Stunning methods for poultry

Characteristics of the large-scale circulation during episodes with high and low concentrations of carbon dioxide and air pollutants at an arctic monitoring site in winter

Welfare implications of gas stunning pigs: 3. the time toloss of somatosensory evoked potential and spontaneous electrocorticogram of pigs during exposure to gases

Pigs were exposed individually to either 90 per cent argon in air (anoxia), a mixture of 30 per cent carbon dioxide and 60 per cent argon in air (hypercapnic anoxia)...

The reactions of turkeys to the presence of either 90 per cent argon in air (anoxia), 72 per cent carbon dioxide in air or a mixture of 30 per cent carbon dioxide and 60 per cent argon in air with 3 per cent residual oxygen were tested. The majority of the turkeys did not avoid a feeding chamber containing either argon or the mixture of carbon dioxide and argon, but 50 per cent of the turkeys avoided a feeding chamber containing 72 per cent carbon dioxide in air. It is concluded that from the point of view of welfare, either 90 per cent argon in air or a mixture of 30 per cent carbon dioxide and 60 per cent argon in air, would be preferable to a high concentration of carbon dioxide for stunning/killing turkeys.

The e.c.g., monitored by telemetry, was used to study changes in the heart activity of sheep bled out after electrical stunning or carbon-dioxide anaesthesia. The decrease in ventricular rate which occurs as sheep are bled out after electrical stunning is apparently attributable to increasingly severe anoxia, rather than to changes in blood pressure. The heart rate at sticking is directly related to the heart rate before electrical stunning, but no relationship was found between the wattseconds used and the heart rate at sticking. However, the greater the number of wattseconds applied, the lower the minimum heart rate recorded after sticking. Exposure to carbon dioxide caused an initial tachycardia, followed by a decreased heart rate and then a secondary increase. The rate rose further when the sheep were removed from the gas. As the percentage of carbon dioxide used increased, the duration of heart activity after sticking decreased. Since high stunning currents cause early atrioventricular block, they might adversely affect bleeding out, if this is dependent on heart activity. High concentrations of carbon dioxide results in earlier termination of heart activity and might affect bleeding out similarly. The lower heart rate of sheep before electrical stunning may indicate that it is inherently less stressful than carbon-dioxide anaesthesia and so less likely to affect meat quality.

ASSIMILATION AND RESPIRATION OF EXCISED LEAVES AT HIGH CONCENTRATIONS OF CARBON DIOXIDE

Spontaneous electroencephalograms (EEG) and somatosensory evoked potentials (SEPS) were recorded in turkeys while they were kept in an atmosphere of either 49 or 86 per cent carbon dioxide in air. The time to the loss of SEPS was not related to the concentration of carbon dioxide, but the time to the onset of an isoelectric EEG was shorter at the higher concentration of carbon dioxide. In comparison with other gas stunning methods it was considered that stunning with these high concentrations of carbon dioxide would not have any welfare advantages over stunning in argon with 2 per cent residual oxygen or in a mixture of 30 per cent carbon dioxide and 60 per cent argon in air.

The concentration and isotopic abundances of carbon dioxide in rural and marine air

BACKGROUND: Elevated levels of carbon dioxide in gym air can diminish the benefits of physical activity and pose health risks for children.. AIM: to access carbon dioxide concentration in the air of school gyms during physical education classes. MATERIAL AND METHODS: A total of 612 measurements were taken to estimate the concentration of carbon dioxide in the air. These measurements were conducted in two separate gymnasiums: in Gym 1, designated for primary classes with an area of 77 m2, and Gym 2, used by middle and high school students with an area of 293 m2. Measurements were taken at 12 different points, both around the perimeter and in the central part of each gym. The height when measuremenmts were taken ranged from 0 to 230 cm. To assess the carbon dioxide concentration in the gym air, the background level was calculated based on GOST 30494-2011 standards (761.5 ppm). Student’s t-tests for independent samples were used to compare the data. Additionally, a regression analysis was utilized to estimate the spatial distribution of carbon dioxide within the gymnasiums. RESULTS: In Gym 1, the initial concentrations ranged from 845 to 1267 ppm, slightly exceeding the expected throughput. Throughout the training session, the carbon dioxide content increased by 1.6 to 2.3 times. By the end of the session, the carbon dioxide content reached 1934 to 1948 ppm at an estimated respiration level of 1.0 to 1.9 m. In Gym 2, the carbon dioxide content increased by 1.1 to 1.2 times by the end of the class. At a height of 0.0 to 1.7 m, the concentration of carbon dioxide was measured at 1016 to 1023 ppm. CONCLUSION: After 20 minutes of training at the expected intensity, carbon dioxide levels in the air exceed not only the background level of 761.5 ppm, but also the permissible level of 1000 ppm. This study highlights the importance of daily monitoring of carbon dioxide levels in school gymnasiums during training sessions and sporting events. Such monitoring is crucial for ensuring the health and safety of students and athletes.

Optimization of environmental factors affecting tertiary treatment of municipal wastewater by Chlorella protothecoides in a lab scale photobioreactor

Stunning: controlled atmosphere stunning

STUNNING | CO2 and Other Gases

STUNNING | CO2 and Other Gases

In the wheat cylinder bioassay technique as previously used here 5 sections have been enclosed in a 2 X f in. assay tube together with 0-5 ml. of the test solution. A method developed for estimating the amount of carbon dioxide which accumulates in these tubes through the respiration of the enclosed sections has shown that the level can rise to 20 per cent, after 24 hrs. at 25° C. In the presence of a 100 p.p.m. IAA (6x io~4 M.) test solution, growth of 5 enclosed sections is depressed from 8 hrs. onwards and they eventually shrink, releasing their accumulated IAA back into the solution. The growth of sections under various gas mixtures of carbon dioxide in air has also been followed and these experiments show that section length is reduced approximately linearly with respect to increasing carbon dioxide concentration up to 20 per cent, in air, both in the presence and absence of a 100 p.p.m. IAA solution. The slope of the fitted regression line, however, is much steeper when the test solution contains IAA—i.e. there is a large interaction. In the presence of IAA, growth-time data show that a reduction in the growth rate, as compared with that in normal air, can be detected after only 4 hrs. at the highest carbon dioxide concentration. In the absence of IAA, high concentra tions of carbon dioxide accelerate growth during the first 8 hrs. of the assay but depress it later. The mechanism of action of this interaction is unknown but it is not shown at very high concentrations of IAA, e.g. 1,000 p.p.m. (6x io-3 M.).

1. The welfare and carcase quality implications of stunning/killing 7-week-old Japanese quail with either an electric current, 90% argon in air or a mixture of 30% carbon dioxide and 60% argon in air were investigated in 3 separate experiments. 2. The results showed that exposure of quail to either argon or the carbon dioxide-argon mixture resulted in loss of posture on average at 9 and 8 s respectively. In both gas mixtures, convulsions started 6 s after the loss of posture and the duration of clonic phase (wing flapping) did not differ significantly between the 2 gas mixtures. However, the duration of the tonic phase was found to be slightly longer with the carbon dioxideargon mixture than with argon alone (P <0.05). 3. The absence of a positive response to toe pinching performed soon after the loss of posture indicated that the birds became unconscious and insensible to pain before the onset of convulsions. 4. Carcase dissection showed that, in comparison with the electrical stunning, gas stunning/killing of quail in transport containers eliminated the problem of broken bones and significantly reduced haemorrhaging in breast and leg muscles.