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Lameness in dairy cows is a clinical sign resulting from multiple diseases that affects animal welfare. The aim of this study was to evaluate the consistency of lameness prevalence estimations between farm managers and locomotion scoring conducted by trained observers, in confined and grazing dairy systems. The study was conducted on 18 dairy farms in Argentina. The locomotion of the lactating cows was scored by trained observers using a four-point visual scale from 0 to 3. Farm managers were interviewed about the number of lame cows in the herd. The consistency of lameness prevalence detected by the farm manager and the observers was assessed by computing the Lin's concordance and correlation coefficient. The comparison of grazing systems versus confined systems on lameness prevalence was analyzed using a generalized mixed model, assuming a binomial distribution for the errors. On average, farm managers estimated a lower prevalence of lameness (p < 0.01) compared with the trained observers; 2.24% and 7.06%, respectively. Based on the estimations from trained observers, we could not detect differences (p = 0.19) in lameness prevalence between confined and grazing systems.
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Welfare assessment of dairy cows by in-person farm visits provides only a snapshot of welfare and is time-consuming and costly. Possible solutions to reduce the need for in-person assessments would be to exploit sensor data and other routinely collected on-farm records. The aim of this study was to develop an algorithm to classify dairy cow welfare based on sensors (accelerometer and/or milk meter) and farm records (e.g. days in milk, lactation number). In total, 318 cows from six commercial farms located in Finland, Italy and Spain (two farms each) were enrolled for a pilot study lasting 135 days. During this time, cows were routinely scored using 14 animal-based measures of good feeding, health and housing based on the Welfare Quality® (WQ®) protocol. WQ® measures were evaluated daily or approximately every 45 days, using disease treatments from farm records and on-farm visits, respectively. WQ® measures were supplemented with daily temperature-humidity index to account for heat stress. The severity and duration of each welfare measure were evaluated, and the final welfare index was obtained by summing up the values for each cow on each pilot study day, and stratifying the result into three classes: good, moderate and poor welfare. For model building, a machine-learning (ML) algorithm based on gradient-boosted trees (XGBoost) was applied. Two model versions were tested: (1) a global model tested on unseen herd, and (2) a herd-specific model tested on unseen part of the data from the same herd. The version (1) served as an example on the model performance on a herd not previsited by the evaluator, while version (2) resembled a custom-made solution requiring in-person welfare evaluation for model training. Our results indicated that the global model had a low performance with average sensitivity and specificity of 0.44 and 0.68, respectively. For the herd-specific version, the model performance was higher reaching an average of 0.64 sensitivity and 0.80 specificity. The highest classification performance was obtained for cows in poor welfare, followed by cows in good and moderate welfare (balanced accuracy of 0.77, 0.71 and 0.68, respectively). Since the global model had low classification accuracy, the use of the developed model as a stand-alone system based solely on sensor data is infeasible, and a combination of in-person and sensor-based welfare evaluation would be preferable for a reliable welfare assessment. ML-based solutions, even with fair discriminative abilities, have the potential to enhance dairy welfare monitoring.
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Bienestar del Animal , Industria Lechera , Animales , Bovinos , Femenino , Industria Lechera/métodos , Granjas , Lactancia , Leche , Proyectos PilotoRESUMEN
The present study had 2 objectives: the first was to analyze the possible impact of transport on weight loss and mortality during transport, and first-week mortality. The second was to monitor the environmental condition (i.e., temperature, humidity, and so on) variability during transport with an effect on day-old chicks. Probe equipment was installed in a truck of a poultry company from Spain, including a total of 66 journeys made in commercial conditions between May and November 2017. Animal-based measures collected included BW (before and after transport), mortality during transport, mortality during the first week of life, which were contrasted against a series of environmental variables including air temperature, RH, and carbon dioxide (CO2) atmospheric concentration for every journey, number of day-old chicks (%) per journey, transport duration (h), zones inside the loading area (zone 1, near to the cabin; zone 2, in the central point; and zone 3, close to the back doors), height (1, top; 2, medium; and 3, bottom), mo (May to November), number of stops, type of stop during journey (farm stops and driver stops), time to start the journey, as well as other intrinsic factors of chicks (gender, breed [Ross and Cobb], breeder flock age [wk] and egg storage day). Because the database included random factors, longitudinal data, and repeated measures, a multivariate model was used to analyze the data. The results showed that chick weight loss was positively associated with journey duration and RH. No effect of environmental variables was found on mortality during transport. However, chick mortality during the first week of life was related with the percentage of day-old chicks loaded per journey and chick gender. In conclusion, owing to the environmental heterogeneity during transport and the effect of the environment on chick weight during transport and mortality at first week of life, there is an urgent need to refine the air-conditioning and ventilation systems of day-old chick transport toward a greater environmental homogeneity.
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Animales Recién Nacidos , Pollos , Transportes , Pérdida de Peso , Animales , Animales Recién Nacidos/fisiología , Peso Corporal , Pollos/fisiología , Humedad , Mortalidad , España , TemperaturaRESUMEN
On-farm practices like premature weaning and frequent regrouping induce stress to pigs. Early socialization or environmental enrichment in piglets reduce weaning stress, as suggested in previous studies. Little research with both effects and in commercial settings was found. The aim was to investigate the effects of preweaning socialization and environmental enrichment on life-long performance in 661 Danbred pigs. Two treatments were distinguished during the suckling period: control (CON, 24 litters) and enriched (ENR, 24 litters). Control piglets were raised in barren farrowing pens; ENR piglets were provided with six enrichment objects from birth, and two neighboring litters were socialized from Day (D) 14. Pigs were regrouped on D25 (weaning) and D71 (fattening), while keeping the same treatment. Individual body weight was recorded on D1, 14, 23, 27, 31, 38, 69, 79, and after slaughter (carcass weight, CW). Pigs were slaughtered in six batches. Estimated slaughter weight (ESW) was calculated by CWâ¯×â¯1.25. Body weight, CW, and average daily gain (ADG) were analyzed by linear mixed models. Slaughter age was analyzed by Wilcox Rank-Sum test. Body weight and ESW were adjusted to non-linear models to obtain the predicted growth curves of CON and ENR, from birth to the targeted market weight (TMW, 105â¯kg). Average daily gain during the suckling, nursery, and fattening periods, and from birth to slaughter, did not differ between treatments. However, ADG of ENR when moving pigs from farrowing to nursery (4-day period) and from nursery to fattening (10-day period), revealed a better performance than CON (+20.6â¯g/day, Pâ¯=â¯0.02; +53â¯g/day, Pâ¯=â¯0.03, respectively). Enriched pigs tended to be slaughtered 2.8â¯days earlier than CON (Pâ¯=â¯0.08). On the other hand, the predicted growth curves showed a non-significant 2-day window of reaching TMW between treatments (Pâ¯=â¯0.23). Results suggested that enriching the neonatal environment improved the short-term performance after regrouping, and may benefit the life-long performance by reducing time to reach TMW.
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Socialización , Animales , Porcinos , DesteteRESUMEN
Weaning is a critical period in the life of pigs with repercussions on their health and welfare and on the economy of the swine industry. This study aimed to assess the effect of the commercial early weaning on gut microbiota, intestinal gene expression and serum metabolomic response via an integrated-omic approach combining 16S rRNA gene sequencing, the OpenArray gene expression technology and 1H-NMR spectroscopy. Fourteen piglets from different litters were sampled for blood, jejunum tissue and caecal content two days before (- 2d), and three days after (+ 3d) weaning. A clearly differential ordination of caecal microbiota was observed. Higher abundances of Roseburia, Ruminococcus, Coprococcus, Dorea and Lachnospira genera in weaned piglets compared to prior to weaning showed the quick microbial changes of the piglets' gut microbiota. Downregulation of OCLN, CLDN4, MUC2, MUC13, SLC15A1 and SLC13A1 genes, also evidenced the negative impact of weaning on gut barrier and digestive functions. Metabolomic approach pinpointed significant decreases in choline, LDL, triglycerides, fatty acids, alanine and isoleucine and increases in 3-hydroxybutyrate after weaning. Moreover, the correlation between microbiota and metabolome datasets revealed the existence of metabolic clusters interrelated to different bacterial clusters. Our results demonstrate the impact of weaning stress on the piglet and give insights regarding the associations between gut microbiota and the animal gene activity and metabolic response.
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Microbioma Gastrointestinal/genética , Interacciones Microbiota-Huesped/genética , Animales , Bacterias/genética , Ciego/microbiología , Heces/microbiología , Yeyuno/microbiología , Metaboloma/genética , ARN Ribosómico 16S/genética , Porcinos , DesteteRESUMEN
The aim of this study was to determine the possible impact of early socialization and an enriched neonatal environment to improve adaptation of piglets to weaning. We hypothesized that changes in the microbiota colonization process and in their metabolic response and intestinal functionality could help the animals face weaning stress. A total of 48 sows and their litters were allotted into a control (CTR) or an enriched treatment (ENR), in which piglets from two adjacent pens were combined and enriched with toys. The pattern of caecal microbial colonization, the jejunal gene expression, the serum metabolome and the intestinal physiology of the piglets were assessed before (-2 d) and after weaning (+ 3d). A differential ordination of caecal microbiota was observed after weaning. Serum metabolome suggested a reduced energetic metabolism in ENR animals, as evidenced by shifts in triglycerides and fatty acids, VLDL/LDL and creatine regions. The TLR2 gene showed to be downregulated in the jejunum of ENR pigs after weaning. The integration of gene expression, metabolome and microbiota datasets confirmed that differences between barren and enriched neonatal environments were evident only after weaning. Our results suggest that improvements in adaptation to weaning could be mediated by a better response to the post-weaning stress.
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Ciego/microbiología , Microbioma Gastrointestinal , Yeyuno , Lactancia , Animales , Femenino , Yeyuno/metabolismo , Yeyuno/microbiología , Porcinos , DesteteRESUMEN
In beef cattle, feeding behaviour and activity are associated with feed efficiency and methane (CH4) emissions. This study aimed to understand the underlying traits responsible for the contribution of cattle behaviour to individual differences in feed efficiency, performance and CH4 emissions. A total of 84 steers (530±114 kg BW) of two different breeds (crossbreed Charolais and Luing) were used. The experiment was a 2×2×3 factorial design with breed, basal diets (concentrate v. mixed) and dietary treatments (no additive, calcium nitrate or rapeseed cake) as the main factors. The individual dry matter intake (DMI; kg) was recorded daily and the BW was measured weekly over a 56-day period. Ultrasound fat depth was measured on day 56. Based on the previous data, the indexes average daily gain, food conversion and residual feed intake (RFI) were calculated. The frequency of meals, the duration per visit and the time spent feeding per day were taken as feeding behaviour measures. Daily activity was measured using the number of steps, the number of standing bouts and the time standing per day. Agonistic interactions (including the number of contacts, aggressive interactions, and displacements per day) between steers at the feeders were assessed as indicators of dominance. Temperament was assessed using the crush score test (which measures restlessness when restrained) and the flight speed on release from restraint. Statistical analysis was performed using multivariate regression models. Steers that spent more time eating showed better feed efficiency (P=0.039), which can be due to greater secretion of saliva. Feeding time was longer with the mixed diet (P<0.001), Luings (P=0.009) and dominant steers (P=0.032). Higher activity (more steps) in the pen was associated with poorer RFI, possibly because of higher energy expenditure for muscle activity. Frequent meals contributed to a reduction in CH4 emissions per kg DMI. The meal frequency was higher with a mixed diet (P<0.001) and increased in more temperamental (P=0.003) and dominant (P=0.017) steers. In addition, feed intake was lower (P=0.032) in more temperamental steers. This study reveals that efficiency increases with a longer feeding time and CH4 emissions decrease with more frequent meals. As dominant steers eat more frequently and for longer, a reduction in competition at the feeder would improve both feed efficiency and CH4 emissions. Feed efficiency can also be improved through a reduction in activity. Selection for calmer cattle would reduce activity and increase feed intake, which may improve feed efficiency and promote growth, respectively.
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Brassica rapa , Bovinos/fisiología , Ingestión de Alimentos , Metabolismo Energético , Conducta Alimentaria , Metano/metabolismo , Animales , Dieta/veterinaria , MasculinoRESUMEN
Livestock production is a major contributor to greenhouse gas (GHG) emissions, so will play a significant role in the mitigation effort. Recent literature highlights different strategies to mitigate GHG emissions in the livestock sector. Animal welfare is a criterion of sustainability and any strategy designed to reduce the carbon footprint of livestock production should consider animal welfare amongst other sustainability metrics. We discuss and tabulate the likely relationships and trade-offs between the GHG mitigation potential of mitigation strategies and their welfare consequences, focusing on ruminant species and on cattle in particular. The major livestock GHG mitigation strategies were classified according to their mitigation approach as reducing total emissions (inhibiting methane production in the rumen), or reducing emissions intensity (Ei; reducing CH4 per output unit without directly targeting methanogenesis). Strategies classified as antimethanogenic included chemical inhibitors, electron acceptors (i.e. nitrates), ionophores (i.e. Monensin) and dietary lipids. Increasing diet digestibility, intensive housing, improving health and welfare, increasing reproductive efficiency and breeding for higher productivity were categorized as strategies that reduce Ei. Strategies that increase productivity are very promising ways to reduce the livestock carbon footprint, though in intensive systems this is likely to be achieved at the cost of welfare. Other strategies can effectively reduce GHG emissions whilst simultaneously improving animal welfare (e.g. feed supplementation or improving health). These win-win strategies should be strongly supported as they address both environmental and ethical sustainability. In order to identify the most cost-effective measures for improving environmental sustainability of livestock production, the consequences of current and future strategies for animal welfare must be scrutinized and contrasted against their effectiveness in mitigating climate change.
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Crianza de Animales Domésticos/métodos , Bienestar del Animal , Cambio Climático , Ganado , Animales , Metano , RumiantesRESUMEN
An experiment with 360 lambs grouped into three Spanish commercial categories, (Pascual, 13-16 kg; Recental, 9-13 kg and Lechal <7 kg carcass weight) and kid goats (7 kg) was performed to assess stunning effectiveness after head-only (HO) and head-to-body (HB) electrical stunning with intensity currents of 0.3, 0.5 and 0.7 Amperes (A) compared to 1.0 A. After stunning, all animals showed tonic-clonic muscular activity and epileptiform EEG, absence of rhythmic breathing, corneal reflex, spontaneous blinking and pain sensibility. The quiescent EEG occurred earlier (P < 0.05) in HB compared to HO in all categories. More animals recovered corneal reflex and rhythmic breathing before onset of the quiescent activity after HO (from 15 to 50%) compared to HB (from 0 to 15%) (P < 0.05). Concluding, HO and HB electrical stunning with 0.3, 0.5 and 0.7 A induce effective stunning similar to 1.0 A in lambs and kid goats. After stunning and sticking, brain failure occurs earlier in HB than HO system.
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Mataderos , Bienestar del Animal , Electrochoque/veterinaria , Cabras/fisiología , Oveja Doméstica/fisiología , Crianza de Animales Domésticos , Animales , Electrochoque/normas , EspañaRESUMEN
In the UK, it has been suggested that abattoirs are ideal locations to assess the welfare of sheep as most are slaughtered at abattoirs either as finished lambs or cull ewes. Data from abattoirs could provide benchmarks for welfare indicators at a national level, as well as demonstrating how these change over time. Additionally, feedback could be provided to farmers and regulatory authorities to help improve welfare and identify high or low standards for quality assurance or risk-based inspections. A systematic review of the scientific literature was conducted, which identified 48 animal-based indicators of sheep welfare that were categorised by the Five Freedoms. Their validity as measures of welfare and feasibility for use in abattoirs were evaluated as potential measures of prior sheep welfare on the farm of origin, at market, or during transportation to the abattoir. A total of 19 indicators were considered valid, of which nine were considered theoretically feasible for assessing sheep welfare at abattoirs; these were body cleanliness, carcass bruising, diarrhoea, skin lesions, skin irritation, castration, ear notching, tail docking and animals recorded as 'obviously sick'. Further investigation of these indicators is required to test their reliability and repeatability in abattoirs. Novel welfare indicators are needed to assess short-term hunger and thirst, prior normal behaviour and long-term fear and distress.
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Mataderos , Bienestar del Animal , Ovinos , Agricultura , Crianza de Animales Domésticos , Animales , Estudios de Factibilidad , Transportes , Reino UnidoRESUMEN
Antibodies against GnRF elicited by vaccination with Improvac are expected to have the same effects on the gonads of female pigs as those observed in males and thus suppress estrus. The objective of this study was to evaluate whether a 3- or a 4-dose regimen of Improvac was effective in inducing and maintaining suppression of estrus in intact Iberian female pigs through 14 months of age. Sixty 18-week-old gilts were randomly assigned to one of the following three treatment groups: control (PBS injected), V3 (3-dose Improvac regimen), and V4 (4-dose Improvac regimen). Animals were tested for the presence of standing estrus in the presence of a boar three times per week until study completion at 60 weeks of age. Blood samples were regularly collected to determine the serum levels of anti-GnRF antibodies and progesterone. The weight and size of the uterus and the weight and activity of the ovaries were assessed at the time of euthanasia. For both treatment groups V3 and V4, a large reduction in the incidence of standing estrus was observed when compared to the control group (P < 0.0001). No significant differences between the V3 and V4 groups were observed. Both V3 and V4 groups had higher serum anti-GnRF antibody levels than the control group from 28 days after the first vaccination until the end of the study. In addition, both V3 and V4 groups had lower levels of progesterone than the control group from Day 112 until the end of the study (P < 0.0001 in all cases). Mean ovary weights at study end in treatment groups V3 and V4 were significantly lower (P < 0.0001) than those for the control group and not significantly different between the V3 and V4 groups. An onset of immunity of 2 weeks after the second vaccination and a long-lasting immunity of at least 20 weeks after the third vaccination were observed. In summary, both the 3-and 4-dose Improvac regimens were efficacious in reducing the incidence of standing estrus, serum progesterone levels, and the development of the uterus and ovaries.
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Estro/efectos de los fármacos , Hormona Liberadora de Gonadotropina/inmunología , Porcinos/fisiología , Útero/efectos de los fármacos , Vacunación/veterinaria , Vacunas Anticonceptivas/uso terapéutico , Animales , Anticuerpos/sangre , Femenino , Tamaño de los Órganos/efectos de los fármacos , Progesterona/sangre , Útero/patologíaRESUMEN
As part of the project "Religious slaughter (DIALREL): improving knowledge and expertise through dialogue and debate on issues of welfare, legislation and socio-economic aspects", this paper discusses an evaluation of current practices during Halal and Shechita slaughter in cattle, sheep, goats and poultry. During religious slaughter, animals are killed with and without stunning by a transverse incision across the neck that is cutting the skin, muscles (brachiocephalic, sternocephalic, sternohyoid, and sternothyroid), trachea, esophagus, carotid arteries, jugular veins and the major, superficial and deep nerves of the cervical plexus. In this report, the restraint methods, stunning, neck cutting, exsanguination, slaughter techniques and postcut handling in the abattoir were assessed for religious slaughter. Information about the procedures used during religious slaughter in Belgium, Germany, Italy, the Netherlands, Spain, the UK, Turkey and Australia was collected by means of spot visits to abattoirs. To standardize the information gathered during the spot visits three guidelines were designed, one for each species, and translated into the national languages of the countries involved. The document included questions on the handling and restraint methods (stunning, neck cutting/exsanguination/slaughter techniques and postcut handling performed under religious practices) and for pain and distress of the animal during the restraint, neck cutting and induction to death in each abattoir. Results showed differences in the time from restraining to stun and to cut in the neck cutting procedures and in the time from cut to death.
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Mataderos , Manipulación de Alimentos/métodos , Religión , Bienestar del Animal , Animales , Australia , Bovinos , Cultura , Bases de Datos Factuales , Europa (Continente) , Humanos , Aves de Corral , Ovinos , TurquíaRESUMEN
The aim of this study was to assess unconsciousness in pigs during and after the exposure to gas mixtures of 70% nitrogen (N(2)) and 30% carbon dioxide (CO(2)) (70N30C), 80% N(2) and 20% CO(2) (80N20C) and 85% N(2) and 15% CO(2) (85N15C) compared with 90% CO(2) in air (90C) by means of the Index of Consciousness(®)(IoC), their behaviour and the absence of brain stem reflexes. The experiment included three trials of 24 pigs divided into four groups according to the number of treatments. Half of the group was exposed for a short time and the other half for a long time (3 and 5 min for the N(2)/CO(2) mixtures exposure and 2 and 3 min in 90C exposure, respectively). During exposure, the IoC and the electroencephalography suppression rate (ESR) were assessed, as well as the time to onset and percentage of gasping, loss of balance, vocalizations, muscular excitation and gagging. At the end of the exposure, the corneal reflex, rhythmic breathing and sensitivity to pain were each assessed at 10 s intervals for 5 min. Brain activity decreased significantly (P < 0.05) 37.60 s after the start of the exposure to 90% CO(2), which was significantly earlier than in 70N30C, 80N20C and 85N15C exposure, (45.18 s, 46.92 s and 43.27 s, respectively). Before brain activity decreased, all pigs experienced gasping and loss of balance and a 98% muscular excitation. The duration of the muscular excitation was longer in animals exposed to 70N30C, 80N20C and 85N15C than 90C (P < 0.01). After a long exposure time, all animals exposed to 90C died, whereas the 30.4% of animals exposed to N(2)/CO(2) gas mixtures survived. Pigs exposed to 85N15C recovered corneal reflex and sensitivity to pain significantly earlier than when exposed to 90C. Exposure to 90C causes a higher aversive reaction but a quicker loss of consciousness than N(2)/CO(2) gas mixtures. Exposure to N(2)/CO(2) gas mixtures causes a lower percentage of deaths and an earlier recovery of the brain stem activity than 90C, whereas the time to recover the cortical activity is similar. In conclusion, the inhalation of N(2)/CO(2) gas mixtures reduces the aversion compared with high concentrations of CO(2); however, the period of exposure for inducing unconsciousness may be longer in N(2)/CO(2) gas mixtures, and the signs of recovery appear earlier, compared to CO(2).
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Mataderos , Bienestar del Animal/normas , Dióxido de Carbono/farmacología , Nitrógeno/farmacología , Porcinos/fisiología , Inconsciencia/inducido químicamente , Inconsciencia/fisiopatología , Administración por Inhalación , Análisis de Varianza , Animales , Dióxido de Carbono/administración & dosificación , Relación Dosis-Respuesta a Droga , Combinación de Medicamentos , Electroencefalografía/veterinaria , Femenino , Modelos Lineales , Nitrógeno/administración & dosificación , Dimensión del Dolor/veterinaria , Respiración/efectos de los fármacos , Factores de TiempoRESUMEN
The Majorcan Black Pig (MBP) was used as a model of differentiated traditional system within the Q-PorkChains project. The MBP farms were taken as an example of traditional system using a local breed which claims for high meat quality products. Welfare Quality® protocol was applied at the slaughterhouse and improvement strategies related to ante-mortem conditions and technological meat quality were defined. Pork carpaccio from MBP was elaborated to evaluate its sensory properties as an alternative to the existing MBP products. MBP tenderloins were better suited than those from pigs from a commercial breed to elaborate this product.
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Mataderos/normas , Bienestar del Animal , Cruzamiento , Abastecimiento de Alimentos/normas , Carne/normas , Mejoramiento de la Calidad , Gusto , Crianza de Animales Domésticos , Animales , Humanos , Carne/análisis , Productos de la Carne/análisis , Productos de la Carne/normas , Porcinos , TecnologíaRESUMEN
The aim of this study was to assess the effect of exposure to the gas mixtures of 70% nitrogen (N2) and 30% carbon dioxide (CO2; 70N30C), 80% N2 and 20% CO2 (80N20C) and 85% N2 and 15% CO2 (85N15C) on aversion, stunning effectiveness and carcass, as well as meat quality in pigs, and to compare them with the commercial stunning of 90% CO2 (90C). A total of 68 female pigs were divided into four groups and stunned with one of the gas mixtures. During the exposure to the gas, behavioural variables (retreat attempts, escape attempts, gasping, loss of balance, muscular excitation and vocalizations) were recorded, and at the end of the stunning, corneal reflex and rhythmic breathing were assessed. After slaughter, meat quality parameters such as pH at 45 min post mortem (pH45) and at 24 h post mortem (pHu), electrical conductivity, drip loss and colour, in the Longissimus thoracis (LT) and Semimembranosus (SM) muscles were measured, and the presence of ecchymosis on the hams was noted. The PROC MIXED and the PROC GENMOD of SAS® were used to analyse the parametric and binomial variables, respectively. The 'gas mixture' was always considered a fixed effect and the 'live weight' as a covariate. To assess the correlation between meat quality and behaviour measures, PROC CORR was used. Pigs exposed to 90C showed a higher percentage of escape attempts and gasping, a lower percentage of vocalization and shorter muscular excitation phase than pigs exposed to the other N2 and CO2 mixtures (P < 0.05). After stunning, no pig exposed to 90C showed corneal reflex or rhythmic breathing, whereas 85% and 92% of the animals exposed to N2 and CO2 mixtures showed corneal reflex and rhythmic breathing, respectively. Animals stunned with 80N20C and 85N15C had a lower pH45 (P < 0.01) than animals exposed to 90C. Electrical conductivity in the SM muscle was lower (P < 0.001) in 90C and 70N30C pigs than in 80N20C and 85N15C pigs, whereas in LT, it was lower (P < 0.05) in 90C pigs than in 85N15C. As the CO2 concentration of the gas mixture was decreased, the prevalence of exudative pork increased. Twenty-five percent of animals exposed to N2 and CO2 mixtures (n = 68) had ecchymosis in their carcasses, whereas no animal stunned with 90C had ecchymosis. In conclusion, although N2 and CO2 stunning exhibit fewer signs of aversion than 90C, their induction time to unconsciousness is longer, and this may negatively affect meat and carcass quality.