Pre-slaughter Treatment Research Articles

Change in physiological parameters of calves of various breeds under the transport and pre-slaughter stress

Levakhin VI, Gorlov IF, Azhmuldinov EA, Levakhin YI, Duskaev GK, Zlobina EY, Karpenko EV. 2017. Change in physiological parameters of calves of various breeds under the transport and pre-slaughter stress. Nusantara Bioscience 9: 1-5. The purpose of the research was to study the effect of the animal breed on the stress resistance of young cattle during the motor transportation. Six groups of animals were chosen for the experiment. The first group consisted of calves crossbred from dairy Black and White cows with Hereford bulls, the second – of calves crossbred from dairy cows of Bestuscheff breed with Hereford bulls, the third – of calves purebred of Simmental, the fourth – of calves purebred of Hereford, the fifth – of calves purebred of Aberdeen-Angus, and the sixth – of calves purebred of Limousine breed. The total length of transport was 180 km of highways and local roads. The route consisted of a 5-hour trip without a rest period. The greatest loss in the body weight was determined in the Limousine calves. The calves purebred of Hereford and Simmental breeds are more stress-resistant during the transporting and the pre-slaughter treatment.

The Effect of Non-Stunned and Stunned Halal Slaughter Method on Broiler Breast Meat Quality

Purpose: This study was designed to investigate the effect of pre-slaughter treatment, i.e. stunned vs. non-stunned, on the quality attributes of Halal broiler breast meat. Design/Methodology/Approach: Samples of non-stunned broiler breast meat (n=10) and stunned broiler breast meat (n=10) which have undergone the Halal slaughter method were analysed on the quality parameters of protein solubility, emulsion activity index, emulsion stability index, pH, water holding capacity (drip loss and cooking loss), texture (shear force textural analysis), meat colour (L, a, b analysis) and sensory evaluation. The results were then analysed for statistical differences using the Mann-Whitney Test on SPSS. Findings: The study revealed that stunned meat had a significantly higher protein solubility compared to non-stunned meat (p<0.05). However, no significant differences were found between the two samples for emulsion activity index, emulsion stability index, pH and water holding capacity. Texture analysis revealed that cooked samples of stunned meat was significantly tougher than cooked samples of non-stunned meat (p<0.05). This correlated with sensory analysis where the non-stunned meat was preferred on overall. Non-stunned meat samples exhibited significantly lower lightness (L*) and yellowness values (b*) and significantly higher redness (a*) and Chroma (C*) values as compared to stunned meat (p<0.05). Research limitations/Implications: Further analysis on glycogen content, lactic acid content and measurements of proteolytic activity (cathepsins and calpains) could be undertaken to further support the study. A trained panel using a scoring method with a bigger sample group could be undertaken for more detailed sensory analysis. Originality/Value: There are studies comparing different stunning methods on broiler meat quality but no present study comparing non-stunning and stunning on Halal broiler meat quality.

Wonder world of phages: potential biocontrol agents safeguarding biosphere and health of animals and humans- current scenario and perspectives.

Darwin's theory of natural selection and concept of survival of fittest of Wallace is a universal truth which derives the force of life among all live entities on this biosphere. Issues regarding food safety along with increased drug resistance and emerging zoonotic infections have proved that multidisciplinary efforts are in demand for human and animal welfare. This has led to development of various novel therapies the list of which remains incomplete without mentioning about phages. Homologous and non-homologous recombination along with point mutation and addition of new genes play role in their evolution. The rapid emergence of the antibiotic resistant strains of bacteria have created keen interest in finding necessary alternatives to check microbial infections and there comes the importance of phages. Phages kill the bacteria either by lysis or by releasing holins. Bacteriophages; the viruses that live on bacteria are nowadays considered as the best biocontrol agents. They are used as replacers of antibiotics; food industry promoter; guard of aquatic life as well as of plants; pre-slaughter treatment agents; Generally Recognized As Safe (GRAS) food additives; Typing agent of bacteria; active tool of super bug therapy; in post harvest crops and food and during post infection and also to combat intracellular pathogens viz. Mycobacteria and Mycoplasma. Cyanophages/phycophages are particularly useful in controlling blooms produced by various genera of algae and cyanobacteria. By performing centrifugation studies and based on electron microscopy certain virus like particles containing ds RNA have been confirmed as mycophages. They are well proven as threat to pathogenic fungi (both fungal hyphae and yeast). Those that infect yeasts are called zymophages. Virophages have exquisite specificity for their viral host, hence can extensively be used for genetic studies and can also act as evolutionary link. After the discovery of very first virophage till now, a total of 3 virophages have been discovered including the Sputnik virophages that are used to study genetic recombination. Virophages also find their application in antiviral therapy; as engineer of ecological system etc. In brief, present review deals with various dimensions of these beneficial viruses that are being used and can be successfully used in future for safeguarding biosphere including animal and human health.

Relationship of transport distance, sex on live weight loss of pigs during transit to slaughter house

The transport distance have a significant impact on the levels of stress burden on animals before slaughter and have an impact on veterinary decision-making about meat edibility and also on the quality of slaughtered animal meat. The objective of the study was to determine live weight, dress weight and body weight loss during transportation of different sex group of pigs into the Slaughtering house. The body weight loss during preslaughter treatment of animals was recorded and carcass value traits were assessed in details. Relationship between pig live weight and dress weight was reported as dress weight = 1.06 + 0. 73 live weight. There were significant effect of sex and transport distance on live weight at slaughter, carcass weights and dressing percentage (p<0.01). Pigs given the short transport (4 Km) lost 23.01 % and pigs given the long transport (90 Km) 29.37% of their initial live weight. Overall, dressing percentage was negatively correlated with the percentage loss of live weight in transport (P<0.01). As conclusion, long transportation of the pigs is a great stress factor and has adverse effects on the live weight of the pigs.

Effect of pre-slaughter management regarding transportation and time in lairage on certain stress parameters, carcass and meat quality characteristics in Kivircik lambs

Thirty Kivircik lambs were used to investigate effect of pre-slaughter treatment on certain haematological and biochemical parameters, carcass and meat quality characteristics. Lambs were divided into three treatments: 75 min transport and lairage for 18 h (TS-L18 h); 75 min transport and lairage for 30 min (TS-L30 min) and no pre-slaughter transport and lairage for 30 min (NTS). Treatment, as a main effect, did not influence haematological and biochemical parameters, but sampling time significantly affected these parameters, except total protein. Plasma cortisol concentration at exsanguination in TS-18 h, TS-30 min and NTS treatments were 117.34, 119.23 and 72.51 ng/ml, respectively. pH of longissimus dorsi muscle was higher in TS-L30 min than other treatments. TS-L30 min lambs had the highest shear force value, the lowest WHC and cooking loss. TS-L30 min treatment yielded the darkest meat immediately after cutting and 1 h later. Meat redness, yellowness and chroma values were similar in treatments.

Slaughter value, meat quality, creatine kinase activity and cortisol levels in the blood serum of growing-finishing pigs slaughtered immediately after transport and after a rest period

The experimental materials comprised 44 hybrid [female (Polish Large White x Polish Landrace) x male Duroc] growing-finishing pigs. The animals were randomly divided into two groups: 24 pigs were slaughtered immediately after transport and 20 pigs were slaughtered after a 24-hour rest period in the lairage. The meat content of pork carcasses, carcass dressing percentage, the proximate chemical composition, physicochemical and sensory properties of meat and shear force values were determined. Serum creatine kinase activity and cortisol levels were determined in blood samples collected before transport and during carcass bleeding. Pigs slaughtered immediately after transport, compared with those slaughtered after a 24-hour rest period, were characterized by a higher meat content of the carcass and a higher carcass dressing percentage. Pre-slaughter handling had no effect on pork quality. The incidence of normal-quality meat, partially PSE (pale, soft, exudative) meat and PSE meat was similar in both groups. Chemical analysis showed that the content of dry matter, total protein, fat and minerals in meat was comparable in both groups. As regards the functional properties of the pork, samples from the carcasses of pigs that had rested before slaughter had a higher contribution of the red color component. Meat from pigs slaughtered immediately after transport had more desirable sensory properties. Pre-slaughter resting had a significant effect on those analyzed physiological parameters which were found to be good indicators of pre-slaughter stress. Serum creatine kinase activity and cortisol levels were higher in blood samples collected after transport (during carcass bleeding) than in samples collected before transport, pointing to a strong stress response of animals to pre-slaughter treatment. The decrease in serum cortisol levels in blood samples collected during bleeding from the carcasses of pigs slaughtered after a 24-hour rest period, compared with samples collected from animals slaughtered immediately after transport, suggests that rest before slaughter alleviated stress induced by pre-slaughter handling operations.

Management of young goats during prolonged fasting affects carcass characteristics but not pre-slaughter liveweight or cortisol

Effects of pre-slaughter management (72 h continual fasting; 24 h feeding within 72 h fasting; 24 h feeding plus 6 h additional transport within 72 h fasting) and of water availability, gender, weaning 3 weeks before slaughter, initial liveweight (LW) and body condition score (CS) on LW, plasma cortisol and carcass characteristics were studied in young goats. The goats (n = 229) were ~16 weeks of age, with a mean ± s.d. LW of 13.7 ± 2.4 kg. Pre-slaughter treatment did not significantly affect LW or carcass weight at slaughter, but goats fed within the fasting period had lighter-coloured meat compared with the continually fasted goats and the goats fed and transported during the fasting period. Interactions between fasting treatment and gender were evident for hot carcass weight (HCW), retail yield (kg) and dress (% pre-fasting LW). Fasting treatment also interacted with water availability for HCW and with weaning status for GR (12th rib, 110 mm from mid-line) tissue depth. Interactions were evident between gender and water availability for LW at slaughter, and between gender and weaning status for retail yield (% HCW). Weaning status interacted with pre-fasting LW to influence LW at slaughter, and fasting treatment interacted with pre-fasting body CS to influence dress (% pre-slaughter LW). The effects of gender, weaning status, water availability, initial LW and CS on the pre-slaughter LW and carcass characteristics were generally consistent with our previous findings on time off feed. The results show benefits of providing high-quality feed and water and of minimising transport of goat kids during prolonged pre-slaughter fasting. They provide additional information for estimation of carcass characteristics of young goats to be marketed for meat and to aid in the further development of welfare standards for goats. Further research on interactions between gender and pre-slaughter management factors that influence goat carcass characteristics and meat quality is warranted.

Kinetics of Phage-Mediated Biocontrol of Bacteria

Bacteriophages (phages) are the viruses of bacteria. One subset of phages, those that can be described as obligately lytic, can effect an active phage therapy because their population growth occurs at the expense of bacterial survival. That is, phages can be employed to reduce bacterial loads--such as in animals preslaughter, in foods postharvest, or in humans postinfection--and in the process can actually increase what in pharmacological terms would be their antibacterial dose. This self-amplification may provide advantages if either antibacterial dosing or penetration to target bacteria is otherwise constrained. One situation in which these kinetic aspects of drug delivery may be constrained is in preslaughter treatment of food animals toward control of zoonotic pathogens (e.g., Escherichia coli O157:H7 in cattle). In such treatment, the self-amplifying nature of phages may be harnessed, though potentially under time constraints. In this discursive I cover three areas. The first is semantic, where I contrast the terms phage therapy and phage-mediated biocontrol of bacteria, both of which are employed to describe similar but perhaps not identical procedures. Second, I consider the importance of time in therapy or biocontrol procedures while contrasting passive versus active therapies. Third, I discuss conceptually how to go about modifying phage characteristics to increase rates of phage population growth and do so explicitly by casting phage infection in terms of Michaelis-Menten saturation kinetics. I conclude suggesting that phage therapy ultimately may be rationally guided by theoretical considerations of the impact of phage properties on rates of phage population growth.

The performance and meat quality of Bonsmara steers raised in a feedlot, on conventional pastures or on organic pastures

The effects of production system (feeding regime and time on feed) on growth performance, yield and economics and the effects of feeding regime, pre-slaughter treatment and electrical stimulation on meat quality were evaluated. Sixty Bonsmara steers were divided into three treatment groups, viz. feedlot, organic pasture and conventional pasture feeding. The feedlot and conventional pasture groups received a diet consisting of the same components, while the organic group received a diet with approved organic components. Initial weight, final live weight, warm carcass weight, cold carcass weight, warm and cold dressing percentage, average daily gain (ADG), pH at one and 24 hours post mortem, intramuscular fat content of the loin and subcutaneous back fat thickness were measured. The effects of electrical stimulation, feeding regime and pre-slaughter rest (recovery days at the abattoir) on meat tenderness were also investigated. Feedlot cattle had significantly higher final weights, warm and cold carcass weights, warm and cold dressing percentage, ADG, intramuscular fat content and back fat thickness measurements than organic and conventional pasture cattle. Pre-slaughter resting of animals for a week at the abattoir had no effect on meat tenderness, but electrical stimulation showed a significant positive response. Growth and carcass results were used to calculate price and feed margin for the different production systems. Feedlot cattle showed a higher profit than conventional and organic pasture groups, mainly due to faster and more efficient growth. The organic pasture cattle showed higher profit than the conventional pasture cattle as a result of the premium paid for the organically produced meat.

Modifications of Trout (Oncorhynchus mykiss) Muscle Proteins by Preslaughter Activity

The effect of two different preslaughter procedures (limited or 15-min intense muscular activity) on muscle trout proteins was investigated. Muscle was sampled 45 min and 24 h post-mortem, proteins were separated using two-dimensional electrophoresis, and spots of interest were tentatively identified by MALDI-TOF spectrometry. Twenty-nine and 4 spots were differentially represented between the two groups of fish at 45 min and 24 h post-mortem, respectively. Spots that could be identified corresponded mainly to proteins involved in energy-producing pathways (triosephosphate isomerase, enolase, pyruvate dehydrogenase) or to structural proteins (desmin, cap-Z, myosin heavy chain fragment). Persistent under-representation of desmin, a key cytoskeletal protein, in fish submitted to intense muscular activity suggests that such a preslaughter treatment can have an effect on post-mortem muscle integrity.

Effects of available dietary carbohydrate and preslaughter treatment on glycolytic potential, protein degradation, and quality traits of pig muscles1

The current study was conducted to determine the interactive effects of a glycogen-reducing diet fed to finishing pigs and length of preslaughter transportion on muscle metabolic traits, proteolysis of intermediate filament and costameric proteins, and meat quality traits. Large White gilts and barrows (n = 48) were selected at 88 kg of BW and individually fed for 21 d a diet (2.6 kg/d) either high (HC) or low (LC) in available carbohydrates. Six gilts and 6 barrows fed the HC and LC diets were subjected to 0 or 3 h of transportation on the day of slaughter. Muscle temperature and pH were measured at 0.5, 1.5, 2.5, 3.5, 4.5, 5.5, and 24 h postmortem in the LM and 24 h postmortem in the dark (STD) and light (STL) portion of the semitendinosus. At 24 h postmortem, glycolytic potential (GP) was determined in the LM, STD, and STL, as well as proteolysis of titin, nebulin, desmin, vinculin, and talin in the LM and STD. The GP was lower (P < 0.05) in muscles from LC-pigs than in muscles from HC-pigs. The LC diet also resulted in lower (P < 0.05) pH, and a darker (P = 0.03), less (P < 0.01) yellow color in the STL. The LC diet decreased (P = 0.04) cooking losses in the STL and STD. The 3-h journey further decreased (P = 0.05) the GP in the STD, regardless of the diet, but transport had no effect (P > or = 0.67) on the GP of the LM and STL. Ultimate pH of the LM was lower (P = 0.02), and both portions of the semitendinosus were darker (P = 0.01) and less yellow (P < 0.01), in pigs transported 3 vs. 0 h. In pigs transported for 3 h, intact vinculin tended to be more (P = 0.08) degraded in the LM, which coincided with lower (P = 0.04) drip losses in the LM of pigs transported for 3 compared with 0 h. Increased (P < 0.01) proteolysis of titin paralleled lower (P = 0.02) shear force values in the STD of pigs transported 3 vs. 0 h. Although the present results demonstrated the potential of a glycogen-reducing diet to alter the GP of different porcine muscles, the effect of these changes on meat quality traits was limited to higher ultimate pH and darker color in the STL. The positive effects of length of transportation on water-holding capacity (LM and STD) and meat color (STD and STL) were only partially related to the resting muscle glycogen concentration because the 3-h transport lowered the GP only in the muscle with the lowest basal glycogen concentration.

Early post-mortem discrimination of water-holding capacity in pig longissimus muscle using new ultrasound method

Newly developed ultrasound equipment was tested for on-line determination of water-holding capacity (WHC) early post mortem (p.m.). The experiment was based on measurements of m. longissimus dorsi (LD) from 10 pigs, five of which were treated to result in pork with high WHC and five to result in pork with low WHC. Ultrasound measurements were carried out on the carcass of each pig every ten minutes from 15 to 85min p.m. at three locations of the LD. Low field nuclear magnetic resonance (NMR) measurements were performed on excised samples simultaneously with the ultrasound measurements and at 24h p.m. Drip loss was measured by Honikel's bag method. The ultrasound experiment demonstrated that classification of meat with high and low WHC was possible, but only at 85min p.m., and only by the measurements obtained at the posterior end of the LD. NMR measurements underlined that there are structural differences in meat influenced by pre-slaughter treatment prior to 85min p.m. However, meat properties that determine WHC were apparently not expressed sufficiently to be registered by the applied pragmatic handheld ultrasound equipment before 85min p.m.

A comparison of halothane homozygous negative and positive pietrain sire lines in relation to carcass and meat quality, and welfare traits

Barrows ( n=164) and gilts ( n=249) from crosses of a Pietrain homozygous halothane recessive (Pi nn) and two Pietrain homozygous dominant (Pi NN-a and Pi NN-b) sire lines with Landrace×Large White NN sows, were used to study the effect of terminal sire and pre-slaughter treatment on meat quality and animal welfare. The pigs from each of the two farms where they were finished were delivered to the abattoir in two batches differing in the pre-slaughter conditions. A total of 90 pigs (54 NN and 36 Nn) were assigned to a long pre-slaughter treatment (6 h transport and 14.5 h lairage) and 89 (57 NN and 33 Nn) to a short pre-slaughter treatment (4.5 h transport and 2.5 h lairage) in Farm 1, and 118 (65 NN and 53 Nn) to the long (7 h transport and 14 h lairage) and 114 (66 NN and 48 Nn) to the short pre-slaughter treatment (1.5 h transport and 2 h lairage) in Farm 2. In Farm 1, heart rate of 3 NN and 3 Nn gilts was recorded throughout loading and transport and blood samples from 5 NN and 5 Nn were collected before loading and after transport to measure cortisol, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH). Carcasses were classified and commercial cutting was carried out. At 24 h, meat quality was assessed on the Longissimus thoracis muscle by measuring electrical conductivity (PQM), colour (Minolta CR 200 and Japanese scale), pHu and drip losses. Halothane carriers showed a higher mean heart rate and higher increase in CPK levels ( P<0.05) after transport in the short pre-slaughter treatment than halothane free pigs. No effect was observed in cortisol or LDH values. Pi NN-a sired pigs had a higher live and carcass weight ( P<0.001) and loin depth ( P<0.05), but lower killing out percentage ( P<0.01) and leg yield ( P<0.01) compared with the progeny of the other two terminal sires. Gilts were leaner ( P<0.001), had a higher killing out percentage ( P<0.001) and higher yields of primal cuts ( P<0.001) compared with barrows. Pi nn sired pigs had poorer meat quality (higher PQM values in both farms, P<0.01) than Pi NN-a sired pigs. Long pre-slaughter treatment resulted in darker meat ( P<0.01) in both farms and in higher pHu ( P<0.001) in Farm 1 than short pre-slaughter treatment. Conversely, pigs subjected to the short pre-slaughter treatment showed higher PQM values ( P<0.01) in Farm 1 and higher PSE percentage ( P<0.05) in both farms compared to the ones subjected to the long pre-slaughter treatment. These results suggest that Pietrain halothane free sire lines could produce similar results on carcass quality to halothane carriers, without compromising meat quality and welfare.

Effect of pre-slaughter physiological conditions on the oxidative stability of colour and lipid during chill storage of sliced, retail packed roast ham

Pre-slaughter physiological conditions (A serving as control, B subjected to treadmill exercise immediately prior to stunning, C epinephrine injection 15 h prior to slaughter, and D epinephrine injection 15 h prior to slaughter and subjected to treadmill exercise immediately before stunning) were found to significantly affect colour and lipid oxidation of sliced, retail packed roast ham, produced from nitrite-cured (78 ppm nitrite) M. Longissimus dorsi. The pre-slaughter treatment resulted in variations in the level of glycogen, lactate, ATP and IMP and pH development as monitored in Longissimus dorsi muscles, with the lowest ultimate pH (pH u) in muscles from non-epinephrine treated pigs (treatments A and B). The initial tristimulus L ∗-value and the L ∗-value during chill storage of sliced roast ham packed in laminates with low or with very low oxygen transmission rate (OTR=40 and <0.5 cm 3/m 2/atm/24 h, respectively) were significantly affected by treatment, although the effect of the treatments was different during storage for 28 days (interaction between treatment and storage time). Roast ham from treatments A and B generally had a paler appearance (higher L ∗-values) than from treatments C and D. No differences in the initial tristimulus a ∗-values (redness) were found. During chill storage, a pronounced colour fading (decrease in a ∗-values) was seen for laminate with low OTR, with a tendency of better colour stability for treatment C than A, but with no differences for the other treatments. For laminates with very low OTR, the cured meat pigment was stable with no decreases in a ∗-values during storage. Lipid oxidation (thiobarbituric acid reactive substances, TBARS) in products in laminates with low OTR increased during storage and was significantly higher for roast ham from non-epinephrine treated pigs (A and B) than for ham from epinephrine-treated pigs (C and D). Statistical analysis relating pH and the level of glycogen, lactate, creatine phosphate, ATP and IMP in the individual pigs to the product quality parameters revealed that the ultimate level of lactate was the most important single parameter affecting product quality. After 28 days of chill storage, roast ham from pigs subjected to treatments C and D were more likely to support bacterial growth than from treatments A and B. In conclusion, the results show that pre-slaughter physiological conditions are of importance for chemical as well as for microbiological changes in retail stored roast ham.

Effects of halothane gene and pre-slaughter treatment on meat quality and welfare from two pig crosses

Pigs from crosses of a Piétrain (Pi) and a Large White×Piétrain (LwPi) heterozygous (Nn) boar lines with Landrace×Large White homozygous negative (NN) sows, were used to study the effect of halothane gene and pre-slaughter treatment on animal welfare and meat quality. A total of 83 gilts (47 NN and 36 Nn) were assigned to a long treatment (3 h 15 min transport and 12 h lairage) and 73 (39 NN and 34 Nn) to a short treatment (30 min transport and 2 h lairage). Heart rate was recorded throughout loading and transport. Blood samples were collected before loading, after transport, and at exsanguination to measure cortisol, creatine phospho-kinase (CPK) and lactate dehydrogenase (LDH). Carcasses were classified and commercial cutting was carried out. Meat quality was assessed on the Longissimus thoracis muscle by measuring electrical conductivity (PQM), colour (Minolta CR 200 and Japanese scale) and ultimate pH. Loin drip losses were assessed at 24 h. Halothane carriers showed a higher increase in cortisol levels after transport and exsanguination in the long treatment ( P<0.05) as well as in LDH and CPK after exsanguination in the short treatment ( P<0.05). In this treatment, halothane-free pigs recovered during lairage when comparing LDH and CPK increases after exsanguination to their increases after transport. No effect of the halothane gene on heart rate was observed. Pi sired pigs were leaner and had higher yields of leg and loin compared with LwPi sired pigs ( P<0.001), but no differences in meat quality were observed between crosses. Halothane carriers had a higher estimated lean content ( P<0.01) and shoulder and leg yields ( P<0.01), but poorer meat quality than non-carriers (i.e. higher incidence of PSE meat, P<0.001). Although pre-slaughter treatment and halothane genotype did not significantly affect pHu, significantly higher L*, a* and b* values found in the short treatment and Nn individuals indicated paler meat. These results suggest that for improving meat quality and welfare the halothane gene should be removed from breeding schemes.

Effects of halothane genotype and pre-slaughter treatment on pig meat quality. Part 1. Post mortem metabolism, meat quality indicators and sensory traits of m. Longissimus lumborum

Forty-eight castrated F 2 offspring of Piétrain and Large White pigs were allocated to a 3 × 2 factorial design in order to study the interactive effect of halothane genotype (NN, Nn and nn) and pre-slaughter treatment [referred to as ‘Experimental’ (EXP) and ‘Commercial-like’ (COL) conditions; the latter combining short transportation, mixing unfamiliar pigs and slaughtering shortly after transport] on muscle post mortem changes and meat quality. The pigs were slaughtered over 4 days. Pre-slaughter glycogen depletion in M. longissimus lumborum (LL) was greater in the nn pigs, compared with the two other genotypes. Lactate accumulation post mortem in LL muscle was greater and the pH value at 40 min post mortem was lower in nn compared with NN pigs. Nn pigs were close to nn pigs for lactate accumulation and showed intermediate pH values in the LL muscle. In the M. semimembranosus (SM), NN and Nn pigs showed the same rate of post mortem changes, as evidenced by similar glycogen, lactate, creatine phosphate and ATP levels, and pH values at 40 min post mortem. Pre-slaughter treatment did not affect the rate of post mortem changes in both muscles and no interactive effect with halothane genotype was found. The pigs slaughtered under the ‘COL’ conditions had a significantly higher ultimate pH in the LL and SM muscles than those slaughtered under the ‘EXP’ conditions. The LL muscle from nn pigs was paler (higher L*) than that of NN and Nn pigs. In SM muscle, Nn pigs showed a significantly higher L* value than NN pigs. Drip loss of the LL muscle was significantly higher in nn compared with NN pigs, the heterozygous pigs being intermediate. Sensory evaluation of the LL muscle showed that nn pigs had a lower colour intensity and colour homogeneity of raw meat than NN and Nn pigs. Tenderness was significantly lower in nn compared with NN pigs, the Nn pigs being intermediate. Pre-slaughter treatment significantly increased ultimate pH in both muscles (LL and SM) but did not affect significantly the rate of pH fall (pH 40). It did not affect any of the meat quality traits and no interactive effect with halothane genotype was found. These results confirmed the influence of the halothane gene on the kinetics of muscle post mortem changes and related meat quality traits. They also confirmed the intermediate position of heterozygous pigs in terms of meat quality.

Effects of halothane genotype and pre-slaughter treatment on pig meat quality. Part 2. Physico-chemical traits of cured-cooked ham and sensory traits of cured-cooked and dry-cured hams

Forty-eight castrated F 2 offspring of Piétrain and Large White pigs were allocated to a 3×2 factorial design in order to study the interactive effect of halothane genotype (NN, Nn and nn) and pre-slaughter treatment (referred to as ’Experimental’ (EXP) and ’Commercial-like’ (COL) conditions; the latter involving short transportation, mixing unfamiliar pigs and slaughtering shortly after transport) on the qualities of cured-cooked and dry-cured hams. At 24 h post mortem, the hams were collected and assigned to cured-cooked (right ham) and dry-cured (left ham) ham processing. A sample of M. semimembranosus (SM) was collected before cooked ham processing, was used for chemical composition analysis, cured and then cooked at various temperatures. Cooking losses and compression tests were carried out after cooking on these SM samples. The water and collagen content of SM muscle was significantly higher in nn pigs compared with the two other genotypes. At all cooking temperatures (60, 65 and 70 °C), SM muscles from nn pigs showed higher cooking losses and instrumentally assessed toughness than the other genotypes, the heterozygous pigs being intermediate. The technological yield of cured-cooked ham processing was lower in nn, compared with NN and Nn animals. Cooked hams from nn pigs were drier, tougher, stringier and less smooth than NN and Nn pigs. The heterozygous pigs were similar to normal pigs for all texture characteristics with the exception of toughness for which they got a significantly higher score than NN pigs. The pigs slaughtered under the COL conditions had a better slice cohesiveness and a significantly lower dryness, than pigs slaughtered under the EXP conditions. The effect of HAL genotype on slice cohesiveness was significant only when pigs were slaughtered under the EXP conditions. Dry-cured hams from nn pigs showed significantly more visual defects, but were less tough, smoother and more fondant (softer) than NN and Nn pigs. The dry-cured hams from pigs slaughtered under the COL conditions had a better cohesiveness between muscles and a more intense yellow colour of fat than those from pigs slaughtered under the EXP conditions. COL pigs were also judged significantly less tough, smoother and more fondant than EXP ones. Overall, the effects of pre-slaughter treatment were small compared with those of the HAL genotype. The effects of HAL genotype on the sensory traits of cured-cooked ham were similar to those reported for fresh meat. However, the good textural characteristics of dry-cured ham processed from HAL positive pigs are somewhat surprising and need to be confirmed.

Influence of housing conditions on responses of pigs to preslaughter treatment and consequences for meat quality

The effects of housing conditions on behavioural and cortisol responses during preslaughter treatment, as well as the consequences for meat quality, were studied in 48 slaughter pigs. Pigs were either raised in intensive housing conditions ("standard" treatment: standard farrowing crates (4.2 m2) followed by standard rearing pens (0.5 m2/pig) and fattening pens (0.8 m2/pig) or in extensive conditions ("enriched" treatment: larger farrowing pens (7.2 m2) followed by larger rearing and fattening pens (both 1.2 m2/pig), all provided with straw).No differences in behaviour during transport or in any of the meat quality variables were found between treatments. During pre-slaughter handling, stockmen needed significantly less time to load pigs from standard housing conditions (standard: 56.8 ± 11.9 s; enriched: 93.7 ± 12.5 s). Standard pigs may have been more motivated to leave their pens in order to explore another environment than pigs from the enriched housing pens. Rise in salivary cortisol levels due to transport (standard: 6.68 ± 0.80 ng mL−1; enriched: 3.63 ± 0.58 ng mL−1) was difficult to interpret as omission of straw during the hours prior to transport apparently led to high baseline cortisol levels in enriched pigs (8.63 ± 1.27 ng mL−1 vs. 2.60 ± 0.37 ng mL−1 in standard pigs). The extensive housing system should be preferred as it is known to have positive effects on pig welfare, and does not lead to impaired meat quality. Key words: Behaviour, housing, meat quality, physiology, pigs, slaughter

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.

Effects of regular moving and handling on the behavioral and physiological responses of pigs to preslaughter treatment and consequences for subsequent meat quality.

The effects of regular moving and handling during the finishing period on behavioral and physiological responses of pigs during preslaughter treatment and consequences for meat quality were studied. From the age of 10 wk onward, 144 pigs were housed in groups of four (two gilts and two castrates) and subjected to one of the following treatments. The Environment treatment allowed pigs to move freely for 8 min outside their home pen. Then the pigs were transported in a box for 2 min, and after which they were returned to their home pen. In the Handling treatment, an experimenter remained for 3 min in the pen, and whenever a pig made contact, it was gently stroked. The experimenter then walked for an additional 1 min, without attempting to pat or stroke any pigs but subsequently held each pig in a tight grip for about 5 s. This entire procedure was then repeated. A Control treatment was also included, in which the pigs were subjected to no treatment. The Environment and Handling treatments were applied twice a week at the age of 15, 17, 19, 21, and 23 wk. At 25 wk of age, pigs were transported to the abattoir. They were held unmixed in the truck and in lairage and were manually stunned. The stockmen needed significantly less time to move Environment pigs out of their pen and into the transport box. There were no differences between treatments in salivary cortisol concentrations before or after transport. Environment and Handling pigs had paler meat than Control pigs. Glycogen content at 1 h after death and water-holding capacity were lower in Environment pigs than in Control pigs, but this did not lead to a higher incidence of PSE meat. We conclude that the pigs that had experience with leaving their home pen and some of the transport conditions were much easier to handle at loading. Pigs that are easier to move are less likely to be subjected to rough handling, which implies improved welfare, and the workload for personnel at the time of marketing is reduced. Differences in meat quality due to treatment were slight.