Fat Firmness Research Articles

The influence of sex (boars and gilts) on growth, carcass and pork eating quality characteristics

AbstractBoar and gilt pigs from three genotypes (with 0, 0·25 and 0·50 Duroc inclusion level) were reared from 30 to 90 kg live weight on seven feeding regimens which involved combinations of diet formulation and feeding level. A diet of conventional energy and protein level (CEP; 14·2 MJ/kg digestible energy, 205 g/kg crude protein, 10 g/kg lysine) and a diet of higher energy and lower protein (HELP; 14·7 M]/kg digestible energy, 166 g/kg crude protein, 7·0 g/kg lysine) were used. One treatment involved feeding the HELP diet ad libitum, with the other six treatments involving feeding the CEP diet ad libitum, restricted, or in combinations of ad libitum and restricted. A total of 721 animals comprising similar numbers of boars and gilts were used to estimate sex differences for growth performance, carcass and meat quality, and eating quality. Tissue growth rates were predicted from regression equations based on P2fat depths or ham-joint dissection, developed from subsamples of animals that were subjected to full-side dissection. Overall when compared with gilts, boars grew faster (838 v. 799 gtday, P < 0·001), had improved food conversion ratios (2·39 v.2-55, P < 0·001) but had similar daily food intakes and lean and subcutaneous fat growth rates. Lean tissue food conversions did not differ significantly between the sexes. Killing-out proportions were higher for gilts (0·766 v. 0·749 , P < 0·001), however P2 backfat thickness and lean proportions did not differ between the sexes. The firmness of the mid-back fat, assessed subjectively and using a penetrometer, was greater for gilts than for boars. The tenderness of pork loin chops, assessed by a trained sensory panel, was judged to be better for boars than for gilts but there was no sex difference in overall acceptability. The fat from boars had a higher level of abnormal odour and boar odour. There was a sex × dietary treatment interaction for boar odour with the HELP diet producing the highest levels and the biggest difference between the sexes for odour scores.

The influence of the proportion of Duroc genes on growth, carcass and pork eating quality characteristics

AbstractA study was carried out involving 721 pigs, comprising boars and gilts, with either 0, 0.25 , or 0.50 Duroc inclusion level, which were produced by mating Large White boars with Large White × British Landrace sows, Large White boars with Duroc × (Large White × British Landrace) sows, or Duroc boars with Large White × British Landrace sows, respectively. Animals were reared on one of seven different feeding regimens from 30 to 90 kg live weight. Tissue growth rates were determined using a triple sampling procedure based on a combination of full-side and ham joint dissection on subsamples of pigs (127 and 366 pigs, respectively) and P2 backfat thickness on the remainder. Initial body composition was determined at 30 kg on subsamples of the three genotypes. Daily food intakes increased with increasing Duroc inclusion but live-weight gains were similar for the three genotypes. Lean and fat growth rates and food conversion ratios were greatest for the 0·50 Duroc group, although the genotype differences were small. Killing-out proportions and P2 fat depths were higher for the 0.25 and 0·50 Duroc groups. The proportion of lean in the carcass was lower (P < 0·01) for 0·50 Duroc pigs. Japanese colour scores and EEL reflectance indicated that the longissimus muscle was darker for the 0·25 and 0·50 Duroc genotypes. Subcutaneous fat firmness scores and penetrometer readings taken in the mid back indicated softer fat for the 0 Duroc group. Intramuscular fat levels increased (P < 0·01) with increasing Duroc inclusion (10.4, 11.2, and 18·2 g/kg for the 0, 0.25, and 0.50 groups respectively). Cooked longissimus from pigs with 0·50 Duroc had a lower shear force and was judged to have a stronger pork odour and to be more tender and acceptable than that from the 0 Duroc group. The 0.25 Duroc group showed a small improvement in tenderness but a weaker pork odour and similar overall acceptability compared with the 0 Duroc group. This study suggests that the use of the Duroc in crossing systems in the United Kingdom will have limited impact on growth performance but that 0·50 Duroc inclusion will result in fatter carcasses, higher intramuscular fat levels and improved eating quality.

Effect of sex on meat quality of Spanish lamb breeds (Lacha and Rasa Aragonesa)

AbstractThe influence of sex on the meat quality of Lacha (L) and Rasa Aragonesa (RA) lambs was studied. Male and female L lambs were given ewes' milk and were slaughtered at 25 and 24 days of age corresponding to 11·4 and 10·9 kg live weight (LW), respectively. Male and female RA lambs were weaned at 58 days (16·0 kg LW) and then given concentrate and barley straw until slaughter at 89 and 91 days of age, corresponding to 24·5 and 23·1 kg LW, respectively. The parameters measured on the carcasses were: hot carcass weight, cold carcass weight, conformation, colour, firmness and thickness of dorsal fat and colour of muscle rectus abdominis. Parameters measured on longissimus dorsi muscle were: ultimate pH (pHu), instrumental colour (L*, a*, b*), myoglobin concentration, ash, crude protein, fat, moisture and water-holding capacity (WHC). Iodine value and fatty acid composition were studied in the intramuscular (IM), intermuscular (IN) and subcutaneous (SC) fat depots. Females of both breeds had higher amount of IM fat (P < 0·001 and P < 0·05 for L and RA breeds, respectively) and firmer SC fat than males (P < 0·05). There were no differences between sexes in pHu, myoglobin concentration, WHC and the L*, a* and b* colour parameters. No significant differences between sexes were observed in the total saturated fatty acids, total unsaturated fatty acids and in the iodine value in the three fat depots studied in both breeds. However, the females of the breed had significantly higher proportions offatty acids with 15 carbon atoms (pentadecanoic (C15:0)) and with 16 carbon atoms (palmitic (C16:0)and palmitoleic (C16:1)) than the males in the three depots. The females of Rasa Aragonesa breed had a higher proportion of palmitoleic acid (C16:1)in the IM depot (P < 0·001) and of palmitic acid (C16:0)in the SC depot (P < 0·05) than the males. The absence of significant differences in the unsaturated fatty acid content between males and females showed that at the low slaughter weight, sex had no effect on the nature and composition of fat.

Oxidative stability and dietary treatment with vitamin E, oleic acid and copper of fresh and cooked pork chops

Research has been conducted on the effects of feed supplementation with vitamin E, oleic acid (sunflower oil) and copper on some quality characteristics of pork chops. The study was based on the measurement of pH 45′ and 24 hr post mortem, proximate composition, colour both objective and sensory, colour stability after packing in oxygen permeable film and protective atmosphere, copper and iron contents, vitamin E content in fresh and cooked chops, peroxide and TBARS value in raw and cooked meat, total cholesterol, cholesterol oxides and aldehydes in cooked meat, sensory evaluation of the eating quality of cooked chops and iodine number of subcutaneous fat. Vitamin E content was significantly higher with oil and vitamin supplementation. No variation has been observed in copper and iron contents. A higher stability of the colour of meat packed under modified atmosphere has been observed with increasing vitamin E content, but the same did not apply with meat packed in oxygen permeable film. No differences have been observed on fatty acid oxidative stability of fresh m. longissimus dorsi and cooked chops (peroxide and TBARS values), on cholesterol oxidation and aldehydes production of cooked chops with increasing vitamin E content. Iodine number in supplemented animals reached levels normally considered at risk for fat firmness.

Selective improvement of porcine fat firmness by a diet enriched in medium‐chain fatty acids

AbstractThe effects of 4% fat either rich in medium‐chain fatty acids (MCFA; saturated fat) or in polyenoic fatty acids (PUFA; unsaturated fat) isoenergetically exchanging carbohydrates of a low‐fat diet (control) on performance and product quality were evaluated with 180 growing pigs. Growth, carcass and meat quality were not affected by the fat treatments. Although elevated in blood serum, cholesterol was not increased in belly meat when the MCFA‐rich diet was fed. Fatty acid composition of backfat reflected dietary fat composition. The significantly lowest shelf life and melting temperatures were found with the unsaturated‐fat diet. When compared with control, fat tissue PUFA contents were slightly higher in the saturated‐fat diet, and fat melting temperatures were somewhat lower. In contrast, the use of this MCFA‐enriched diet increased penetrometer firmness in pure 4°C temperated backfat by more than 50% as compared with control and to about the tenfold level of the firmness obtained in the unsaturated‐fat diet. Impression of flavour and odor in lean and fatty meat were not systematically affected by the diets. The present results show a high potential of MCFA‐enriched diets to selectively increase fat firmness in pigs without greater undesired side effects on other traits of product quality.

The effect of dietary oil containing (n-3) fatty acids on the fatty acid, physicochemical, and organoleptic characteristics of pig meat and fat.

An investigation was made to alter the fatty acid composition of pork and a pork product in line with human dietary advice while not adversely affecting factors controlling consumer acceptability. Pigs (n = 150) were assigned to three dietary treatments with 25 intact male-female pairs per treatment. Diet A (control) contained 3% of a 4:1 (wt/ wt) tallow-soybean oil mixture. Diets B and C contained 2% rapeseed oil plus 1% fish oil. Diets A, B, and C were supplemented with 100, 100, and 250 mg of all-rac-alpha-tocopheryl acetate/kg of diet, respectively. Pigs were given ad libitum access to feed from 52 kg live weight until 95 kg (slaughter). Sausages were prepared from the resulting cuts. Tissues of pigs were evaluated in terms of fat firmness, color, fatty acid composition, and contents of alpha-tocopherol and thiobarbituric acid-reactive substances (TBARS). Organoleptic characteristics of chops and sausages were evaluated by a trained taste panel. Pigs fed Diets B and C had improved feed conversion ratios (P < .05) and ADG compared with control pigs. The levels of n-3 (omega-3) polyunsaturates were significantly increased in the tissues and sausage from pigs fed Diets B and C with associated alterations in n-6 to n-3 fatty acid ratios that accorded with contemporary human dietary recommendations. Levels of alpha-tocopherol and TBARS were significantly altered in the tissues. There were no appreciable differences between treatments in carcass characteristics, including color. The overall organoleptic acceptability of chops and sausages was not different between the treatments.

Whole rapeseed in pig finishing diets - effects on carcase and meat quality

Whole rapeseed can be used to provide energy economically in pig finishing diets. There has been concern that the unsaturated nature of the oil can give rise to adverse effects on fat firmness, visual appeal and eating quality of pork. Danish workers, for example, have recommended inclusion at no more than 4% of finishing rations (Madsen et al, 1992). MLC's Blueprint for Pork (MLC, 1992) limits whole rapeseed to between 4 and 5% of the diet due to its restriction on total oil content to 3.5%.A trial was designed to establish whether any carcase or sensory quality differences result from inclusion of 5 or 10% whole rapeseed in pig diets.

Whole rapeseed in pig finishing diets - effects on carcase and meat quality

Whole rapeseed can be used to provide energy economically in pig finishing diets. There has been concern that the unsaturated nature of the oil can give rise to adverse effects on fat firmness, visual appeal and eating quality of pork. Danish workers, for example, have recommended inclusion at no more than 4% of finishing rations (Madsen et al, 1992). MLC's Blueprint for Pork (MLC, 1992) limits whole rapeseed to between 4 and 5% of the diet due to its restriction on total oil content to 3.5%.A trial was designed to establish whether any carcase or sensory quality differences result from inclusion of 5 or 10% whole rapeseed in pig diets.

Performance and carcass characteristics of swine when fed diets containing canola oil and added copper to alter the unsaturated:saturated ratio of pork fat.

A 3 x 2 trial was conducted to determine the effects of adding canola oil (0, 5, or 10%) and copper sulfate (0 or 250 ppm Cu) to diets of growing-finishing swine on performance, carcass characteristics, and carcass fat fatty acid composition. The trial used 180 pigs (27 kg). Grower diets (.80% lysine for 0% canola oil diet) were given from 27 to 57 kg of BW and finisher diets (.64% lysine) from 57 to 102 kg. Diets were formulated to constant ME:lysine ratio within the grower and finisher phases. Over the entire growing-finishing period, the addition of canola oil to the diets resulted in linear improvements in rate of gain (P less than .05) and feed efficiency (P less than .01). Dietary additions of canola oil had no effect (P greater than .10) on resulting backfat thickness or longissimus muscle area but resulted in reductions (P less than .01) in loin marbling and color and carcass fat firmness, mostly noted in pigs fed the diets with 10% canola oil. Canola oil additions at 5 and 10% levels, respectively, resulted in a 23 and 37% reduction (P less than .01) in saturated fatty acids, 3 and 8% increase (P less than .01) in monounsaturated fatty acids, and 37 and 77% increase (P less than .01) in polyunsaturated fatty acids in the carcass fat compared with the diets without canola oil. The addition of canola oil to diets of growing-finishing swine had a favorable influence on animal performance and on increasing the unsaturated:saturated ratio of the carcass fat.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the Duroc and Large White as terminal sire breeds and their effect on pigmeat quality

AbstractThe experiment examined the effect of breed, diet and sex on pig performance and carcass quality. Eight sires of the Duroc and Large White breeds each produced four experimental litters. Two boar and two female pigs from each litter were reared under standard conditions to 38 kg and then one of each sex was allocated to each of two finishing diets. These were cereal-based diets with and without 16 g/kg soya oil. Following slaughter at 80 kg, loin chops taken from half of the pigs (two litters per sire) were subjected to detailed investigation of physical, chemical and organoleptic characteristics. Lifetime live-weight gain was similar for both breeds but Duroc-sired pigs had greater voluntary food intakes and poorer food conversion efficiencies in the finishing stage. They also had greater killing-out proportions (775 v. 755 g/kg, P &lt; 0·001) and backfat thickness at slaughter (284 v. 27·2 mm at P1 + P3, P &lt; 0·05). Fat firmness measured by penetrometer at 4°C was lower in Duroc-sired pigs (738 v. 792 units, P &lt; 0·001). The proportion of extractable intramuscular lipid was greater in chops from Duroc-sired pigs (13·8 v. 10·4 g/kg, P &lt; 0·001). There were no significant effects of breed or diet on the eating quality of the grilled chops as assessed by a trained taste panel and a consumer panel.

Influence of sectility speed on the relationship between sensory and instrumental evaluation of edible fat firmness

For three samples of butter and margarine each the dependence of sample temperature and the applied sectility speed on instrumentally determined wire sectility forces is described in terms of semilogarithmic and double logarithmic regression equations, respectively. The mean cutting speed in sensory firmness assessments was found to be 976 mm·min−1. A close agreement of sensory and instrumental firmness evaluations of butter and margarine was observed only at instrumentally applied sectility speeds approaching the cutting speed used in sensory experiments.

Genetic components of carcass and meat quality traits in Meishan and Large White pigs and their reciprocal crosses

AbstractThe prospect that genes from the Chinese Meishan pig will be used to improve reproductive performance of European pigs requires that the Meishan is evaluated for traits of economic importance and the genetics of any breed effects investigated. Entire male and female pigs of four genotypes; purebred Meishan (MS) and Large White (LW) pigs and both reciprocal Fl crossbred genotypes (MS ♂ × LW ♀and LW ♂ × MS ♀), were fed ad libitum and slaughtered at about 70 kg. After slaughter, carcass weight, dimensions and conformation were recorded and fat depths at the shoulder, mid back and loin were measured on the carcass, together with fat depths and eye muscle dimensions recorded on a section cut at the last rib position. Drip loss, muscle reflectance and pH were measured and subjective assessments of fat firmness, fat separation, muscle marbling and muscle colour were made. Genotypic means and genetic crossbreeding effects (direct additive and heterosis effects and maternal additive effects) were estimated using restricted maximum likelihood procedures. When compared with the LW, MS carcasses had a similar killing-out proportion but were shorter with a poorer conformation. MS carcasses had substantially greater fat depths and reduced eye muscle dimensions in comparison with the LW. Differences between genotypes for fat depths and muscle dimensions were largely controlled by direct additive gene action, there was little evidence of direct heterosis and hence Fl crosses were intermediate between the purebreds. Significant genotype × sex interaction meant that genotypic differences for these traits were much greater in females than in males. Significant direct additive genetic differences between female genotypes were found for fat firmness, fat separation and drip loss, but these effects may in part have been a consequence of subcutaneous fat depth differences between genotypes. The degree of marbling was greater in MS females than in females of the other three genotypes and these genotypic differences did not seem to be associated with subcutaneous fat depth. Muscle from MS males was darker in colour with a lower reflectance than that from LW males. Genotype × sex interaction was such that genotypic differences for meat and fat quality traits differed between sexes.

Effects of age, castration, and season on difficulty of pelt removal in lambs.

Sixty-four white-faced rams and wethers were dressed with the aid of a commercial pelt puller. The effects of age, castration, and season on difficulty of pelt removal and pelt damage were evaluated. Lambs were divided into two age groups (5 and 12 mo) within gender (ram and whether) and season (spring and fall). A greater force (P less than .05) was required to remove pelts from rams than from wethers in both 5- and 12-mo-old groups. Older lambs slaughtered in the fall required more force (P less than .05) to remove their pelts than did those slaughtered in the spring, but differences by season did not exist for 5-mo-old lambs. The difference between rams and wethers in percentage of live weight that was closely shorn pelt weight was not significant (P greater than .05). The area of grain crack in the flank expressed as a percentage of total area of the skin was lower (P less than .05) for skins from 5-mo-old lambs and ram lambs than it was for skins from 12-mo-old lambs and wether lambs, respectively. Factors involved in difficulty of pelt removal in ram lambs included crosscut shoulder weight, fat firmness, and carcass weight. Difficulty of pelt removal in wether lambs was best predicted by including crosscut shoulder weight and bodywall thickness in multiple regression equations.

Genetic and phenotypic parameters for carcass traits, meat and eating quality traits in pigs

Genetic relationships for carcass traits with meat and eating quality traits were estimated from data on 40 litter groups, which were essentially full-sibs, of two boars and two gilts. Duroc and halothane negative Landrace pigs were performance tested on ad libitum or restricted diets with an average slaughter weight of 80 kg. Half carcasses were dissected and loin joint chops were used for objective measurements of meat quality and trained taste-panel assessment of eating quality. Genetic parameters were estimated using an animal model in a restricted maximum likelihood analysis. Slaughter weight was fitted as a covariate for each feeding regime. Heritabilities of lean weight (0.75 s.e. 0.17) and meat quality traits: intramuscular fat content (0.53 s.e. 0.17), subcutaneous fat firmness (0.43 s.e. 0.15) and moisture content (0.27 s.e. 0.15), muscle pH (0.20 s.e. 0.16) and colour (0.20 s.e. 0.16); were generally higher than for eating quality traits: flavour (0.16 s.e. 0.19), tenderness (0.23 s.e. 0.16) and juiciness (0.18 s.e. 0.18). The genetic correlations suggest that selection for increased lean weight would result in increased muscle moisture content but decreased muscle pH and intramuscular fat content. Eating quality would also be reduced as pork flavour and juiciness would become poorer. The reduced carcass fat weight would result in less subcutaneous fat which would be less firm due to increased moisture content and increased concentrations of polyunsaturated fatty acids.

Influence of age and testosterone levels on masculine development in rams.

Fifty wethers and 51 spring-born rams were divided into five groups and slaughtered at different seasons of the year at average ages of 271, 361, 459, 557 or 652 d to determine the age and season at which differences in secondary sex characteristics could be detected. Serum testosterone concentrations and testes weights were low in January when the rams were 271 d of age and again in April at 361 d of age. By July, at 459 d of age, testosterone concentrations and testes weights had peaked and then decreased the following November at 557 d and February at 652 d. In contrast with plasma testosterone concentrations and testes weights, buckiness scores, splenius to semimembranosus or semitendinosus muscle ratios, splenius muscle weights and neck and shoulder percentages were not seasonal. All of these measures increased significantly up to July and continued to increase slowly, but not significantly, thereafter. Muscle color and texture scores and rib eye color scores tended to increase in a linear manner for both rams and wethers as age increased. Subcutaneous fat from rams was yellower and softer than that from wethers over all age groups. Ram fat firmness did not change (P greater than .05) with age, and the only significant change in ram fat color was between the groups at 271 and 361 d of age. Overall, season of year coupled with higher levels of serum testosterone was related to initial development of secondary sex characteristics in ram lambs.

The influence of dietary linoleic acid on backfat firmness in bacon weight pigs

There is a growing concern in the UK meat industry over carcasses containing soft fat, which prove difficult to cut and process. This may be caused by the feeding of high levels of unsaturated fatty acids resulting in high levels in carcass fat, and hence soft fat. This trial examined the critical levels of linoleic acid affecting fat firmness.

Genetic effect's on pork product composition and quality

Genetic variation in pig meat composition and quality offers the possibility of manipulating both between and within line composition in order to Improve the end product. The extent of this variation has been evaluated on batches of PIC pigs sent to the Meat and Livestock Commission for carcass assessment and full side dissection. In the last two years, hind loin samples from these carcasses have gone to the Institute of Food Research, Bristol for taste panel assessment, chemical analysis, and measurements of fat firmness and androstenone concentration.289 entire males of eight pure lines (20-55 per line) were slaughtered at 90-100 kg liveweight following performance test on ad libitum feeding from 33 kg. The ration contained 13.8 MJ DE, 200g crude protein and 10g lysine per kg. Standard MLC dissection procedures were followed. At IFR, the SOXHLET method was used to determine the concentrations of extractable fat, moisture, total nitrogen and ash In the m. longissimus.

Fatty acid profiles and sensory and carcass traits of tissues from steers and swine fed an elevated monounsaturated fat diet.

Twelve Angus X Hereford steers were assigned to either a control high-energy diet or a test diet consisting of 20% rapeseed at the expense of 20% corn. Twelve pigs were allotted to a control diet and two test diets containing either 10 or 20% canola oil (CO). Both CO and oil in the rapeseed contained 60 to 64% oleic acid. Cattle fed rapeseed exhibited little effect from the diet due to apparent indigestibility of the rapeseed. Total saturated fatty acids decreased from 40% in adipose tissue of the control pigs to 15% in the 20% CO-fed pigs. The ratio of monounsaturated to saturated fatty acids (M/S) increased from 1.19 in adipose tissue from control pigs to 3.63 with the addition of 20% CO to the diet. In muscle, the M/S ratio increased from 1.21 in control pigs to 2.46 in the 20% CO treatment group. The percentage of the saturated fatty acids in muscle decreased from 42% in the control to 23% in the 20% CO treatment. Significant increases in "oiliness" and decreases in fat firmness were observed when increasing levels of canola oil were fed. Sensory traits, cooking loss and shear-force values of pork chops were similar among treatment groups. In conclusion, monounsaturated fatty acid content can be elevated substantially in pork without adversely influencing the quality of the meat, thus producing a product perceived to be more healthful by the consumer.

Backfat quality in boars and barrows at 90 kg live weight

ABSTRACTForty male commercial hybrid pigs, half castrated at 10 days of age, were used in a study to determine whether boars at bacon weight (90 kg live weight) have different fat quality from barrows. Fat quality was defined as the firmness and cohesiveness of subcutaneous fat, both properties being measured using an Instron materials testing instrument. Within each group of boars and barrows, half the pigs were fed a normal commercial diet and half a lower energy diet at a lower level of food intake. The latter diet provided relatively more energy as C18:2 (linoleic acid).Firmness of subcutaneous fat was related to fat thickness and to concentrations of the chemical components in the fat which are affected by fat thickness. The single best predictor of firmness was C18:0 (stearic acid). Cohesiveness was less closely related to fat thickness and was most associated with the concentration of C18:2.On the low energy/high C18:2 diet, all the pigs were judged to have soft fat, the difference between boars and barrows being small and explained by the difference in fat thickness. On the normal commercial diet, some barrows had particularly firm fat but they had thicker fat than any of the boars. Most (0·84) of the pigs in the experiment had P2 values (fat thickness over the m. longissimus at the last rib) between 8 and 15 mm. In this range there was no difference in firmness between boars and barrows. Cohesiveness was also similar between boars and barrows.

Quality, palatability and weight loss of pork as affected by electrical stimulation

Forty-five swine ( n = 15, stress-susceptible pigs, fasted for 18 h; n = 15, normal pigs, fasted for 48, 60 or 72h; n = 15, normal pigs, fasted for 18 h) were slaughtered. One side of each pig was electrically stimulated (ES)—550 V, 2–6 A, seventeen impulses, 1·8 s on and 1·8 s off per impulse—and the opposite side was not stimulated (NS). Ham and loin temperatures were monitored at 12 and 24 hours post mortem. Carcass quality—marbling, loin eye colour, loin eye firmness, subcutaneous fat firmness and belly firmness—was evaluated at 24 hours post mortem. Sides were fabricated into four lean cuts at 48 hours; cuts were placed on open metal racks in a 2°C cooler and weight loss was measured after 24, 48 and 72 hours storage. At 120 hours post mortem, loin chops were cut, frozen (−24°C for 45 days) and subsequently used to determine thaw loss, cooking loss, Warner-Bratzler shear (WBS) force and palatability. Ham temperatures (12 h) were significantly ( P < 0·05) lower for the ES sides from the stress-susceptible, short-fast (SSF) group but not for normal, long-fast (NLF) or normal, short-fast (NSF) groups. ES produced lighter coloured, softer loin eyes in the SSF group but darker coloured, firmer loin eyes and firmer subcutaneous fat in the NLF group. No significant differences ( P > 0·05) were detected for thaw loss, cooking loss, palatability ratings or WBS values between ES and NS in the SSF group but chops from ES sides of NLF animals had significantly ( P < 0·05) higher ratings for muscle fibre tenderness, overall tenderness and overall palatability. Weight losses of the lean cuts from the ES sides were higher ( P < 0·05) than those from NS sides in only three of sixty comparisons of cuts from the three groups of swine. These data suggest that ES had very minimal effects on quality, palatability or weight loss of pork.