weekly starter intake did not differ between enhanced treatments. Gain of BW was greater for calves fed HMR than for LMR, but was unaffected by starter CP. Carcass weights at 5 wk were greater for HMR but did not differ between starter CP content. At 10 wk, carcass weights were heavier for HMR and had a greater percentage of empty BW for HMR + CCS than for HMR + HCS. At 10 wk, the weights of reticulorumen and liver were greater for calves fed HMR + HCS than for those fed HMR + CCS. At 5 wk, empty BW gain for HMR contained more water and less fat and ash than in calves fed LMR. At 10 wk, empty BW gain for calves fed HMR + HCS contained a greater percentage of water and less fat than for calves fed HMR + CCS. Plasma ß-hydroxybutyrate was greater after weaning for calves fed HMR + HCS than for those fed HMR + CCS. After weaning, calves fed HMR had greater plasma total protein concentration than those fed LMR, and total protein was greater for calves fed HMR + HCS than those fed HMR + CCS. Plasma urea N was greater for calves fed HMR treatments, and postweaning was greater for calves fed HMR + HCS. A high-CP starter had minimal effect on empty BW gain before weaning, but after weaning it tended to increase mass of reticulorumen and liver.

Muscle gene expression associated with increased marbling in beef cattle.

The objective of this study was to identify specific bovine genes expressed within skeletal muscle that are associated with intramuscular fat deposition. Twenty-eight Angus-Simmental cross steers and heifers were harvested at the University of Illinois Meat Science Laboratory. Four pairs of animals were identified based on similar adjusted backfat thickness but differing amounts of intramuscular fat within each pair. RNA was extracted from muscle samples devoid of visible fat and microarray analysis was performed. Based on this analysis, 9 genes were selected and expression was subsequently confirmed by qPCR. Expression levels of MYH3, HOXD10, MXRA8, and CASQ2 were increased in animals with high marbling, whereas levels of NPNT, MRC1, DNER, and CYPB4 were decreased in high marbled animals. The remaining gene, ACTN2 was determined to be a false positive and was, therefore, excluded from further study. Despite the positive results of the preliminary study, associations between gene expression and intramuscular fat content did not extend to the larger population of cattle. A significant negative association existed between expression of MRC1 and marbling level (P = 0.04). Therefore, this study was unable to identify a particular skeletal muscle gene set whose expression correlated well with marbling levels in the larger population of beef cattle.

Effect of antioxidant inclusion and oil quality on broiler performance, meat quality, and lipid oxidation.

The objective of the present study was to evaluate the effect of antioxidant inclusion and oil quality on broiler performance, meat quality, shelf life, and tissue oxidative status. Ross 308 male broilers were allotted to a randomized complete block design in a 2 × 2 factorial arrangement. Factors consisted of antioxidant (ethoxyquin and propyl gallate) inclusion at 2 levels (0 or 135 mg/kg) and oil quality (fresh soybean oil, control diet peroxide value <1 mEq/kg, or oxidized soybean oil, diet peroxide value 7 mEq/kg). Each treatment included 12 pen replicates comprising 24 birds for a total of 1,152 birds on trial allotted to 48 pens. On the final day of the study, 1 bird from each pen was killed by cervical dislocation and used for determination of tissue oxidative status. Another 5 broilers from each pen were processed at a commercial slaughtering facility. Immediately after processing, carcasses were transported to the University of Illinois Meat Science Laboratory (Urbana) for further analysis. With the exception of 2 responses (liver vitamin A and serum vitamin A), no interactions were found between antioxidant inclusion and oil quality. Body weight and weight gain were increased by dietary antioxidant inclusion (P < 0.001) and fresh oil (P < 0.001). Feed intake was increased in broilers fed the antioxidant (P = 0.047) and fresh oil (P = 0.062). Antioxidant inclusion had no effect on G:F (P = 0.18). Antioxidant supplementation had no effect on carcass weight (P = 0.202), dressing percentage (P = 0.906), breast yield (P = 0.708), or breast ultimate pH (P = 0.625) and had minimal effect on breast color. Antioxidant supplementation (P = 0.057) reduced breast thiobarbituric acid reactive substances after 7 d of display. Fresh oil decreased liver thiobarbituric acid reactive substances, whereas antioxidant inclusion increased serum and liver vitamin A and E concentration. The presence of an antioxidant in the feed protects lipids from further oxidizing, therefore increasing broiler performance and improving shelf life when using oxidized oil.

Sodium citrate as a replacement for sodium chloride in a brine solution when evaluated in cows of different backfat thickness.

The objective of this study was to evaluate seven muscles from cow forequarters, which were selected based on backfat thickness; an indicator of supplemental feed before slaughter: Moderate cover (Moderate ⩾ 0.76cm) and Thin cover (Thin ⩽ 0.51cm). In addition, enhancement with a brine solution containing either Sodium Chloride or Sodium Citrate was evaluated for differences in shelf-life and meat quality. Moderate carcasses had increased carcass weight, increased fat cover and a lower yield for some of the muscles compared to Thin. However, there were minimal differences for palatability and shelf-life compared to Thin. Trained panelists detected minimal differences between Citrate and Chloride for palatability. Citrate resulted in visually darker steaks, but less discoloration during the display period. Results indicate that while selection of cow carcasses based upon backfat thickness results in minimal quality differences; compared to enhancement with Chloride, Citrate minimally impacts palatability and will extend product shelf-life by reducing discoloration.

Contribution of lean, fat, muscle color and degree of doneness to pork and beef species flavor.

Flavor is an important contributor to consumer acceptability of meat, our objective was to characterize the impact of species-specific fat/lean sources, fat level, degree of doneness and muscle color are on pork and beef flavor. Three separate experiments were conducted. Patties were formulated differently for each experiment in order to evaluate the desired variables. Experiment. 1: Flavor from combination patties (same species lean/fat or combination of species lean/fat) was not impacted by degree of doneness (66°C vs. 71°C). Beef flavor was highest in samples made with beef lean, regardless of species fat type. Pork flavor was highest in samples made with pork lean and had higher flavor intensity scores. Experiment. 2: Beef flavor was not increased in all-beef patties formulated with higher fat levels. Pork patties formulated with higher fat content increased pork flavor. Experiment. 3: All-beef and all-pork patties formulated with light or dark lean did not impact flavor in either species.

Characterization of striping in fresh, enhanced pork loins.

To investigate the striping phenomenon in fresh, enhanced pork, a series of experiments were undertaken to identify possible causes of the problem. No one factor (individual brine components, brine pH, ingredient concentration, enhancement pressure, meat and brine pH, or enhancement level) was specifically identified, which could be used to reduce the severity of the striping problem. Furthermore, tumbling the product for 2h, did not reduce the amount of striping, indicating once striping has occurred, it is permanent. Evaluation of the striping pattern indicates that the stripes are formed not only at the needle injection site, but also follow the muscle fiber orientation. The use of darker pork provided more of a contrast when evaluating striping, thus exacerbating the perceived level of striping.

The effect of pH on shelf-life of pork during aging and simulated retail display.

The pork industry uses pH to differentiate product of varying quality; thus, the effect of pH on shelf-life is important as time during transport is extended. The objective was to develop regression equations to predict shelf-life over a range of ultimate pH (5.42-6.26). Shelf-life was evaluated after vacuum aging pork loin sections 0, 7, 14, 21, or 28d and during 3d of simulated retail display (4.5°C) for pork loin chops. Correlation coefficients indicated a strong relationship between pH and quality measurements. Regression analysis with Aging Day and pH was able to explain 87% of the variation in aerobic plate counts for pork. After 28d of vacuum aging, loin sections from the upper end of the pH distribution had about a 3log(1000X) greater aerobic plate count than did the lower end pH product. An increase in pH resulted in pork with lower L*, a*, b* and R(630)-R(580) values and as Aging Day increased, instrumental measurements of color increased slightly. Although higher pH is associated with improved pork quality, higher pH and longer aging periods will result in increased microbial proliferation and decreased shelf-life. Thus, an intermediate pH may provide the most desirable combination of quality and shelf-life when extensive aging is used.

The effect of ractopamine hydrochloride (Paylean(®)) on lean carcass yields and pork quality characteristics of heavy pigs fed normal and amino acid fortified diets.

Effects of ractopamine hydrochloride (RAC) on carcass parameters in heavy weight (133.24±8.07kg) finishing pigs (n=278) given amino acid fortified (AA) or 16% crude protein (CP) diets were evaluated. A total of seven experimental diets were formulated; RAC was added at 0, 5 and 20ppm to the 16% CP diets (CP0, CP5 and CP20, respectively) and at 0, 5, 10 and 20ppm to the AA fortified diets (AA0, AA5, AA10 and AA20, respectively). Carcass, tenderloin, and ham weights were heavier (P<0.05) for RAC AA diets vs. AA0. Loin weight was heavier (P<0.05) for AA20 vs. AA0 and CP20 vs. CP0. No differences (P>0.05) were observed for color or firmness scores. Carcass muscle score, ham weight and protein% were greater (P<0.05) for RAC diets. Moisture was greater (P<0.05) and fat was lower (P<0.05) for AA5 and AA20 vs. AA0 and CP5 and CP20 vs. CP0. Feeding RAC to late finishing swine increases carcass yields and protein% with lower fat% for pigs weighing up to 136kg.

Effect of different dietary levels of natural-source vitamin E in grow-finish pigs on pork quality and shelf life.

Improving pork quality and shelf life is important in today's swine industry because higher levels of DDGS are incorporated into pig diets. Relatively high level of poly-unsaturated fatty acids (PUFA) in DDGS may increase pork susceptibility to lipid oxidation and thus reduce pork shelf life. Antioxidants such as vitamin E may delay the onset of pork lipid oxidation when used as an ingredient in the diet. This experiment examined carcass characteristics, meat quality, shelf life, and color stability in pork from pigs (n=150) fed five levels of a natural vitamin E (Nova-E) and one level of synthetic vitamin E. Natural vitamin E and synthetic vitamin E had no effect on carcass characteristics or meat quality. Increasing dietary natural vitamin E from 10 to 200mg/kg decreased lipid oxidation. Lipid oxidation of pork chops and ground pork was similar between pigs fed 40mg/kg and higher levels of natural vitamin E, indicating no additional benefits from supplementing beyond 40mg/kg natural vitamin E. Supplementing 200mg/kg synthetic vitamin E decreased pork lipid oxidation when compared to supplementing 10mg/kg natural vitamin E. High levels of natural vitamin E or synthetic vitamin E, however, did not prevent discoloration of loin chops. These data indicate that natural vitamin E was effective to help reduce lipid oxidation and the effective minimal level of dietary supplementation appeared to be 40mg/kg.

The influence of early post-mortem enhancement and accelerated chilling on pork quality.

To improve pork quality, the effectiveness of early post-mortem enhancement and accelerated chilling were investigated. The four treatments evaluated were: Enhancement with Accelerated Chilling (ENAC), Accelerated Chilling Only (ACO), Enhancement with Conventional Chilling (ENCC), and Conventional Chilling Only (CCO). ENAC had a higher (P<0.05) pH than all other treatments. CCO resulted in the highest (lightest; P<0.05) L(∗), while ENAC had the lowest L(∗) value (darkest; P<0.05). Subjective color and striping did not differ (P>0.05) between ENAC and ENCC, although ENAC was numerically higher for both parameters. Sensory analysis for juiciness and tenderness were not different (P>0.05) between ENAC and ENCC, but both were higher (P<0.05) than ACO and CCO. Enhancement early post-mortem coupled with accelerated chilling may be used to improve instrumental color and pH over conventional processing methods.

Effect of enhancement and ageing on flavor and volatile compounds in various beef muscles.

To identify and quantify selected flavor-active volatile compounds and relate them to sensory characteristics, the gluteus medius (round), rectus femoris (round), vastus lateralis (round), vatsus medialis (round), teres major (chuck), infraspinatus (chuck), complexus (chuck), serratus ventralis (chuck), psoas major (loin) and longissimus dorsi (loin) were removed from heifer carcasses, enhanced, vacuum packaged, aged for 7 or 14days, steaks were cut, vacuum packaged and frozen (48h). Flavor-active volatiles affected by enhancement and ageing in the various muscles included nonanal, 2,3-octanedione, pentanal, 3-hydroxy-2-butanone, 2-pentyl furan, 1-octen-3-ol, butanoic acid, pentanal and hexanoic acid, compounds often associated with lipid oxidation. Enhancement decreased hexanal and hexanoic acid. Ageing decreased butanoic acid. Pentanal content varied among muscles depending on enhancement and ageing. Livery off-flavor was positively correlated with pentanal, hexanal, 3-hydroxy-2-butanone and hexanoic acid. Rancid off-flavor was correlated with pentanal and with 2-pentyl furan but not with hexanal.

Effect of ractopamine level, gender, and duration of ractopamine on belly and bacon quality traits.

The objective was to determine belly and bacon quality traits in pigs fed ractopamine (RAC) for various durations during finishing. A 2×3×2 factorial arrangement was used with barrows and gilts, fed RAC levels of 0.0, 5.0, or 7.4ppm, for 21 or 28d prior to harvest. Bellies were fabricated and measured for length, thickness, firmness, and processing yields. Once processed, 1.27cm slices were removed at 25%, 50%, and 75% the distance from the blade end, packaged and digitally imaged using a Chem1 Genius(2) Bio Imaging System. Total slice area (TA), total slice length (TL), secondary lean length (SL), secondary lean area (SA), and percent lean area (TA - all lean components=LA) were determined by tracing images in Adobe Photoshop Elements. A composite sample from the three slices was used for proximate analysis to determine moisture and fat composition for each belly. Feeding RAC increased belly yield, TA, TL, SA, and LA (P<0.05), but did not alter moisture or fat composition (P>0.05). Gilts had decreased firmness and higher pump uptakes compared to barrows (P<0.05). Additionally gilts had increased TL, SL, and LA with lower fat and higher moisture content (P<0.05). RAC feeding duration had no significant effect on belly or bacon quality traits (P>0.05), furthermore, no interactions were found to be significant (P>0.05). RAC administration during finishing resulted in improved belly and bacon yields with no negative effects on the quality traits evaluated.

Evaluating an objective method to measure fresh pork loin firmness.

The purpose of this study was to develop an objective method for measuring fresh pork loin firmness. A total of 42 fresh boneless pork loins were collected from a range of subjective firmness scores based on the whole boneless loin to create a population suitable for creating a prediction equation. Loins were subjectively scored by panelists prior to objectively being measured with a Texture Analyzer. An R(2) value of 0.54 was achieved for the prediction equation that was generated. A second trial was performed to test the equation resulting in an R(2) value of 0.30 concerning subjective and objective values. The results from these studies indicate that it is possible to create a standardized protocol in order to determine objective firmness that would be useful for future studies and for the development of hand held or online firmness measuring devices.

Antioxidant and modified atmosphere packaging prevention of discoloration in pork bones during retail display.

The objective of this study was to evaluate the ability of antioxidants to prevent discoloration in pork rib bones. Pork rib bones were removed from carcasses, frozen (-20°C, 24h), split lengthwise, exposed to antioxidant solutions (ascorbic acid, citric acid, propyl gallate or ascorbic/EDTA mix), packaged (modified atmosphere [80% O(2) and 20% CO(2)] or air), then displayed in a retail case at 4°C for 8days. Dark pigment formation was visually evaluated during the display period. Instrumental color was determined at the end of the 8-day display period. Visual bone discoloration increased over time for all treatments. After 2days of display, samples treated with propyl gallate were visually redder, less discolored and less green/black than samples treated with other antioxidants. After 8days of display, propyl gallate-treated samples had higher a* and b* values, as well as chroma (intensity). However, this difference was no longer large enough to be visually detected.

Ham and belly processing characteristics of immunological castrated barrows (Improvest) fed ractopamine hydrochloride (Paylean).

Effects of sex class (physically castrated, PC or immunologically castrated, IC) and diet (0 or 5mg/kg ractopamine hydrochloride, RAC) on characteristics of ham and bellies were determined from pigs slaughtered in three groups with similar ending live weights. One carcass per pen per marketing group (n=8) was selected to evaluate further processing characteristics. Data were analyzed as a 2×2 factorial design with a split plot in time and fixed effects of sex, diet, marketing group, and their interactions. IC fresh bellies were thinner (P<0.01) and softer (P<0.01) than PC bellies. IC hams and bellies were leaner (P<0.05) than those from PC pigs. RAC feeding did not affect (P>0.05) fresh ham or belly characteristics but decreased (P<0.01) fat in cured PC bellies. Marketing group affected (P<0.05) fresh quality, processing characteristics, and composition of hams and bellies. Immunological castration and RAC produced leaner finished products but did not alter processing yield of hams or bacon.

Benchmarking value in the pork supply chain: Processing characteristics and consumer evaluations of pork bellies of different thicknesses when manufactured into bacon.

Impact of belly thickness on processing yields and consumer evaluations of finished bacon products was measured. Before processing through a commercial facility, pork bellies (n=96 per group) were sorted into three target thickness groups: "thin" (approximately 2.0cm); "average" (approximately 2.5cm); "thick" (approximately 3.0cm). Processing yields at various production points were recorded and samples from each thickness group were evaluated by consumers for palatability characteristics and visual appearance. Bacon manufactured using "thick" bellies had the highest processing yields through the smoking and cooking phase. "Thin" bellies had the lowest slicing yields and generated the highest percentage of less valuable "#2 slices" (slice profile less than 1.9cm at any point) and "ends and pieces." Consumers found that bacon manufactured from "average" thickness bellies did not have deficiencies in palatability characteristics, but bacon manufactured from "thin" bellies lacked crispiness and bacon manufactured from "thick" bellies lacked flavor. Consumers found the lean-to-fat ratio and the visual appearance of bacon from "thick" bellies was less appealing than bacon from "thin" and "thick" bellies. Moreover, consumers showed much stronger purchase intent for bacon from "thin" and "average" bellies. Belly thickness impacted processing yield and consumer palatability evaluations of bacon. Producers need to minimize production of "thin" bellies because of reduced processing yields and "thick" bellies because of reduced consumer appeal.

Benchmarking value in the pork supply chain: Characterization of US pork in the retail marketplace.

Retail pork from eight US cities was obtained for quality and palatability evaluations. Boneless pork loin chops were classified into one of three quality categories - "high," "average," or "low" - with higher quality chops possessing more desirable color, marbling, juiciness, and shear force characteristics than lower quality chops. Loin chops that were enhanced (injected with solution to improve juiciness and/or tenderness) had higher (P<0.05) pH, less purge and cook loss, and higher palatability ratings compared to non-enhanced chops. Hams compared by their protein fat free (PFF) classifications showed that ham and water product received the highest (P<0.05) ratings for juiciness and tenderness, and ham with natural juices received the highest (P<0.05) texture, ham flavor intensity, and smoke flavor ratings. Bacon was compared by price/brand categories; however, the highest priced, national branded bacon (US$12.03/kg) was similar (P>0.05) for most quality and all palatability traits to the lowest priced, national branded bacon (US$6.47/kg) and the store branded bacon (US$8.30/kg) even though retail prices differed widely. Overall, there were tremendous ranges in values for these products indicating that retail pork is quite variable and that efforts to improve the quality and consistency of it must continue.

Benchmarking value in the pork supply chain: Processing and consumer characteristics of hams manufactured from different quality raw materials.

Impact of fresh ham quality on finished ham product characteristics was evaluated. Bone-in hams destined for spiral-sliced ham manufacturing were sorted into two pH groups before processing: pH⩽5.5 and pH⩾5.6. For boneless hams, raw materials were sorted into groups with different levels of pale, soft, and exudative (PSE) product before manufacturing into sliced vacuum packaged hams: "Low PSE" (⩽5% PSE muscle), "Intermediate PSE" (20-30% PSE muscle) or "High PSE" (40-60% PSE muscle). Few differences were observed between the pH⩽5.5 and pH⩾5.6 groups in objective color measures and drip loss in bone-in spiral-sliced hams stored under refrigeration, however, after frozen storage, hams from the pH⩽5.5 group had lower L*- and a*-values and had much higher drip loss than those from the pH⩾5.6 group. Processing yields for bone-in spiral-sliced hams were similar through cooking and chilling, however, the pH⩾5.6 group had higher yields after slicing. For boneless hams, defects occurred at a greater frequency in hams formulated with a greater percentage of PSE raw materials than those with lower amounts of PSE. Differences in objective color measures and purge were minimal over the duration of storage time, but hams formulated with greater percentages of PSE raw materials were lighter in appearance and had less redness. Consumers gave lower color responses for hams formulated with "High PSE" amounts, but did not differentiate between hams manufactured with lower quantities of PSE muscle. However, when consumers directly compared packages of ham, there was distinct discrimination against hams manufactured with greater amounts of PSE. Purchase intent showed that consumers favored ham manufactured from fresh ham muscles containing low quantities of PSE tissue. Further research is needed to determine the optimal ratio of allowable PSE product in formulation that enables processors to maximize consumer appeal with the economic realities of sorting out PSE pork.

Impact of ractopamine hydrochloride on growth performance, carcass and pork quality characteristics, and responses to handling and transport in finishing pigs.

The effect of feeding ractopamine hydrochloride (RAC) on growth performance, carcass and pork quality, and blood acid-base and catecholamine responses to handling and transport in finishing pigs was evaluated using a randomized complete block design to compare 2 RAC levels (0 vs. 10 mg/kg). Crossbred pigs ( = 144) were housed in single-sex pens (barrow or gilt) of 3 with 24 pens/RAC level. The study was carried out for a 28-d period from 104.0 ± 5.99 to 136.7 ± 6.44 kg BW. At the end of the growth study, pigs were subjected to handling and transport procedures that involved an initial aggressive handling procedure (pigs moved 50 m with 8 shocks from an electric prod) followed by a 30-min transport on a standard livestock trailer at a floor space of 0.46 m/pig followed by a final gentle handling procedure (pigs moved 100 m using sort boards and slap paddles). A blood sample was taken and rectal temperature was measured 2 h before (baseline) and immediately after the final handling procedure (final). Barrows ( = 72) were harvested and carcass and pork quality were measured. Feeding RAC increased ( ≤ 0.05) ADG (19.6%), ADFI (4.2%), and G:F (14.8%). The increase in plasma epinephrine levels from baseline to final was greater ( ≤ 0.05) for pigs fed RAC; there was a trend ( ≤ 0.10) for pigs fed RAC to have greater final blood lactate and to show a greater change from baseline to final in blood bicarbonate, partial pressure of and total carbon dioxide, and oxygen saturation levels. However, there were no differences between treatments for changes from baseline to final in rectal temperature, blood pH and lactate, and plasma norepinephrine levels. The incidence of physical indicators of stress and of nonambulatory, noninjured pigs during the handling and transport procedures was similar for the 0 and 10 mg/kg RAC levels. Final farm BW was 4.1 kg heavier, carcass yield was 1.4 percentage units greater, and LM area was 5.18 cm greater for pigs fed RAC compared to the control ( ≤ 0.05). Minolta a* and b* values were lower ( ≤ 0.05) and ultimate pH (0.05 units) and Warner-Bratzler shear force (0.43 kg) were greater ( ≤ 0.05) for pigs fed 10 compared to 0 mg/kg RAC. These results confirm the substantial improvement from feeding 10 mg/kg RAC in growth performance and carcass yield and suggest relatively limited effects on pork quality and on responses to the handling and transport procedures used in this study.