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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., (The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).)

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 β-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., (Copyright © 2021 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

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.

The study was performed to evaluate the effect of feeding ractopamine (RAC) to physically castrated barrows (PC), immunologically castrated barrows (IC), and gilts (gilts) using a randomized complete block design with a 3 × 3 factorial arrangement of treatments: 1) sex (PC, IC, and gilts) and 2) RAC inclusion level (0, 5, and 7.5 mg/kg). The IC received 2 doses of gonadotropin releasing factor analog-diphtheria toxoid conjugate (Improvest; Zoetis, Kalamazoo, MI) at the start of the study (wk 16 of age; 69.6 ± 2.96 kg BW) and 4 wk later. The study used 180 pigs housed in groups of 4 (5 groups/sex × RAC subclass) and was performed over a fixed time of 61 d with RAC being fed for the final 26 d of study. Diets were formulated to meet requirements of intact males for the first 35 d and of intact males fed 7.5 mg/kg RAC for the remainder of the study. Pigs had ad libitum access to feed and water throughout the study period. At the end of the study, pigs were harvested at a commercial facility and HCW and last rib backfat thickness were measured. There were no treatment interactions (P > 0.05) for any variables. For the overall study period, IC had greater (P ≤ 0.05) overall ADG compared to PC, which grew faster (P ≤ 0.05) than gilts (1,246, 1,083, and 1,025 g/d for IC, PC, and gilts, respectively; SEM = 20.3); ADFI was lower (P ≤ 0.05) for gilts than IC and PC, which had similar ADFI (3.36, 3.37, and 2.87 kg/d, respectively; SEM = 0.051); and G:F was greater (P ≤ 0.05) for IC than gilts and greater for gilts than PC (0.371, 0.322, and 0.358 kg/kg, respectively; SEM = 0.0039). For the period from the second dose to the end of study, IC had greater (P ≤ 0.05) ADG (28.6%), ADFI (12.3%), and G:F (14.3%) than PC. Carcass yield was lower (P ≤ 0.05) for IC compared to PC and gilts (72.8, 75.0, and 74.6%, respectively; SEM = 0.25). Feeding RAC increased (P ≤ 0.05) ADG (15.7 and 14.5% for 5 and 7.5 mg/kg, respectively), G:F (17.1 and 16.4%, respectively), carcass weight (3.7 and 3.2 kg, respectively), and carcass yield (1.0 and 1.0 percentage unit, respectively) compared to the control. These results highlight sex differences in and effects of RAC on growth and carcass characteristics and suggest that the relative response to RAC is similar in IC and PC.

Growth performance and carcass characteristics of physically castrated (PC) and immunologically castrated (IC) pigs fed ractopamine hydrochloride (RAC; 5 mg/kg) were evaluated in 64 pens of 22 pigs each. Male pigs were randomly assigned to castration method at birth. Pigs in the PC group were physically castrated at 5 d of age while IC pigs were administered Improvest at 11 and 18 wk of age. Pigs entered the grow-finish barn at approximately 9 wk of age (d 0). Dietary treatments (control or RAC) were initiated on d 87. Final treatment arrangement was a 2 × 2 factorial of castration method and diet. Data were analyzed using a mixed model with fixed effects of castration method, diet, market group, and all 2- and 3-way interactions. Pen was the experimental unit. From d 0 to 65, IC pigs had 11.2% greater (P < 0.01) G:F and 11.6% less (P < 0.01) ADFI than PC pigs, but ADG was increased 1.0% in PC pigs compared with IC pigs (P < 0.01). From d 65 to 87, IC pigs had 7.9% greater (P < 0.01) ADG and 12.1% greater (P < 0.01) G:F than PC pigs while having similar (P = 0.16) ADFI. At the initiation of diet (RAC) treatments, BW of all treatments were similar (P ≥ 0.32). From d 87 to 120 (RAC feeding period), IC pigs had 10.0% greater (P < 0.01) ADG and 10.5% greater (P < 0.01) ADFI than PC pigs while having similar (P = 0.64) G:F. Feeding RAC increased (P < 0.01) ADG by 16.9% and G:F by 17.9% while having no effect (P = 0.42) on ADFI from d 87 to 120. There were no significant interactions between castration method and diet on growth performance from d 87 to 120. For the entire study (d 0-120), IC pigs had 2.6% greater (P < 0.01) ADG, 4.6% less (P < 0.01) ADFI, and 7.3% greater (P < 0.01) G:F than PC pigs. Averaged over market groups, IC pigs were 2.5 kg heavier (P < 0.01) and had similar (P = 0.10) carcass weights and 1.8 percentage units less (P < 0.01) dressing yields than PC pigs. Additionally, IC pigs had 1.3 mm less (P < 0.01) fat and 1.7 mm less (P < 0.01) loin depth than PC pigs. Pigs fed RAC were 2.9 kg heavier (P < 0.01) and had 2.3 kg heavier (P < 0.01) carcasses and 2.2 mm deeper (P < 0.01) loins but similar (P = 0.21) dressing yields and tended (P < 0.10) to have 0.4 mm less fat than control-fed pigs when averaged over market groups. Group 3 pigs were the heaviest (P < 0.01) at slaughter and had the heaviest (P < 0.01) carcasses, greatest (P < 0.01) dressing yields, and the most (P < 0.01) carcass fat of all market groups. Overall, immunological castration and RAC were additive in terms of improving growth performance and carcass characteristics.

Effects of feeding ractopamine (RAC; 5 mg/kg) to physically castrated (PC) and immunologically castrated (IC) pigs on carcass characteristics, cutting yields, and loin quality were evaluated using 285 carcasses. Male pigs were randomly assigned to sex treatments (PC and IC) at birth and fed the same nursery diets before allotment into 32 pens with 22 pigs per pen in a grow-finish barn. Pigs in the PC group were physically castrated at approximately 5 d of age, and pigs in the IC group were administered Improvest at 11 and 18 wk of age. Diet treatments (control or RAC) were initiated on study d 87. Pigs were marketed at 12 d (4.5 wk post-second Improvest dose), 19 d (5.5 wk post-second Improvest dose), and 33 d (7.5 wk post-second Improvest dose) following the start of final diet treatments. Three carcasses per pen were selected for evaluation of cutting yields and loin quality. Data were analyzed using PROC MIXED in SAS with fixed effects of sex, diet, market group, and their interaction; carcass (N = 285) was the experimental unit. Carcasses from RAC-fed pigs were heavier (P < 0.01) and had deeper (P = 0.02) loins than control-fed carcasses. Carcasses from IC pigs were similar (P = 0.22) in weight but had less (P < 0.01) fat and shallower (P = 0.02) loins when compared to PC carcasses. There were differences (P < 0.05) among market groups for carcass weights, fat depths, loin depths, and estimated carcass leanness. For cutting yields, RAC-fed carcasses had greater (P ≤ 0.03) bone-in lean and total carcass cutting yields than control-fed carcasses while there were no differences (P > 0.05) between RAC-fed and control-fed carcasses when evaluating LM color, marbling, firmness, pH, drip loss, and tenderness. Carcasses from IC pigs had greater (P < 0.05) boneless lean yields, bone-in lean yields, and total carcass cutting yields than PC carcasses. There were minimal differences (P < 0.05) in LM marbling, firmness, composition, and tenderness between PC and IC pigs. There was an interaction (P = 0.03) between sex and diet for LM composition. Control-fed PC loins had more (P < 0.01) lipid than all other treatment combinations. Market group had effects (P < 0.05) on carcass cutting yields, LM color, marbling and firmness scores, pH, purge loss, composition, and tenderness. The results from this study indicated RAC and immunological castration were additive in terms of improving carcass cutting yields while having minimal effects on pork quality.

The study used a randomized complete block design (blocking factor was date of start on test) with 5 treatments: 1) physically castrated barrows (PC), 2) intact males (IM), 3) gilts (G), 4) immunologically castrated barrows (IC), and 5) immunologically castrated barrows fed ractopamine at 5 mg/kg (IC+RAC). The study used 192 pigs and was performed from the 16 wk of age (67.2 ± 2.52 kg BW) to a pen mean BW of 132.5 ± 3.60 kg. For IC+RAC, ractopamine was fed for the final 23 d of the study. Pigs were housed in groups of 4 (10 groups for PC, IM, G, and IC and 8 groups for IC+RAC) in a finishing building at a floor space of 1.18 m(2)/pig. Diets were formulated to meet requirements of IM except that the diet for the IC+RAC fed during the ractopamine feeding period was formulated to meet requirements of pigs on that treatment. Pigs had ad libitum access to feed and water throughout the study period and were individually weighed at the start, wk 2 and 4, and subsequently every week until the end of study. For the overall study period, IC had greater (P ≤ 0.05) ADG than the other genders (1,150, 1,024, 1,064, and 954 g/d for IC, PC, IM, and G, respectively; SEM = 25.8) and required fewer days to reach slaughter weight than the other genders (58.1, 61.6, 61.6, and 66.5 d for IC, PC, IM, and G, respectively; SEM = 1.26). Overall ADFI was less (P ≤ 0.05) for IM and G than IC and PC, which were similar (P > 0.05) in this respect (3.11, 3.06, 2.68, and 2.75 kg/d for IC, PC, IM, and G, respectively; SEM = 0.061). Overall G:F was greater (P ≤ 0.05) for IM than the other genders; IC had greater overall G:F than PC and G, which were similar in this respect (0.371, 0.335, 0.397, and 0.347 kg/kg for IC, PC, IM, and G, respectively; SEM = 0.0068). Immunologically castrated barrows had greater (P ≤ 0.05) ADG (30.7%) and ADFI (22.5%) than PC from the second week following the second Improvest dose to the end of the study. During the ractopamine feeding period, IC+RAC had greater (P ≤ 0.05) ADG (11.6%) and G:F (17.3%) than IC. The results of this study confirmed previously observed gender differences and effects of ractopamine on growth performance and that IC grew faster and had greater feed efficiency than PC during the study period.

The objective was to determine which tissue components contributed to the reduction in carcass yield of immunologically castrated (IC) barrows when compared to physically castrated (PC) barrows. The carcass yield of an IC barrow is less than the carcass yield of a PC barrow. This has historically been attributed to the presence of testicles, but the testes have only accounted for approximately 0.25% of live weight. This experiment included PC barrows, intact males, IC barrows, IC barrows fed ractopamine hydrochloride, and gilts. When the pigs reached 15 wk old, they were weighed, assigned to treatments (intact male or IC barrow), and penned in groups of 4 pigs per pen. Pigs designated for immunological castration were given injections at approximately 16 wk old and approximately 20 wk old. Pigs were eligible for harvest 33 d after the second injection when the average weight of the pen reached 130 kg. Immunologically castrated barrows lost on average 0.7% units more live weight during transport and lairage than PC barrows, intact males, or gilts. Physically castrated barrows had a 1.43% unit advantage over IC barrows in carcass yield. The differences in yield can be attributed to differences in testicles, reproductive tract, intestinal mass, gut fill, and some visceral organs. Testicle weight accounted for a 0.28% unit reduction in carcass yield of IC barrows when compared to PC barrows. Additional reproductive tract weights accounted for differences of 0.10% units. Intestinal mass (empty large intestine, small intestine, and stomach) was 0.2% units heavier in IC barrows when compared to PC barrows. Livers from IC barrows were 200 g heavier (P < 0.05) and kidneys were 40 g heavier than the same organs in PC barrows. These 2 organs combined for a 0.15% unit difference in carcass yield between IC and PC barrows. Gut fill, testicles, reproductive tract, intestinal mass, and the liver and kidney accounted for 0.97 of 1.43% unit differences in carcass yield between IC and PC barrows. Immunologically castrated barrows had less marbling than PC barrows, but there were no other differences in pork quality parameters. Cutability differences were less than reported in previous experiments, but IC barrows still had a 1.0% unit advantage in lean cutting yield and a 0.7% unit advantage in carcass cutting yield when compared to PC barrows.

The objective of this experiment was to test the hypothesis that the reduced carcass fat quality that is often observed in pigs fed diets containing distillers dried grains with solubles (DDGS) may be ameliorated if corn germ, beef tallow, palm kernel oil, or glycerol is added to diets fed during the finishing period. A total of 36 barrows and 36 gilts (initial BW 43.7 ± 2.0 kg) were individually housed and randomly allotted to 1 of 6 dietary treatments in a 2 × 6 factorial arrangement, with gender and diet as main factors. Each dietary treatment had 12 replicate pigs. A corn-soybean meal control diet and a diet containing corn, soybean meal, and 30% DDGS were formulated. Four additional diets were formulated by adding 15% corn germ, 3% beef tallow, 3% palm kernel oil, or 5% glycerol to the DDGS-containing diet. Growth performance, carcass characteristics, and LM quality were determined, and backfat and belly fat samples were collected for fatty acid analysis. There was no gender × diet interaction for any of the response variables measured. For the entire finisher period (d 0 to 88), diet had no effect on ADG, but pigs fed 3% palm kernel oil tended (P < 0.10) to have less ADFI and greater G:F than pigs fed the control diet. Barrows had greater (P < 0.01) ADG and ADFI, and less (P < 0.001) G:F than gilts. Pigs fed the DDGS diet had reduced (P < 0.05) loin eye area compared with pigs fed the control diet, but diet had no effect on other carcass characteristics. Barrows had greater (P < 0.001) final BW at the end of both phases, greater (P < 0.001) HCW and backfat thickness, and tended (P = 0.10) to have greater dressing percentage, but less (P < 0.001) fat-free lean percentage than gilts. Backfat of pigs fed the 5 DDGS-containing diets had less (P < 0.05) L* values than pigs fed the control diet and backfat of gilts had greater (P < 0.001) a* and b* values than barrows. Pigs fed the control diet had greater (P < 0.05) belly flop distance compared with pigs fed the 5 DDGS-containing diets, but no differences were observed among pigs fed the diets containing DDGS. Barrows had heavier (P < 0.001) bellies and greater (P < 0.001) belly flop distances than gilts. Diet had no effect on carcass fat iodine value (IV), but gilts tended (P = 0.07) to have greater backfat IV and greater (P = 0.05) belly fat IV than barrows. In conclusion, the hypothesis that carcass fat quality of pigs fed diets containing DDGS can be improved by inclusion of corn germ, beef tallow, palm kernel oil, or glycerol in finishing diets could not be confirmed.

Study objectives were to evaluate ractopamine hydrochloride's (RAC) effect on performance, carcass characteristics, and tenderness of early weaned beef steers. Steers were assigned to a control diet (0 mg RAC·steer⁻¹·d⁻¹), 200 mg RAC mg·steer⁻¹·d⁻¹, or 300 mg RAC·steer⁻¹·d⁻¹. Steers fed 200 and 300 mg RAC·steer⁻¹·d⁻¹ gained 14.84 kg and 14.57 kg more live weight and produced 13.22 and 14.90 kg more hot carcass weight, respectively, than controls. Feed conversions for steers fed 200 or 300 mg RAC·steer⁻¹·d⁻¹ of RAC increased 45.2% and 47.3% and average daily gain increased 55.5% and 54.5% compared to controls, respectively. Feeding either dose of RAC increased (P<0.05) loin muscle area and increased (P<0.05) Warner-Bratzler shear force (WBSF) values compared to controls, however the magnitude of WBSF difference diminished (P>0.05) over 14 days of postmortem aging. Results of this study confirm that RAC increases weight gain and feed efficiency, minimally impacts carcass quality and has manageable impacts on tenderness when fed at either 200 or 300 mg steer⁻¹·d⁻¹., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Our objectives were to characterize the effects of ractopamine hydrochloride (RAC) on fresh meat and further processing characteristics of muscles (serratus ventralis and triceps brachii) from the shoulders of finishing pigs. Two hundred forty shoulders originating from 120 carcasses (60 barrows and 60 gilts) were selected from a commercial population of pigs. A 2 × 2 factorial in a completely randomized design was used, with factors of RAC inclusion in the diet (0 or 7.4 mg/kg, as-fed basis) and sex (barrow or gilt). Paired shoulders (120 rights and 120 lefts) were transported from a federally inspected slaughter facility under refrigeration to the University of Illinois Meat Science Laboratory for evaluation. Subsequently, right and left shoulders were separated and designated for 2 separate experiments. Shoulders from right side were used in Exp. 1 to determine further processing characteristics. Cellar trimmed (CT) butts from the Boston butt of the shoulders were cured and dried-cured to manufacture cottage bacon and coppa, respectively. Shoulders from left side were used in Exp. 2 to determine fresh meat characteristics. Pigs fed RAC had greater shoulder weights and increased yields of cuts from the shoulder. Feeding RAC decreased Boston butt fat content (P = 0.01) but had no effect on picnic fat content (P = 0.86). Pigs fed RAC had greater (P < 0.01) iodine values than controls (67.00 vs. 64.95, respectively). Inclusion of RAC in the diet had no effect on cottage bacon cooked yield (P = 0.33), but it decreased (P < 0.01) cottage bacon fat content without having an effect on protein content (P = 0.50). In addition, cottage bacon from RAC shoulders had greater slice total area (P = 0.01) and less seam fat (P = 0.01) than controls. Ractopamine hydrochloride had no detrimental effect on coppa processing characteristics and visual appearance. Cottage bacon and coppa from RAC pigs had sensory characteristics similar to controls. Shoulders from pigs fed RAC might be of benefit to the industry because they provide more pounds of sellable product with no detrimental effects on processing characteristics.

A total of 280 pigs (initial BW: 42.5 ± 4.6 kg) were used to determine effects of adding corn germ (15.6% CP; 16.6% acid hydrolyzed ether extract; 21.7% NDF) to diets fed to growing-finishing pigs. Pigs were ransssdomly allotted to 1 of 8 dietary treatments in a 2 × 4 factorial arrangement of treatments with 2 levels of distillers dried grains with solubles (DDGS; 0 or 30%) and 4 levels of corn germ (0, 10, 20, or 30%). Each diet was fed to 10 pens with either 3 or 4 pigs per pen. Pigs were fed phase 1, 2, and 3 diets for 28, 28, and 27 d, respectively. At the conclusion of the experiment, 1 pig in each pen that had a BW that was closest to the average BW for the pen was harvested. For the overall experimental period, regardless of the level of DDGS, there was no effect of corn germ on pig growth performance, but inclusion of 30% DDGS in the diet reduced (P < 0.001) ADG, ADFI, and final BW. There were no effects of corn germ on carcass composition, muscle quality, or fat quality, but LM marbling and firmness were reduced (P < 0.05) by inclusion of DDGS in the diet. The L* value of LM decreased (linear and quadratic; P < 0.05) as corn germ was included in diets containing no DDGS, but that was not the case when corn germ was added to diets containing 30% DDGS (corn germ × DDGS; P < 0.01). Inclusion of DDGS in the diet reduced (P < 0.001) the L* value for backfat, but there were no effects of corn germ on backfat color measures. Inclusion of corn germ in diets containing no DDGS increased belly length (quadratic; P < 0.05), but that was not observed if corn germ was added to diets containing 30% DDGS. There was also a decrease in belly flop distance as corn germ was added to diets containing no DDGS (linear; P < 0.001), but no effects of corn germ were observed in diets containing 30% DDGS. However, inclusion of DDGS in the diet reduced (P < 0.001) the belly flop distance. In conclusion, addition of up to 30% corn germ in diets containing 0 or 30% DDGS did not negatively affect pig growth performance, carcass composition, or muscle quality, but belly firmness was reduced.

The objective was to evaluate the effect of feeding oxidized corn oil with or without a dietary antioxidant (AOX) on performance, tissue oxidative status, and meat quality in barrows. One hundred sixty barrows were arranged in a 2 × 2 factorial of treatments in a complete randomized block design with 8 pens per treatment and 5 pigs per pen. Diets contained 5.0 mg/kg of 1 of 2 types of corn oil (fresh or oxidized) with or without antioxidant. Final oxidized oil was produced in a heated container by continuously bubbling air heated to 95°C at a rate of 80 L/min to reach a target peroxide value of approximately 150 and 7.5 mEq/kg in the final diet. After 56 d, barrows fed diets formulated with fresh oil had increased ADG (P = 0.03) and ADFI (P = 0.04) and heavier final BW (P = 0.03) than barrows fed oxidized oil. Increased G:F (P = 0.07) was observed for barrows fed diets with AOX after 28 d of feeding but not after 56 d of feeding (P = 0.67) when compared with barrows not fed AOX. An increase (P = 0.06) in plasma thiobarbituric acid reactive substances (TBARS) values, a decrease (P = 0.03) in plasma glutathione peroxidase (GPx) enzyme activity, and a decrease (P = 0.01) in liver vitamin E concentrations were observed in barrows fed diets with oxidized oil. Dietary AOX reduced plasma protein carbonyl content regardless of oil type (P = 0.04). Barrows fed fresh oil had 4.4% heavier HCW (P = 0.01) and 0.7 percentage units increase in dressing percentage (P = 0.01) compared with barrows fed oxidized oil. Loin TBARS values from barrows fed AOX were lower (P < 0.001) after 14 and 21 d of storage in both fresh and oxidized oil groups. In summary, oxidized oil impaired growth performance and caused oxidation stress. Dietary AOX partially ameliorated the negative effects of oxidized oil in finishing pigs by reducing protein oxidation and improving shelf life.

Body weights of finishing pigs can be variable within a finishing barn near the time of slaughter; therefore, it is common to market pigs over a period of time. This allows lighter pigs more time to gain BW and approach a desired end point. Use of immunological castration late in life to control boar taint, as an alternative to physical castration early in life, increases cutting yields of finishing male pigs compared with physical castrates. Because of common marketing strategies, it is important for advantages in cutting yields to span a broad spectrum of slaughter ages and BW. The primary objectives in this study were to evaluate carcass cutting yields, pork quality, belly quality, and bacon processing characteristics of immunologically castrated (IC) male pigs fed a moderate level of distillers dried grains with solubles and slaughtered at either 4 wk (early slaughter group) or 6 wk (late slaughter group) post-second injection. A total of 156 male pigs (physical castrates or IC males) were selected from a population of 1,200 finishing pigs. Data were analyzed with the MIXED procedure of SAS as a split-split plot design. Body weights of IC males were 3.60 kg heavier (P = 0.03) than physical castrates when slaughtered at 4 wk post-second injection and 7.52 kg heavier (P < 0.0001) than physical castrates when slaughtered at 6 wk post-second injection. Because of a lack of interaction (P > 0.05) between sex and time of slaughter post-second injection, some response variables were pooled. Hot carcass weights were not different (P = 0.57) between physical castrates (91.98 kg) and IC males (92.52 kg). There was a 2.77 percentage unit decrease (P < 0.001) in dressing percentage of IC males (71.78%) compared with physical castrates (74.55%). Lean cutting yields of IC males were 2.62 percentage units greater (P < 0.0001) than physical castrates and carcass cutting yields were 2.27 percentage units greater (P < 0.0001) for IC males when compared with physical castrates. There were no differences between IC males and physical castrates for shear force (P = 0.09), ultimate pH (P = 0.57), objective color (P ≥ 0.31), subjective color score (P = 0.64), or drip loss (P = 0.30). Bellies from IC males were thinner (P = 0.01) and had narrower belly flops (P < 0.0001) than bellies from physical castrates. There were no differences (P = 0.74) in cured belly cooked yield between IC males and physical castrates. Overall, immunological castration improved cutting yields, did not affect pork quality, made fresh bellies thinner, and did not affect cured belly characteristics when pigs were fed a moderate level of distillers dried grains with solubles during the finishing phase of production.

Unlabelled: The objective was to evaluate high-pressure processing (HPP) with varying liquid (water) temperatures on pork quality and textural properties of frankfurters. HPP pressurization liquid temperatures were 15.5 °C (HPP Low) and 29.4 °C (HPP Med). Analyses were conducted using paired boneless loins and paired boneless hams. Loins were evaluated for pH, purge loss, objective color, subjective color, firmness; and changes in color after a bloom period. Eight independent batches (2 batches each of HPP Low, paired untreated, HPP Med, and paired untreated) of frankfurters were manufactured from the outside portion of the ham and the knuckle. Both HPP treatments resulted in higher (P < 0.05) ultimate pH and less (P < 0.05) purge loss of the loin. Loin tenderness was not different among either HPP treatment temperature groups when compared to untreated controls except HPP Med chops were more tender (P = 0.02) than untreated controls. Salt-soluble protein extractability of inside ham muscles was lower (P < 0.05) for both HPP treatment levels when compared to untreated controls, but was not different between the 2 HPP treatment levels. Textural properties of frankfurters were not different for either HPP treatment group when compared to its respective untreated control for any parameter except springiness. HPP Low frankfurters had lower (P = 0.10) springiness values than untreated controls. Fracturability of HPP Med samples was lower (P = 0.12) than untreated controls. Overall, HPP caused higher ultimate pH and increased water-holding capacity, but did not affect tenderness of fresh meat or textural properties of frankfurters., Practical Application: HPP can be used on prerigor pork as means to improve fresh pork quality. Loins from HPP-treated pork sides had higher ultimate pH values and less package purge loss. Tenderness values were not affected positively or negatively by HPP treatment. The high pH and water-holding capabilities of treated samples have positive implications for further processing applications. Frankfurter textural properties suggest emulsified products can be made with pressurized pork without sacrifice to the textural profile., (© 2011 Institute of Food Technologists®)

The objective of this experiment was to determine if increasing lysine in the diets of immunologically castrated (IC) male pigs would affect further processed product characteristics when compared with physical castrates or entire males. Raw materials for this experiment were derived from a previous experiment evaluating carcass characteristics. Physical castrates, IC males, and entire males were assigned to 1 of 4 diet programs with increasing lysine in a step-down lysine inclusion program that culminated with the following concentrations in the late finishing diet: physical castrate with low lysine (0.7%), IC with low lysine (0.7%), IC with low/medium lysine (0.8%), IC with medium/high lysine (0.9%), IC with high lysine (1.0%), and entire with high lysine (1.0%). Bellies were injected with a cure solution to a target of 110% of original green weight, and weighed again to determine brine uptake. Hams were injected with same cure solution to a target of 130% of green weight. Cure solution was formulated for a finished product inclusion of 1.5% salt, 0.34% phosphate, 0.05% sodium erythorbate, 0.11% sugar, and 0.014% sodium nitrate. Physical castrates had thicker (3.77 cm) bellies (P<0.05) than all treatment groups, except IC males fed low/medium lysine (3.73 cm). Entire males (2.85 cm) had the thinnest (P<0.05) bellies of all treatment groups. There were no differences (P>0.05) in percentage brine uptake for cured bellies among IC males regardless of dietary lysine (range 9.93 to 10.67%). Cooked yield of cured bellies was not different (P>0.05) among physical castrates or IC males regardless of lysine inclusion. Cooked yield of cured bellies from entire males (95.12%) was less (P<0.05) than cooked yield for any other treatment group. Pumped weight differences of cured hams among treatment groups were similar to green weight differences, and there were no differences (P>0.05) among any treatment groups for pump uptake percentage. There were also no differences in cook loss percentages among any treatment group. Therefore, differences in cooked yield are a reflection of initial green weight. There were no differences (P>0.05) for protein fat-free values among any treatment groups. Therefore, it can be concluded, in this population of pigs, there were no differences in further processed product characteristics among physical castrates and IC males., (© 2011 American Society of Animal Science. All rights reserved.)

The objective was to investigate the effect of various doses and durations of ractopamine hydrochloride (RAC) on pig HCW, cutting yields, and meat quality. Late-finishing pigs (approximately 93 kg) were allotted to 12 treatments 35 d before slaughter. Treatments consisted of negative control (NEG; 13.1% CP, 0.64 TID Lys), positive control (POS; 17.8% CP, 0.94 TID Lys), and 2 RAC doses (5 and 7.4 mg/kg) with 5 different feeding durations for each dose (7, 14, 21, 28, or 35 d). Pigs on ractopamine-duration diets were fed NEG until incorporation of RAC, and then the diet was switched to POS to comply with label requirements. A subset of 240 pigs was utilized to determine the effects of RAC on carcass cutting yields. This subset was selected by taking the 5 pigs closest to the average pen weight from 4 complete replicates. Differences in response to RAC between 5 and 7.4 mg/kg were not significant. Therefore, RAC dosages were pooled, resulting in an average dose of 6.2 mg/kg, which was then compared with NEG and POS diets. Ractopamine increased (P < 0.05) HCW by 2.5 and 2.3 kg compared with the NEG and POS diets, respectively. Hot carcass weight also increased linearly (P=0.003) as RAC duration increased. Indicators of carcass leanness increased with RAC compared with NEG. Estimated carcass lean percentage increased (P=0.010) 1 percentage unit from 54.79 to 55.79%, carcass cut yield increased (P<0.001) 1.23 percentage units from 50.61 to 51.84%, and (P=0.006) boneless lean cut yield increased 1.27 percentage units from 36.71 to 37.98%. Ractopamine decreased (P=0.002) subjective marbling scores 0.49 units from the NEG value of 3.0, but RAC did not differ (P=0.203) from POS. Subjective color values and shear force aging curves for RAC were not significantly different from NEG or POS. Overall, RAC had greater responses in carcass weight and cut yield than NEG, and had minimal effects on meat quality., (© 2011 American Society of Animal Science. All rights reserved.)

The objective of this experiment was to determine if increasing lysine in the diets of immunologically castrated (IC) male pigs would increase percentage fat free lean and carcass cutting yields when compared with physical castrates. The anti-gonadotropin-releasing factor (GnRF) immunological product (Improvest, Pfizer Animal Health) is used worldwide to immunologically castrate entire male pigs to control boar taint and take advantage of the inherent ability of the entire male to deposit more muscle, less fat, and grow more efficiently than physically castrated males. The immunization process essentially allows the pig to grow as an entire male pig for most of its life and then removes any boar odor (boar taint) before slaughter. Reported lean meat advantages may also provide economic benefits to the domestic meat industry. Approximately 1,200 male pigs [physical castrates, IC males, and entire males] were each assigned to 1 of 4 diet programs which differed in lysine content. In each case, lysine was fed in a conventional step-down program that culminated with the following concentrations in the late finishing diet: physical castrates fed low lysine (0.7%), IC fed low lysine (0.7%), IC fed low/medium lysine (0.8%), IC fed medium/high lysine (0.9%), IC fed high lysine (1.0%), and entire males fed high lysine (1.0%). At 25 wk of age (5 wk post-second injection), pigs were individually weighed and the 2 pigs (n=96) in each pen closest to the median pig BW were selected and slaughtered. The right side of each carcass was dissected into soft tissue, skin, and bone. Proximate composition was determined on the soft tissue to determine percentage fat-free lean. The left side of each carcass was weighed and initially fabricated into ham, loin, belly, and whole shoulder. Each primal piece was weighed again and further fabricated into respective subprimal cuts. Immunological castration did not change (P>0.05) shear force values or ultimate pH when compared with either physical castrates or entire males. Marbling appeared to decrease as dietary lysine was increased among IC males. As expected, IC males had a greater (P<0.05) percentage fat-free lean than physical castrates but less (P<0.05) than entire males. Immunologically castrated males fed diets with medium/high and high lysine had greater (P<0.05) lean cutting yields and carcass cutting yields than physical castrates. Lean cutting yield and carcass cutting yields appeared to increase as dietary lysine was increased among IC males. Overall, immunological castration improved carcass cutability, increased percentage fat free lean, and had no effect on pork quality when compared with physical castrates., (© 2011 American Society of Animal Science. All rights reserved.)

The surface sheen phenomenon in enhanced beef steaks, packaged under modified atmosphere, was studied using various combinations of processing techniques and brine formulations. There was no effect (P > 0.05) of time between enhancement and when steaks were cut on surface sheen. Beef temperature less than 0 °C prior to enhancement, resulted in less (P ≤ 0.05) sheen and less retained pump (P ≤ 0.05) than beef greater than 2 °C. Removal of phosphate from the brine resulted in lower (P ≤ 0.05) sheen, and the addition of lactate decreased (P ≤ 0.05) sheen but resulted in less (P ≤ 0.05) retained pump. Sheen was correlated (P ≤ 0.05) with pump uptake (r = 0.58) and pH (r = -0.29). Results indicate that surface sheen can be significantly affected by ingredients used, but caution must be taken as retained brine and pH can also be affected, causing secondary influences on instrumental and visual traits., (Copyright © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.)

The effects of dietary energy source and feed withdrawal on muscle glycolytic potential (GP) and blood acid-base responses to handling were investigated in slaughter-weight pigs (initial BW 94.7 ± 1.01 kg). Crossbred pigs (n = 96; 48 barrows, 48 gilts) were used in a randomized complete block design with a 4 × 2 × 2 factorial arrangement of treatments: l) diet [control, high fat (10% supplemental fat), low-digestible carbohydrate (20% total starch), and high-fat/low-digestible carbohydrate (10% supplemental fat and 20% total starch)]; 2) feed withdrawal (0 and 36 h); and 3) sex (barrow and gilt). Diets were fed for 28 d before the feed withdrawal treatment was applied, at the end of which all pigs were individually moved through a 12.20-m-long × 0.91-m-wide passageway for 16 laps (195 m total distance), with the assistance of an electric goad (2 times per lap). Longissimus muscle biopsies were collected at the beginning of the feeding and feed withdrawal periods and immediately after and 4 h after the handling procedure. Venous blood was collected 2 h before and immediately after the handling procedure to measure acid-base responses. At the end of the feeding period, pigs fed the control and high-fat diets were heavier (P < 0.001) than those on the low-digestible carbohydrate and the high-fat/low-digestible carbohydrate diets (129.8, 130.9, 114.0, and 122.1 kg, respectively; SEM 1.91). Diet, feed withdrawal, and sex did not affect (P > 0.05) blood acid-base responses to handling. Muscle GP at the end of the feeding period and 4 h posthandling was least (P < 0.05) for pigs fed the high-fat diet and similar for the other 3 diet treatments. Pigs subjected to 36 h compared with 0 h of feed withdrawal had less GP (P < 0.05) immediately after and 4 h after the handling procedure. There was an interaction between diet and feed withdrawal treatments for changes in GP from the start of feed withdrawal to 4 h posthandling. The reduction in GP was greater (P < 0.05) for fasted than for fed pigs receiving the control and high-fat diets, but was similar (P > 0.05) for fasted and fed pigs receiving the 2 low-digestible carbohydrate diets. In conclusion, neither dietary energy source nor fasting affected blood acid-base responses to handling; however, fasting-induced changes in LM GP were diet dependent.

The objective was to evaluate high pressure processing (HPP) on postmortem metabolism and pork quality. Six pigs were randomly selected immediately after slaughter. After splitting, one side was randomly designated for HPP of 215 MPa for 15 s with water temperature at 33 °C and the other side (non-pressure treated) served as the control. Chilled sides were fabricated into loins, boneless picnic, boneless Boston butt, and ham. Samples were cut from the loin, inside portion of the ham and cushion (M. triceps brachii). Pork quality, lipid oxidation, connective tissue solubility, protein functionality, sensory analysis, and processed characteristics of restructured hams were evaluated. HPP partially inhibits postmortem metabolism, indicated by lower muscle lactate levels and higher ultimate pH values. Cook and drip loss were both reduced in HPP treated muscles compared to controls. HPP treated sides were more tender than controls. Collagen content was not different between HPP and control groups., (© 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.)

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.

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.

Gilts (n=45) were used in this study to characterize the effect of genotype on loin characteristics and quality over the length of the loin. Three diverse genotypes included a high quality Duroc line (A), a Duroc based composite line selected for lean growth (B), and an F1 cross of the two (C). After harvest, bone-in loins were removed from the carcass and cut perpendicular to the backbone at the 5th/6th rib, 7th/8th rib, 10th/11th rib, last rib, midlumbar, and the loin/sirloin juncture. Quality measurements were obtained at the 5th/6th rib, 10th/11th rib, and the loin/sirloin juncture. Digital images were taken of each surface (n=6) and analyzed for the determination of loin muscle area (LMA), muscle width, muscle depth (at three locations across the loin face), and fat depth. The average loin depth was calculated and used to calculate the loin depth:width ratio as an indication of loin shape or conformation. Loins from line A had the lowest (P<0.05) subjective color score, had the highest (P<0.05) amount of marbling, and were the firmest (P<0.05) of all three lines. There were also differences (P<0.05) between genetic lines for LMA, width, all three depths, fat depth, and depth:depth ratios. The most posterior portions of the loin had the largest (P<0.05) LMA, loin width, fat depth, and muscle depth 1. However, the more anterior portions of the loin had greater (P<0.01) values for the depth:width ratio and muscle depth:depth ratios., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Ractopamine hydrochloride (RAC) has consistently led to an advantage in carcass cutting yields of finishing pigs and remains a common feed additive in US finishing pig diets. Less is known about the effect of RAC on further processing characteristics. Some researchers have reported advantages in ultimate pH of the LM in pigs fed RAC. If a greater ultimate pH was also observed in hams, the increased pH could affect further processing characteristics and lead to better protein interaction and improved textural properties. The objective of this experiment was to determine if RAC-fed pigs yielded hams with a greater ultimate pH, and if so, whether or not that advantage improves textural properties and water retention of further processed hams. Two hundred hams from barrows and gilts fed RAC or control diets were selected based on HCW. Hams were fabricated into 5 separate pieces to determine cutting yields, and 6 muscles were evaluated for ultimate pH. Hams were processed to make cured and smoked hams. Ractopamine increased cutting yields of the whole ham (P < 0.0001), inside (P < 0.01), outside (P < 0.01), and knuckle (P < 0.01) when expressed as a percentage of chilled side weight. Ultimate pH of the rectus femoris, vastus lateralis, and semitendinosus were all 0.06 pH units greater (P < 0.05), the biceps femoris was 0.04 pH units greater (P = 0.02), and the semimembranosus and adductor muscles were 0.03 pH units greater in pigs fed 7.4 mg/kg of RAC when compared with control pigs. Cured hams from RAC-fed pigs were heavier at all stages of production. No differences were detected in binding strengths (P = 0.88) or protein fat-free values (P = 0.13) between RAC (9.06 kg and 20.37) and control hams (9.01 kg and 20.13). Ractopamine increased cutting yields, total weight of cured hams, and ultimate muscle pH. Ractopamine can be fed to pigs to achieve the desired growth characteristic advantages and cutting yields without affecting further processed ham characteristics.

Two studies were conducted with refined glycerin (97.7 and 97.5% glycerin for studies I and II, respectively) to determine ME content and effects on growth performance and carcass and pork quality measures of finishing pigs. An energy balance study using 24 barrows (21.5 ± 0.6 kg initial BW) determined the apparent ME content of glycerin using a generalized randomized block design with 2 dietary treatments: 1) control (99.85% corn + vitamins and minerals) and 2) glycerin (30% of corn in the control diet replaced with glycerin). A 7-d adaptation was followed by a 5-d collection period for feces and urine. The energy content of diets, feces, and urine was determined by bomb calorimetry. The DE of the glycerin diet was greater (P < 0.01) than that of the control diet (4,298 vs. 3,902 kcal/kg of DM); however, the ME content of the 2 diets was similar (3,820 vs. 3,723 kcal/kg of DM). The ME of refined glycerin (estimated by difference) was 3,584 kcal/kg of DM. A growth study was conducted with 128 gilts housed in groups of 4 and reared from 92.5 ± 0.24 kg of BW for a 28-d period, using a split-plot design with a 4 × 2 factorial arrangement of treatments: 1) dietary glycerin level (0, 5, 10, and 15%) and 2) preslaughter handling (gentle vs. intense). The handling treatment was included to simulate the range in handling intensities that are likely to be experienced in practice. At the end of the 28-d period, one-half of the pens on study were slaughtered and used for carcass and pork quality evaluation with 2 pigs from each pen being subjected to each of the preslaughter handling treatments. There were no interactions (P > 0.05) between dietary glycerin and preslaughter handling treatment. Dietary glycerin had no effect (P > 0.05) on growth performance, carcass measures, or meat quality. There were no differences (P > 0.05) between the gentle and intense handling treatments for carcass or pork quality measures. In conclusion, feeding glycerin to finishing pigs at up to 15% of the diet had no negative effect on growth performance or carcass and pork quality characteristics.

Pigs (n = 240) were allotted in a 5 x 2 factorial arrangement with 5 levels of distillers dried grains with solubles (DDGS): 0, 15, 30, 45, and 60%, and 2 ractopamine (RAC) levels: 0 and 5 mg/kg. Four pigs per pen (2 barrows, 2 gilts) closest to pen mean BW were used for meat quality evaluation. Loins (n = 119) were evaluated for objective color; moisture and fat; subjective color, marbling, and firmness; and drip loss. Bellies (n = 119) were evaluated for weight, length, width, thickness, objective fat color, and firmness. Cured bellies were evaluated for pump yield, cook loss, and sliced bacon cook loss. Loin thiobarbituric acid reactive substances (TBARS) were evaluated on enhanced (salt and phosphate) boneless chops held in modified atmosphere (80% O(2)/20% CO(2)) packages for 0, 7, 14, and 21 d. Bacon TBARS were evaluated on sliced bacon held in vacuum packages for 0, 28, 56, and 84 d. Fat samples were collected from each jowl and belly and evaluated for fatty acid profile and iodine value (IV). Increasing DDGS decreased subjective marbling (P = 0.0134) and firmness (P = 0.0235), and increased drip loss (P = 0.0046). Distillers dried grains with solubles did not affect loin pH, subjective or objective color, percent moisture, or percent fat (P > 0.05). The RAC decreased subjective color (P = 0.0239), marbling (P = 0.0445), and a* (P = 0.0355). Increasing DDGS decreased belly weight (P = 0.0155), length (P = 0.0008), thickness (P = 0.0019), and firmness (P = 0.0054); decreased belly fat L* (P = 0.0818); and increased belly cook loss (P = 0.0890). Ractopamine did not affect any belly measurements, and there were no DDGS x RAC interactions (P > 0.05). Distillers dried grains with solubles did not affect loin TBARS at 0, 7, or 14 d. At 21 d, loin TBARS from 30, 45, and 60% DDGS groups were increased compared with 0 and 15% groups (P < 0.05). Ractopamine did not affect (P > 0.05) loin TBARS, and there were no (P > 0.05) DDGS x RAC interactions. Distillers dried grains with solubles and RAC did not affect bacon TBARS (P > 0.05). Increasing DDGS increased belly (P = 0.0207) and jowl (P < 0.0001) IV, and decreased MUFA:PUFA in belly (P < 0.0001) and jowl (P < 0.0001) fat. Ratio of SFA:unsaturated fatty acids decreased in jowl (P = 0.0002) and belly fat (P = 0.2815). Ractopamine did not affect fatty acid profiles or IV, and there were no DDGS x RAC interactions (P > 0.05). Results indicate that increased DDGS have minimal effects on loin quality, but decrease belly quality, bacon processing characteristics, and fat stability. Ractopamine does not negatively affect these characteristics and does not interact with DDGS.

Analyses were conducted to evaluate the ability of the USDA yield grade equation to detect differences in subprimal yield of beef-type steers and calf-fed Holstein steers that had been fed zilpaterol hydrochloride (ZH; Intervet Inc., Millsboro, DE) as well as those that had not been fed ZH. Beef-type steer (n = 801) and calf-fed Holstein steer (n = 235) carcasses were fabricated into subprimal cuts and trim. Simple correlations between calculated yield grades and total red meat yields ranged from -0.56 to -0.62 for beef-type steers. Reliable correlations from calf-fed Holstein steers were unobtainable; the probability of a type I error met or exceeded 0.39. Linear models were developed for the beef-type steers to predict total red meat yield based on calculated USDA yield grade within each ZH duration. At an average calculated USDA yield grade of 2.9, beef-type steer carcasses that had not been fed ZH had an estimated 69.4% red meat yield, whereas those fed ZH had an estimated 70.7% red meat yield. These results indicate that feeding ZH increased red meat yield by 1.3% at a constant calculated yield grade. However, these data also suggest that the calculated USDA yield grade score is a poor and variable estimator (adjusted R(2) of 0.31 to 0.38) of total red meat yield of beef-type steer carcasses, regardless of ZH feeding. Moreover, no relationship existed (adjusted R(2) of 0.00 to 0.01) for calf-fed Holstein steer carcasses, suggesting the USDA yield grade is not a valid estimate of calf-fed Holstein red meat yield.

Ractopamine hydrochloride (RAC) and zilpaterol hydrochloride (ZH) are beta-adrenergic agonists that improve growth performance and affect carcass characteristics. The objective of this study was to evaluate the comparative effects of RAC and ZH when fed to beef steers during the last 33 d of the finishing period. Three hundred crossbred beef steers (516 +/- 8 kg) were grouped by BW, BCS, and breed type and randomly assigned to 1 of 3 treatments (10 steers per pen; 10 pens per treatment). Treatments were control (no beta-agonists added), RAC (200 mg of ractopaminexhdx(-1)d(-1), for 33 d), or ZH (75 mg of zilpaterolxanimalx(-1)d(-1), for 30 d, removed 3 d for required withdrawal period). Steers were slaughtered, carcass characteristics were evaluated, and cut-out yields were determined. Both RAC and ZH increased final BW, ADG, feed efficiency (G:F), and HCW compared with controls (P < 0.05). Compared with RAC, ZH decreased ADG, ADFI, and final BW, but increased HCW and dressing percentage (P < 0.05). Carcass yield was not affected by RAC in this experiment, whereas ZH decreased adjusted fat thickness and KPH, increased ribeye area, improved yield grade, and increased cut-out yields, when compared with controls (P < 0.05). Marbling, lean maturity, and skeletal maturity were not different between treatments (P > 0.05). Steaks from RAC steers had greater (P < 0.05) Warner-Bratzler shear force (WBSF) values than steaks from control steers at 3 and 7 d of aging, but did not differ from controls after 14 d of aging. Steaks from ZH steers had greater WBSF values (P < 0.05) than steaks from controls and RAC steaks throughout the 21-d postmortem aging period. Although both beta-adrenergic agonists were effective at improving feedlot performance, RAC showed no negative effect on WBSF after 14 d, whereas WBSF values for ZH steaks were significantly greater than controls after 21 d.

In mice, the myostatin (Mstn) null mutation and treatment with clenbuterol both increase muscle growth and decrease fat mass. Our objective was to determine whether mechanistic overlap exists by administering clenbuterol to Mstn null mice. Male Mstn null and wild-type mice of similar genetic backgrounds received either 0 (control) or 20 p.p.m. clenbuterol in tap water free choice for 14 days. Several traits were measured to estimate muscle and fat growth. The Mstn null mutation resulted in increased body and empty carcass weight, increased muscle weights and decreased fat pad weights. Fat content was reduced and protein content was increased in the empty carcasses of Mstn null mice. Similarly, treatment with clenbuterol resulted in increased body and empty carcass weight, increased muscle weights and reduced fat pad weights. Fat content of empty carcasses and viscera was reduced and protein content of empty carcasses was increased with clenbuterol treatment. A significant interaction of genotype and clenbuterol treatment would indicate an altered responsiveness of Mstn null mice to clenbuterol. However, only the weight of gastrocnemius muscles exhibited a significant (P = 0.01) interaction of genotype and clenbuterol treatment, indicating that Mstn null mice were less responsive to clenbuterol compared with wild-type mice. Thus, for all other traits, the impact of Mstn null mutation and clenbuterol treatment was completely additive. These data suggest that disruption of Mstn function does not alter the response of mice to β-adrenergic agonists.

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.

Zilpaterol hydrochloride (ZH) is designed to increase carcass leanness, chilled side weight (CSW), and percent saleable yield. The objective of this study was to evaluate the effect of a single dose of ZH on cutability and subprimal yield of calf-fed Holstein steers when fed for increasing durations. Two hundred forty steers were fed 8.3 mg/kg of ZH on a DM basis for 0, 20, 30, or 40 d, with a 3-d withdrawal before slaughter. After slaughter, steers were fabricated into 4 pieces (round, loin/flank, rib/plate, and chuck), packaged in combos, shipped to 2 locations, and further fabricated into subprimal pieces and trim. Trim was collected from each primal and separated into groups based on composition of 90, 80, and 50% lean. Zilpaterol hydrochloride increased (P = 0.01) CSW by 6.22 kg and saleable yield by 6.4 kg when included in the diet for 20 d. Furthermore, saleable yield as a percentage of CSW was increased (P = 0.03) 1.18 percentage units when included in the diet for 20 d. Steers fed ZH for 20 d had heavier strip loins (4.47 vs. 4.12 kg, P = 0.02), tenderloins (2.75 vs. 2.49 kg, P = 0.02), and ribeye rolls (5.74 vs. 5.30 kg, P = 0.01) than steers not fed ZH. These advantages are further demonstrated as a percentage of CSW. Strip loins (P = 0.06), tenderloins (P = 0.04), and ribeye rolls (P = 0.04) of ZH-fed steers had a greater percentage of CSW than controls. Zilpaterol hydrochloride also increased the percentage of CSW of the 3 primary components of the round when fed for 20 d. The knuckle was 0.10 percentage units heavier (P = 0.11), the top round was 0.24 percentage units heavier (P = 0.04), and the bottom round was 0.22 percentage units heavier (P = 0.03) in ZH-fed steers when compared with steers not fed ZH. Based on these data, it can be concluded that ZH significantly increased subprimal cutting weights, yields, and percentage saleable yield of calf-fed Holstein steers when fed for at least 20 d before slaughter. Zilpaterol hydrochloride increased percentage of CSW of subprimal cuts from Holstein steers in the round and to a lesser degree in the loin.

The objective of these studies was to evaluate the effects of zilpaterol hydrochloride (ZH), fed for 0, 20, or 30 d, on meat quality attributes of calf-fed Holstein steers. Steers were slaughtered at a commercial facility, and carcasses were selected by HCW to represent the pen mean. Further carcass selection was based on quality grade (Choice and Select) and yield grade. Proximate composition, measures of water holding capacity, and tenderness using Warner-Bratzler shear force after 7, 14, or 21 d postmortem were evaluated on the shoulder clod (triceps brachii), top butt (gluteus medius), and strip loin (longissimus lumborum). Percentage of purge for the 3 subprimals was not different (P > 0.05) among ZH treatments. Steers fed ZH for 20 d or 30 d had decreased (P < 0.05) percentages of fat in the triceps brachii, compared with 0-d ZH. Percentage of fat was less (P < 0.05) in the gluteus medius and longissimus lumborum when steers were fed ZH for 30 d compared with those steers fed ZH for 0 d. Percentage of fat was greater in Choice triceps brachii (P < 0.05) and longissimus lumborum (P < 0.10) compared with Select. Thaw loss was not different (P > 0.05) for any muscle due to ZH treatment. Only longissimus had a greater (P < 0.05) cooking loss with ZH treatment. Cooking loss was not different (P > 0.05) for the gluteus medius or longissimus lumborum due to quality grade or aging day. At each aging day, the 20- and 30-d ZH longissimus lumborum had greater (P < 0.05) shear force values than 0 d; however, 20- and 30-d ZH had a greater absolute change in shear force from 7 to 21 d than that of 0 d ZH. Triceps brachii steaks were less tender (P < 0.05) after ZH treatment, but gluteus medius steaks were not different (P > 0.05). There was no difference (P > 0.05) in shear force due to quality grade. Results illustrate the use of ZH in calf-fed Holstein steers will have minimal effects on purge, thaw, or cooking loss. Percentage of intramuscular fat will decrease, especially when fed for longer durations. Steaks from ZH treated steers were tougher than steaks from control animals at all aging times, but ZH steaks became more tender with postmortem aging.

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.

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.

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.

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.

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.

Sixty-four market-weight (130.0 +/- 0.65 kg) barrows (n = 16) and gilts (n = 48) were used in a split-plot design with a 2 x 2 x 2 factorial arrangement of treatments: 1) handling intensity (gentle vs. aggressive), 2) transport floor space (0.39 vs. 0.49 m(2)/pig), and 3) distance moved during handling (25 vs. 125 m) to determine the effects of multiple concurrent stressors on metabolic responses. For the handling intensity treatment, pigs were moved individually approximately 50 m through a handling course with either 0 (gentle) or 8 (aggressive) shocks from an electric goad. Pigs were loaded onto a trailer and transported for approximately 1 h at floor spaces of either 0.39 or 0.49 m(2)/pig. After transport, pigs were unloaded, and the distance moved treatment was applied; pigs were moved 25 or 125 m through a handling course using livestock paddles. Rectal temperature was measured, and blood samples (to measure blood acid-base status) were collected 2 h before the handling intensity treatment was applied and immediately after the distance moved treatment was applied. A LM sample to measure glycolytic potential was collected after the distance moved treatments on a subset of 32 pigs. There were handling intensity x distance moved interactions (P < 0.05) for several blood acid-base measurements. In general, there was no effect of distance moved on these traits when pigs were previously handled gently. However, when pigs were previously handled aggressively, pigs moved 125 compared with 25 m had greater (P < 0.05) blood lactate and less (P < 0.05) blood pH, bicarbonate, and base-excess. Pigs transported at 0.39 compared with 0.49 m(2)/pig had a greater (P < 0.01) increase in creatine kinase values; however, transport floor space did not affect any other measurements. Data were analyzed by the number of stressors (the aggressive handling, restricted transport floor space, and 125-m distance moved treatments) experienced by each pig (0, 1, 2, or 3). As the number of stressors experienced by the pig increased, rectal temperature, blood lactate, and LM lactate increased linearly (P

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.

Carcass characteristics, meat quality traits, and sensory attributes were evaluated in late-finishing barrows and gilts, weighing between 100 to 130 kg of BW, fed 0, 5, or 7.4 mg/kg of ractopamine hydrochloride (RAC) for the final 21 to 28 d before slaughter. Carcass data were collected from carcasses from barrows and gilts (n = 168), and all primal cuts from the right sides of these carcasses were fabricated to calculate primal yields as a percentage of the HCW. Subjective (National Pork Producers Council and Japanese) color, firmness, and marbling scores were determined on the LM of each loin and the semimembranosus muscle (SM) of the ham, whereas the moisture, extractable lipid, Warner-Bratzler shear force (WBSF), and trained sensory evaluations (juiciness, tenderness, and pork flavor) were measured on the LM samples only. Gilts produced heavier (P < 0.05) HCW than barrows, whereas feeding RAC increased (P < 0.05) HCW over pigs fed diets devoid of RAC. Carcasses from gilts also had greater (P < 0.02) primal cut and lean cut (P < 0.01) yields than barrows, and dietary inclusion of 5 mg/kg of RAC increased (P < 0.05) total boneless cut and lean cut yields when compared with carcass from pigs fed 0 or 7.4 mg/kg of RAC. Warner-Bratzler shear forces values were greater (P < 0.05) in the LM of gilts than barrows, but only juiciness scores were greater (P < 0.03) in LM chops from barrows than gilts. The LM from barrows had greater intramuscular lipid (P < 0.001) than the LM from gilts, and even though the LM from pigs fed 5 mg/kg of RAC had greater (P < 0.04) WBSF values than the LM from pigs fed 0 or 7.4 mg/kg of RAC, including RAC in the late-finishing diets for 21 or 28 d did not affect sensory panel rating or percentages of moisture and intramuscular lipid. In summary, addition of RAC in the late-finishing diet improved carcass and primal cut yields when it was fed at 5 and 7.4 mg/kg without altering pork quality traits regardless of whether RAC was fed for 21 or 28 d.

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.

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.

Fresh pork loins (n = 290) were selected from a commercial packing facility based on subjective marbling of the intact loin and 24-h pH to determine the influence of marbling on sensory attributes. The study was designed using pigs from a similar genetic background, raised in similar production facilities, and slaughtered on a single kill day to minimize the effects of genetics, management, environment, and slaughter day. Loins were vacuum-packaged, transported to the University of Illinois Meat Science Laboratory, and aged for 7 d, after which a chop was removed from the area of the tenth rib for proximate analysis. Quality measurements, including National Pork Producers Council color, marbling, and firmness, ultimate pH, Minolta L*, a*, and b*, and drip loss, were determined after aging. After the proximate composition was completed, 150 loins were selected to provide a continuous and uniform distribution of extractable lipid, ranging from 1 to 8%, and a pH range from 5.5 to 5.8. Trained sensory panel analyses (end point cooking temperatures of 62, 71, or 80 degrees C) as well as measurement of Warner-Bratzler shear force (cooked to 71 degrees C) were performed on chops from the 150 loins. Consumer evaluation was also conducted on a subset (n = 40) of these loins, which were broken down into 5 discrete levels of intramuscular lipid, with averages of 1.6, 2.5, 3.6, 4.5, and 5.7% extractable lipid. Consumers were also asked to select the chops they would most prefer from a retail display case based on the amount of marbling present. Results from the consumer portion of the study indicated that intramuscular fat content had limited effects on perceived tenderness, juiciness, pork flavor, and oiliness; some significant differences (P < 0.05) were detectable, but they were numerically small. Most consumers also selected lean chops from the retail case, with nearly 50% selecting chops with less than 1.7% extractable lipid. Warner-Bratzler shear force was negatively related (P < 0.0001) to extractable lipid, with an R(2) value of 0.10. Results from the trained panel sensory analysis indicate that the percentage of extractable lipid did not correlate strongly with perceived tenderness, juiciness, or pork flavor for this group of pork loins that was controlled for genetics, pH, management, and day of slaughter.

Four Midwestern packing plants (designated as plants A, B, C, and D) were visited on 53 occasions, and tissue samples were collected postmortem from a total of 2,019 pigs to determine the frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead (DOA), nonambulatory-noninjured (NANI), and normal animals. The sampled pigs came from approximately 130,000 animals from 454 farms and were transported on 861 trailer loads, with an average of 152 pigs/load and an average pig live BW/load of 125 (SD 7.02) kg/pig. Frequency of animals with the HAL-1843 mutation was low, with only 2.7% of the pigs being either homozygous recessives (nn, 0.45%) or carriers (Nn, 2.3%) for the mutation and 97.3% of the pigs being homozygous for the normal allele (NN). The mutation was present in all 3 classes of pig, with 1.8% of normal, 1.8% of NANI, and 4.7% of DOA animals having at least 1 copy. Two of the plants (A and C) had a greater frequency (P < 0.05) of carrier (3.7 and 3.5 vs. 1.1 and 1.0 for plants A and C vs. B and D, respectively) and homozygous recessive (1.0 and 0.9 vs. 0.0 and 0.0, respectively) animals than the others (plants B and D). There was a greater frequency (P < 0.05) of carriers in DOA animals than in the normal or NANI pigs (3.7 vs. 1.7 and 1.5 for DOA vs. normal and NANI, respectively). The 55 pigs that had at least 1 copy of the mutation came from 53 farms; therefore, the mutation was relatively widespread, being present in approximately 11% of the farms sampled. Although the HAL-1843 mutation is still present in commercial pig populations in the United States, its low frequency in DOA and NANI pigs suggests that it is not a major cause of these transport losses.

Beef complexus (chuck), serratus ventralis (chuck), vastus lateralis (round), vastus medialis (round), and longissimus dorsi (loin) muscles were enhanced (0.3% salt, 0.4% phosphate), vacuum packaged, and aged for 7 or 14 d. Enhancement increased positive sensory attributes (tenderness, juiciness, beef flavor, saltiness) and decreased negative attributes (off-flavors) of all muscles but had greater effects on some than on others. It increased the oily mouthfeel (10%) and saltiness (40%) and decreased the L* value and chroma of the complexus (chuck). It increased tenderness, juiciness, and beef flavor and decreased off-flavors, visual red and brown colors, shear value, and cook loss of the serratus ventralis (chuck), vastus lateralis (round), vastus medialis (round), and longissimus dorsi (loin). Aging slightly decreased rancid and liver off-flavor scores, visual brown color, and shear value and increased the hue angle and L* and b* values.

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.

The objective of this study was to evaluate the effects of enhancement and aging on quality characteristics of the gluteus medius (round), rectus femoris (round), teres major (chuck), infraspinatus (chuck), and psoas major (loin). Muscles were enhanced, vacuum packaged, and aged for 7 or 14 d. Aging affected enhanced compared with nonenhanced beef differently. After 7 d of aging, enhanced beef experienced more cook loss and was less red (higher hue angle, lower a* values, and chroma) than did nonenhanced beef; after 14 d of aging, these differences were lost. Enhancement increased tenderness and brown color of the gluteus medius (round); however, it decreased visual green and red colors. Enhanced gluteus medius experienced 3.1% lower purge losses, lower L* values, and chroma than their nonenhanced counterparts. Enhancement increased infraspinatus (chuck) tenderness and visual brown color, and decreased visual red and green colors, purge loss, L* value, a* value, and chroma. The enhanced infraspinatus was substantially more tender than the other muscles evaluated, other than the gluteus medius; however, it was also substantially more visually brown. Enhancement decreased purge loss of the psoas major. Enhancement increased L* and a* values, hue angles, and chroma than other enhanced muscles. After enhancement the tenderness of the rectus femoris increased by 10%, decreased purge losses from 4.5% to 1.7%, and decreased green color by 18%. It reduced L* and a* values and chroma. Aging increased tenderness. Overall, muscles from the chuck (infraspinatus and teres major) appeared to benefit the most from enhancement.

Previous research has demonstrated that increasing the CP concentration from 16 to 26% in milk replacers fed to male preruminant dairy calves at 1.5% of BW (DM basis) daily resulted in increased ADG, G:F, and deposition of lean tissue. However, the effects of dietary CP would be expected to vary depending on ME intake. Here, male Holstein calves < 1 wk old were used to determine the effects of feeding rate and CP concentration of isocaloric, whey protein-based milk replacers on growth and body composition. After a 2-wk standardization period, calves were assigned randomly to an initial baseline group or to treatments in a 2 x 4 factorial arrangement of feeding rate (1.25 or 1.75% of BW daily, DM basis) and milk replacer CP concentration (14, 18, 22, or 26% of DM). No starter was offered, but calves had free access to water. After a 5-wk feeding period, calves were slaughtered and body composition was determined. Increasing the feeding rate increased (P < 0.05) ADG, G:F, empty-body gains of chemical components and energy, the percentage of fat in empty BW gain and in the final empty body, and concentrations of IGF-I and insulin in plasma. Increasing the feeding rate decreased (P < 0.01) percentages of water and protein in the empty body and decreased urea N in plasma. Increasing dietary CP concentration linearly increased (P < 0.05) ADG, body length, heart girth, and gains of water and protein but linearly decreased (P < 0.05) fat gain. As dietary CP increased, fat content in empty body gain decreased, and water and protein increased. Increasing CP concentration increased (quadratic, P < 0.02) G:F, with greatest efficiencies for calves fed 22% CP. Gross energetic efficiency (retained energy:intake energy) was greater (P < 0.05) for calves fed at 1.75% of BW daily. Efficiency of dietary protein use for protein gain was greater for calves fed at 1.75% of BW daily but was not affected by dietary CP. The ratio of protein gain to apparently digestible protein intake above maintenance decreased as dietary CP increased. Interactions (P < 0.05) of feeding rate and CP concentration for gains of water and protein indicated that when dietary CP was 26% the ME supply limited protein use by calves fed at 1.25% of BW daily. Body composition of preruminant calves can be markedly altered by manipulating the protein to energy ratio in milk replacers. These dietary effects on body composition and growth are not predicted by current NRC standards.