The effect of two handling and slaughter systems on skin damage, meat acidification and colour in pigs

Animal welfare towards sustainability in pork meat production

Animal welfare is an important pillar of sustainability in meat production and is associated with other aspects of this concept, such as animal health, productivity, food safety, food quality and efficiency from a cost of production perspective. These interactions are present at all stages of the production cycle, from the beginning of the animals' farm life until their slaughter. On farm, some of the main welfare issues are related to neonatal mortality and low level of sensory input, which are likely to engender stereotypes and injurious behaviours, such as tail-biting. Pre-slaughter handling refers to the interaction between humans and animals prior to and during transport and at slaughter. Strategies to reduce pre-slaughter stress will benefit carcass and meat quality, being the training of stockpeople one of the most cost-effective policies to improve animal welfare. These strategies include also the implementation of standard monitoring procedures to detect signs of consciousness after stunning, before sticking and during bleeding until death occurs.

Meat Quality of Crossbred Porkers without the Gene RYR1 (T) Depending on Slaughter Weight

The first aim of the study was to compare selected meat quality parameters in porkers without the gene RYR1 (T) (ryanodine receptor gene). These were porkers slaughtered at 100 to 115 kg and 116 to 130 kg live weight. The second aim of the study was to determine the occurrence frequency of standard-quality meat (red, firm, nonexudative [RFN]) and the occurence frequency of defective meat (pale, soft, exudative [PSE] and acid, soft, exudative [ASE]). The analysis was conducted on the longissimus lumborum muscle in 114 crossbred porkers. The porkers were a cross of Camborough 22 sows and boars from lines 337PIC (Pig Improvement Company), Norsvin Landrace and Pietrain. All of the animals were provided with identical environmental and nutritional conditions. The average weight of the slaughtered animals in the light and heavy groups was 110 kg and 122 kg, respectively. Both groups had the same average post-slaughter meatiness (56.5%). A statistical analysis of selected meat-quality parameters did not show any significant differences between the weight groups. On the other hand, the classification based on carcass quality showed an occurence frequency of defective meat in heavier crossbred porkers (116 to 130 kg) that was three times higher than in those crossbred animals which weighed 100 to 115 kg when slaughtered. In porkers without the gene RYR1 (T) , the defective meat types PSE and ASE occurred with a frequency of 17.54%.

Characteristics of bruises in carcasses of cows sourced from farms or from livestock markets

Bruises in cattle develop after the application of force, and they provide evidence for sub-optimal animal welfare. The aim of this study was to describe the gross characteristics of bruises in cows arriving at the slaughterhouse directly from farms or through the livestock market. The number of bruises and their distribution on the carcass as well as their severity, shape, size and colour were assessed post mortem in a slaughterhouse in Chile. A total of 258 cow carcasses were evaluated, and a total of 846 bruises were found on 243 of the carcasses. Cows that had passed through a livestock market (M-carcasses) had in total 563 bruises (mean 3.8 bruises/carcass, s.d. 2.0), whereas cows transported directly from farms (F-carcasses) had in total 283 bruises (mean 2.5 bruises/carcass, s.d. 1.8). The backs of F-carcasses had twice as many bruises as M-carcasses (32.9% and 16.2%, respectively), whereas bruises in the rib area were more frequently observed in M-carcasses (13.1%) than in F-carcasses (8.1%). Superficial bruises (grade 1) were the most frequently observed (66.2% of all bruises). Regarding the size of the bruises, 64 (7.6%) were classified as large, 271 (32.0%) as medium and 511 (60.4%) as small. Irregularly shaped bruises were the most frequent (91.1%, n = 771), followed by linear (3.8%, n = 32), circular (3.1%, n = 26) and tramline-shaped bruises (1.9%, n = 16). The latter were noticed only in M-carcasses, which may indicate that these animals were beaten more frequently with sticks or other rod-shaped objects. Fresh, bright red-coloured bruises were found more frequently on all the animals (69.5% from farms and 70.5% from market) compared with bluish (29.7% and 29.3%, respectively) and yellow bruises (0.4% and 0.2%, respectively). The method of selling was significantly associated with the number of bruises on the carcass (P < 0.001) and the anatomical site (P < 0.05), but not with the severity, shape and colour of the bruises. Increased fat coverage reduced the severity of bruises (P < 0.001). This study shows that, in Chile, market animals have more bruises than those sourced directly from farms, and their distribution is different. More information about the causes of infliction may help reduce bruises and it may also improve their welfare. Further studies are required to elucidate whether the causes of the high bruising in the case of animals passing through markets are related only to extra handling (repeated loading, unloading, transportation, eventual mixing) or to the way of handling by personnel and inadequate design.

Strategies to promote farm animal welfare in Latin America and their effects on carcass and meat quality traits

Several initiatives, including research and development, increasing stakeholders' awareness and application of legislation and recommendation, have been carried out in Latin America to promote animal welfare and meat quality. Most activities focused on the impact of pre-slaughter conditions (facilities, equipment and handling procedures) on animal welfare and meat quality. The results are encouraging; data from Brazil, Chile and Uruguay showed that the application of the improved pre-slaughter handling practices reduced aggressive handling and the incidence of bruised carcasses at slaughter in cattle and pigs. These outcomes stimulated some to apply animal welfare concepts in livestock handling within the meat production chain as shown by the increasing demand for personnel training on the best. To attend this demand is important to expand local studies on farm animal welfare and to set up (or maintain) an efficient system for knowledge transfer to all stakeholders in the Latin America meat production chains. However, it is clear that to promote the long-term progress in this field is important to deliver practical solutions, assuring that they match the technical and financial conditions of those who are the target of training programs.

Risk assessment of skin damage due to pre-slaughter conditions and RYR1 gene in pigs

A polychotomous logistic regression was used to assess the risk factors for skin damage prior to slaughter. A total of 116 deliveries (15,695 pigs) from commercial farms to five Spanish pig abattoirs were surveyed. The skin damage condition was described as an ordinal response (1: no damage; 2: very slight damage; and 3: slight or more damage). The abattoir by the season (p<0.01), the floor surface of the lorry (p=0.02), and the mixing of unfamiliar pigs at loading (p=0.01) influenced the occurrence of skin blemishes. Skin damage increased with on-farm fasting time (p<0.01), loading time (p<0.01), lairage time (p<0.01), as well as with carcass weight (p<0.01). In winter transports the risk of skin damage decreased (p<0.01) at higher space allowance in the lorry. The risk of developing PSE and DFD pork increased with the skin damage score (p<0.01). The nn genotype for the RYR1 gene was less prone to skin damage but at the same time it is more sensitive to skin damage in relation to PSE risk. It is concluded that the skin damage score can be used as a rapid indicator of animal welfare and pork quality.

Head current during and blood splashes after electrical stunning in relation to characteristics of the pig's body

In order to evaluate electrical stunning in relation to the incidence of blood splashes, meat quality and carcass quality parameters, 2035 pigs, heterozygous for the halothane gene, were observed during slaughter at a commercial slaughterhouse. The head current during electrical stunning is significantly higher (P<0.01) in gilts with a lower live weight (P<0.0001) or cold carcass weight (P<0.0001) and a higher lean meat percentage (P<0.0001). Also the incidence of blood splashes in the ham is significantly higher in gilts (P<0.0001) with a higher lean meat percentage (P=0.0028; odds ratio=1.11), a lower live weight (P=0.003; odds ratio=0.98) and a lower type number (P=0.0074; odds ratio=0.64). For barrows, no significant parameters were revealed. These results suggest that the variability in incidence of blood splashes can be explained by the variability of current density depending both on sex and body characteristics. Thus, electrical stunning can be improved by providing an energy level, based on the body characteristics of the pig.