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 35 h 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 4 h during Summer and less than 2 h 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 24 h post-mortem in the M. gracilis for meat quality.     

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 24 h 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.     

Finishing diet,temperament and lairage time effects on carcass and meat quality traits in steers

Sixty Hereford (H) and Braford (B: 3/8 Zebu and 5/8 H) steers were finished on: D1) rangeland plus corn grain (1% of live weight) (H n = 15, B n = 15); and D2) high quality pasture (H n = 15, B n = 15) to study the effect of diet, temperament and lairage time on carcass and meat quality. Steers were slaughtered the same day in two groups, spending 15 and 3 h in pens, respectively (50% from D1, 50% from D2 in each group). Animals from D1 had better carcass performance without effect of the diet on meat quality. Regardless of breed, calmer steers showed higher average daily gain and lower shear force values. Carcasses from animals in the long lairage group had a better rate of pH decline and more tender meat, suggesting that more than 3 h preslaughter time should be necessary to rest and recover, mainly depending on lairage conditions.     

Effects of fasting prior to slaughter on pH development and energy metabolism post-mortem in M. longissimus dorsi of pigs

The aim of this study was to investigate the effect of pre-slaughter fasting time, sex and feeding regime on the development of energy metabolism and pH in M. longissimus dorsi (LD) post-mortem in pigs. Two hundred and seventy pigs of the commercial Norwegian crossbreed Noroc (LYLD) were used involving two sexes (gilts and castrates), two feeding regimes (restricted and ad libitum) and four different fasting treatments: (F4) 4 h fasting, (F175) 17.5 h fasting on the farm, (FO175) 17.5 h fasting overnight at the abattoir, and (FO265) 26.5 h fasting overnight at the abattoir. Additionally the pigs experienced two different abattoir lairage times as fasting treatment F4 and F175 had a lairage time of 1.5 h, while fasting treatment FO175 and FO265 had a lairage time of 23.0 h. A short fasting time of 4 h led to a delayed degradation of glycogen, slow decline in pH and a lower ultimate pH_{45 h} post-mortem (pHu) in the LD compared with a fasting time of 26.5 h which resulted in a rapid breakdown of glycogen and pH decline early post-mortem and a high pHu. Proglycogen was degraded in favour of macroglycogen under anaerobic conditions post-mortem. Feeding the animals in the morning before delivery if slaughtered the same day, results in low pH reduction rate and a low pHu compared with pigs fasted overnight either on farm or at the abattoir. Aiming a higher pHu in LD it should be recommended not to feed the pigs in the morning at the day of slaughter.     

Effects of different lairage times after long distance transportation on carcass and meat quality characteristics of Hungarian Simmental bulls

The objective of this study was to determine the effects of three lairage times (24 h, 48 h and 72 h) on the meat quality of tame trained to lead Hungarian Simmental bulls subjected to long commercial transportation of approximately 1800 km. A total of 30 bulls, with an average age of 24 months, were used. During the lairage, bulls received 0.5 kg concentrate feed per animal per day and ad libitum access to the hay and water. As the lairage duration increased, the pH_ult decreased (P < 0.05). Bulls lairaged for 24 h had lower L*, b* and H* values than those lairaged for 48 h and 72 h (P < 0.05). The effect of lairage time on WHC, cooking loss and Warner–Bratzler shear force values was not significant. The b* value was considered the best predictor of muscle pH_ult. In conclusion, 72 h quiet lairage time is recommended after transportation in order to prevent the adverse effects of transportation on meat quality.     

Animal welfare and meat quality: The perspective of Uruguay,a “small” exporter country

Public sensitivity towards animal welfare has risen in recent years. Uruguay is a primary meat exporter. Therefore, it is compulsory not only to provide good quality and safe meat, but also to project a welfare friendly image. Uruguayan meat production systems are mainly based on rangeland pastures but, due to international meat prices and the opening of new markets, intensive fattening systems increased. These systems include a wide range of feeding alternatives between pasture and concentrate utilization, involving differences in terms of animal welfare, carcass and meat quality, that require to be studied. Accordingly, some husbandry practices associated mainly with extensive systems must be evaluated, as well as their applicability to international recommendations related to pre-slaughter handling which may not be suitable for local conditions. In the present paper we share scientific results related to the impact of different production systems, husbandry practices and pre-slaughter procedures associated to animal welfare and meat quality in Uruguayan conditions.     

Effects of lairage time on welfare indicators,energy metabolism and meat quality of pigs in Beijing

A total of forty Duroc–Landrace–Large White female pigs (90 ± 5 kg) were used to study the effects of different lairage times (0 h, 3 h, 8 h, 24 h) on welfare, energy metabolism and meat quality. The results showed that lairage time of 3 h led to a lower blood cortisol, a decreased drip loss and a delayed degradation of glycogen in muscles compared with pigs without rest, while lairage times of 8 h and 24 h resulted in a significant increase in pork toughness. It was concluded that three hours of lairage was appropriate to reduce pre-slaughter stress and obtain better meat quality for pigs transported for 4 h in winter, under the most frequent commercial conditions in Beijing, China. No lairage, or excessively long lairage time, might compromise animal welfare and meat quality.     

The efficacy of disinfectant misting in the lairage of a pig abattoir to reduce Salmonella and Enterobacteriaceae on pigs prior to slaughter

Water misting/showers are used in abattoir lairages to improve meat quality, and to cool and calm pigs after transport and during hot weather. One novel approach, which has not been investigated to date, is to add a disinfectant to the misting water as a means of topically reducing Salmonella on pigs prior to slaughter, thereby potentially controlling this organism in the abattoir. The objective of this study was therefore to evaluate misting with water or with Virkon^® S (an approved disinfectant for use in the presence of animals), for their ability to topically reduce Salmonella on high seroprevalence pig herds before stunning and to reduce Enterobacteriaceae.Three experimental groups were investigated: control group (i.e., no misting); water group (misting with cold, 15–17 °C, water, herein referred to as water); and a disinfectant group (misting with 0.5% Virkon^® S). As pigs entered the abattoir, each animal was swabbed along its back before being allocated to its experimental group. Each group was randomly assigned to one of 3 lairage pens that were separated by non-trial pens. After 30 min of misting with water or disinfectant, pigs were moved to the stunning area, where each pig was again swabbed, as above. Swabs were analyzed for the presence of Salmonella and enumeration of Enterobacteriaceae.Before misting, Salmonella prevalence on the pigs was 79.0%, 72.1% and 83.6% for the control, water and disinfectant groups, respectively. After misting, Salmonella prevalence increased to 94.3% in the water group; whereas for the disinfectant group, the prevalence increased marginally to 85.9%. No change in Salmonella prevalence was detected for the control group. In line with the Salmonella results, no significant differences were observed in Enterobacteriaceae counts in the control group at either time point (4.37 and 5.01 log₁₀ CFU/cm², respectively) or in the disinfectant group before and after misting (4.02 and 4.26 log₁₀ CFU/cm², respectively). However, a 2.3 log₁₀ CFU/cm² increase in Enterobacteriaceae was recorded for the water group after misting as compared to before misting (p < 0.05).Since misting with water alone increased topical Salmonella contamination on pigs before slaughter, a risk assessment based on known Salmonella data, meat quality and welfare is recommended to determine whether its use is justifiable. On the other hand, the findings from this study suggest that misting with Virkon^® S at 0.5% could have a role in topical antisepsis of pigs contaminated with Salmonella prior to slaughter and as such this warrants further investigation.     

Effect of lairage duration on rabbit welfare and meat quality

This study determined whether short (2 h) or long (8 h) lairage at an abattoir had an effect on plasma stress indicators (haematocrit, glucose, lactate, creatine phosphokinase and corticosterone), instrumental meat quality (pH24, water holding capacity, colour, raw and cooked texture) and sensory meat quality (using a trained sensory panel) in rabbits. The effect of the position of the animals on a multifloor rolling cage stand during lairage was also assessed. Lairage time had a significant effect on blood stress indicators, but only a slight effect on meat quality traits. A lairage duration of 6–8 h is recommended.     

Detection and characterization of Salmonella in lairage, on pig carcasses and intestines in five slaughterhouses

In this study, conducted at five slaughterhouses, individual pigs were sampled and followed up from stunning to cooling down of the carcasses. In this way, Salmonella prevalence and possible risk points were described. At the lairage area, pens were sampled using overshoes. At stunning and bleeding, pigs were individually identified and subsequently swabs were taken of the oral cavity and the carcass after polishing, splitting and forced chilling. Additionally, duodenum, ileum, rectum and mesenteric lymph nodes were extracted and samples were taken of the scalding water. All samples were submitted to Salmonella isolation and Salmonella isolates were serotyped and genotyped by pulsed-field gel electrophoresis (PFGE). Of all samples taken (n = 1953), 14.1% were Salmonella positive. The prevalence of S. in the lairage area varied widely (from 0 to 100%) between the slaughterhouses. Of the sampled pigs (n = 226), 48.2% were positive in at least one sample. Statistical analysis revealed that the contamination of the lairage area was related to a higher amount of positive carcasses after polishing. Furthermore, the contamination of the carcasses after splitting and forced chilling was related to the contamination level of the carcass after polishing. A relation between the outer (carcass) contamination and the inner (gut content and lymph nodes) contamination of a pig could not be established. The predominant serotypes were S. Typhimurium (58.7%) and S. Derby (17.4%). Genotyping revealed 46 different PFGE profiles among the 276 Salmonella isolates. The same genotype at the lairage area as in the oral cavity of the pigs was found in 95%. The results indicate that the lairage area is a primary source of Salmonella in slaughter pigs and that carcass contamination originates from the environment rather than from the pig (inner contamination) itself. It further shows that slaughterhouses vary in their capability of dealing with Salmonella positive pigs. A slaughterhouse specific approach is needed, however, general guidelines should be provided to decrease the contamination level of the lairage area and the slaughter environment.