Effect of a novel steak fabrication method by trimming subcutaneous and intermuscular fats on palatability and calorie content of beef ribeye steaks

This study investigated the effects of a novel steak fabrication method, involving removal of both subcutaneous and intermuscular fats between the longissimus thoracis (LT) and spinalis dorsi (SD) muscles before cooking, on beef ribeye steak palatability and calorie content. Canada AA (n = 10) and AAA (n = 10) ribeyes were fabricated into steaks either with (fat-on) or without (fat-off) subcutaneous and intermuscular fats. Fat-on steaks had shorter cooking times and lower cooking losses than fat-off steaks (P < 0.001), regardless of quality grade. There were treatment × quality grade interactions for initial (P < 0.01) and sustainable juiciness (P < 0.05) of the LT samples and initial juiciness (P < 0.05) of the SD samples, with the fat-on AA samples being more juicy than the fat-off AA samples, but the AAA treatments were not different from each other. Regardless of quality grade, fewer panelist responses indicated livery flavour (P < 0.05) for fat-on compared to fat-off LT samples. Regardless of fat-on/fat-off treatment, AA compared to AAA samples had more responses for bloody/serumy (P < 0.01) and unidentified off-flavours (P < 0.05) in LT samples. However, AAA samples had more responses for metallic off-flavour in LT (P = 0.059) and SD (P < 0.05). There were no differences in calorie content between fat-on compared to fat-off steaks (P > 0.1) regardless of quality grade and muscle type, or between AA and AAA steaks regardless of cooking with fat-on or off (P > 0.1). Maintaining the subcutaneous and intermuscular fats while cooking will improve ribeye steak palatability without increasing calorie content, especially for leaner steaks.

Muscle of dark and normal beef differs metabolically

Reduction in muscle glycogen triggered by adverse antemortem handling events alters postmortem energy metabolism and results in a high ultimate pH and dark, firm and dry beef, often referred to as 'dark-cutting'. However, the relationship between atypical dark (AT) beef, postmortem energy metabolism and underlying tissue characteristics remains somewhat unclear. Cattle harvested in the US and Canada representing normal (pH < 5.6), AT dark (pH 5.6-5.8) and dark cutting (DC; pH > 5.8) beef were analyzed for tissue characteristics related to energy metabolism. Results show AT dark beef is more oxidative but similar to normal beef in glycolytic potential and nucleotide abundance. Mitochondria DNA content (P < 0.05, Canada; P < 0.005, US) and oxidative enzymes for DC and AT dark beef were greater (P < 0.01; Canada and US) compared to normal beef. Myoglobin tracked (P < 0.01) with color classification. These findings show both DC and AT beef are inherently more oxidative and raise the possibility that more oxidative muscle may be more prone to develop dark beef.

Impact of a constant current electrical stimulation (CCES) system and hormonal growth-promoting (HGP) implants on meat quality and palatability of finished steers

This study evaluated the effects of a constant current electrical stimulation (CCES) system and hormonal growth-promoting (HGP) implants on the quality and palatability of the longissimus thoracis et lumborum (LTL) from yearling-finished steers. The experiment used a total of 46 Angus cross steers, which were either non-implanted (n = 20) or implanted with trenbolone acetate and estradiol benzoate (n = 26). The CCES was applied to one side of each carcass during the slaughter process, whereas the other side remained unstimulated. Regardless of the application of HGP implants, the CCES reduced pH at 3 and 72 h post-mortem and shear force at all ageing times (P < 0.05), improved colour at 72 h post-mortem and during the retail display (P < 0.05), increased initial and overall tenderness (P < 0.01), and decreased the amount of perceived connective tissue and the proportion of trained panelists detecting spongy texture (P < 0.05) compared to meat from unstimulated carcass sides. Although CCES increased meat purge losses and reduced moisture content (P < 0.05), this did not affect meat juiciness (P > 0.10). CCES interacted with HGP to prevent increase in drip loss (P > 0.10), increase frequency of panelists detecting bloody/serumy flavour and typical texture, and reduce the proportion of panelists detecting rubbery texture in meat (P < 0.05). Regardless of stimulation treatment, meat from implanted animals had a more pronounced pH decline at 72 h post-mortem (P < 0.05) and a higher proportion of panelists finding no off-flavours (P < 0.05) or bloody/serumy flavour (P < 0.01) than non-implanted cattle. The CCES system tested in this study improved LTL quality and palatability of heavier beef carcasses.

Effects of in-the-bag dry-ageing on meat quality, palatability and volatile compounds of low-value beef cuts

This study evaluated the effects of in-the-bag dry-ageing (BDA) (21 and 42 d) on meat quality, palatability, and volatile compounds of clod heart, brisket, and flat iron cuts from steers. In all cuts, BDA increased moisture losses (P < 0.05), but this did not reduce the juiciness of 21 d BDA versus wet-aged (WA) steaks. In clod heart, BDA increased overall tenderness at 21 d compared to 21 d WA (P < 0.01). Regardless of ageing period, BDA of clod heart increased beef flavour and salty taste and decreased sour-dairy and stale/cardboard flavours and concentrations of volatile compounds derived from lipid oxidation compared to WA (P < 0.05). In brisket, BDA increased salty taste and fatty aroma and reduced bloody/serumy flavour, whereas decreased beef and buttery flavours and intensified some unpleasant aromas/flavours (P < 0.05) for both ageing periods. The BDA of flat iron increased several undesirable aromas/flavours and decreased sweet taste and beef and buttery flavours (P < 0.05), regardless of ageing period. Overall, BDA for 42 d decreased meat quality and palatability and increased concentrations of volatile compounds from lipid oxidation, especially in flat iron cuts. Value could be recovered by customizing BDA periods by cut.

Influence of Maternal Corn Supplementation of Beef Cattle on Muscle Fiber Type and Meat Quality of their Offspring

ObjectivesTo determine the influence of corn supplementation of beef cows during winter and their impact on offspring beef quality attributes.Materials and MethodsForty-seven multiparous Angus beef cows carrying male calves were assigned randomly to two dietary treatments: corn supplementation at 0.2% BW (SUP; n = 24) vs. non-supplementation (NSUP; n = 23) at d 110 d of gestation for 22 wks. Ad-libitum access to low-quality forage was provided to both groups. At 7 d post-calving, a muscle biopsy was collected from the longissimus dorsi muscle (LD) of each calf for muscle fiber typing. Offspring were managed as a single group from nursing through to the backgrounding phase. Thereafter, the steers were placed in the feedlot and assigned to 4 pens (blocks) based on BW and offered ad-libitum access to a 100% corn silage-based ration (76.97% TDN, 11.07% CP), salt and minerals. When the steers reached a final BW of 615 kg (∼16 mo of age), they were slaughtered in a commercial abattoir. A second LD muscle biopsy sample was obtained at 45 min postmortem (PM) for muscle fiber typing. At 96 h PM, striploins (n = 42) were collected, aged for 14 d and samples obtained for Warner Bratzler shear force (WBSF), proximal composition, myofibril fragmentation index (MFI), collagen analysis and objective color evaluation. Data were analyzed as a randomized block design.ResultsImmunofluorescent analysis for the myosin heavy chain (MHC) isoform on the proportion of the fiber type or fiber dimensions was not influenced by maternal dietary treatment at both ages (P > 0.05). However, regardless of maternal dietary treatment, the proportion of fiber type IIA decreased while type IIAX increased in samples from steers at 16 mo of age compared with samples from steers at 7 d of age. No differences were observed between dietary treatment groups in proximate composition (P = 0.8), MFI (P = 0.29), or collagen content (P 0.98); however, WBSF values tended to be higher in steers from SUP cows than steers from NSUP dams (P = 0.07). Maternal dietary treatment had no influence on objective color evaluation at the retail display (P > 0.05). Objectives traits were not affected by dietary treatment × display time interaction (P = 0.92).ConclusionOur findings indicate that corn supplementation of cows during mid to late gestation has minimal effects on muscle fiber type and beef quality of their offspring. Thus, corn supplementation of low-quality forage offered during mid to late gestation did not have detrimental effects on muscle fibers and meat quality of offspring.

Potential of near infrared (NIR) spectroscopy and dual energy X-ray absorptiometry (DXA) in predicting pork belly softness

Pork bellies (n = 198) were scanned with dual energy X-ray absorptiometry (DXA). Visible and near-infrared reflectance (Vis-NIR) spectra were collected from the lean (latissimus dorsi), subcutaneous fat and intermuscular fat layers. Belly-flop angle and subjective belly scores were collected as measures of pork belly softness. Vis-NIR spectra from a single fat layer could explain between 72.7 and 81.1% of the variation in pork belly softness (43.6-72.4% in validation set). The combination of the lean and subcutaneous layers improved the calibration model fit to 79.7-99.9% (66.3-71.5% in validation set). The DXA estimates explained 62.3% of variation in pork belly softness (65.2% in validation set). Results indicated that DXA and NIR technologies could potentially be utilized for pork belly softness sorting in the pork industry.

Phenotypic and genetic relationships of residual feed intake measures and their component traits with fatty acid composition in subcutaneous adipose of beef cattle

Feed efficiency is of particular interest to the beef industry because feed is the largest variable cost in production and fatty acid composition is emerging as an important trait, both economically and socially, due to the potential implications of dietary fatty acids on human health. Quantifying correlations between feed efficiency and fatty acid composition will contribute to construction of optimal multiple-trait selection indexes to maximize beef production profitability. In the present study, we estimated phenotypic and genetic correlations of feed efficiency measures including residual feed intake (RFI), RFI adjusted for final ultrasound backfat thickness (RFIf); their component traits ADG, DMI, and metabolic BW; and final ultrasound backfat thickness measured at the end of feedlot test with 25 major fatty acids in the subcutaneous adipose tissues of 1,366 finishing steers and heifers using bivariate animal models. The phenotypic correlations of RFI and RFIf with the 25 individual and grouped fatty acid traits were generally low (<0.25 in magnitude). However, relatively stronger genetic correlation coefficients of RFI and RFIf with PUFA traits including the -6:-3 ratio (0.52 ± 0.29 and 0.45 ± 0.31, respectively), 18:2-6 (0.45 ± 0.18 and 0.40 ± 0.19, respectively), -6 (0.43 ± 0.18 and 0.38 ± 0.19, respectively), PUFA (0.42 ± 0.18 and 0.36 ± 0.20, respectively), and 9-16:1 (-0.43 ± 0.20 and -0.33 ± 0.22, respectively) were observed. Hence, selection for low-RFI or more efficient beef cattle will improve fatty acid profiles by lowering the content of -6 PUFA, thus reducing the ratio of -6 to -3 along with increasing the amount of 9-16:1. Moderate to moderately high genetic correlations were also observed for DMI with 9-14:1 (-0.32 ± 0.17) and the sum of CLA analyzed (SumCLA; -0.45 ± 0.21), suggesting that selection of beef cattle with lower DMI will lead to an increase amount of 9-14:1 and SumCLA in the subcutaneous adipose tissue. However, unfavorable genetic correlations were detected for ADG with 11-18:1 (-0.38 ± 0.23) and SumCLA (-0.73 ± 0.26), implying that selection of beef cattle with a better growth rate will decrease the contents of healthy fatty acids 11-18:1 and SumCLA. Therefore, it is recommended that a multiple-trait selection index be used when genetic improvements of fatty acid composition, feed efficiency, feed intake, and growth are important in the breeding objective.

Phenotypic and genetic correlations of fatty acid composition in subcutaneous adipose tissue with carcass merit and meat tenderness traits in Canadian beef cattle

Bivariate animal models were used to estimate phenotypic and genetic correlations between 9 carcass merit and meat tenderness traits with 25 individual and grouped fatty acids in the subcutaneous adipose tissue of a population of 1,366 Canadian beef cattle finishing heifers and steers. In general, phenotypic correlations were low (<0.25 in magnitude) except for moderate phenotypic correlations of 9-17:1 (-0.29 ± 0.16), 18:0 (0.26 ± 0.14), 11-18:1 (-0.33 ± 0.15), 11-18:1 (0.35 ± 0.14) with Warner-Bratzler shear force measured 3 d postmortem and between 14:0 (-0.36 ± 0.1), 9-14:1 (-0.34 ± 0.08), 9-16:1 (-0.36 ± 0.08), 9-18:1 (0.26 ± 0.07), and sum of branched-chain fatty acids (BCFA; -0.27 ± 0.06) and back fat thickness (BFAT). Genetic correlations were also low for most of the traits. However, moderate to moderately high genetic correlations (0.25 to 0.50 in magnitude) were detected for some traits, including 17:0 (0.4 ± 0.11), 18:0 (0.44 ± 0.12), 9-14:1 (-0.47 ± 0.11), 9-16:1 (-0.43 ± 0.11), and the -6:-3 PUFA ratio (-0.5 ± 0.15) with HCW; 9-14:1 (-0.41 ± 0.13) and 9-16:1 (-0.42 ± 0.13) with BFAT; 17:0 (0.43 ± 0.19) and BCFA (0.45 ± 0.19) with lean meat yield; 13-18:1 (0.40 ± 0.15) with carcass marbling score; sum of CLA (0.45 ± 0.22), 18:2-6 (0.47 ± 0.17), and sum of PUFA (0.48 ± 0.17) with overall tenderness measured 3 d postmortem; the -6:-3 PUFA ratio (0.41 ± 0.22) and sum of CLA (0.42 ± 0.25) with overall tenderness measured 29 d postmortem; and BCFA (0.41 ± 0.27) with Warner-Bratzler shear force measured 29 d postmortem. The genetic correlations observed in this study suggest that contents of some fatty acids in beef tissue and carcass merit and meat tenderness traits are likely influenced by a subset of the same genes in beef cattle. Due to some antagonistic genetic correlations, multiple-trait economic indexes are recommended when fatty acid composition, carcass merit, and meat tenderness traits are included in the breeding objective.

Nitrite Embedded Vacuum Packaging Improves Retail Color and Oxidative Stability of Bison Steaks and Patties

Bison meat is prone to rapid discoloration under traditional aerobic retail packaging conditions. The aim of this study was to determine if the color stability of bison steaks and burger patties could be improved through packaging meat with a vacuum-sealed film containing embedded sodium nitrite. Bison bulls (n = 40) were slaughtered and the longissimus lumborum (LL) and rhomboideus (RH) were removed. Following a postmortem aging period of 6, 13, or 20 d steaks were obtained from the LL. RH muscles aged 6 d were ground (85:15 lean to fat) and formed into 140 g patties. One steak and two burger patties from each carcass side were placed into either a polystyrene tray overwrapped with oxygen permeable polyvinyl chloride film (CONT) or a polyethylene tray vacuum sealed with film coated in sodium nitrite (113 mg × m–2; NIT); meat was placed under simulated retail conditions for 4 d. A 3-way interaction was observed between packaging type, whole muscle aging and time in retail display for objective (L*, Chroma, and Hue) and subjective (lean color score and proportion of surface discoloration) color measures from steaks (P < 0.0001). The CONT packaged meat showed an increased area of discoloration and in metmyoglobin after 4 d in retail display (P < 0.0001); NIT meats did not show a higher area of discoloration or metmyoglobin after retail display. Additionally, NIT packaged steaks and burger patties lightened (higher L*) and became redder over the course of the retail display period. Thiobarbituric acid reactive substances (products of lipid peroxidation) did not increase in NIT packaged burger patties after 4 d under retail conditions, however, there was a significant increase observed for CONT packaged burger patties (P < 0.0001). NIT packaging appears to effectively improve the color stability of bison meat under retail conditions, making this packaging strategy well suited to address the issue of rapid discoloration.

Palatability of Beef from Cattle Fed Extruded Flaxseed before Hay or Mixed with Hay

This study was undertaken to evaluate the eating quality of longissimus thoracis steaks and hamburgers (80/20 gluteus medius to perirenal fat) with enhanced profiles of potentially healthy fatty acids. The profile of health favorable fatty acids (n-3, vaccenic and rumenic) was improved in beef by feeding co-extruded flaxseed (flaxseed, peas, and alfalfa) and alfalfa-grass hay as a total mixed ration (TMR), and further enhanced by feeding co-extruded flaxseed before alfalfa-grass hay (Non-TMR). Compared to TMR, feeding steers the Non-TMR resulted in tougher steaks (P < 0.05) with lower beef flavor (P < 0.01) and greater off-flavor (P < 0.01) intensity to an extent that might be detectable by consumers. High levels of trans-monounsaturated fatty acids, mainly of vaccenic acid, were associated with a fishy off-flavor, although actual changes in flavor may relate to correlated combined effects of conjugated fatty acids, atypical dienoic acids and ɑ-linolenic acid. Diet had no significant effect on sensory attributes of hamburgers, but when panelists described off-flavors, they noted more ‘other’ off-flavors (P < 0.05) with fishy and stale/cardboard notes being more prominant in Non-TMR hamburgers. Overall, beef samples with threshold levels of vaccenic acid over 6.12% of total fatty acids resulting from feeding flaxseed products, while of potentially greater health benefit, may pose challenges in terms of eating quality. Areas worthy of further investigation to ensure acceptable eating quality might be the influence of ageing on antioxidant capacity in beef with enhanced fatty acid profiles, and the potential use of protective packaging to limit deterioration.

Sequential Feeding of Lipid Supplement Enriches Beef Adipose Tissues with 18:3n-3 Biohydrogenation Intermediates

The present study was designed to determine if feeding steers extruded flaxseed and hay (25 and 75%; DM basis) together as a total mixed ration (TMR), or sequentially (non-TMR) would result in different enrichments of polyunsaturated fatty acids (PUFA) and their biohydrogenation intermediates (BHI) in beef adipose tissues [subcutaneous (SC) vs perirenal (PR) fat]. Forty-eight Angus cross steers (325 ± 16 kg) were stratified by weight to six pens, and pens were randomized to either TMR or non-TMR and fed ad libitum for an average of 242 days. The concentrations of α-linolenic acid increased by 18 mol% in both SC and PR in non-TMR steers compared to TMR steers (P < 0.01). trans 18:1 isomers were more concentrated in PR than SC (14.4 vs 9.5 mol%; P < 0.01) and increased by 10 mol% in both fat depots for non-TMR (P < 0.01). Other BHI including non-methylene-interrupted 18:2 (atypical dienes), conjugated linoleic acids and conjugated linolenic acids (CLnA) were affected by diet × tissue interactions (P < 0.01). The CLnA and CLA contents were higher in both fat depots when feeding the non-TMR, but the effect of diet was more pronounced in PR than in SC (P < 0.01). Atypical dienes were highest in PR from non-TMR and lowest in TMR fed steers (4.3 and 3.6 mol%) with SC contents being intermediate. The sequential feeding of lipid supplement can thus profoundly affect the enrichment of PUFA and their BHI in beef fat and their differentially enrichment is also fat depot dependant.

Compositional and dimensional factors influencing pork belly firmness

We explored various dimensional and compositional factors that can influence the perception of pork belly firmness. Bellies from 198 pigs of three different genotypes, two sexes, two slaughter weights and three different diets were recovered and belly firmness was assessed using the belly-flop angle and a 5-point scale subjective measurement. Dimensional and compositional factors were recorded on intact and sheet-ribbed bellies. Subjective belly score was negatively correlated with belly-flop angle (r=-0.89). Regression analysis accounted for 77 and 83% of the variability in subjective belly firmness and belly-flop angle measurement, respectively. Belly length, weight and width influenced both measures of belly firmness, but these effects were more important for the belly-flop angle. After correcting flop angle using belly length, the effect of belly weight disappeared and the effect of other traits was more like those observed for subjective scoring. Hence, undue effect of belly length should be corrected for if this set-up is to be implemented in commercial plants.

Control Points To Reduce Movement of Central Nervous System Tissue during Beef Slaughter

Consumption of central nervous system tissue (CNST) from cattle with bovine spongiform encephalopathy (BSE) is thought to cause the human neurological disease, variant Creutzfeldt-Jacob disease. To identify points of cross-contamination of beef carcasses with CNST, 55 young beef cattle were slaughtered and processed through a federally inspected multispecies abattoir. The objectives of this study were to evaluate CNST spread following the placement of a plug in the penetration site of the skull after captive bolt stunning, to evaluate cross-contamination of carcasses before and after splitting, to compare the effects of hot water pasteurization (84°C for 10 s) versus cold water wash (10°C for 30 s) for reducing CNST on the carcass, and to examine other possible sources of cross-contamination in the abattoir. Results indicated that the use of a plastic plug reduced CNST contamination near the bolt penetration site. This study also confirmed that carcass splitting resulted in an increase in CNST contamination at various areas of the carcass. Hot water pasteurization appeared to be an effective means of removing CNST contamination from carcasses in most of the areas sampled.

Review: Pork belly quality, bacon properties and recent consumer trends

Soladoye, P. O., Shand, P. J., Aalhus, J. L., Gariépy, C. and Juárez, M. 2015. Review: Pork belly quality, bacon properties and recent consumer trends. Can. J. Anim. Sci. 95: 325–340. Several factors can affect pork belly quality and, subsequently, bacon quality. Going by the recent trends in the bacon market and bearing in mind the more choosy nature of the consuming populace, it is imperative to consider the factors that can affect or improve bacon quality, thereby sustaining the current market surge. In as much as both genetic and environmental factors have been identified as largely affecting muscle food quality, nutritional interventions also seem to be a very viable tool to improve the quality of meat and its products. Processing and storage methods can also affect bacon quality, including microbial quality, physicochemical attributes and palatability. Both objective and subjective measures have been explored in assessing belly quality, most of which use belly softness and fatty acid profile as yardsticks, whereas bacon quality has been widely assessed only subjectively in terms of fat quality and slice integrity. Although consumers’ and producers’ quality perceptions seem to be in conflict, it is the responsibility of all stakeholders in the bacon industries to come together in ensuring a balanced approach to satisfy both parties along the production chain.

Effects of production system and growth promotants on the physiological maturity scores in steers

López-Campos, Ó., Aalhus, J. L., Larsen, I. L., Juárez, M. and Basarab, J. A. 2014. Effects of production system and growth promotants on the physiological maturity scores in steers. Can. J. Anim. Sci. 94: 607–617. Over a 2-yr period, 224 crossbred steers were allotted to a 2×2×2 factorial arrangement of treatments to determine the effect of the production system (calf-fed vs. yearling-fed), growth implant strategy (non-implanted vs. implanted) and β-agonist supplementation (no ractopamine vs. ractopamine) on physiological indicators of maturity. Dentition and ossification scores along the vertebral column were collected post-mortem during head inspection and grading. Dentition score was significantly affected (P<0.001) by production system, but not by implant (P=0.68) or β-agonist (P=0.31). There were significant interactions (P<0.001) between production system and implant strategy on the frequencies of carcasses showing ossification in the thoracic, lumbar and sacral vertebral processes. There was a significant interaction (P<0.0001) between the production system and implant strategy on the frequencies of the carcasses considered as <21 or >21 mo of age based on a segregation model using only physiological maturity assessments. These data emphasize the inability of physiological scores to accurately reflect chronological age, with overall classification accuracies of 0.68 and 0.53 for dentition and ossification scores. The highest overall classification accuracies were obtained using the thoracic (0.74) or lumbar (0.69) ossification scores. Implants accelerate the ossification process, particularly in younger animals, thus having a dramatic effect on numbers of animals eligible to be categorized as <21 mo of age based on physiological maturity evaluation.

The relation of carcass physiological maturity to meat quality in the Canadian Bison Grading System

López-Campos, Ó., Aalhus, J. L., Galbraith, J., Larsen, I. L., Juárez, M., Uttaro, B. and Robertson, W. M. 2014. The relation of carcass physiological maturity to meat quality in the Canadian Bison Grading System. Can. J. Anim. Sci. 94: 55–62. A total of 119 bull (n=62) and heifer (n=57) bison carcasses were selected to determine the effectiveness of youthful to intermediate physiological maturity [ossification at the 9th/10th/11th thoracic spinous processes (≤50%; 51–65%; 66–80%)] range to accurately classify bison carcasses with respect to quality. Carcasses were classified into three maturity groups according to ossification at the 9th/10th/11th thoracic spinous processes (≤50%; 51–65%; 66–80%). Carcass, meat quality and sensory evaluation data were then collected. Bull carcasses were significantly (P<0.0001) heavier than heifers (308.0 vs. 228.6 kg), while heifers had higher (P<0.0001) marbling scores than bulls (368 vs. 289). For both genders, ossification group had little or no impact (P>0.05) on any of the meat quality traits. Gender had an impact on the shear force values for both fresh (P<0.0001) and frozen/thawed (P=0.0002) samples, with bulls having higher values than heifers. Panellists detected differences between heifers and bulls in initial tenderness (P<0.0001; 7.11 vs. 6.27), flavour intensity (P=0.005; 5.40 vs. 5.14), amount of connective tissue (P=0.0002; 7.64 vs. 7.18), and overall tenderness (P=0.003; 7.13 vs. 6.50). Only initial juiciness was significantly affected (P=0.02) by the ossification group (5.38, 5.64 and 5.76). A gender×ossification group interaction was also detected for flavour intensity (P=0.004) and off-flavour intensity (P=0.03), but the magnitudes of the differences were in the order of one-half panel unit or less, generally below the detection of most consumers. The range of physiological maturity studied had limited effects on meat quality and support the elimination of an intermediate physiological maturity grade (51–80% ossification) from the Canadian Bison Grading System.

Effect of multiple vacuum packs on colour development and stability in beef steaks

Avilés, C., Juárez, M., Larsen, I. L., Rodas-González, A. and Aalhus, J. L. 2014. Effect of multiple vacuum packs on colour development and stability in beef steaks. Can. J. Anim. Sci. 94: 63–69. The aim of this study was to compare the colour stability of steaks from longissimus dorsi muscle previously submitted to four treatments of vacuum packaging and aged for 15 d. Muscle portions were either vacuum packed and aged for 15 d (NRP), or repacked after 2 h (RP2h), 8 d (RP8d) and after 2 h and 8 d (RP2h+8d). Purge loss values from RP8d and RP2h+8d treatments were higher (P=0.019) than those from NRP and drip loss was higher (P=0.001) for RP2h and RP8d. Colour changes during a 30-min period of exposure to atmospheric oxygen immediately after opening the packages were similar for repackaged-aged steaks and NRP steaks (P>0.05). Nevertheless, colour stability during subsequent retail display under atmospheric air conditions was affected by the packaging treatment. The decrease in chroma values (P=0.043) and the increase in hue (P=0.011) between day 3 and day 6 was minimum for RP2h+8d, compared with NRP, RP2h and RP8d. Also, the proportion of pigment in the myoglobin form in these three treatments dramatically increased from day 3 to day 6, while no effect was observed for RP2h+8d (P=0.005). Similarly, the decrease over time in the proportion of pigment in the oxymyoglobin form in meat from the RP2h+8d treatment was much lower (P=0.002) than for the other three packaging treatments. Changes in colour stability associated with multiple vacuum packagings may confound results in experimental designs. Thus, if beef colour is to be evaluated, repeated vacuum packaging should be limited.

Effect of dietary inclusion of triticale dried distillers' grain and oilseeds on quality and fatty acid profile of meat from feedlot steers

This study compared carcass, meat quality and fatty acid profiles of longissimus thoracis (LT) from feedlot cattle fed barley grain with or without oilseed (OS). Six diets containing no oilseed (No-OS), 10% ground flaxseed (FS), 10% high oleate sunflower seeds (SS) with or without 30% triticale dried distiller's grain (DDGS) were prepared. Feeding DDGS increased chroma at 24 and 144 h post mortem. Feeding FS increased weight% of LT PUFA (P<0.05) compared to No-OS or SS. An OS by DDGS interaction occurred for 18:3n-3 (P<0.05) where FS increased weight% of 18:3n-3 (P<0.05), a response accentuated (P<0.05) by DDGS. Feeding DDGS increased weight% of LT 18:2n-6 (P<0.05), but neither OS nor DDGS affected conjugated linoleic acid (CLA, t7,c9 &c9,t11-18:2). Feeding FS increased weight% of n-3 FA, and both FS and SS increased t10-18:1 with no effect on CLA or t11-18:1. Combination feeding of DDGS and FS further increased weight% of n-3 FA and tempered increases in t10-18:1 with no effect on CLA or t11-18:1. The findings suggest a new strategy to increase beef omega-3 fatty acids efficiently through inclusion of a combination of DDGS and FS in feedlot diet.

Characterization of Canadian grade standards and lean yield prediction for cows

Rodas-González, A., Juárez, M., Robertson, W. M., Larsen, I. L. and Aalhus, J. L. 2013. Characterization of Canadian grade standards and lean yield prediction for cows. Can. J. Anim. Sci. 93: 99–107. Commercial carcasses (n=120) were selected to benchmark the current Canadian grading system for cows (D1, D2, D3, D4;>50% ossification) in comparison to A/AA grades youthful carcasses [over (OTM) and under (UTM) 30 mo of age based on dentition but <50% ossification]. With the exception of the D3 and D4 grades, D1 and D2 carcass grades had similar carcass yield attributes compared with OTM and UTM carcasses; however, rib-eye area from UTM carcasses was the largest (P<0.05), followed by D1, D2 and OTM. As expected, both OTM and UTM grades had lower ossification scores (P<0.05); however, D4 grade showed the highest marbling score (P<0.05). For carcass composition, compared with all other grades, the D3 grade had the highest proportion of lean (P<0.05) due to a lower proportion of dissectible fat (P<0.05); however, it had the lightest carcass weight (P<0.05). Using simple measures of carcass characteristics (grade fat, rib-eye area, marbling and ossification) a prediction equation to estimate lean yield (R 2=0.825; Cp=4.31) could be used to more accurately assess carcass value in cows; however, validation of the equation on a separate population would be required before its application.

Short Communication: Erythrocytes assayed early ante mortem can predict adipose tissue and muscle trans-18:1 isomeric profiles of steers fed red clover silage supplemented with flaxseed

Mapiye, C., Dugan, M. E. R., Turner, T. D., Rolland, D. C., Basarab, J. A., Baron, V. S., McAllister, T. A., Block, H. C., Uttaro, B. and Aalhus, J. L. 2013. Short Communication: Erythrocytes assayed early ante mortem can predict adipose tissue and muscle trans-18:1 isomeric profiles of steers fed red clover silage supplemented with flaxseed. Can. J. Anim. Sci. 93: 149–153. Steers were fed a red clover silage-based diet with or without flaxseed to evaluate over time the effects of flaxseed supplementation on erythrocytes (ERC) trans(t)18:1 isomers composition and their relationships to adipose tissue and muscle t18:1 profiles at slaughter. Concentrations of most ERC t18:1 isomers in steers fed flaxseed increased (P<0.01) markedly in the first 2 mo and increased gradually thereafter. Strong (P<0.01) correlations of t9-, t10- and t11-18:1 isomers were observed from month 2 to 6 between ERC and beef tissues collected at slaughter from steers fed flaxseed. Findings suggest that ERC sampled as early as 2 mo into the feeding period can be indicative of variation in beef t18:1 isomeric profile at a later slaughter date when feeding red clover silage with flaxseed.

Reduced age at slaughter in youthful beef cattle: Effects on carcass merit traits

López-Campos, Ó., Basarab, J. A., Baron, V. S., Aalhus, J. L. and Juárez, M. 2012. Reduced age at slaughter in youthful beef cattle: Effects on carcass merit traits. Can. J. Anim. Sci. 92: 449–463. Two-hundred and twenty-four spring-born British×Continental crossbred steers were used in a 2-yr project to evaluate the effect of production system (calf-fed vs. yearling-fed) and its interaction with breed cross and hormone implant strategies, with and without β-adrenergic agonist on carcass characteristics. Carcasses from yearling-fed steers were 32% heavier (P<0.001), resulting in higher (P<0.05) dressing percentages, grade fat and rib-eye (longissimus thoracis) area (REA) (1.1, 32 and 10%, respectively). However, despite being lighter, the estimated lean yield percentage was 3% greater (P=0.010) in carcasses from calf-fed steers. No difference (P>0.05) was observed for marbling scores between production systems. Use of hormonal implants increased (P<0.001) weights of live animals and carcasses (7 and 9%, respectively). However, non-implanted yearling-fed steers had the lowest proportion of Canada Quality Grade A and the highest proportion of Canada Quality Grade AAA carcasses (P<0.001). Moreover, the observed increase (P=0.016) in marbling scores (up to 37%) from British cross-bred steers disappeared with the use of implants. The only effect observed on carcass traits from the use of β-adrenergic agonists was an increase of 6% in REA (P=0.032). The main production system effect observed for carcass composition was a lower (P=0.008) proportion of bone in carcasses from yearling-fed steers. The use of hormonal implants increased (P<0.001) the proportion of lean and decreased (P=0.019) the proportion of fat (P<0.05). Overall carcass composition of steers with large Continental influence (>50%) had a higher proportion of lean and bone and a lower proportion of fat than carcasses from 50–75% British steers (P<0.001), which was also reflected in the composition of several individual primal cuts (e.g., rib, short-loin, flank, chuck and plate). The interactions amongst production systems and the other production factors studied were minimal. Therefore, despite expected differences in carcass size, reducing age at slaughter did not have a negative impact on Canadian beef carcass traits.

Modification of beef quality through steer age at slaughter, breed cross and growth promotants

Girard, I., Aalhus, J. L., Basarab, J. A., Larsen, I. L. and Bruce, H. L. 2012. Modification of beef quality through steer age at slaughter, breed cross and growth promotants. Can. J. Anim. Sci. 92: 175–188. A 23 factorial experiment tested the interactions of slaughter age (12–13 or 18–20 mo), growth implants use (Component E-S, TE-S), ractopamine hydrochloride (RAC) feed supplementation use and breed cross [Hereford–Aberdeen Angus (HAA) or Charolais–Red Angus (CRA)] on pH, temperature, objective colour measurements, relative myoglobin states, sarcomere lengths, shear force, and water losses of m. semitendinosus (ST) and m. gluteus medius (GM) from 112 crossbred steers. In the ST, age affected objective colour measurements by increasing chroma and decreasing lightness (L*) and hue angle (P<0.05). Metmyoglobin (MMB) content of the ST also increased with steer age (P<0.05). In the GM, yearling-fed steers had greater MMB content than calf-fed steers, while hue angle varied the opposite way (P<0.05). Other variations in meat colour and myoglobin contents were more complex in the GM than the ST as they involved three-way interactions between the different treatments. Shear force and purge loss of the ST increased with implantation (P<0.05) with no change in sarcomere length (P>0.05). Shear force standard deviation was similar for breed crosses when yearling-fed but greatest for CRA breed cross when calf-fed (P<0.05). In both muscles, purge loss was increased by RAC supplementation (P<0.05). RAC supplementation did not affect sarcomere length and shear force in both muscles (P>0.10). In the GM, shear force increased with age and with CRA genetics (P<0.05). Results indicated that producers seeking to reduce beef toughness should consider using British crossbreds, exclude the use of hormonal implants and slaughter process steers at 12 to13 mo of age.

Modification of muscle inherent properties through age at slaughter, growth promotants and breed crosses

Girard, I., Aalhus, J. L., Basarab, J. A., Larsen, I. L. and Bruce, H. L. 2011. Modification of muscle inherent properties through age at slaughter, growth promotants and breed crosses. Can. J. Anim. Sci. 91: 635–648. A 24 factorial experiment tested the interactions of slaughter age (12–13 or 18–20 mo), growth hormone use, β-adrenergic agonist (β-AA) use and breed cross [Hereford–Aberdeen Angus (HAA) or Charolais–Red Angus (CRA)] on the composition, fibre types, and connective tissue characteristics of m. semitendinosus (ST) and m. gluteus medius (GM) from 112 crossbred steers. Muscle weights increased with slaughter age, implantation and CRA genetics (P<0.05), but were not affected by ractopamine hydrochloride (RAC) (P>0.10).Animal age increased fast glycolytic (FG) and decreased fast oxidative glycolytic (FOG) fibre percentages by 7.2 and 6.6%, respectively, in the ST and increased slow oxidative (SO) and FOG fibre areas in both muscles (P<0.05). Cross-sectional areas of all fibre types were increased in the ST with implantation. In the GM, implantation increased SO (3.1%) and reduced FOG (3.2%) fibre percentages, while RAC reduced the SO (3.8%) and increased the FG (6.1%) fibre percentages (P<0.05).Only GM total collagen content increased with slaughter age (P<0.05),but collagen solubility decreased with slaughter age for both muscles (P<0.05). CRA genetics increased FG percentage in the GM of yearling-fed steers and increased moisture and protein and reduced fat contents of both muscles (P<0.05). In the muscles studied, IMP, slaughter age and animal genetics induced greater changes in muscle inherent properties than RAC.

Effect of flaxseed and forage type on carcass and meat quality of finishing cull cows

Hernández-Calva, L. M., He, M., Juárez, M., Aalhus, J. L., Dugan, M. E. R. and McAllister, T. A. 2011. Effect of flaxseed and forage type on carcass and meat quality of finishing cull cows. Can. J. Anim. Sci. 91: 613–622. Sixty-two cull cows were fed one of four diets in a 2×2 factorial arrangement, consisting of barley silage or grass hay with or without flaxseed to influence fatty acid composition. After slaughter, carcass grade, meat quality and sensory data were collected. Silage increased live (P=0.002) and carcass (P=0.001) weights of the cows as compared with hay. Muscle width (P=0.013) and score (P=0.010) and rib-eye area (P=0.002) were enhanced when silage was included in the diet, whereas supplementation with flaxseed increased (P=0.003) grade fat depth by 29%. Most subjective and objective retail evaluation traits in steaks from the left longissimus thoracis and ground meat were negatively affected (P<0.05) by the length of the retail display time. Moreover, dietary hay increased (P=0.015) the lean colour values in steaks and ground beef, which was corroborated by lower L* (P=0.009) and higher hue (P=0.010) in steaks and lower L* (P=0.049), chroma (P=0.005) in ground beef as compared with cows fed silage. A significant interaction between forage type and flax inclusion for thiobarbituric acid reactive substances (TBARS) (P=0.050) was observed. After sensory evaluation, steaks from cows fed silage had an increase (P=0.030) in beef flavour intensity when compared with cows fed hay, whereas inclusion of flaxseed in the diet decreased (P<0.001) beef flavour intensity in steaks from cows fed both forage sources. Sensory evaluation of ground beef found that hay-fed cows with flaxseed supplementation had decreased (P=0.03) beef flavour intensity, while the same effect was not observed in ground beef from cows fed silage with flaxseed. Results from this study show that inclusion of flaxseed in the diet reduced off-flavours in steak, but for ground beef this response depended on the source of forage in the diet.

Oxidative stability in grinds from omega-3 enhanced pork

Juárez, M., Dugan, M. E. R., Larsen, I. L., Thacker, R., Rolland, D. C. and Aalhus, J. L. 2011. Oxidative stability in grinds from omega-3 enhanced pork. Can. J. Anim. Sci. 91: 623–634. In order to investigate the effect of enhancing n-3 fatty acid levels in carcasses on the retail and sensory characteristics of pork grinds, as well as the ability of increasing dietary levels of vitamin E to stabilize the increase in PUFA levels from flaxseed supplementation, 81 pigs were used in a 3×3 factorial experiment. Dietary treatments included three lengths of time (0, 3 and 6 wk) of flaxseed supplementation and three levels of vitamin E (40, 200 and 400 mg kg feed−1). α-Tocopherol tissue levels increased with dietary vitamin E supplementation (P<0.001), and fat softness (P=0.018) and total PUFA and n-3 fatty acids (P<0.001) increased with flaxseed supplementation. Most other animal performance, carcass and lean pork quality traits were not affected (P>0.05) by dietary treatments. In ground pork, the increase in TBARS after 6 d in retail was lower (P<0.001) with increasing dietary vitamin E levels. However, vitamin E had no effect (P>0.05) on the higher (P<0.001) TBARS levels observed in grinds from flaxseed fed pigs. The dietary addition of flaxseed negatively modified (P<0.05) all the sensory attributes of both cooked and reheated products. Increasing the fat content of the grinds up to 30% seemed to counteract (P>0.05) the negative effects of feeding flaxseed for 3 wk. Feeding vitamin E was not able to prevent negative effects (P<0.05) observed during retail display in grinds with either increasing fat content or higher n-3 fatty acids from dietary flaxseed. However, increasing dietary vitamin E only showed a protective effect (P<0.05) on retail appearance after long periods of ageing.

A survey comparing meat quality attributes of beef from credence attribute-based production systems

Markus, S. B., Aalhus, J. L., Janz, J. A. M. and Larsen, I. L. 2011. A survey comparing meat quality attributes of beef from credence attribute-based production systems. Can. J. Anim. Sci. 91: 283–294. Two branded beef programs based on producer-defined production systems differentiated by intangible credence attributes (Organic and Natural) were compared with Commodity beef to determine meat quality and assess consumer acceptability. In each of four slaughter seasons (winter, spring, summer and fall) longissimus lumborum muscle samples were collected from two industry slaughter plants; Organic n=30, 30, 27 and 31; Natural n=30, 27, 29 and 25; Commodity 1 n=12 and 18 for spring and summer, respectively; Commodity 2 n=14 and 12 for spring and fall, respectively. Samples were vacuum packaged and aged for 16±2 d at 2°C. Seasonal effects (P<0.01) were evident for mean shear force, composition, drip loss, colour and pH. While all mean shear values were classified as being tender (<5.6 kg), a smaller proportion of steaks were classified as tender in the Organic beef compared with the Natural and Commodity beef (55.9 vs. 70.3 and 78.6%; P<0.01), indicating that even after industry normal ageing times there was higher tenderness variability in the Organic beef. Fat content (SEM=0.23; P<0.01) was lowest for the Organic line (3.98%) with Natural (5.34%) and Commodity being intermediate (5.73%). Some statistically significant differences (P<0.05) in mean scores for aroma, juiciness, flavour, tenderness and overall acceptability of cooked beef steaks were observed amongst the three production systems when samples were not matched on the basis of intramuscular fat (IMF). Clearly there are measureable differences in quality between “credence” based production systems and commodity beef with an overall better quality in Commodity beef. However, if the consumer is willing to pay for credence-based attributes then there is an opportunity for these production systems to improve the quality of their product, specifically in respect to age at slaughter and content of IMF.

Inclusion of flaxseed in hay- and barley silage diets increases alpha-linolenic acid in cow plasma independent of forage type

Feeding flaxseed to cattle may be a means of increasing omega-3 fatty acid levels in ruminant products, but possible interactions with conserved forages have not been investigated. Twelve Holstein cows were used in a replicated 4 × 4 Latin Square experiment. Cows were fed one of four 50:50 forage:concentrate diets (DM basis): hay (hay control, HC), hay plus 15% ground flaxseed (hay-flaxseed, HF), barley silage (silage control, SC), and barley silage plus 15% ground flaxseed (silage-flaxseed, SF). Plasma concentrations of alpha-linolenic acid (ALA) did not differ between SC and HC diets. Flaxseed increased ALA (P < 0.05), but levels were not influenced by forage type. Flaxseed slightly increased 18:2n-6 (P < 0.05) and some n-6 and n-3 elongation and desaturation products, particularly arachidonic acid (ARA) and eicosapentaenoic acid (EPA). Flaxseed also increased C18:0 (P < 0.05) with this increase being greater (P < 0.01) for cows fed SF than HF. Feeding flaxseed also increased plasma C18:1-trans isomers (P < 0.01), predominantly vaccenic acid (VAA, 18:1-t11), with this increase being greater (P < 0.05) in cows fed HF than SF. Although conjugated linoleic acid (CLA) was increased (P < 0.001) with flaxseed it was not influenced by forage type (P = 0.06). Overall, feeding flaxseed increased plasma ALA, EPA, ARA and CLA independently of forage type. Feeding flaxseed with silage, however, resulted in more 18:0, while feeding flaxseed with hay resulted in greater accumulations of plasma 18:1-trans isomers mainly in the form of VAA.

Extended ageing time and temperature effects on quality of sub-primal cuts of boxed beef

Most of the information indicating ageing improves tenderness has been collected on the loin and rib-eye muscles over relatively short ageing times, assuming that all muscles will react similarly. In the present study, the effect of extended ageing times on instrumental texture (56 d) and sensory characteristics (42 d) of six different beef sub-primals [striploin (SL), inside round (IR), outside round (OR), eye of round (ER), blade eye (BE) and chuck tender (CT)] was studied. The effects of two ageing temperatures (1 and 5°C) were also compared. In general, ageing increased tenderness (P < 0.05) of SL, BE, ER and CT sub-primals, although BE shear force increased after 42 d of ageing. On the other hand, ageing had no effect on IR tenderness (P > 0.05) and resulted in a decrease in tenderness of OR (P < 0.05) until day 35, with a later increase after 42 d of ageing. Increasing ageing temperature (5°C) had limited effect on tenderness, but ageing time and temperature increases led to lower flavour and higher off-flavour intensity (P < 0.05) of the studied sub-primals. These results suggest that cut-specific maximum ageing times and rigid adherence to temperature maximums would be of benefit to optimize post-slaughter processes and meat quality.Key words: Beef, ageing, tenderness, muscle

Evaluation of wheat or corn dried distillers’ grains with solubles on performance and carcass characteristics of feedlot steers

A study was conducted on crossbred steers (n = 275; 376 ± 24 kg) to evaluate performance and carcass quality of cattle fed wheat or corn dried distillers’ grains with solubles (DDGS). The control ration contained 86.6% rolled barley grain, 5.7% supplement and 7.7% barley silage (DM basis). The four treatments included replacement of barley grain at 20 or 40% of the diet (DM basis) with wheat or corn DDGS. Steers were slaughtered at a common end weight of 645 kg with 100 steers randomly (n = 20 per treatment) selected for determination of the retail yield of sub-primal boneless boxed beef (SPBBB). Data were analyzed as a completely randomized design using pen as the experimental unit. Feeding increasing levels of wheat DDGS led to a quadratic increase in dry matter intake (DMI) (P < 0.01), whereas increasing levels of corn DDGS led to a quadratic decrease in DMI (P = 0.01). Average daily gain was not influenced (P = 0.13) by feeding wheat or corn DDGS, but cattle fed corn DDGS exhibited a quadratic increase (P = 0.01) in gain:feed. As a result, a quadratic increase (P < 0.01) in calculated NEg of the diet was observed as corn DDGS levels increased. A linear decrease (P = 0.04) in days on feed (169, 166 and 154 d) was noted when increasing levels of wheat DDGS (0, 20 and 40%) were fed. Dressing percentage increased in a linear fashion with wheat DDGS (P < 0.01) inclusion level and in a quadratic fashion (P = 0.01) as corn DDGS inclusion level increased although other carcass traits were not affected (P > 0.10) by treatment. The results indicate that replacement of barley grain with corn or wheat DDGS up to 40% of the diet (DM) can lead to superior performance (improved gain:feed or reduced days on feed, respectively) with no detrimental effect on quality grade or carcass SPBBB yield.Key words: Dried distillers’ grains with solubles, corn, wheat, feedlot performance, carcass quality, steers

Dietary vitamin E inhibits the trans 10-18:1 shift in beef backfat

Forty feedlot steers were fed a barley-grain-based finishing diet typical for western Canada, with two levels of supplementary vitamin E (468 or 1069 IU head-1 d-1) and the effect on backfat trans-18:1 isomeric profile was determined. Feeding 1068 IU vitamin E reduced the total trans-18:1 content in backfat (P < 0.01), as well as the percentage of trans 10-18:1 (P < 0.001), which are related to an increased risk for cardiovascular diseases. On the other hand, trans 11-18:1 (vaccenic acid) the precursor for cis 9,trans 11-18:2 (rumenic acid), which have several purported health benefits, increased (P < 0.01). Vitamin E could, therefore, be used to decrease trans-18:1 in beef and improve its isomeric profile.Key words: Beef, trans fatty acid, vaccenic acid, vitamin E

Subcutaneous fat composition of youthful and mature Canadian beef: emphasis on individual conjugated linoleic acid and trans-18:1 isomers

A comprehensive evaluation of the fatty acid composition of subcutaneous adipose tissue from beef cattle produced in western Canada was undertaken to determine if the current Canadian grading system is able to distinguish classes of animals with value added potential due to their fatty acid composition. Grades included youthful Canadian Yield Grade 1 A/AA beef, under (YUTM) and over (YOTM) 30 mo of age and the four mature grades (D1, D2, D2 and D4). Subcutaneous fat between the 12th and 13th ribs over the longissimus muscle was obtained from 18–21 animals per grade. Fatty acids were analyzed using a combination of silver-ion HPLC and GC with a highly polar 100 m column. There were no differences in total trans-18:1 content amongst grades, but adipose tissue from grade D1, D2 and D4 had more 11t-18:1 than YUTM (P < 0.05), whereas adipose tissue from YUTM carcasses had more 10t-18:1 than all other grades (P < 0.05). Adipose tissue from YUTM carcasses also had less total CLA (P < 0.05) than the D grades, mainly due to a lower level of 9c,11t-CLA, but they had slightly more 7t,9c-CLA and 10t,12c-CLA (P < 0.05). Adipose tissue from YOTM and D grades contained more n-3 fatty acids relative to YUTM (0.56% vs. 0.29%; P < 0.05) and lower n-6:n-3 ratios (P < 0.05). Overall, older animals (YOTM and D grades) had adipose tissue compositions with higher levels of fatty acids with reported health benefits. Taken together, these higher levels may provide opportunities for value added marketing if regulatory authorities allow claims for their enrichment based on demonstrated health benefits. Higher concentrations of beneficial fatty acids, however, need to be considered within the context of the complete fatty acid profile and it would be important to demonstrate their advantages in the presence of relatively high levels of saturated fatty acids. Key words: CLA, trans, vaccenic acid, rumenic acid, beef, adipose tissue

Growth performance, carcass characteristics and pork quality of pigs fed diets containing meal from conventional or glyphosate-tolerant canola

Growth performance, carcass characteristics and pork quality were evaluated for pigs fed barley and wheat-based diets, which included meal from conventional or transgenic glyphosate-tolerant (Roundup-Ready®) canola. One hundred and forty-four pigs (72 gilts and 72 barrows) weighing 30 ± 3 kg were assigned, three to a pen, on the basis of gender and weight to receive one of four dietary treatments formulated using canola meal from two commercial sources (COM1 and COM2), non-transgenic parental control (PCC) or transgenic (RRC) canola. Pigs were fed a grower diet (75 g kg-1 canola meal) until 60.5 ± 4.0 kg and then a finishing diet (150 g kg-1 canola meal) to 108.6 ± 7.3 kg at slaughter. Pigs receiving the COM1 and COM2 diets had an overall higher (P < 0.0001) daily feed intake (DFI) compared with pigs fed the PCC and RRC diets. Corresponding average daily gain (ADG) was also increased (P = 0.02) for COM1-fed pigs, although feed conversion efficiencies (FCE) of the pigs were similar (P > 0.05) among diets. Gilts had lower overall DFI (P < 0.0001), ADG (P < 0.0001) and FCE (P = 0.04) compared with barrows. Pigs receiving the PCC and RRC diets had heavier (P = 0.002) liver weights than those pigs fed the COM1 and COM2 diets (2.06 and 2.05 kg vs. 1.95 and 1.96 kg, respectively). Postmortem decline in pH and temperature of the longissimus thoracis (LT) muscle from pigs were not different (P > 0.05) among the dietary treatments. Characteristics of pork quality for the LT muscle, which included objective colour and shear force were also not affected (P > 0.05) by dietary source of canola meal. Gross composition of commercial pork cuts were similar (P > 0.05) among the dietary treatments with the exception of small differences for intermuscular (P = 0.04) and body cavity (P = 0.02) fat in the picnic cut and body cavity (P = 0.02) fat in the loin cut. Differences in DFI, ADG and liver weights of the pigs may be related to higher content of antinutritional glucosinolates (µmoles g-1) in the PCC (20.20) and RRC (15.04) varieties compared with COM1 (7.55) and COM2 (7.46) sources of canola meal. Key words: Transgenic canola, growth, pork quality, pigs

Effect of sunflower seed supplementation on the fatty acid composition of muscle and adipose tissue of pasture-fed and feedlot finished beef

This study examined the effects of whole sunflower seed (WSS) supplementation on pasture and in finishing diets on the fatty acid profile of muscle [gastrocnemius (GN), longissimus thoracis (LT), intercostals (IC)] and adipose tissue [subcutaneous (SQ), intermuscular (IM)]. Ninety-six yearling steers averaging 410 kg were randomly allocated to three pasture (P) dietary treatments: (1) supplemented with WSS (P-WSS, n = 48); (2) supplemented with cracked barley grain (P-BAR, n = 24), and (3) not supplemented (P-CON, n = 24). Steers rotationally grazed meadow bromegrass-alfalfa pasture for 66 d. After 66 d on pasture, half the steers from each dietary treatment were trucked to a feedlot where they were adjusted to finishing diets. The remaining 48 steers continued with their dietary treatment on stockpiled pasture for an additional 47 d (SD = 11) until they were slaughtered directly off pasture. In the feedlot, half the steers from each pasture dietary treatment were fed either a control (83% rolled barley, 10% alfalfa hay, 5% barley silage, 1% molasses and 1% vitamin/mineral premix; F-CON) or a WSS supplemented diet (68% rolled barley, 15% WSS, 10% alfalfa hay, 5% barley silage, 1% molasses and 1%; F-WSS). Provision of WSS to steers grazing pasture for 113 d followed by direct slaughter increased cis-9, trans-11 CLA content in the muscles by 17.0 to 29.1% (GN, 0.570 vs. 0.467; LT, 0.515 vs. 0.399; IC, 0.531 vs. 0.454 mg 100 mg-1 fat) and in adipose tissue by 32.0% in IM (0.636 vs. 0.482 mg 100 mg-1 fat) and 40.3% in SQ (0.839 vs. 0.598 mg 100 mg-1 fat) fat depots compared with control steer slaughtered directly off pasture. On pasture supplementation of WSS also increased C18:1 trans-11 content in muscle by 20.1 to 40.8% and in IM adipose tissue by 55.0%. The inclusion of WSS in finishing diets increased CLA cis-9 trans-11 content in muscle by 31.5 to 209.0% and in adipose tissue by 40.7% in the SQ fat and 25.6% in the IM fat. It also increased C18:1 trans-11 content in muscle by 80.0 to 207.3% and in adipose tissue by 181% in the IM fat and 224% in the SQ fat. Strong, positive relationships were observed between tissues in the concentration of CLA cis-9 trans-11, C18:1 trans-11 and C18:3 (R2, 0.69–0.88; P < 0.0001). The results indicate that increasing the dietary polyunsaturated fatty acids in beef cattle diets increased the levels of CLA cis-9 trans-11 and C18:1 trans-11 in muscle and fat tissues. Key words: Beef, pasture, feedlot, fatty acid profile, conjugated linoleic acids, vaccenic acid

Effect of feeding sunflower seeds on the performance, carcass characteristics, meat quality, retail stability and sensory characteristics of pasture-fed and feedlot finished beef

This study examined the effects of whole sunflower seed (WSS) supplementation on production parameters, carcass traits, and organoleptic characteristics of beef from steers slaughtered directly off pasture or after receiving a finishing diet. Ninety-six yearling steers (410 kg; SD = 44 kg) were randomly allocated to three pasture (P) dietary treatments: (1) supplemented with P-WSS (n = 48), (2) supplemented with cracked barley grain (P-BAR, n = 24), and (3) not supplemented (P-CON, n = 24). Steers rotationally grazed meadow bromegrass-alfalfa pasture for 66 d during the summer and consumed WSS and BAR at a rate of 0.75 and 1.79 kg head-1 d-1, respectively. At the end of summer grazing half the steers from each pasture dietary treatment group were moved to a feedlot (F) where they were fed high barley-based finishing diets. The remaining 48 steers continued with their dietary treatments on stockpiled pasture for an additional 47 d (SD = 11) until they were slaughtered directly off pasture. In the feedlot, half the steers from each pasture dietary treatment were fed either a control [83% rolled barley, 10% alfalfa hay, 5% barley silage, 1% molasses and 1% vitamin/mineral mix on a dry matter (DM) basis; F-CON] or a F-WSS diet (68% rolled barley, 15% WSS, 10% alfalfa hay, 5% barley silage, 1% molasses and 1% vitamin/mineral mix on a DM basis) for a further 94 d until slaughter. Supplementation of BAR on pasture increased average daily gain (ADG), while supplementation of WSS had no effect on ADG compared with no supplementation (0.73 vs. 0.58 vs. 0.55 kg d-1, P = 0.023). Inclusion of 15% WSS in the finishing diet decreased ADG (1.46 vs. 1.72 kg d-1, P = 0.038), dry matter intake (DMI) (11.6 vs. 12.6 kg d-1, P = 0.058) and had no effect on feed to gain ratio (8.0 vs. 7.4 kg d-1, P = 0.160). Provision of WSS on pasture or in finishing diets had no effect on carcass traits and organoleptic characteristics of beef from steers slaughtered directly off pasture or after receiving a finishing diet. Slaughtering steers directly off pasture, regardless of pasture dietary treatment, adversely affected most carcass merit, meat quality and retail appearance and acceptability parameters compared with steers finished on a high-barley grain diet. These results indicate that increasing the dietary polyunsaturated fatty acids threefold in the pasture dietary treatment or greater than eightfold in the finishing diets had a small negative effect on animal growth rate and no adverse effect on carcass merit, meat quality and retail acceptability. Key words: Polyunsaturated fatty acids, retail acceptability, beef cattle

The impact of antemortem nutrition in beef cattle on carcass yield and quality grade

Three thousand and thirty-six crossbred steers and heifers averaging 570 ± 7.1 kg were used in the present study to test the efficacy of providing antemortem nutrition for 12 to 24 h pre-slaughter on carcass yield, grade and meat quality. All cattle were transported for up to 6 h prior to being held overnight at one of three midwestern USA abattoir sites. While at the abattoir, the cattle were randomly assigned to one of three treatments: control (offered water only 12 to 24 h pre-slaughter, which is industry standard practice); placebo (offered 2 kg per head of a rice hull-corn-based pelleted feed for 12 to 24 h pre-slaughter plus ad libitum water); or nutritional therapy (offered 2 kg of an energy/amino acid/electrolyte product plus ad libitum water for 12 to 24 h pre-slaughter). The cattle offered antemortem nutritional therapy displayed a 20% or greater retention of quality grade score (P < 0.01) and a significant reduction in dark-firm-dry beef (P < 0.05) compared with either the placebo or control animals. In addition, animals receiving nutritional therapy treatment had a greater retention of carcass weight (≥ 2 kg, P < 0.05) compared with control cattle. Data from the present study suggest that the use of antemortem nutrition, especially for overnight-held cattle, may be effective in reducing carcass loss and quality grade reduction. Key words: Antemortem, nutrition, beef, cattle