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Effects of processing (prerigor vs. postrigor), packaging (vacuum vs. PVC overwrap) and various antioxidants [sodium tripolyphosphate (STP); butylated hydroxyanisole (BHA); butylated hydro xytolulene (BHT) plus citric acid (BBC); α-tocopherol (Toc); and ascorbyl palmitate plus α-tocopherol (APT)] on the oxidation of restructured pork chops after storage at 4°C were evaluated. Three barrows were slaughtered on separate days and were used as replicates in the experiment. One side of each carcass was boned within 1 h postmortem (prerigor) and the remaining side was boned after 24 h at 4°C (postrigor). Restructured chops were formulated to contain 25% fat and six 4.5-kg batches were randomly allotted to the six antioxidant treatments: (a) 0% NaCl (NSC); (b) 0.5% NaCl (SC); (c) 0.5% NaCl + 0.5% STP; (d) 0.5% NaCl + BBC; (e) 0.5% NaCl + Toc; and (f) 0.5% NaCl + APT. Batches were stuffed in a fibrous casing, frozen for 2 h and sliced (19 mm). The sliced chops were randomly allotted to vacuum and PVC overwrap packaging treatments and evaluated for discoloration and TBA value on days 0, 4, 8, 12 and 16. Vacuum packaging reduced discoloration scores and lowered TBA values (P0.01) on days 8, 12 and 16. TBA values for all antioxidant treatments differed from the SC treatment on days 12 and 16 (P0.05). These data indicate that antioxidants and/or vacuum packaging are effective methods of controlling discoloration and oxidation of restructured pork during storage; however, processing time postmortem did not affect (P0.05) the rate of lipid oxidation. more...

Ninety carcasses were used to evaluate the effects of feeding ractopamine (RAC) to gilts, physically castrated (PC) barrows, and immunologically castrated (IC) barrows. Finishing diets (0, 5, and 7.5 mg/kg RAC) were fed for the last 26 d before slaughter starting 7 d after the second dose of Improvest. Carcasses from IC barrows had less ( P P = 0.02) than PC carcasses but had more ( P ≤ 0.04) fat than gilt carcasses. Feeding RAC increased ( P = 0.03) bone-in carcass yields by 1.4 percentage units. Gilt and IC carcasses had 2.0 percentage units greater ( P P = 0.01) bone-in lean yields, and 1.5 percentage units greater ( P = 0.04) bone-in carcass yields than PC carcasses. Loin firmness, pH, and marbling were unaffected by sex and RAC feeding ( P ≥ 0.22). Bellies from IC carcasses were 0.3 cm thinner ( P ≤ 0.05) than PC but 0.3 cm thicker ( P ≤ 0.05) than gilts. Flop distances of IC bellies were similar to gilt bellies but reduced ( P ≤ 0.05) 13 cm compared with PC bellies. Iodine values of IC bellies were similar to PC bellies but reduced ( P ≤ 0.05) 3 units compared with gilts. Feeding RAC did not affect ( P ≥ 0.23) fresh belly characteristics. Overall, immunological castration and feeding RAC were additive in terms of improving carcass cutability but had only minimal effects on fresh pork loin or belly quality. more...

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 (P0.01) and softer (P0.01) than PC bellies. IC hams and bellies were leaner (P0.05) than those from PC pigs. RAC feeding did not affect (P0.05) fresh ham or belly characteristics but decreased (P0.01) fat in cured PC bellies. Marketing group affected (P0.05) 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. more...

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. more...

The objective of this experiment was to test the hypothesis that the reduced carcass fat qual- ity 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 fi nishing 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 addi- tional 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, car- cass characteristics, and LM quality were determined, and backfat and belly fat samples were collected for fatty acid analysis. There was no gender × diet inter- action for any of the response variables measured. For the entire fi nisher 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) fi nal BW at the end of both phases, greater (P < 0.001) HCW and backfat thickness, and tended (P = 0.10) to have greater dressing percent- age, 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 fl op distance compared with pigs fed the 5 DDGS-containing diets, but no differenc- es were observed among pigs fed the diets containing DDGS. Barrows had heavier (P < 0.001) bellies and greater (P < 0.001) belly fl op 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 con- taining DDGS can be improved by inclusion of corn germ, beef tallow, palm kernel oil, or glycerol in fi nish- ing diets could not be confi rmed. more...

Our objective was to determine sensory, processing and shelf-life characteristics of ground pork mixed with commercial salt varieties of different purities. Commercially available salt preparations ranging from 0.223 to 3.714 mg/kg combined copper, iron and manganese were included at 1 g/100 g in ground pork patties. Patties were stored frozen for 0, 3, 6 or 9 weeks, and then evaluated for lipid oxidation, break strength, and sensory characteristics. Furthermore, the ability of different commercial salts to extract meat proteins was evaluated. Inclusion of any salt in ground pork patties increased lipid oxidation at 3, 6 and 9 weeks of storage, increased break strength and increased salty flavor. Furthermore, all salts were more effective at extracting salt-soluble proteins than buffer containing no salt. Few meaningful differences, however, were detected between different commercial salts. All salts tested resulted in equal amounts of lipid oxidation with storage, salty flavor, and protein extraction. With regards to break strength, patties with highest purity salt required marginally more force to break than patties with less pure salts. These data suggest that differing purity levels of salt included at 1 g/100 g in pork patties have little effect on sensory, shelf-life or processing characteristics of ground pork. more...

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. more...

The objective of this study was to determine the effect of feeding ractopamine hydrochloride (RAC) in an equal weight marketing scenario. Barrows and gilts (n = 427) were assigned to 3 different RAC feeding programs before slaughter: control (0 mg/kg), 5 mg/kg for up to 35 d, or 5 mg/kg for 21 d followed by a step-up to 7.4 mg/kg for up to 14 d. Treatments including RAC were pooled and compared against control pigs using single df estimate statements. Coefficient of variation in beginning BW of RAC (7.16%) and control pigs (6.95%) did not (P = 0.68) differ; however, RAC-fed pigs had a lower (P < 0.01) market BW CV (3.91%) than controls (5.27%). Pigs fed RAC reached market weight 2.5 d earlier (P = 0.01) than control pigs (26.8 vs. 29.3 d). Ractopamine-fed pigs had a 21% greater (P < 0.01) ADG than control pigs, even though ADFI did not (P = 0.19) differ between RAC and control pigs. Pigs fed RAC produced 3% heavier HCW (P < 0.01), 3% greater loin depths (P = 0.05), and a 1 percentage unit greater dressing percent (P < 0.01) than control pigs. Sort loss per kilogram was less (P < 0.01) for RAC-fed than control-fed pigs, with 8 control pigs having HCW less than the sort loss threshold compared with only 2 RAC pigs. Ractopamine can be an important tool in reducing the variation in market weight and sort loss of finishing pigs. more...

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 more...

The objective of this experiment was to determine if increasing lysine in the diets of immu- nologically castrated (IC) male pigs would increase per- centage fat free lean and carcass cutting yields when compared with physical castrates. The anti-gonado- tropin-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 eco- nomic benefits to the domestic meat industry. Approxi- mately 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. Proxi- mate 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 respec- tive 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 medi- um/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 im- proved carcass cutability, increased percentage fat free lean, and had no effect on pork quality when compared with physical castrates. more...

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 (P0.05) than all treatment groups, except IC males fed low/medium lysine (3.73 cm). Entire males (2.85 cm) had the thinnest (P0.05) bellies of all treatment groups. There were no differences (P0.05) 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 (P0.05) among physical castrates or IC males regardless of lysine inclusion. Cooked yield of cured bellies from entire males (95.12%) was less (P0.05) 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 (P0.05) 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 (P0.05) 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. more...

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. more...

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 0.05) 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 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. more...

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 (P0.01) 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 (P0.05) between dietary glycerin and preslaughter handling treatment. Dietary glycerin had no effect (P0.05) on growth performance, carcass measures, or meat quality. There were no differences (P0.05) 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. more...

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. more...

The objective of this study was to determine whether culled beef cows fed a high-concentrate diet (FED) would have improved live performance, carcass traits and muscle characteristics compared with forage fed (CON) cows. In addition, ractopamine (RAC) supplementation was evaluated for added benefits over high concentrate alone. Live weight, average daily gain, hot carcass weight, ribeye area, marbling, quality grade and carcass fat measurements increased (P ≤ 0.05) by realimentation. As a percent of hot carcass weight, muscle yields did not differ (P > 0.05). Lipid content increased (P ≤ 0.05) in 5 out of the 10 muscles from FED cows. Cows fed ractopamine showed some numeric improvements over feeding alone, but few statistical differences (P > 0.05). This may result from variability associated with cull cows, and warrants investigation into the best dose/duration for ractopamine. However, realimentation by itself was able to improve cull cow quality. PRACTICAL APPLICATION The U.S. beef industry continues to explore new avenues to enhance undervalued sectors of the production system. Through realimentation, cull cow quality can be improved. The data presented herein demonstrate that feeding a high-concentrate diet to cull cows increases both live and carcass weights. In addition, high concentrate-fed cull cows display more marbling and whiter fat cover than those fed at maintenance level. Qualification for premium programs, heavier weights and overall higher quality may lead to increased value for this underutilized sector of the beef industry. more...

From an experiment in which 60 beef cull cows were assigned to one of three feeding treatments, forage fed, high concentrate or high concentrate plus ractopamine, 10 muscles were removed from both sides of the carcass. Muscles from one side of the carcass were enhanced with a solution to target 0.3% salt and 0.3% phosphate in the final product. Minimal to no differences were observed in color, pH, sensory characteristics or shear force as a result of dietary treatment. Enhancement resulted in muscles with higher (P ≤ 0.05) pH and darker color. Sensory scores for juiciness and tenderness were improved (P ≤ 0.05) with enhancement. The Adductor was the only muscle not exhibiting lower shear values due to enhancement (P > 0.05). To add further value to meat from cull cows, enhancement could be utilized, independent of feeding regimen prior to slaughter. PRACTICAL APPLICATIONS The use of enhancement in the beef industry has become common practice, particularly in beef from lower grading cattle. However, research examining the improvement in palatability with enhancement has focused mainly on younger cattle. Our research demonstrates that enhancement is able to improve the sensory characteristics of meat from cull cows. Thus, in meat from older animals, which is usually characterized as being less palatable, enhancement could be used to improve the organoleptic traits. This practice may assist the beef industry in capturing further value from cull cows. more...

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 2 h, 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. more...

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 more...

Beef complexus (chuck), serratus ventralis (chuck), vastus lateralis (round), vatsus 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 ventrali (chuck), vastus lateralis (round), vastus medialis (round), and longissiumus 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. more...

Ractopamine HCl (RAC) is a phenethanolamine β-adrenergic agonist used as a feed supplement that repartitions nutrients from fat deposition to increased protein synthesis and muscle protein accretion without deleteriously affecting pork quality. This literature review, as well as meta-analyses of the available results, was undertaken to evaluate the live performance, carcass, and pork quality responses to the various dietary inclusion levels (0, 5, 10, and 20 mg/kg) of RAC. Consensus of literature and meta-analysis indicated that pigs fed RAC, regardless of dietary inclusion level, gained faster (P more...

The objective of this study was to develop a model system to evaluate the effects of freezing, exposure to enhancement solution and modified atmosphere on discoloration of pork rib bones. Bones were removed from carcasses, split along the transverse plane, then frozen (−20C) or held at 4C for 24 h. Half of each temperature pretreatment group was exposed to a 4% phosphate/4% NaCl enhancement solution, while half served as controls. Samples were packaged in modified atmosphere packaging (80% O2/20% CO2) or air and displayed in a retail case (4C, 24 h). Visual discoloration occurred during the first 10 h of display; additional visual darkening (brown, green/black) occurred in previously frozen samples, while refrigerated samples remained redder. After 24 h, Commission Internationale de l'Eclairage L*, a* and b* values indicated that previously frozen samples were darker and less red. The frozen samples contained more methemoglobin per gram of protein than those that had never been frozen. more...

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. more...

One hundred eighty barrows were evaluated to determine the effects of ractopamine hydrochloride (RAC) on lean carcass yields and pork quality. The pens were blocked by weight (six pens per block) with starting block weights of 69.0, 70.7, 73.8, 76.6, 78.4, and 84.3 kg. Pens within a block were assigned randomly to one of three RAC treatments so each treatment in a block was replicated twice. Treatments (as-fed basis) included control diet, 10 ppm of RAC added (R10), and 20 ppm of RAC added (R20) and ranged from 25 to 41 d depending on block. Pigs were slaughtered by blocks when block average live weights were 109 kg. Gain and feed efficiency were improved (P 0.05). Dressing percentage was higher (P 0.05) among treatments. Carcass weights were heavier (P 0.05) among dietary treatments. Trained sensory evaluation panel results for tenderness decreased in a low-dose plateau response fashion for nonenhanced chops (P = 0.004). Tenderness of enhanced chops decreased linearly (P = 0.04) with increasing RAC concentrations. No differences (P > 0.05) were found in juiciness or flavor of enhanced or nonenhanced chops. Feeding RAC to late-finishing swine resulted in faster growing, more efficient animals with increased boneless subprimal yields, and it had little effect on pork juiciness and flavor. more...

This study was carried out to evaluate the effect of feed withdrawal and handling intensity on blood acid-base responses and muscle glycolytic potential in slaughter-weight pigs. Sixty crossbred pigs (BW = 107.7 +/- 0.56 kg; 44 barrows and 16 gilts) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments: 1) feed withdrawal (0 vs. 24 h), and 2) handling intensity (low vs. high). The high-intensity handling treatment consisted of moving the pigs through a passage (12.2 m long x 0.91 m wide) for eight laps using an electric goad two times per lap. Pigs in the low-intensity handling treatment were moved at their own pace through the passage for eight laps using a livestock panel and paddle. Biopsy samples were collected from the LM at the beginning of feed withdrawal, at the end of the handling procedure, and 4 h after handling. Blood samples were collected 2 h before and immediately after the handling procedure. There were no interactions between feed withdrawal and handling intensity for any of the variables measured. Feed withdrawal decreased (P < 0.05) baseline and posthandling body temperature (38.85 vs. 38.65 degrees C; SEM = 0.060 and 39.70 vs. 39.37 degrees C; SEM = 0.04, respectively) and blood glucose, lowered (P < 0.05) baseline partial pressure of oxygen and partial pressure of carbon dioxide, and increased (P < 0.01) baseline and posthandling plasma free fatty acid concentrations. High-intensity handling produced higher (P < 0.01) posthandling lactate and glucose, and lower (P < 0.01) posthandling blood pH (7.33 vs. 7.18 +/- 0.02, respectively), bicarbonate, base excess, and total carbon dioxide than low-intensity handling. Longissimus muscle glycolytic potential of fasted pigs was lower (P < 0.01) than in fed pigs at the end of the handling procedure (177.2 vs. 137.0 micromol/g of wet tissue; SEM = 10.08, respectively). There was no effect of handling intensity on longissimus muscle glycolytic potential. Feed withdrawal did not attenuate the blood acid-base changes caused by handling; however, the combination of feed withdrawal and handling decreased muscle glycolytic potential. more...

The objective of this study was to characterize the sensory properties of four common meat products (ground beef, fresh pork sausage, smoked sausage, and frankfurters) all manufactured with nonsolvent extracted textured soy protein (NSTSP) used as a lean meat replacement. High levels (45%) NSTSP added to ground beef and fresh pork sausage resulted in products which were more mushy with much more off-flavor than control samples, whereas juiciness was unaffected. Addition of 30% or 45% NSTSP increased ( P 0.05) neither texture and mouth feel nor off-flavor of smoked sausage. Up to 30% NSTSP had no effect on either texture or mouth feel nor on off-flavor of frankfurters. Addition of NSTSP increased off-flavor of all products except frankfurters. Practical levels of lean replacement appear to be less than 30% for these meat products. more...

Forty-eight barrows and forty-eight gilts (PIC 337 sires x PIC C22 dams) were evaluated to determine the effects of feeding ractopamine hydrochloride (RAC) and different cereal grains on the carcass and fat quality in late finishing pigs. The study was carried out using four replicates with 24 animals in each replicate (four pigs per pen, six pens per replicate, two replicates per slaughter date, 12 pens per slaughter date). Treatments for the experiment included corn, wheat, and barley (early finisher period); and corn, corn + RAC, wheat, wheat + RAC, barley, and barley + RAC for the late finisher period. Ractopamine was fed at the level of 10 mg/kg (as-fed basis) of feed. Pigs were allotted to early finisher period treatments at approximately 45 kg BW. Pigs were then given late finisher period treatments at approximately 80 kg BW and fed for 28 d. The dietary digestible lysine level for all diets was maintained at 2.7 g/Mcal of ME. Pigs fed the wheat and corn diets during the late finisher period had a greater (P more...

Yearling (12 Angus, 12 Wagyu≥Angus) and 2-year old heifers (12 Angus, 12 Wagyu≥Angus) were fed elevated levels of Vitamin D3and/or Vitamin E to evaluate beef quality. Warner-Bratzler shear force (WBS) and sensory characteristics were determined on steaks from the Longissimus lumborum (LL) aged 21 days and on steaks from the Gluteus medius (GM) and Psoas major (PM) aged 7 days. Steaks were cut from all muscles, displayed for 5 days then L*value and hue angle were determined. Vitamin E supplemented heifers received the highest sensory tenderness and juiciness scores, while no differences were observed among other treatments. D3+E supplemented Angus LL had higher WBS values than other treatments and breeds. Display time affected both color measures for all muscles, but especially hue angles of GM and PM. Vitamin treatment affected LL and GM color measures in yearlings to a greater extent than in 2-year olds. more...

A study was conducted to characterize the relationship between Longissimus thoracis ultimate pH (LTpH) and pork quality. Animals (n =47) were selected based on LTpH measured at 24 h postmortem. Data were analyzed using regression procedures with ultimate pH as the independent variable, and relationships were determined to be linear (L), quadratic (Ql or cubic (C). Ultimate pH explained 79% (C) of the variation in subjective color, which increased as pH increased. Drip loss, purge loss and L* value decreased as LTpH increased (R2 = 0.57C, 0.77 Q and 0.68 Q, respectively). Shear force decreased and sensory juiciness increased as LTpH increased (R' = 0.26 Q and 0.46C, respectively). However, offlavor intensity increased as LTpHfell below pH 5.2 or exceeded 6.1(R2= 0.52C). Increasing LTpH, up to a point, will improve fiesh pork quality and processed meat properties, whereas, above approximately 6.1, of-jlavor may increase. more...

The objective of this study was to evaluate shelf-life, color and sensory characteristics of pork chops from loin sections (n = 12/treatment) injected (110% original weight) with a potassium lactate/potassium acetate solution (2%) + phosphate (0.35%)/salt (0.35%), compared with those injected with sodium lactate (3 %) + phosphate/salt, or phosphate/salt alone, to control loins. After 96 h of display, aerobic plate counts (CFU/cm 2 ) were significantly lower (P more...

Chemical, physical, and sensory characteristics of low-fat beef patties containing carbohydrate-lipid composites (CLCs) were compared with those of all-beef patties. The CLC gels contained high-amylose cornstarch, maltodextrins, and canola oil. CLC patties had higher moisture, cooking yield, and fat retention than 20%-fat control patties. CLCs improved tenderness and juiciness and decreased cohesiveness of low-fat beef patties compared with 10%-fat control patties. Despite differences in CLC gel firmness, patties made with CLC gels containing corn, potato, and tapioca maltodextrins had similar physical and sensory properties. These results suggest that CLC gels perform well as a partial fat replacer in beef patties while providing flexibility in gel firmness selection. more...

The objective of this study was to evaluate the effects of dietary vitamin E supplementation on characteristics of enhanced beef cuts during retail display. Twelve steers were fed either a control (E-) diet or a diet supplemented with dl-alpha tocopheryl acetate (E+) for 117 days prior to slaughter. Paired strip loins, clods, and inside rounds served as the control (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% phosphate on a finished weight basis. Steaks were cut (2.5 cm) for sensory evaluation and retail display. No flavor or texture differences existed in strip steaks due to vitamin E. Enhanced steaks were more tender, juicy and salty than controls, however they discolored more rapidly than did controls. Steaks from supplemented cattle were slightly, but significantly, less discolored, indicating that vitamin E may provide some improvements in color stability of enhanced meat products. Vitamin E supplementation may improve short term color stability (up to 2 days in display) of retail beef enhanced by injection of a salt-phosphate solution. more...

The objective of this study was to evaluate the effects of supplementing vitamin E into the diets of finishing cattle on quality characteristics of beef pumped with a phosphate/salt solution (enhanced) the cooked and held in a simulated foodservice situation. Twelve steers were fed either a control (E−) diet or a diet supplemented with dl -α-tocopheryl-acetate (E+). Paired clod roasts were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% phosphate in the finished product. Following injection, clods were allowed to equilibrate then frozen. A flavor profile panel evaluated texture attributes and aroma characteristics of roasts immediately after cooking and after 1 and 2 h of hot-holding. Pumping improved taste and textural attributes of the hot-held clod roasts. Dietary vitamin E supplementation reduced thiobarbituric acid reactive substances (TBARS) from ∼0.61 to ∼0.42, but over the 2-h time period, did not significantly improve aroma quality of beef roasts. more...

Intact sides were subjected to accelerated chill (AC: -3OC for 2.5 h, 4C for 20-22 h) or conventional chill (CC: 4C for 22-24 h). Color, drip loss, and pH were evaluated 24 h postmonem at three sites (inner, mid, and outer) in the Semimembranosus (SM) and Biceps femoris (BF) with the inner site closest to the femur. Zle Longissimus thoracis (LT) and the Longissimus lumborum (LL) were also evaluated. Accelerated chill improved color and drip loss of the Longissimus muscle. Accelerated chill had no fleet on the quality measurements of the ham, although site differences occurred. The fleets of genotype on color, drip loss, andpH in the loin and ham muscles were not consistent in the muscle groups studied. Compared to CC, AC has beneficial fleets on fresh pork quality of the Longissimus muscle, but not the ham muscles. more...

Beef round roasts were injected (to 110% of original weight) to result in 0.4% sodium chloride and 0.4% phosphate on a finished weight basis. Steaks from enhanced roasts were more (P

ABTRACT Boneless, paired pork loins (n=120) were selected based on pH at 14 h postmortem. Ultimate pH, drip loss, instrumental color (L*, a*, and b* values), and proximate analysis were determined prior to pumping. Paired loins were cut into four sections and pumped to 100%, 106%, 112% or 118% of original weight to result in a product containing 0.4% sodium tripolyphosphate (STP) for Experiment 1 (Exp. 1) and 0.4% STP plus 0.4% salt for Experiment 2 (Exp. 2). In Exp. I, additional pump level increased (P more...

Halothane negative Durocs (n=36) were slaughtered, and subjected to: accelerated chill (AC: -30C for 2 h, with air circulation, followed by equilibration at 4C for 20-22 h), conventional chill (CC: 4C for 22-24 h with water sprayed every 2 h until 12 h postmortem), and slow chill (SC: 10-12C for 12 h followed by equilibration at 4C for 10-12 h). Color, pH, and drip loss were determined for the Semimernbranosus (SM) Biceps femoris (BF), Longissirnus thoracis (LlJ, and Longissirnus lumborum (LL). In the ham muscles, AC decreased b * values and drip loss. Decreased drip loss was restricted to the outer sites. Ham muscles were darkest in the mid location and lightest in the inner locations. In the Longissirnus, AC decreased pH but did not afect color or drip loss. Compared to SC, ACproved beneficial, however, AC had no advantages over CC in pigs with minimal predisposition to quality problems. more...

The objective of this study was to compare the effects of longissimus glycolytic potential (GP) and of time of feeding of supplemental magnesium sulfate heptahydrate on carcass and pork quality traits. The study was carried out in a 2 x 2 x 4 factorial arrangement; the treatments were sex (castrate vs gilt), GP (Low [normal] vs High), and time of feeding of magnesium sulfate-fortified diets (0 [control] vs 2 vs 3 vs 5 d prior to slaughter). Glycolytic potential was determined on a biopsy sample of longissimus from the live animal prior to the start of the study. A total of 144 pigs were allotted to the feeding-time treatments on the basis of sex (castrate and gilt), weight, and GP. Pigs were placed in individual pens and had free access to water. Prior to the start of the study, pigs were given ad libitum access to a standard finisher diet. During the study, animals were fed at a fixed level of 2.75 kg of a standard finisher diet/day; the fortified diet contained 3.2 g/d of additional magnesium. At the end of the feeding period, animals were transported to a commercial packing facility and slaughtered within 15 min of arrival. Fresh meat quality was measured on the longissimus. There were no treatment interactions. Carcass traits were similar across time of feeding treatments. Backfat thickness at the last lumbar vertebra and 10th rib were lower (P < 0 .05) for High than for Low GP pigs. High GP pigs had lower ultimate pH (P < 0.001) and higher drip (P < 0.05) and purge loss (P < 0.01) than Low GP pigs. Drip loss was reduced (P < 0.05) for pigs fed the magnesium-fortified diet for 5 and 2 but not for 3 d compared to controls (8.98, 7.29, 7.89, and 7.41 for the 0-, 2-, 3-, and 5-d treatments, respectively, SEM 0.447). Purge loss was similar for all of the time of feeding treatments. Longissimus L* values were lower (P < 0.05) for the 2-d treatment than for the controls. Results from this study suggest an inconsistent effect of short-term feeding of magnesium sulfate on muscle color and drip loss in pigs with both Low (normal) and High GP. more...

The objective of this research was to examine the impact of supplementation with creatine monohydrate (CMH) on the quality of various muscles from normal and heterozygous halothane carrier pigs. Twenty-nine crossbred pigs, 16 normal (NN) and 13 halothane carrier (Nn) genotypes, were supplemented with 0 or 25 g x pig(-1) x d(-1) of CMH for 5 d before slaughter. Supplemented pigs gained 2.26 kg more weight (P 0.05) drip loss or muscle composition. Supplementation with CMH also resulted in lower L* values in two ham muscles, semitendinosus (5.15 units) (P < 0.05) and semimembranosus (1.95 units) (P < 0.10) for Nn carcasses. Genotype had significant effects on most quality indicators, with Nn carcasses producing lower-quality lean as evidenced by less desirable subjective and objective color and higher drip losses. Genotype also affected the composition of several muscles, with the NN carcasses having more fat and less moisture. more...

The objective of this study was to evaluate the effects of pumping, cooking method and endpoint temperature on quality of fresh pork chops. The longissimus was removed from 30 paired pork sides. One side was pumped to 110% of original weight (0.4% phosphate, 0.4% salt+added water). Chops were cut (2.5 cm thick) then fried or grilled to 70 or 80 °C. As endpoint temperature increased from 70 to 80 °C, pork flavor increased (P more...

Pork loins were pumped to 110% of original weight with solutions containing 0.35% salt and 0.35% phosphate (P), salt and phosphate plus 3% sodium lactate (SL), or salt and phosphate plus 2.5% potassium lactate/potassium acetate (PL/PA). Chops were evaluated freshly cooked and precooked, stored (4C, 2 days) and reheated. Chops from SL and PL/PA chops experienced lower cook losses than unpumped controls. Reheating produced additional cook losses which were unaffected by enhancement treatment. Enhancement produced reheated chops with lower shear values and higher tenderness scores than those of freshly cooked controls, and addition of either SL or PL/PA produced even more dramatic results. Warmed-over flavor after reheating precooked chops was reduced by the SL enhancement solution. more...

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 (P0.01) 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 (P0.01) fat and shallower (P = 0.02) loins when compared to PC carcasses. There were differences (P0.05) 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 (P0.05) between RAC-fed and control-fed carcasses when evaluating LM color, marbling, firmness, pH, drip loss, and tenderness. Carcasses from IC pigs had greater (P0.05) boneless lean yields, bone-in lean yields, and total carcass cutting yields than PC carcasses. There were minimal differences (P0.05) 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 (P0.01) lipid than all other treatment combinations. Market group had effects (P0.05) 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. more...

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. more...

High pressure water (110 kPa) was compared to the Whizard knife (WK) with respect to quantity and composition of tissue recovered from thoracic, lumbar, and cervical vertebrae of swine and beef carcasses. High pressure water (HPW) recovered tissue contained less collagen than that recovered using the WK. A higher percentage of tissue was recovered from beef bones by WK than by HPW, but HPW tissue was higher in noncollagen protein. Recovery differed due to vertebral location; thoracic and lumbar vertebrae yielded a higher percentage of tissue than did cervical vertebrae. Centrifugation at 4000 x g was required to reduce the moisture content of HPW-recovered tissue to that of WK-recovered tissue, Fat content of HPW-recovered beef tissue was lower than that of WK-recovered tissue, however the reverse was true for tissue recovered from pork vertebrae. Recovery method had no effect on total protein or ash content. more...

Animals (n = 72) with longissimus glycolytic potential (GP) values ranging from 113.8 to 301.1 μmol/g of tissue, were classified as having low (n = 24), moderate (n = 24), and high (n = 24) GP levels. Meat quality measurements such as longissimus ultimate pH and subjective color score decreased, while Hunter L* values, percentage drip loss and purge loss increased for animals classified as having either high or moderate GP levels compared to those with low GP values. Animals with higher GP had decreased longissimus protein content and improved taste panel tenderness scores and lower shear force indicating superior eating quality. Increasing aging time from 2 to 21 days decreased shear force and improved taste panel tenderness scores. These data indicate that both glycolytic potential level within the muscle and aging time can have significant effects on pork quality characteristics. more...

Phosphate-salt pump effects were evaluated on sensory characteristics of pale, soft, exudative (PSE) pork, normal and dark, firm and dry (DFD) pork. Water-holding capacity, instrumental color (L*, a*, b*), pH, and muscle color scores were determined at 24 h postmortem on pork loin pairs (n=21 pairs). Based on color score, paired loins were assigned to PSE, normal or dark, firm, dry groups. PSE muscles were lighter, redder and more yellow than normal or DFD muscles; hue angle indicated that DFD muscles were actually closer to the true red axis of the CIE Lab Color Space. Drip and purge losses were higher (p more...

Effects of fat content (8 or 24%), processing temperature (–2, 1, 4C), plate size (2, 5, 5 mm), mixing time (3, 5, 8 min), and patty formation pressure (50, 100, or 150 kg) on characteristics of low-fat ground beef patties were evaluated. Reduced fat patties required less force to break when ground at –2C (2 mm plate) than when ground at 4C. Rubberiness increased as plate size increased. Rubbery scores were lowest at 4C/2 mm plate. Reduced-fat patties had lower cook losses. Increasing grinding temperature from –2 to 4C decreased break force, Kramer shear and cohesive texture. Break force was highest for patties mixed 8 min at –2C. Patty forming pressure affected breaking strength, cohesiveness, and cook loss. Production of reduced-fat ground beef patties by grinding through a 2mm plate at 4C, mixing for 2 min and forming patties at 150 kg pressure minimized rubbery texture and instrumental measures of patty hardness. more...

Whole, boneless pork loins were pumped to result in a final concentration of 0% to 2% sodium lactate (SL) and/or 0% to 0.4% sodium tripolyphosphate (STP) resulting in a 3 × 3 factorial design. Three replications were randomly presented to 10 trained sensory panelists for evaluation. Physical properties of the loins were also evaluated. Sensory evaluation results suggested that there was a trend for juiciness and tenderness to be enhanced by the addition of STP. Pork flavor, salt intensity, and alkalinity were enhanced by SL. Pump yields increased while purge loss was reduced with the addition of STP. Color was not affected by SL or STP. No difference in peak force and energy required to shear samples was observed. Results from this study suggest that pork loins pumped with SL and STP had enhanced moisture retention with few detrimental effects on sensory characteristics. more...

The objective of the study was to investigate the influence of amino acid-deficient diets and high dietary leucine levels offered for intervals of either 21 or 35 days pre-slaughter on the intramuscular fat content of pig muscle. Twenty-four hybrid gilts were offered individually ad libitum one of four diets that comprised combinations of amino acid levels (supplemented or deficient: 5·6 v. 4·0 g lysine per kg) and low or high leucine levels (10·3 v. 30·3 g leucine per kg). Live weights at the start of the study were 74·5 and 87·0 kg for pigs on the 35- and 21-day feeding regimens, respectively. There were no significant effects of dietary amino acid level, leucine level, or feeding interval on food intake, daily live-weight gain or food efficiency. Pigs given the amino acid-deficient diets had lower killing-out proportions (736 v. 747 (s.e. 3·4) g/kg; P < 0·05) and longissimus dorsi muscle areas (32·6 v. 35·7 (s.e. 0·71) cm2, P < 0·01) than those given amino acid-supplemented diets. Subjective score for longissimus dorsi colour indicated that pigs on the high leucine diet had darker muscle than those on the low leucine diet. Intramuscular fat contents of the longissimus dors i muscle at the Wth/llth rib and the 3rd/4th lumbar vertebra and of the semimembranosu s muscle were increased by 19, 18 and 18 g/kg, respectively (P < 0·05), for pigs given amino acid-deficient compared with those given amino acid-supplemented diets. Dietary leucine level had no significant effect on intramuscular fat level. Pigs given the diets for 35, compared with 21, days had higher fat levels in the semimembranosu s muscle (52 v. 30 (s.e. 5·2) g/kg; P < 0·01) but not in the other two muscle locations studied. This study suggests that relatively short-term feeding of amino acid-deficient diets can produce substantial increases in intramuscular fat levels. more...

A surimi-like material was made from finely minced beef or pork by water washing followed by screening to remove connective tissue. Changes in component proteins, amino acid composition and vitamin, mineral and cholesterol content occurring during preparation were investigated. Total amino acid nitrogen contents of water-washed beef and pork were higher than those of the respective muscle by 7% and 6.5%. Among 16 amino acids measured, histidine and glycine decreased in both water-washed beef and pork, while others increased compared to original muscle. Thiamin content decreased after washing. Surimi-like beef and pork had less cytoplasmic minerals (K, Na, Mg) but more minerals associated with proteins or subcellular organelles (Ca, Cu, Zn, Fe). Fat content decreased, although cholesterol concentration was not changed by washing. more...