Effect of halothane genotype, breed, feed withdrawal, and lairage on pork quality of belgian slaughter pigs

Effect of terminal sire line and timing second vaccination on effectiveness of immunocastration, performance, and carcass and meat quality

Performance (from 10 weeks until slaughter), carcass and meat quality, and effectiveness of immunocastration was compared in crossbred offspring of stress positive (BP+) and negative (BP-) Belgian Piétrain and Canadian Duroc (CD) given the second vaccination of Improvac® at different times (4, 6, 8 weeks before slaughter). CD offspring had a significantly higher daily gain (DG) and feed intake (DFI), and lower predicted lean meat percentage (LMP) and dressing yield compared to BP+ and BP-, while feed conversion ratio (FCR) did not differ. CD offspring had significantly lower drip loss and higher pH_i, intramuscular fat content than BP+ and BP- (except for pH_i). No significant effect of vaccination time on DG nor FCR was observed. Predicted LMP tended to increase as time-post injection decreased, while meat quality was minor affected. Earlier vaccination had no effect on the effectiveness of immunocastration based on testosterone and GnRH-binding.

Quality characteristics of fresh loin and cooked ham muscles as affected by genetic background of commercial pigs

This study was performed to investigate meat quality traits of loin and ham of commercial pigs as affected by genetic differences in carcass and growth traits of the parent lines. Three hybrid sow lines were crossbred with two types of Belgian Piétrain with different breeding goals (BP_growth and BP_carcass emphasizing daily growth and carcass conformation, respectively). Pig live performance and carcass quality of 270 offspring were measured, and meat quality of the loin and (cooked) ham was evaluated on 216 animals. Despite the differences in pig live performance and carcass quality for sow line, little effect on meat quality was observed. Only a lower (p < 0.05) intramuscular fat content of ham and a tendency (p < 0.1) toward lower cooking yield was observed in offspring of the sow line with the highest versus the lowest carcass lean content. Loin traits were only weakly associated with fresh and cooked ham quality traits.

Performance and carcass, loin and ham quality in crossbreds from three terminal sire lines

This study was designed to compare performance, carcass and meat quality of crossbred of a hybrid sow x three sire lines, i.e. stress positive Belgian Piétrain (BP), stress negative French Piétrain (FP) and Canadian Duroc (CD). BP offspring had a significantly higher carcass yield (p < .001) and lean meat content (p < .001) in comparison with FP, which was higher than CD. BP offspring had significantly lower pH (p < .05), water-holding capacity (WHC) (p < .001) and intramuscular fat (IMF) (p < .001) content in the loin compared to FP and CD, but these meat quality parameters, with the exception of pH, were superior for CD as compared to FP. In accordance with loin quality, pH_i, pH_u, WHC and IMF of BP were significantly lower (p < .05) compared to CD in the fresh and cooked ham. Most often, FP offspring could not be differentiated from the other offspring, with the exception of cooking loss of the cooked ham. Trained and consumer taste panels resulted in no significant differences (p > .1) in sensory attributes, however, consumers preffered CD based on ranking.

Effects of Housing, Short Distance Transport and Lairage on Meat Quality of Finisher Pigs

Simple Summary

Knowledge of stressful stimuli is a fundamental aspect to improve and evaluate animal welfare. Animal stressors vary in function of, for example, housing, climate and handling technique. That is why it is important to investigate animal welfare in different circumstances (e.g., type of housing, climate and region). Belgian pig production is based on the Piétrain breed which is associated with the halothane gene and hence with the genetic susceptibility to stress. In pigs, there is a negative correlation between stress in the last few hours of their life and the final meat quality. In our research we investigated several potential parameters that could influence the meat quality of pork. We can conclude that numerous parameters on farm, during transport and in slaughterhouse influence meat quality. Specifically, reducing lung lesions by vaccination during raising, no mixing of pigs during the transport process, sufficient lairage time and transporting no extreme muscled pigs can improve meat quality. Adequate control and application of guidelines on farm, transport and slaughterhouse level are necessary to improve animal welfare, but also to reduce deterioration of meat quality important for the financial aspect and the appreciation of the consumer.

Abstract

Transport and associated handling can have adverse effects on pig welfare and meat quality. The purpose of the study was to determine (the variation of) effects of farm management, climate parameters, transport and lairage conditions on the meat quality of fattening pigs, heterozygous for the halothane gene. A total of 4763 fattening pigs were transported from 1 farm to a commercial slaughterhouse (distance 110 km) in 121 transports. From 2404 carcasses, carcass temperature and pH were measured 45 min post-mortem; 48 hours post-mortem pH, electrical conductivity, drip loss and meat color were registered. During the raising period sex, conditions at weaning (purchased or not as piglet, vaccination against mycoplasma) and (type of) pen during fattening (i.e., from about 22 kg to 105 kg) were registered to relate with pork quality. Transport season, weather parameters, regrouping or not during loading, transport combination (truck, trailer and driver), transport compartment and transport conditions (loading density, transport duration and unloading time) were monitored. At the slaughterhouse, duration of lairage and carcass conformation were followed up to examine correlations with meat quality parameters. Effects of farm management, climate parameters during transport, transport and slaughterhouse conditions on pork quality were demonstrated. Specifically, reducing lung lesions by vaccination during raising, no mixing of pigs during the transport process, sufficient lairage time and transporting no extreme muscled pigs can improve meat quality.

Effects of pre-slaughter short-term factors on pork quality

We examined the effects of pre-slaughter short-term factors including season of the year, duration of transportation and lairage time, as well as sex of pigs, on pork quality. Meat samples were collected from 590 pigs (females, entire and castrated males) that were slaughtered in a commercial abattoir in Greece over a 15-month period. Meat quality parameters pH, colour, drip loss, cooking loss, Warner–Bratzler shear values and sarcomere length were measured on the longissimus dorsi. DNA was isolated from blood samples and the frequency of the recessive halothane gene mutation HALn was determined. The results demonstrated that pork quality with respect to pH and L* values was normal in 93.9% of the samples, with 5.1% of samples classified as PSE (pale, soft and exudative) and 1.0% as DFD (dark, firm and dry). Duration of transportation was critical: brief and long transfers had the ability to impair meat quality. A lairage time of 2–4 h before slaughter was adequate when the pigs were free of HALn and the climatic conditions were not extreme. Season of the year was a very important factor, with significant variations recorded in meat-quality parameters between winter and summer months. Finally, the sex of the animals was responsible for differences in meat quality, but these differences were small and unlikely to be identified by the consumers.

Prediction of carcass lean content by real-time ultrasound in Pietrain and negative stress Pietrain

Real-time ultrasound data of backfat thickness, longissimus muscle depth and longissimus area were carried out on 335 pigs (164 gilts and 171 barrows) using the Pie Medical Scanner 200 equipped with an ASP-18 probe and 3·5 MHz to predict carcass lean content in positive stress Pietrain (TT) and negative stress Pietrain (CC or CT). They were given food ad libitum and slaughtered at an average age of 213 days and an average weight of 101 kg. The day before slaughter, longitudinal and transverse images were taken at the last rib. After slaughter, the lean meat content was estimated by a CGM (capteur gras-maigre) equipped with an 8-mm diameter Sydel probe. The carcass lean proportion was higher in homozygote TT than homozygote CC and heterozygote CT individuals (P < 0·05). Gilts had more lean meat than barrows (P < 0·05). The correlation between the lean meat proportion and ultrasound backfat thickness (UBFT) or ultrasound longissimus muscle depth (ULMD) respectively was moderate. The prediction of lean meat proportion using UBFT, ULMD and ULMA gave an R2 which varied from 0·35 to 0·79. Real-time ultrasound is a tool that could potentially be used to predict the composition of pig carcasses before slaughter particularly if measurements can be taken with a higher degree of accuracy than at present.

Sound levels above 85 dB pre-slaughter influence pork quality

This study investigates whether sound levels above 85 dB(A), determined in literature as a critical sound level to induce stress in pigs, has also an effect on the pH of pork. Sound levels were recorded during pre-slaughter phases. A measure was taken after the arrival of the truck at the slaughterhouse, during unloading, lairage and just before stunning. The pH of the Longissimus thoracis or lumborum, 30 min after sticking (pH(30LT)) was measured. 8508 pigs were examined and the pH was measured on the carcasses. The results show that the cut-off value of 85 dB(A) during the pre-slaughtering phase is not only a threshold to evaluate animal welfare but can also be associated with a slower drop of pH if sound levels are b85 dB(A). Finally a linear mixed model for pH(30LT) was built with the sound level during lairage and the sound level prior to stunning as independent variables, having statistically the highest impact on pH(30LT) of pork.

Pre-slaughter handling and pork quality

Environmental variables, as sound levels, were collected during the pre-slaughter process in 18 different Belgian commercial slaughterhouses. Four pre-slaughter phases were determined: firstly after arrival of the truck at the slaughterhouse and just before unloading, secondly during unloading, thirdly at lairage and finally while moving to the stunner. A total of 8508 pigs was examined during the pre-slaughter process, of which the pH(LT) (M. longissimus thoracis), at 30 min post-mortem was measured. For each pre-slaughter phase, variables which might influence pork quality were determined. Moreover, this study made it possible to infer a checklist to represent and predict PSE traits of pork for all kind of pre-slaughter situations. The checklist shows also that the impact on pork quality is more decisive for the variables measured close to the stunning phase. Hence, this information is useful for the industry to optimize handling of pigs, reducing the risk for PSE traits.

Pre-slaughter rectal temperature as an indicator of pork meat quality

This study investigates whether rectal temperature of pigs, prior to slaughter, can give an indication of the risk of developing pork with PSE characteristics. A total of 1203 pigs were examined, measuring the rectal temperature just before stunning, of which 794 rectal temperatures were measured immediately after stunning. pH30LT (M. Longissimus thoracis) and temperature of the ham (Temp30Ham) were collected from about 530 carcasses, 30 min after sticking. The results present a significant positive linear correlation between rectal temperature just before and after slaughter, and Temp30Ham. Moreover, pH30LT is negatively correlated with rectal temperature and Temp30Ham. Finally, a linear mixed model for pH30LT was established with the rectal temperature of the pigs just before stunning and the lairage time. This model defines that measuring rectal temperature of pigs just before slaughter allows discovery of pork with PSE traits, taking into account pre-slaughter conditions.

Influence of loading method and stocking density during transport on meat and dry-cured ham quality in pigs with different halothane genotypes

The effect of loading method and stocking density in transit on meat and dry-cured ham quality was investigated in pigs with different halothane genotypes. A total of 507 Italian heavy pigs, supplied by two farms, were loaded by ramp or lift and transported unmixed for 35-55 min to the abattoir at a stocking density of either <0.4 or >0.6m(2) per 100 kg pigs. After overnight lairage in separate pens with free access to water, the pigs were slaughtered. Halothane genotype was assessed post mortem. Four hundred and thirty-nine pigs had a homozygous dominant (NN) genotype and 68 pigs were heterozygous (Nn). Carcass skin damage, meat quality traits and ham curing parameters were evaluated. Loading method and stocking density showed a negligible effect on meat and dry-cured ham quality while the predominant factor affecting these was the halothane genotype. Nn pigs produced meat with a faster rate of pH fall and lower water holding capacity as well as ham with higher weight losses in salting and greater incidence of defects in the dry-cured product. There were insignificant interactions between halothane genotype and loading method or stocking density. Overall, irrespective of pre-slaughter treatment, the Nn pigs were less suitable for the production of high quality products such as dry-cured ham.

Bayesian meta-analysis of the effect of fasting, transport and lairage times on four attributes of pork meat quality

Technological meat quality is a significant economic factor in pork production, and numerous publications have shown that it is strongly influenced both by genetic status and by rearing and slaughter conditions. The quality of meat is often described by meat pH at different times postmortem, as well as by color and drip loss. A meta-analysis based on a database built from 27 studies corresponding to a total of 6526 animals classified was carried out. The purpose of this meta-analysis was to study the effect of fasting, lairage and transport durations on four main attributes of the technological pork meat quality. A Bayesian hierarchical meta-regression approach was adopted. The results of our meta-analysis showed that fasting time had a significant effect on pH measured 24h post-mortem (pHu) and drip loss (DL) measured in longissimus muscle. While, lairage affected only the pHu in semimembranosus muscle. Interestingly, we found that DL was the lone attribute that was affected by transport time and its interaction with fasting time.

Meat and carcass quality in two pig lines of different stress-susceptibility genotype and their crosses

In order to investigate differences in carcass and meat quality between lines of different stress susceptibility, 150 pigs were slaughtered on 15 slaughter days, consisting of equal numbers of stress-susceptible (nn) pigs of a boar line, stress-resistant (NN) pigs of a sow line and stress-carrier (Nn) crosses of these two lines. Carcass quality was determined by a SKGII-device which combined four physical measurements into a carcass lean estimate and a conformation score, and meat quality traits were measured on the carcass and on a loin slice. Killing-out proportion was lower for the NN line compared with the Nn crosses and the nn line. Lean content increased and conformation score improved as the number of n alleles in the respective genotypes increased but the Nn genotype was closer to the nn genotype than to the NNgenotype. Similarly, a large difference in meat quality was found between the NN and the nn line, whereas the difference in meat quality between the Nn and the nn genotype was smaller than expected. This was probably due to the low-voltage stunning procedure. In addition, the method of transporting the pigs to the abattoir (by truck or by foot, for a distance 125 m) had a pronounced effect on meat quality in the loin.

The prevalence of PSE characteristics in pork and cooked ham--effects of season and lairage time

A total of 180 pigs was slaughtered in the same slaughterhouse, but divided in six different trials distributed over Winter (December-March) and Summer (April-September). Meat quality measurements (pH, electrical conductivity, color and/or water-holding capacity) were carried out 30 min, 24 and/or 35h after slaughter in three different muscles: M. gracilis, M. semimembranosus and M. longissimus dorsi. A tendency towards a higher proportion of PSE meat during Summer was found in the examined muscles. Moreover a higher protein, higher dry matter content, a lower water/protein ratio and a lower slicing yield were found for the cooked hams suggesting a higher PSE prevalence in the Summer. A lairage time between 2 and 4h during Summer and less than 2h during Winter was related to a lower proportion of PSE meat. The correlation coefficients between the individual meat quality variables were moderate, but showed the predictive power of the pH measured 24h post-mortem in the M. gracilis for meat quality.

Risk assessment of DFD meat due to pre-slaughter conditions in pigs

A polychotomous logistic regression model was used to identify and assess the risk factors for pork becoming dark, firm and dry meat (DFD). A total of 116 deliveries, comprising 3075 commercial pigs delivered from different farms to five commercial Spanish pig abattoirs were surveyed. The DFD condition was described as an ordinal response variable (normal, moderate and serious) based on measurements of pH(24) in the Semimembranosus muscle. The abattoir, the floor of the lorry, the season, the gender, and the stocking density during transportation influenced the risk of DFD, as well as on-farm fasting time, lairage time and estimated carcass lean content. No effect of the RYR1 gene in the risk of DFD was found. Abattoirs should be especially careful with females slaughtered in winter, where the risk of serious DFD is 4.6% higher than with males slaughtered in summer. The risk of DFD increased with high stocking density and lairage time, and with on-farm fasting times longer than 22h. Our results revealed that lowering the stocking density from 0.37 to 0.50m(2) per 100kg pig during transport would increase the risk of DFD pork by 11%.

Association of RYR1 and MYOG Genotype with Carcass and Meat Quality Traits in Grower-finisher Pigs

The study involved 110 hybrid grower-finisher pigs from Polish Large White x Polish Landrace sows sired by Pietrain breed boars and their crossbreds with the 990 line and Duroc. The aim of the study was to determine an association of the polymorphism of RYR1, myogenin (MYOG) genes and carcass meatiness level with carcass slaughter value and meat quality traits in hybrid pigs. Better meat quality was found in pigs of CC genotype at locus RYR1 than in those of CT genotype, with a similar carcass slaughter value and meat chemical composition. No significant differences were found in meat traits (carcass slaughter value) and quality between AA and AB genotypes at locus MYOG. Similarly, no significant differences were found between carcass meatiness ranges adopted in meat quality and its chemical composition, except for water holding capacity, which was higher in pigs with ⪬ 54% meatiness than in those with > 54%. Moreover, interaction was found between carcass meatiness range and RYR1 genotype in relation to backfat thickness and intramuscular fat content, as well as a connection between carcass meatiness range and MYOG genotype in relation to water-soluble protein content. The results indicate the need to continue selection work towards the elimination of allele T RYR1 gene’s in pedigree herds to improve meat quality in fatteners.

A review of welfare in cattle, sheep and pig lairages, with emphasis on stocking rates, ventilation and noise

Appropriate space allowances for animals are yet to be specifically determined for lairage. Space allowances that may be suitable for animals in lairage are suggested, based on reviewed studies of animals in transport, lairage and on farm. The longer animals are in lairage the more space they require, in order to be able to get up and lie down and lie undisturbed by congeners. Little work has been done on air quality and air flow characteristics in lairages. The range of ventilation must be sufficient to control levels of toxic or irritant gases such as carbon dioxide and ammonia and to remove excess heat and humidity; the latter being particularly relevant for pig lairages in hot weather. Intensities of sound measured in lairages often exceed 85 dB and there is evidence to suggest that such levels can be stressful especially for pigs; and human shouting appears particularly aversive to animals. Cattle vocalise in response to painful stimuli and to convey information to conspecifics that may be related to fear and distress. There is limited evidence that sheep adapt to continuous sound, provided it is not too loud, but respond to intermittent sounds such as gates banging and human shouting. Vocal communication between sheep may be less important than that between cattle and pigs. Levels of vocalisation are potential indices of animal welfare. Animals' prior experiences and factors such as sex, group size and constitution, pen design, and climatic or environmental conditions affect their welfare and responses to conditions in lairage.

Effect of the insulin-like growth factor-II and RYR1 genotype in pigs on carcass and meat quality traits

Recently, a new QTN (quantitative trait nucleotide), which is located in the regulatory sequence of the imprinted IGF-II gene was discovered in the pig and is associated with a significant increase in IGF-II mRNA expression in skeletal muscle during postnatal growth. The aim of the current study was to investigate the effect of the IGF-II paternal allele (Apat and Gpat animals that inherited, respectively, the mutant and wild type paternal allele of interest) on carcass and meat quality traits in Nn and NN RYR1 genotypes. A total of 141 animals were measured, almost equally distributed over the IGF-II and RYR1 genotypes and gender. The Apat allele increased carcass lean meat percentage with approximately 4.5% (P<0.001) as a result of decreased backfat thickness. Average live weight daily gain was not affected, hence average daily lean meat gain was significantly higher for Apat compared to Gpat animals. The IGF-II mutation had no noticeable effect on meat quality in contrast with the RYR1 mutation. No interaction effects of both mutations on meat quality were noticed.

The possibility of positive selection for both F18+ Escherichia coli and stress resistant pigs opens new perspectives for pig breeding

F18(+)Escherichia coli infections causing post-weaning diarrhoea and/or oedema disease are a major cause of economic losses in pig industry. To date, no preventive strategy can protect pigs from F18(+)E. coli infections. One of the most attractive approaches to eliminate F18(+)E. coli infections is the selection for pigs that are resistant to F18(+)E. coli infections. However, this strategy was not believed to be favourable because of reports of genetic association with the stress-susceptibility gene in the Swiss Landrace. To investigate this potential association more thoroughly, 131 randomly selected Belgian hybrid pigs were genotyped for both the F18(+)E. coli resistance alleles (FUT1(A)) and the stress-susceptibility alleles (RYR1(T)) and their association was investigated by determining the linkage disequilibrium. This linkage disequilibrium (LD=-0.0149) is close to zero and does not differ significantly from 0 (likelihood ratio test chi(1)(2)=1.123, P=0.29), demonstrating no association between the FUT1(A) and RYR1(T) alleles. Furthermore, only a small fraction (4.6%) of the Belgian pigs was found to be resistant to F18(+)E. coli infections. Our results suggest that selection for F18(+)E. coli resistant pigs might be an attractive approach to prevent pigs from F18(+)E. coli infections, unlike to what has previously been postulated.

Effect of withholding feed from swine before slaughter on carcass and viscera weights and meat quality1

Two experiments were conducted to determine the effect of feed withholding on carcass and viscera weights and meat quality in grow-finish swine. Experiment 1 included 528 pigs that were marketed from 24 pens and subjected to either 6 (control) or 24 h of feed withholding before marketing. Experiment 2 included 324 pigs that were marketed from 36 pens that were subjected to 6 (control), 16, or 24 h of feed withholding before marketing. In both experiments, pigs from each pen were marketed over a 14-d period in three groups, each 7 d apart. In Exp. 1, withholding feed for 24 h decreased viscera weight, carcass weight and yield, and feed intake during the 14-d marketing period compared with the control group (P < 0.05). Subjective measures of color, firmness, and marbling in fresh pork did not differ for the two treatment groups. In Exp. 2, withholding feed for 16 or 24 h decreased (P < 0.05) viscera weight compared with that of the control group. Withholding feed for 24 h decreased feed intake during the 14-d marketing period compared with intake of the control group. Withholding feed for 16 h did not decrease carcass weight, but carcass weights in the 24-h group were lower than those of the 16-h group in this Exp. 2 (P < 0.05). Color, firmness, marbling, and shear force did not differ among treatment groups in Exp. 2; however, cooking loss in pork from the control group exceeded that of the 24-h treatment. Gain:feed and ADG were not affected by treatment during the marketing period in either experiment. We conclude that withholding feed for either 16 or 24 h decreases viscera weight and feed intake during the marketing phase in finishing swine. These changes could potentially benefit both the producer and the processor with only minimal effects on carcass weight and pork quality.

Optimal lairage times and conditions for slaughter pigs: a review

Keeping pigs in lairage provides a buffer to supply the slaughter line and allows the pigs to recover from the stress of transport. It has implications for the pigs' welfare by influencing their behaviour and ease of handling. In terms of pork quality, optimal lairage times for most pigs in the UK are probably one to three hours. Shorter lairage times are associated with more pale, soft, exudative (PSE) meat and longer times are associated with more dark, firm, dry (DFD) meat, more skin blemishes caused by fighting, and a lower carcase yield. However, when pigs have not been previously stressed by handling procedures, resting them in lairage may have no beneficial effects on the pigs' welfare or meat quality. At very high environmental temperatures there is evidence that a holding period of less than one hour may help to reduce the number of PSE carcases. At temperatures above 10 degrees C showering the pigs with water is beneficial. Fasting times need to be controlled to minimise the potential loss of carcase yield while reducing the volume of gut contents to reduce the risk of carcase contamination. Lairages can act as reservoirs of infection by pathogenic bacteria and there is evidence that longer holding times increase the risk of cross-contamination.