RESUMEN

Hemorrhages in meat of broiler chickens are major quality defects. The objective of our study was to characterize the various types of hemorrhages in thigh and breast muscles with respect to their morphological appearance, location, and origin. Chickens were stunned using a water-bath stunner and were either exsanguinated and fixed or perfused with fixative. The morphological appearance of the hemorrhages was determined by the type of tissue in which they were found and by the amount of extravasating blood. Origins of hemorrhages were found only at sites of rupture of venous structures, such as postcapillary venules and small collecting veins. The absence of significant leukocyte infiltration strongly indicated that muscle tissue damage and hemorrhage occurred within the 24 h preceding stunning and slaughter. The locations and types of hemorrhages indicate different underlying mechanisms.

Asunto(s)

Pollos , Hemorragia , Carne , Músculo Esquelético , Tejido Adiposo/irrigación sanguínea , Animales , Electrochoque , Músculo Esquelético/irrigación sanguínea , Venas

RESUMEN

The two main heme proteins, hemoglobin and myoglobin, are important factors determining meat quality aspects such as color and hemorrhage. The extent of hemorrhage in muscle tissue can probably be determined by measuring the hemoglobin content. The objective of this study was twofold: 1) to develop a specific and reproducible method to quantify the hemoglobin and myoglobin content in muscle tissue of broiler chickens, and 2) to study the effect of hemorrhage on the hemoglobin content in muscle tissue. We tested several methods to determine the total heme, hemoglobin, and myoglobin content in broiler chicken muscles on their specificity, sensitivity, and reproducibility. Methods based on immunological techniques appeared to be very specific and sensitive. The results obtained applying these methods on muscle tissue extracts were, however, not reproducible due to concentration effects. A combination of spectrophotometric analysis of the total heme protein concentration and measurement of the myoglobin concentration, applying size exclusion chromatography, proved to be a reliable and reproducible method to determine the hemoglobin and myoglobin content in chicken muscles. The total heme, hemoglobin, and myoglobin contents were related to muscle type. Extensive hemorrhage increased the hemoglobin content.

Asunto(s)

Pollos , Hemoglobinas/análisis , Carne/normas , Músculo Esquelético/química , Mioglobina/análisis , Animales , Hemorragia/veterinaria , Inmunoquímica/normas , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectrofotometría/normas

RESUMEN

In this study we investigated the occurrence of hemorrhages in four groups of electrically stunned broilers, differing with respect to growth rate, age at slaughter, hemodynamic parameters, and ascites mortality. In addition, the effect of three thermal preslaughter conditions on hemorrhage occurrence in thigh and breast muscles was studied. Broilers were either reared at a thermoneutral or low temperature regimen, and were either restricted in their feed consumption or consumed feed ad libitum. Prior to slaughter the broilers were exposed for 2 +/- 0.5 h to either cold (4 +/- 2 C, RH 100%), moderate (19 +/- 2 C, RH: 70 to 80%), or warm (30 +/- 2 C, RH: 60 to 70%) conditions. There was no effect of rearing group, nor was there an interaction between rearing group and preslaughter condition on hemorrhage scores in the thighs or breasts. Preslaughter conditions only affected hemorrhage scores in the left thigh. Scores were highest in broilers exposed to moderate preslaughter conditions. These data indicate that the cause of hemorrhages in muscles is multifactorial. Hemorrhage severity was not diminished in broilers retarded in growth. Pathological hemodynamic adaptations to low rearing temperatures, leading to ascites, did not increase hemorrhage severity, neither upon exposure to moderate nor to cold or warm preslaughter conditions.

Asunto(s)

Ascitis/veterinaria , Pollos/fisiología , Hemorragia/veterinaria , Calor , Enfermedades Musculares/veterinaria , Enfermedades de las Aves de Corral/mortalidad , Envejecimiento , Animales , Ascitis/mortalidad , Presión Sanguínea , Viscosidad Sanguínea , Pollos/sangre , Pollos/crecimiento & desarrollo , Corazón/anatomía & histología , Hematócrito , Tamaño de los Órganos , Tiempo de Protrombina , Estrés Fisiológico , Aumento de Peso

RESUMEN

In this study, the effect of genetic constitution (stock) and rearing temperature on the occurrence of hemorrhages in thighs and breasts of water bath stunned broilers was investigated. Particular attention was given to the relation between the susceptibility for hemorrhages, body composition, and adaptations in blood variables induced by low rearing temperatures. A factorial experiment was performed with five parental stocks, differing with respect to growth rate, feed conversion, and body composition, and two temperature regimens (thermoneutral and below the zone of thermoneutrality). Hemorrhage scores in thighs were dependent on rearing temperature, not on stock, and were highest in broilers reared at low temperatures. In all stocks, high scores in the thighs were accompanied by an increased carbon dioxide pressure and bicarbonate and triiodothyronine concentration of the venous blood, and by an increased relative heart weight, hematocrit, and blood loss at slaughter. Hemorrhage scores in breasts were dependent on stock, confounded with day of scoring. An effect of rearing temperature was present only for the leanest, slow-growing stock having the lowest feed conversion ratio at thermoneutral rearing conditions. Scores in breasts were related neither to body composition nor to metabolic and hemodynamic adaptations to low rearing temperatures. It is concluded that high hemorrhage scores in thighs are related to hemodynamic and metabolic adaptations to an increased need for energy and oxygen caused by low rearing temperatures. Hemorrhage scores are not related to stock-dependent differences.

Asunto(s)

Adaptación Fisiológica/fisiología , Pollos , Hemorragia/veterinaria , Enfermedades Musculares/veterinaria , Enfermedades de las Aves de Corral/fisiopatología , Animales , Bicarbonatos/sangre , Composición Corporal , Dióxido de Carbono/sangre , Corazón/anatomía & histología , Hematócrito/veterinaria , Hemorragia/genética , Hemorragia/fisiopatología , Concentración de Iones de Hidrógeno , Masculino , Enfermedades Musculares/genética , Enfermedades Musculares/fisiopatología , Tamaño de los Órganos , Oxígeno/sangre , Enfermedades de las Aves de Corral/genética , Especificidad de la Especie , Temperatura , Triyodotironina/sangre

RESUMEN

Five trials were conducted to determine the effects of various alternative stunning and restraining methods on the quality of chicken broiler meat. The stunning methods used were electrical whole-body and head-only stunning with different voltages (25 vs 100 V) and frequencies (50 vs 200 Hz), and mechanical captive bolt stunning. Before being stunned, the broilers were restrained either by shackling them by the feet, restraining their heads while they were standing, or placing them in a cone. Convulsions during and after stunning were subjectively scored. At 1 d post-mortem, the pH, color, and the intensity and number of hemorrhages, of breast and thigh muscles were measured. Convulsions were, in order of increasing intensity, observed after whole-body stunning using 50 Hz, whole-body stunning using 200 Hz, head-only stunning, and captive bolt stunning. No differences in ultimate pH were measured. A consistent difference in color was observed between whole-body and head-only stunning. Head-only stunning resulted in darker and more red (P < or = 0.01) breast muscles. Head-only and captive bolt stunning resulted in hemorrhages that were located more distal in the breast muscle than those observed after whole-body stunning. Captive bolt stunning (in a cone) resulted in fewer (P < or = 0.01) hemorrhages in breast and thigh muscles than whole-body stunning (100 V, 50 Hz, shackled), and in a similar level of hemorrhaging as electrical head-only stunning (25 V, 200 Hz, in a cone).

Asunto(s)

Pollos , Tecnología de Alimentos , Hemorragia/veterinaria , Carne/normas , Músculo Esquelético , Enfermedades Musculares/veterinaria , Enfermedades de las Aves de Corral/epidemiología , Restricción Física/veterinaria , Animales , Electricidad , Femenino , Hemorragia/epidemiología , Masculino , Enfermedades Musculares/epidemiología , Restricción Física/métodos , Muslo , Tórax

RESUMEN

Hemorrhages in muscle tissue can be considered as major quality defects of broiler carcasses. They can be induced by stunning, especially electrical stunning. The underlying mechanism, however, is considered to be multifactorial. In this study, the effect of blood circulation disturbances on the severity of hemorrhages induced by electrical stunning was investigated. The disturbances were evoked in two genetically different, fast-growing broiler strains, Ross and Hybro, by rearing the broilers at low ambient temperatures. The broilers were slaughtered by two different electrical stunning methods. Broilers reared at low temperatures showed changes in blood variables and heart weight known to be associated with blood circulation disturbances. There was no effect of rearing temperature on hemorrhage severity. Ross broilers, being the most susceptible to low temperatures, had less severe hemorrhages than Hybro broilers. There was, however, a clear effect of the stunning method on hemorrhage severity. Whole body stunning caused more severe hemorrhages than head stunning in thigh and breast muscles. These results suggest that factors interfering with blood circulation have little or no effect on the occurrence of hemorrhages induced by electrical stunning.

Asunto(s)

Pollos/fisiología , Hemorragia/veterinaria , Enfermedades Musculares/veterinaria , Enfermedades de las Aves de Corral/fisiopatología , Temperatura , Mataderos , Factores de Edad , Crianza de Animales Domésticos/métodos , Animales , Ascitis/epidemiología , Ascitis/veterinaria , Circulación Sanguínea/fisiología , Proteínas Sanguíneas/análisis , Viscosidad Sanguínea , Peso Corporal/fisiología , Pollos/genética , Estimulación Eléctrica , Corazón/anatomía & histología , Hematócrito/veterinaria , Hemorragia/etiología , Hemorragia/fisiopatología , Incidencia , Masculino , Carne/normas , Enfermedades Musculares/etiología , Enfermedades Musculares/fisiopatología , Países Bajos/epidemiología , Tamaño de los Órganos , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/etiología , Índice de Severidad de la Enfermedad

RESUMEN

The influence of preslaughter muscle activity was studied on porcine muscle metabolism and meat quality, whereas other stress factors were minimized. Muscle exercise was stimulated by electrical pulses in anesthetized pigs of different halothane genotypes (NN, Nn, nn). A part of the LM and SM was stimulated during the last 15 min of a 45-min period of anesthesia. The contralateral part of each muscle was taken as a non-stimulated control. Antemortem blood and muscle biopsy samples were taken to study the muscle energy metabolism by measuring different metabolites. The same metabolites and certain meat quality characteristics were determined after slaughter. Stimulated muscle exercise led to lower (P < .01) antemortem glycogen and creatine phosphate concentrations and increased (P < .01) lactate and creatine values in pigs of all halothane genotypes. No difference was seen between the three halothane genotypes in the measured glycogen breakdown just before slaughter. Postmortem glycolysis differed between pigs of different halothane genotypes. This resulted in lower (P < .05) glycogen and creatine phosphate values and higher (P < .05) lactate and creatine concentrations for nn pigs than for NN pigs, with intermediate metabolite concentrations for Nn pigs. Water-holding capacity was lower (P < .05) in exercised muscles of NN and Nn pigs than in the muscles of controls. Meat color was only lighter (P < .05) after muscle stimulation in NN pigs. The exercise did not deteriorate the already light color and lower water-holding capacity in nn pigs. Muscle pH can already be low at slaughter and is not only the result of an increased postmortem glycolysis. Preslaughter muscle exercise is relatively more important in determining meat quality from NN and Nn pigs.

Asunto(s)

Halotano , Carne/normas , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiología , Porcinos/genética , Animales , Cruzamientos Genéticos , Estimulación Eléctrica , Metabolismo Energético/fisiología , Genotipo , Glucógeno/análisis , Glucógeno/metabolismo , Concentración de Iones de Hidrógeno , Lactatos/análisis , Lactatos/metabolismo , Masculino , Contracción Muscular/fisiología , Músculo Esquelético/química , Fosfocreatina/análisis , Fosfocreatina/metabolismo , Porcinos/metabolismo

RESUMEN

Preslaughter muscle temperature in anesthetized pigs of different halothane genotypes (NN, Nn, and nn) was raised or lowered during a 45-min period of anesthesia. The different treatments produced muscle and rectal temperature differentials of 1.5 to 2 degrees C across genotypes. Blood and muscle biopsy samples were taken during the period of anesthesia, to study muscle energy metabolism by measuring different metabolites. After slaughter, the same metabolites and some meat quality characteristics were determined. An increased muscle temperature resulted in lower (P < .01) glycogen concentrations at slaughter and an increased (P < .05) glycogen, creatine phosphate, and ATP breakdown after slaughter in the muscles of these two halothane genotypes. However, the muscle metabolism of NN pigs was not affected by a higher temperature. The muscle metabolism of Nn pigs was more similar to that of NN pigs at low preslaughter temperatures. Elevated temperatures shifted the muscle metabolism of Nn pigs toward that of nn pigs. Water-holding capacity was lowered (P < .01) in all halothane genotypes due to elevated preslaughter muscle temperatures. It was concluded that increases in preslaughter muscle temperature are, in addition to an effect of preslaughter stress conditions, also a causative factor in enhancing ante- and postmortem muscle metabolism. This effect was more pronounced in Nn and nn pigs. Meat quality was influenced negatively in all genotypes by an increased muscle temperature, but more in NN and Nn pigs than in nn pigs. Lowering preslaughter muscle temperatures had the greatest advantage of improving meat quality in NN and Nn pigs.

Asunto(s)

Temperatura Corporal/fisiología , Halotano , Carne/normas , Músculo Esquelético/metabolismo , Porcinos/genética , Animales , Cruzamientos Genéticos , Metabolismo Energético/genética , Genotipo , Masculino , Porcinos/metabolismo

RESUMEN

The experiment involved six halothane-positive (HP) and six halothane-negative (HN) pigs of about 100 kg liveweight. Under general anaesthesia the tibialis cranialis was exposed. The temperature of the muscle was maintained at either 35 or 40°C (in situ). The muscle was stimulated via the peroneal nerve at 0·1 Hz for 10 min then 1 Hz for 10 further min. Twitch contractions were recorded throughout the stimulation, after which the muscle was excised and split into two parts which were kept in paraffin oil at either 35 or 40°C (post-excision temperature) for 2 h. Samples were taken just before and after the 20 min stimulation period, and at 1 and 2 h after muscle excision for determination of pH and concentrations of PC, ATP, IMP, glycogen, G-6-P and lactate. As soon as one muscle was removed, the operation was repeated on the other leg. Both temperatures (35 and 40°C) were applied to each animal in a balanced design. However data were obtained from only 11 pigs at 40°C as one HP pig died accidentally at the beginning of the 40°C experiment. Halothane sensitivity influenced the pH value and the levels of PC, G-6-P and lactate of the muscle in situ (P < 0·01 in all cases). Temperature affected contrction time (P < 0·01). Both halothane sensitivity and Post-excision temperature affected the pH values and the levels of PC, ATP, IMP, G-6-P and lactate (P < 0·01 in all cases) in the excised muscle. By contrast, the in situ temperature treatments did not affect any of the muscle traits measured after excision. It was concluded that the effects of the various treatments on the rate of metabolism in the excised muscle were wholly explainable in terms of temperature from the time of excision, and that the in situ temperature treatments may not be responsible for the differences after excision.

RESUMEN

Muscle metabolism was studied in pigs of different halothane genotypes by taking blood and muscle biopsy samples during a 45-min preslaughter period of anesthesia. Dantrolene was administered to half the pigs of each genotype to investigate whether possible differences in muscle metabolism could be explained by differences in resting myoplasmic calcium concentrations. Dantrolene influenced muscle metabolism of all halothane genotypes to the same extent, leading to higher (P < .05) glycogen and creatine phosphate concentrations and lower (P < .05) lactate and creatine concentrations. Dantrolene could not reduce the small but significant (P < .05) differences observed in resting muscle metabolism between the genotypes, and halothane-positive pigs had lower (P < .05) glycogen and creatine phosphate contents. Postmortem muscle metabolism showed differences (P < .05) between the three halothane genotypes, with the highest rate of glycolysis in halothane-positive pigs. Dantrolene resulted in a significantly slower (P < .05) glycogen and creatine-P breakdown, which led to a less rapid (P < .05) accumulation of lactate and creatine in both muscles. Meat quality characteristics differed between the halothane genotypes but no PSE meat was detected. Dantrolene administration resulted in an elevation (P < .05) of the pH in the longissimus lumborum and in lower (P < .05) rigor values of the semimembranosus, both measured at 45 min after slaughter. Water-holding capacity was higher (P < .05) and Hunter L*-values lower (P < .05) is dantrolene-treated pigs than in the control animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Dantroleno/farmacología , Hipertermia Maligna/veterinaria , Carne/normas , Músculo Esquelético/efectos de los fármacos , Enfermedades de los Porcinos/metabolismo , Anestesia/efectos adversos , Anestesia/veterinaria , Animales , Biopsia con Aguja/veterinaria , Calcio/metabolismo , Creatina/metabolismo , Dantroleno/uso terapéutico , Genotipo , Glucógeno/metabolismo , Halotano , Concentración de Iones de Hidrógeno , Lactatos/metabolismo , Masculino , Hipertermia Maligna/genética , Hipertermia Maligna/metabolismo , Hipertermia Maligna/prevención & control , Músculo Esquelético/metabolismo , Fosfocreatina/metabolismo , Estrés Fisiológico/complicaciones , Estrés Fisiológico/metabolismo , Estrés Fisiológico/veterinaria , Porcinos , Enfermedades de los Porcinos/genética , Enfermedades de los Porcinos/prevención & control

RESUMEN

Pigs of different halothane genotypes were anesthetized 45 min before slaughter. During the period of anesthesia blood samples and muscle biopsy samples were taken to investigate muscle energy metabolism by measuring different metabolites. After exsanguination, the same metabolites and some meat quality characteristics were determined. Minimal differences in resting muscle metabolism seemed to exist between the halothane genotypes. Some significant differences in ante- and postmortem metabolism were found, particularly in creatine and lactate concentrations, but these were not reflected in ultimate meat quality. None of the pigs showed PSE meat and there were no differences in muscle pH and temperature at 45 min and 18 h postmortem. However, rigor, drip loss, and color still showed a significant genotype effect. It was concluded that due to the method of anesthesia there were no differences in muscle metabolism at the moment of slaughter. This may have led to a more uniform ultimate meat quality between pigs differing in their genetic susceptibility toward stress. There were differences in color and drip loss between the halothane genotypes that cannot be explained by differences in pH and carcass temperature at 45 min postmortem.

Asunto(s)

Anestesia Intravenosa/veterinaria , Metabolismo Energético , Carne/normas , Músculos/metabolismo , Porcinos/metabolismo , Equilibrio Ácido-Base , Animales , Azaperona , Análisis de los Gases de la Sangre/veterinaria , Dióxido de Carbono/sangre , Creatina/análisis , Creatina Quinasa/sangre , Femenino , Genotipo , Glucosa/análisis , Glucosa-6-Fosfato , Glucofosfatos/análisis , Glucógeno/análisis , Glucógeno/metabolismo , Imidazoles , Lactatos/análisis , Lactatos/sangre , Masculino , Músculos/química , Oxígeno/sangre , Cambios Post Mortem , Medicación Preanestésica/veterinaria , Porcinos/genética

RESUMEN

Twenty-four veal calves were stunned with a captive bolt. Twelve calves were shackled by the left, the other twelve by the right hindleg. Approximately 1 min after sticking, six carcasses of each of these subgroups were stimulated electrically with equipment relying on a combined high (3000 V, 0·83 pulses s(-1), 1·5 ms duration) and low 35 V, 14 pulsess(-1)) voltage action. The remaining carcasses were left unharmed. At 24 h post-mortem hindquarters were boned to commercial primal cuts. Surrounding connective tissue and cut-up surfaces of primals as well as certain locations vulnerable for blood splash were further dissected. Neither electrical stimulation nor shackling by either of the hindlegs significantly affected the prevalence and severity of blood splash. Post-mortem factors promoting blood splash and possibly related to electrical stimulation and shackling are discussed. At 7 days post-mortem the sensory meat quality was assessed. In general, electrical stimulation did not significantly affect waterbinding and colour characteristics in longissimus (M. longissimus dorsi) and semimembranosus samples. Sarcomere lengths were similar in stimulated and control groups in longissimus but not in semimembranosus muscle. In both muscles shear force values were lower after electrical stimulation. In general, neither longissimus nor semimembranosus samples excised ipsilaterally from the shackled leg side exhibited differences in tenderness and sarcomere length. It is concluded that shackling by one leg or the other does not interfere with the tenderising effect of electrical stimulation.

RESUMEN

In order to combat certain notifiable diseases eradication programs have been developed, which include the destruction of an infected or suspected herd. Experiments were conducted to develop a method for euthanasia of large numbers of pigs. The electrocution experiments under laboratory conditions were performed in a wooden sided box with a steel floor and a curtain of chains. When the pigs touched the chain curtain with their noses, they received a current flow which lasted for more than 2 seconds, and they developed cardiac arrest or fibrillation. The pigs which touched the chain curtain with their rumps vocalised and became recumbent immediately. An automatic electrocution unit was constructed with a conveyor (negative electrode) and 3 curtains of chains (positive electrodes). Over 6000 pigs infected with a notifiable disease were killed with the apparatus. Only 2 piglets younger than 1 week old were not killed by the current (1000 V, greater than 2 s.). From the point of view of animal welfare the automatic electrocution apparatus is an efficient method for killing large numbers of pigs (older than 1 week of age) infected with a notifiable disease.

Asunto(s)

Bienestar del Animal , Eutanasia/veterinaria , Enfermedades de los Porcinos/prevención & control , Porcinos , Animales , Electricidad

Asunto(s)

Monóxido de Carbono/administración & dosificación , Eutanasia/veterinaria , Visón , Animales , Electrocardiografía/veterinaria , Masculino , Métodos

RESUMEN

Since the end of the last century many investigations with electroanaesthesia have been performed in animals and man. The interest in this method of anaesthesia has emerged because anaesthesia is achieved immediately after the onset of the current and the recovery is very rapid after cutting off of the current. Recently a battery operated apparatus became available (Feenix Stockstill) for application of electroanaesthesia and electroimmobilisation under field conditions, and an experiment was conducted with 10 calves, 10 sheep, and 9 pigs, which were equipped with EEG and ECG electrodes, to check the analgesic and other practical effects of the apparatus. The duration of current administration was 20 minutes. Three animals of each species were used as control animals. In all animals, during administration of the current, the breathing movements appeared to be somewhat impaired. The rectal body temperature, the plasma cortisol level, and the pulse rate were raised during the current administration. Moreover, the pulse rate was irregular. The corneal reflex remained positive in all animals, and the reaction to painful stimuli was positive in 15 out of 29 experimental animals. The rectal body temperature, pulse rate, and plasma cortisol level remained constant in the control animals. Before and after administration of the current the electroencephalogram recordings were similar, except in one calf and one sheep, both of which showed patterns suggesting a decreased consciousness. The electrocardiogram recordings showed pronounced changes in cardiac activity. In one pig the heart activity stopped some minutes after the onset of the current. Changes in the electroencephalogram and electrocardiogram were not observed in the control animals during their treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Bovinos , Electronarcosis/veterinaria , Inmovilización , Ovinos , Porcinos , Animales , Temperatura Corporal , Bovinos/fisiología , Electrocardiografía/veterinaria , Electronarcosis/instrumentación , Femenino , Hidrocortisona/sangre , Masculino , Pulso Arterial , Ovinos/fisiología , Porcinos/fisiología

RESUMEN

The levels of vasopressin and oxytocin in the plasma of veal calves, sheep and pigs were determined during and after a general epileptiform insult induced by high voltage stunning. Immediately after stunning, a sharp increase in the vasopressin and oxytocin levels was observed in the plasma, followed by a gradual decrease during the next hour. The duration of the general epileptiform insult was correlated (r = 0·79) with the highest measured levels of vasopressin after electrical stunning in the pigs (p ≤ 0·05). It is suggested that secretion of these neurohypophyseal hormones may affect the memory of aversive experiences during a general epileptiform insult.

RESUMEN

The routine practice of electrocution of foxes by the Fox final apparatus was observed. The measured current was an average 0.31 (+/- 0.01 s.d.) A, the voltage 111.2 (+/- 18.7) V and the stunning time 3.0 (+/- 0.3) seconds (n = 40). The EEG (electroencephalogram) and the ECG (electrocardiogram) were recorded in 12 foxes. The current was initially applied for 1 sec. Ten foxes showed a general epileptiform insult (= unconscious) which was interrupted by a heart fibrillation, based on the EEG and ECG traces. Two foxes showed a general epileptiform insult while the heart fibrillation was incomplete. These two foxes recovered again. After the second stunning with a duration of about 3 seconds the heart fibrillation was complete in these animals. In the EEG and ECG experiments the voltage was on average 110.0 (+/- 7.9) V, the current 0.40 (+/- 0.11) A and the stunning time 1.1 (+/- 0.3) seconds (n = 12). The observations of the method in practice and the EEG and ECG measurements suggest that electrocution of foxes by the Fox final apparatus is a quick and effective method if the current delivery is at least 3 to 4 seconds.

Asunto(s)

Electrochoque , Eutanasia/veterinaria , Zorros/fisiología , Animales , Electrocardiografía , Electroencefalografía , Ética Profesional , Femenino , Masculino

RESUMEN

The present studies are concerned with methods of mechanical and electrical stunning as used in ruminants. The object is to acquire a scientific basis for the correct use of these procedures in slaughter-houses. In all experiments studies on living animals, cerebral activity (electro-encephalogram) was measured using electrodes which had been surgically implanted the previous day. When animals are stunned by concussion, unconsciousness is not induced in every case. When a slaughtering mask was frontally or occipitally applied to the head, unconsciousness was produced. To effectively induce unconsciousness, the bolt of the captive bolt pistol should carry sufficient energy to damage the cerebral cortex and the deeper portions of the brain directly or by shock waves following penetration of the cranium. The forces which may be developed by the variously coloured cartridges of the brands of captive bolt pistol differ markedly. Regulations regarding the relationship between the colour of the cartridge and the potential forces would appear to be essential.

Asunto(s)

Mataderos , Lesiones Encefálicas/veterinaria , Bovinos , Traumatismos por Electricidad/veterinaria , Ovinos , Animales , Venodisección/veterinaria , Lesiones Encefálicas/etiología , Femenino , Masculino , Porcinos , Inconsciencia/veterinaria

RESUMEN

A total of sixty-two calves with body weights of 200 kg and with preimplanted ECoG electrodes on the dura mater, were electrically stunned using various currents, voltages and stunning equipment. To stun 90% of the calves effectively, a current strength of 0·87 A is estimated to be necessary when using scissor model tongs. Effective stunning means immediate (within 1 s) induction of unconsciousness by a general electroplectic insult. Atrial fibrillation is a frequently occurring phenomenon after electrical stunning when the electrodes are placed between the eye and the ear. The relatively short duration of the insult in calves compared with pigs, as well as the clonic spasms occurring 10s after stunning, are major drawbacks to the practical application of electrical stunning of veal calves. The experiments show that these drawbacks can be eliminated by modifying the form and position of the electrodes.

RESUMEN

In seventy Texel breed sheep with a live weight of about 43 kg electrocorticogram (ECoG) electrodes were implanted in the dura mater. The day after the operation the sheep were electrically stunned with scissor model tongs on the head. Various currents and voltages were used. A current strength of 0·33 A was statistically estimated to stun 90% of the sheep effectively, which means an immediate induction of a general epileptiform insult. The duration of an insult, using 600 V, is significantly longer than using 300 V, although the shortest duration was 23 s and 22 s, respectively. In all instances a paroxysmal ventricular tachycardia was observed after stunning. In the interests of animal welfare, electrical stunning of sheep should be performed with an amperage of at least 0·5 A (160 V) and throat cutting should take place within 16 s.