Investigation Into the Humaneness of Slaughter Methods for Guinea Pigs (Cavia porcelus) in the Andean Region

Guinea pigs (Cavia porcelus) are an important source of nonhuman animal protein in the Andean region of South America. Specific guidelines regarding the welfare of guinea pigs before and during slaughter have yet to be developed. This study critically assessed the humaneness of 4 different stunning/slaughter methods for guinea pigs: cervical neck dislocation (n = 60), electrical head-only stunning (n = 83), carbon dioxide (CO₂) stunning (n = 21), and penetrating captive bolt (n = 10). Following cervical neck dislocation, 97% of guinea pigs had at least 1 behavioral or cranial/spinal response. Six percent of guinea pigs were classified as mis-stunned after electrical stunning, and 1% were classified as mis-stunned after captive bolt. Increased respiratory effort was observed during CO₂ stunning. Apart from this finding, there were no other obvious behavioral responses that could be associated with suffering. Of the methods assessed, captive bolt was deemed the most humane, effective, and practical method of stunning guinea pigs. Cervical neck dislocation should not be recommended as a slaughter method for guinea pigs.     

Pre-slaughter factors linked to variation in responses to carbon dioxide gas stunning in pig abattoirs

The stunning process is an important component of slaughter with implications for animal welfare due to the potential distress and pain in the case of a sub-effective or lengthy stun. This study examined the factors correlated with variation in responses to carbon dioxide (CO₂) stunning of pigs in five Australian commercial abattoirs. A total of 1 769 pigs (199–492 focal pigs per abattoir) were individually followed from lairage to post-stunning. A standardised observation protocol was used based on a literature review of the pre-slaughter factors that may influence the reaction to CO₂ stunning, such as animal background, lairage conditions, handling, stunning system and conditions. Pigs lost posture 22.5 ± 0.2 s after commencement of descent of the gondola into the CO₂ chamber. Latency to loss of posture was associated with farm of origin and time of day, which could be linked to various factors. Pigs that crawled or attempted to escape while in the gondola within the CO₂ chamber took longer to lose posture. Crawl and escape attempts differed between abattoirs (0.6–46.2% of the pigs observed) as well as mounting other pigs (1.0–24.3%). Greater amounts of forceful contacts during handling in the race were related to more mounting in the gondola, but to less pigs crawling or attempting to escape. Mounting in the gondola was more frequent for pigs from lairage pens of mixed sexes, followed by pens of entire males and finally pens of females. Males were also twice as likely to show crawl and escape attempts than females. Gasping in the gondola was relatively frequent (63.1–81.8%) and was associated with higher activity in the lairage pen and higher skin injuries. Convulsions (60.1–69.6%) were generally observed after loss of posture. The type of CO₂ system (group-wise vs single-file loading) had no significant effect on behaviour in the gondola. Nevertheless, pigs slaughtered in abattoirs with group-wise loading systems and automatic gates had lower cortisol concentrations post-stunning, which may be linked to minimal handling by stockpeople, other factors related to the systems, or differences in timing of when blood samples were taken. In conclusion, substantial variation in the reaction of pigs to CO₂ stunning was observed between and within abattoirs using a uniform protocol for data collection. This variation in outcomes between abattoirs and stunning systems and the relationships between handling and behavioural outcomes indicates that improvements can be made to reduce aversive responses to CO₂ stunning. In particular, avoiding mixing pigs of different sexes in lairage and aversive handling in the race may reduce aversive response to CO₂ stunning.     

Stunning fish with CO2 or electricity: contradictory results on behavioural and physiological stress responses

Studies that address fish welfare before slaughter have concluded that many of the traditional systems used to stun fish including CO₂ narcosis are unacceptable as they cause avoidable stress before death. One system recommended as a better alternative is electrical stunning, however, the welfare aspects of this method are not yet fully understood. To assess welfare in aquaculture both behavioural and physiological measurements have been used, but few studies have examined the relationship between these variables. In an on-site study aversive behaviours and several physiological stress indicators, including plasma levels of cortisol and ions as well as blood physiological variables, were compared in Arctic char (Salvelinus alpinus) stunned with CO₂ or electricity. Exposure to water saturated with CO₂ triggered aversive struggling and escape responses for several minutes before immobilization, whereas in fish exposed to an electric current immobilization was close to instant. On average, it took 5 min for the fish to recover from electrical stunning, whereas fish stunned with CO₂ did not recover. Despite this, the electrically stunned fish had more than double the plasma levels of cortisol compared with fish stunned with CO₂. This result is surprising considering that the behavioural reactions were much more pronounced following CO₂ exposure. These contradictory results are discussed with regard to animal welfare and stress physiological responses. The present results emphasise the importance of using an integrative and interdisciplinary approach and to include both behavioural and physiological stress indicators in order to make accurate welfare assessments of fish in aquaculture.     

Stunning pigs with nitrogen and carbon dioxide mixtures: effects on animal welfare and meat quality

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.     

Physiological indicators of stress and meat and carcass characteristics in tail bitten slaughter pigs

Background

Tail biting is a common welfare problem in pig production and in addition to being a sign of underlying welfare problems, tail biting reduces welfare in itself. The aim of this study was to evaluate the effects of tail biting on different pre and post mortem indicators of stress in slaughter pigs and on carcass and meat characteristics. A total of 12 tail bitten (TB) and 13 control (C) pigs from a farm with a long-term tail biting problem were selected for salivary cortisol analyses before and after transport to the slaughterhouse. After stunning, samples were taken for the analysis of serum cortisol, blood lactate, intestinal heat shock protein 70 (HSP70), and meat quality characteristics. In addition, body temperature immediately after and muscle temperature 35 min after stunning were measured, as well as lean meat percentage and carcass weight.

Results

TB pigs showed a lower cortisol response to the transport-induced stress than C pigs and also had a lower serum cortisol concentration after stunning. HSP70 content in the small intestine was higher in the TB pigs than in C pigs. TB pigs had a considerably lower carcass weight therefore produced a lower total amount of lean meat per carcass than C pigs.

Conclusions

This study suggests that prolonged or repeated stress in the form of tail biting causes a blunted stress response, possibly a sign of hypocortisolism. In addition, it underlines the importance of reducing tail biting, both from an animal welfare and an economic point-of-view.

     

Assessment of Welfare Issues During Traditional Slaughter of Goats in Pretoria,South Africa

Goats are traditionally slaughtered to celebrate marriages and births, venerate ancestors, address personal problems, or perform a ritual during funerals. The objective of this study was to assess nonhuman animal welfare issues associated with the traditional slaughter of goats in and around Pretoria, South Africa. Participatory research methods were used to interview 105 respondents. Four of those interviewed were visited to observe the slaughter process. The most common method of transport was a vehicle (47%), followed by transport on foot (30%). The distance traveled (68%) was usually less than 10 km, and in all cases, it was less than 50 km. The most common (57%) method of restraining goats during transport was tying all 4 legs together. During slaughter, assistants held the head and legs of the goat (55%). Prior to slaughter, the majority of goats were tied under a tree (66%). In total, 97% of the goats were slaughtered within 24 hr, and no stunning was performed. In this study, animal welfare problems were widespread. Research should be undertaken to find practical ways to address animal welfare issues during traditional slaughter.     

Penetrating Captive Bolt Stunning and Exsanguination of Cattle in Abattoirs

Abattoirs commonly use penetrating captive bolt pistols to stun cattle. Humane slaughter requires that an animal immediately becomes unconscious and does not regain consciousness. In this review we consider the concepts of concussion, unconsciousness, and return to consciousness. We conclude that an animal effectively stunned with a penetrating captive bolt pistol, as indicated by the presence of certain signs and the absence of others, has little possibility of brain function returning. Appropriate monitoring at all stages between stunning and sticking would ensure immediate detection and restunning on those few occasions when brain function was returning. When a captive bolt irreversibly stuns animals, sticking has no role in terms of animal welfare; its only function is to relieve the carcass of blood. With effective initial stunning and subsequent monitoring, specifying a stun-to-stick interval appears unnecessary. Abattoir surveys have indicated that it is possible to approximate, or even actually obtain, 100% successful stunning from a single shot. Furthermore, low prevalence of recovery follows. Thus, penetrating captive bolt stunning can form part of a process for the humane slaughter of cattle. This article outlines an approach to implementing standard operating procedures for checking the effectiveness of captive bolt stunning.     

Penetrating Captive Bolt Stunning and Exsanguination of Cattle in Abattoirs

Abattoirs commonly use penetrating captive bolt pistols to stun cattle. Humane slaughter requires that an animal immediately becomes unconscious and does not regain consciousness. In this review we consider the concepts of concussion, unconsciousness, and return to consciousness. We conclude that an animal effectively stunned with a penetrating captive bolt pistol, as indicated by the presence of certain signs and the absence of others, has little possibility of brain function returning. Appropriate monitoring at all stages between stunning and sticking would ensure immediate detection and restunning on those few occasions when brain function was returning. When a captive bolt irreversibly stuns animals, sticking has no role in terms of animal welfare; its only function is to relieve the carcass of blood. With effective initial stunning and subsequent monitoring, specifying a stun-to-stick interval appears unnecessary. Abattoir surveys have indicated that it is possible to approximate, or even actually obtain, 100% successful stunning from a single shot. Furthermore, low prevalence of recovery follows. Thus, penetrating captive bolt stunning can form part of a process for the humane slaughter of cattle. This article outlines an approach to implementing standard operating procedures for checking the effectiveness of captive bolt stunning.     

Comparison of neural histomorphology in tail tips from pigs docked using clippers or cautery iron

Tail docking of pigs is commonly performed to reduce the incidence of unwanted tail-biting behaviour. Two docking methods are commonly used: blunt trauma cutting (i.e. using side clippers), or cutting and concurrent cauterisation using a hot cautery iron. A potential consequence of tail amputation is the development of neuromas at the docking site. Neuromas have been linked to neuropathic pain, which can influence the longer-term welfare of affected individuals. To determine whether method of tail docking influences the extent of neuroma formation, 75 pigs were allocated to one of three treatments at birth: tail docked using clippers; tail docked using cautery iron; tail left intact. Tail docking was performed at 2 days of age and pigs were kept under conventional conditions until slaughter at 21 weeks of age. Tails were removed following slaughter and subjected to histological examination. Nerve histomorphology was scored according to the following scale: 1=discrete well-organised nerve bundles; 2=moderate neural proliferation and disorganisation affecting more than half of the circumference of the tail; 3=marked neural proliferation to form almost continuous disorganised bundles or non-continuous enlarged bundles compressing the surrounding connective tissue. Scores of 2 or 3 indicated neuroma formation. Scores were higher in docked pigs than undocked pigs (P<0.001), but did not differ between pigs docked using clippers and those docked using cautery (P=0.23). The results indicate that tail docking using either clippers or cautery results in neuroma formation, thus having the potential to affect long-term pig welfare.     

Validation of indicators used to assess unconsciousness in veal calves at slaughter

European legislation states that after stunning regular checks should be performed to guarantee animals are unconscious between the end of the stunning process and death. When animals are killed without prior stunning these checks should be performed before the animal is released from restraint. The validity of certain indicators used to assess unconsciousness under different stunning and slaughter conditions is under debate. The aim of this study was to validate the absence of threat-, withdrawal-, corneal- and eyelid reflex as indicators to assess unconsciousness in calves subjected to different stunning and slaughter methods. Calves (201±22 kg) were randomly assigned to one of the following four treatments: (1) Captive bolt stunning followed by neck cut in an inverted position (n=25); (2) Non-stunned slaughter in an upright position (n=7); (3) Non-stunned slaughter in an inverted position (180° rotation) (n=25); (4) Non-stunned slaughter in an upright position followed by captive bolt stunning 40 s after the neck cut (n=25). Each calf was equipped with non-invasive electroencephalogram (EEG) electrodes before the slaughter procedure. All reflexes were verified once before the slaughter procedure. At the beginning of the procedure (T=0 s) calves were stunned (treatment 1) or neck cut in an upright position (treatment 2, 4) or inverted position (treatment 3). Calves of treatment 4 were captive bolt stunned 34±8 s after the neck cut. Reflexes were assessed every 20 s from T=15 s for all treatments until all reflex tests resulted in a negative response three times in a row and a flat line EEG was observed. In addition, reflexes were assessed 5 s after captive bolt stunning in calves of treatments 1 and 4. Visual assessment of changes in the amplitude and frequency of EEG traces was used to determine loss of consciousness. Timing of loss of consciousness was related to timing of loss of reflexes. After captive bolt stunning, absence of threat-, withdrawal-, corneal- and eyelid reflex indicated unconsciousness as determined by EEG recordings. After non-stunned slaughter, both threat- and withdrawal reflex were on average lost before calves were unconscious based on EEG recordings. The eyelid- and corneal reflex were on average lost after calves had lost consciousness based on EEG recordings and appeared to be distinctly conservative indicators of unconsciousness in non-stunned slaughtered calves since they were observed until 76±50 and 85±45 s (mean±SD), respectively, after EEG-based loss of consciousness.     

Indicators used in livestock to assess unconsciousness after stunning: a review

Assessing unconsciousness is important to safeguard animal welfare shortly after stunning at the slaughter plant. Indicators that can be visually evaluated are most often used when assessing unconsciousness, as they can be easily applied in slaughter plants. These indicators include reflexes originating from the brain stem (e.g. eye reflexes) or from the spinal cord (e.g. pedal reflex) and behavioural indicators such as loss of posture, vocalisations and rhythmic breathing. When physically stunning an animal, for example, captive bolt, most important indicators looked at are posture, righting reflex, rhythmic breathing and the corneal or palpebral reflex that should all be absent if the animal is unconscious. Spinal reflexes are difficult as a measure of unconsciousness with this type of stunning, as they may occur more vigorous. For stunning methods that do not physically destroy the brain, for example, electrical and gas stunning, most important indicators looked at are posture, righting reflex, natural blinking response, rhythmic breathing, vocalisations and focused eye movement that should all be absent if the animal is unconscious. Brain stem reflexes such as the cornea reflex are difficult as measures of unconsciousness in electrically stunned animals, as they may reflect residual brain stem activity and not necessarily consciousness. Under commercial conditions, none of the indicators mentioned above should be used as a single indicator to determine unconsciousness after stunning. Multiple indicators should be used to determine unconsciousness and sufficient time should be left for the animal to die following exsanguination before starting invasive dressing procedures such as scalding or skinning. The recording and subsequent assessment of brain activity, as presented in an electroencephalogram (EEG), is considered the most objective way to assess unconsciousness compared with reflexes and behavioural indicators, but is only applied in experimental set-ups. Studies performed in an experimental set-up have often looked at either the EEG or reflexes and behavioural indicators and there is a scarcity of studies that correlate these different readout parameters. It is recommended to study these correlations in more detail to investigate the validity of reflexes and behavioural indicators and to accurately determine the point in time at which the animal loses consciousness.     

Effects of neonatal surgical castration and immunocastration in male pigs on blood T lymphocytes and health markers

Surgical castration in pig husbandry is criticized for welfare reasons. Thus, it is necessary to evaluate alternative ways of rearing male pigs, such as entire or immunocastrated animals. Immunocastration is a vaccination directed against gonadotropin-releasing hormone (GnRH) to suppress the production of sexual hormones. This study aimed at investigating the effects of these two methods of castration in comparison with intact male pigs on blood T-lymphocyte subsets and function, the immunoglobulin (Ig) response to an influenza vaccine and health markers during sexual development. A total of 70 animals were allocated to three experimental groups: entire (E), surgically castrated at 5 to 6 days of age (SC), and immunized against GnRH at 3 and 4 months of age (IC). Blood samples were collected at 3, 4 and 5 months. At slaughter, global health status and body and spleen weights were measured. Results showed that SC male pigs had fewer blood lymphocytes than E pigs at 4 and 5 months (P<0.05), whereas IC pigs did not differ significantly from E pigs. The percentages of CD3⁺, CD3⁺CD4⁺ and CD3⁺CD8⁺ lymphocytes were not altered by treatment (P>0.1). Compared with E pigs, the SC pigs had a higher percentage of CD3⁺CD4⁺CD8⁺ cells at 4 months, whereas the IC pigs had a higher percentage at 5 months (P<0.05). Regarding γδT cells, SC pigs had a lower percentage than E pigs at 4 and 5 months (P<0.05), whereas IC pigs did not differ significantly from E pigs at any age. However, there were no consequences on T-lymphocyte proliferation and total IgG or anti-influenza Ig. At slaughter, relative spleen weight was decreased in IC pigs, whereas pneumonia score was decreased in SC pigs relatively to E pigs. Overall, no clear functional consequences of either method on commercial pig immune abilities were demonstrated, but more investigations are required to ascertain this conclusion.     

Pre-slaughter conditions, animal stress and welfare: current status and possible future research

The present paper describes the main procedures used to slaughter fowl, pigs, calves and adult cattle, sheep, and farmed fish, starting on the farm and ending with the death of the animal at the abattoir. It reviews the currently known causes of stress, indicated by behavioural and physiological measurements on the animal level, and by post-mortem muscle metabolism. During the pre-slaughter period, psychological stress is due to changes of environment, social disturbances and handling, and physical stress is due to food deprivation, climatic conditions, fatigue, and sometimes pain. The exact causes of stress depend, however, on the characteristics of each species, including the rearing system. For fowl, bird catching and crating, duration and climatic conditions of transport and of lairage and shackling are the main known pre-slaughter stress factors. For pigs, stress is caused by fighting during mixing of pens, loading and unloading conditions, and introduction in the restrainer. Handling and novelty of the situation contribute to the stress reactions. For veal calves and adult cattle, disruption of the social group, handling, loading and sometimes unloading conditions, fatigue, novelty of the situation and for calves mixing with unfamiliar animals are known stress factors. Gathering and yarding of extensively reared lambs and sheep causes stress, particularly when shepherd dogs are used. Subsequent transport may induce fatigue, especially if sheep are commercialised through auctions or markets. In farmed fish, stress is predominantly related to environmental aspects such as temperature, oxygen, cleanliness of the water and, to a certain extent, stocking density and removal of the fish from the water. If transport and lairage conditions are good and their durations not too long, they may allow pigs, calves and adult cattle, sheep, and fish to rest. For certain species, it was shown that genetic origin and earlier experience influence reactions to the slaughter procedure. Stunning techniques used depend on the species. Pigs and fowl are mostly electrically or gas-stunned, while most adult cattle are stunned with a captive bolt pistol. Calves and sheep may be electrically stunned or with a captive bolt pistol. Various stunning methods exist for the different farmed fish species. Potential causes of stress associated with the different stunning procedures are discussed. The paper addresses further consequences for meat quality and possible itineraries for future research. For all species, and most urgently for fish, more knowledge is needed on stunning and killing techniques, including gas-stunning techniques, to protect welfare.     

Framework for integrating animal welfare into life cycle sustainability assessment

Purpose

This study seeks to provide a framework for integrating animal welfare as a fourth pillar into a life cycle sustainability assessment and presents three alternative animal welfare indicators.

Methods

Animal welfare is assessed during farm life and during slaughter. The indicators differ in how they value premature death. All three consider (1) the life quality of an animal such as space allowance, (2) the slaughter age either as life duration or life fraction, and (3) the number of animals affected for providing a product unit, e.g. 1 Mcal. One of the indicators additionally takes into account a moral value denoting their intelligence and self-awareness. The framework allows for comparisons across studies and products and for applications at large spatial scales. To illustrate the framework, eight products were analysed and compared: beef, pork, poultry, milk, eggs, salmon, shrimps, and, as a novel protein source, insects.

Results and discussion

Insects are granted to live longer fractions of their normal life spans, and their life quality is less compromised due to a lower assumed sentience. Still, they perform worst according to all three indicators, as their small body sizes only yield low product quantities. Therefore, we discourage from eating insects. In contrast, milk is the product that reduces animal welfare the least according to two of the three indicators and it performs relatively better than other animal products in most categories. The difference in animal welfare is mostly larger for different animal products than for different production systems of the same product. This implies that, besides less consumption of animal-based products, a shift to other animal products can significantly improve animal welfare.

Conclusions

While the animal welfare assessment is simplified, it allows for a direct integration into life cycle sustainability assessment. There is a trade-off between applicability and indicator complexity, but even a simple estimate of animal welfare is much better than ignoring the issue, as is the common practice in life cycle sustainability assessments. Future research should be directed towards elaborating the life quality criterion and extending the product coverage.

     

An exploration on greenhouse gas and ammonia production by insect species suitable for animal or human consumption

Background

Greenhouse gas (GHG) production, as a cause of climate change, is considered as one of the biggest problems society is currently facing. The livestock sector is one of the large contributors of anthropogenic GHG emissions. Also, large amounts of ammonia (NH₃), leading to soil nitrification and acidification, are produced by livestock. Therefore other sources of animal protein, like edible insects, are currently being considered.

Methodology/Principal Findings

An experiment was conducted to quantify production of carbon dioxide (CO₂) and average daily gain (ADG) as a measure of feed conversion efficiency, and to quantify the production of the greenhouse gases methane (CH₄) and nitrous oxide (N₂O) as well as NH₃ by five insect species of which the first three are considered edible: Tenebrio molitor, Acheta domesticus, Locusta migratoria, Pachnoda marginata, and Blaptica dubia. Large differences were found among the species regarding their production of CO₂ and GHGs. The insects in this study had a higher relative growth rate and emitted comparable or lower amounts of GHG than described in literature for pigs and much lower amounts of GHG than cattle. The same was true for CO₂ production per kg of metabolic weight and per kg of mass gain. Furthermore, also the production of NH₃ by insects was lower than for conventional livestock.

Conclusions/Significance

This study therefore indicates that insects could serve as a more environmentally friendly alternative for the production of animal protein with respect to GHG and NH₃ emissions. The results of this study can be used as basic information to compare the production of insects with conventional livestock by means of a life cycle analysis.     

Welfare of entire male pigs is improved by socialising piglets and keeping intact groups until slaughter

In today's production systems, pigs raised for slaughter are mixed many times, resulting in stress and fighting. The negative consequences of mixing are probably more severe with entire males than with castrates, as they fight more. In this project, we studied a system without castration where entire male pigs met unfamiliar pigs only once. Piglets from two litters were allowed to visit each other from circa 2 weeks of age through an opening between the farrowing pens. Entire males from these litters were kept in intact groups from weaning and onwards, and they were slaughtered pen-wise in intact groups. Control pigs were raised and weaned in their litters and mixed with unknown pigs when moved to the growing–finishing unit. They were slaughtered by split marketing based on individual weight. In total, 96 entire males from 24 litters were studied. Activity and social interactions of pigs were studied by direct observations on three observation occasions per pen for pigs kept in intact groups and four occasions for control pigs. All pigs were inspected for skin lesions during raising and at slaughter. Results showed that fewer pigs in intact groups were resting (17.1% v. 28.5%; P = 0.044) and they showed less aggressive behaviour (16.1 v. 27.7 number of interactions per hour; P = 0.001) than control pigs when moved to the growing–finishing unit. They also got fewer skin lesions compared with control pigs (15 v. 35; P < 0.001). Consequently, control pigs tended to grow slower during the 1st week after mixing; however, growth rate during the whole growing–finishing phase did not differ between treatments (P = 0.205). Control pigs directed more aggressive behaviour towards non-litter mates than towards litter mates during the whole growing–finishing phase, whereas pigs from the other treatment made no difference between litter mates and other familiar pigs. At 67 kg, there was more sexual behaviour (mounting) among control pigs (7.6 v. 3.4; P = 0.033), but after slaughter no differences were found in testis weight or boar taint compounds. At slaughter, more entire males that were slaughtered pen-wise and kept in intact groups were without skin lesions compared with the mixed control pigs (74% v. 13%; P < 0.001). This study shows that the welfare of entire male pigs can be improved by socialising piglets and by keeping them in intact groups during raising and at slaughter.     

Effect of feed restriction on the performance and behaviour of pigs immunologically castrated with Improvac®

For centuries, entire male pigs have been castrated to reduce the risk of boar taint. However, physical castration of pig is increasingly being questioned with regard to animal welfare considerations. Immunization against gonadotrophin releasing hormone (GnRH) provides an alternative to physical castration. Using the currently available commercial product (Improvac®; Pfizer Animal Health), a two-dose regimen of a GnRH vaccine is administered. After the second vaccination, a substantial increase in feed consumption has been reported, which may be associated with increased body fatness and decreased feed efficiency when compared with unvaccinated entire male pigs. The aim of the present study was to investigate the effect of a feed restriction on these traits and on the behaviour of 120 group-housed entire males (five pigs/pen) vaccinated against GnRH. The first vaccination was performed at 62 days of age and the second (V2) at 130 days of age. Pigs were slaughtered in two batches 4 to 5 weeks after V2. They were either offered feed ad libitum over the 22 to 114 kg BW range (AL treatment) or ad libitum up to a maximum of 2.50 (R2.50 treatment) or 2.75 kg/day per pig (R2.75 treatment). Behavioural observations and skin lesion scoring were conducted 1 week before V2, and 1 and 3 weeks after V2. At slaughter, the volumetric lean meat content was measured using an X-ray computed tomography scanner. Between V2 and slaughter, the average feed intakes for the R2.75 and R2.50 treatments were 15% and 22% lower than the average AL feed intake (3.20 kg/day), respectively. Feed restriction was associated with a reduced average daily gain after V2 (846, 932 and 1061 g/day in the R2.50, R2.75 and AL groups, P < 0.01) but had no effect on the feed conversion ratio (3.00 kg feed/kg BW gain on average, P = 0.62). No difference was observed in the lean meat content (71.8%, 70.7% and 70.4% in the R2.50, R2.75 and AL groups, P = 0.14), despite a reduced backfat thickness measured in restrictively fed pigs (12.0, 13.0 and 13.6 mm in the R2.50, R2.75 and AL groups, P < 0.01). Higher skin lesion scores were observed 3 weeks after V2 in R2.50 and R2.75 pigs than in the AL ones (scores 33.4, 27.7 and 25.5, respectively, P = 0.04). These results, combined with an unimproved feed efficiency and no marked change in carcass characteristics, suggest that immunologically castrated pigs should not be restrictively fed during the late finishing period.     

Short-term effects of carbon dioxide on carnation callus cell respiration

The addition of potassium bicarbonate to the electrode cuvette immediately stimulated the rate of dark O₂ uptake of photomixotrophic and heterotrophic carnation (Dianthus caryophyllus L.) callus, of Elodea canadensis (Michx) leaves, and of other plant tissues. This phenomenon occurred at pH values lower than 7.2 to 7.8, and the stimulation depended on the concentration of gaseous CO₂ in the solution. These stimulatory responses lasted several minutes and then decreased, but additional bicarbonate or gaseous CO₂ again stimulated respiration, suggesting a reversible effect. Carbonic anhydrase in the solution increased the stimulatory effect of potassium bicarbonate. The CO₂/bicarbonate dependent stimulation of respiration did not occur in animal tissues such as rat diaphragm and isolated hepatocytes, and was inhibited by salicylhydroxamic acid in carnation callus cells and E. canadensis leaves. This suggested that the alternative oxidase was engaged during the stimulation in plant tissues. The cytochrome pathway was severely inhibited by CO₂/bicarbonate either in the absence or in the presence of the uncoupler carbonylcyanide m-chlorophenyl hydrazone. The activity of cytochrome c oxidase of callus tissue homogenates was also inhibited by CO₂/bicarbonate. The results suggested that high carbon dioxide levels (mainly free CO₂) partially inhibited the cytochrome pathway (apparently at the oxidase level), and this block in electron transport elicited a large transient engagement of the alternative oxidase when present uninhibited.     

Immunocastrated male pigs: effect of 4 v. 6 weeks time post second injection on performance,carcass quality and meat quality

Immunocastration or vaccination against boar taint can be used as alternative for surgical castration of male piglets. The vaccine is administrated twice. After the second vaccination (V2), the pigs behave like barrows instead of boars and their feed intake increases which may result in a lower lean meat percentage. The timing of V2 is therefore crucial to find the right balance between the advantages of entire males and barrows. In this study, we evaluated the effect of time post second injection within the advised time frame (4 v. 6 weeks before slaughter) on behaviour, performance, carcass and meat quality of immunocastrated male pigs. In total, 180 animals (hybrid sow×Piétrain): 60 gilts, 60 male pigs vaccinated 6 weeks before slaughter (IM-6) and 60 male pigs vaccinated 4 weeks before slaughter (IM-4), all slaughtered at comparable slaughter weights. After 20 weeks of age, IM-6 showed more inactive behaviour at the expense of playing and aggressive behaviour. Daily feed intake (DFI), daily gain (DG) and feed conversion ratio (FCR) did not differ significantly between IM-6 and IM-4. Gilts had a lower DFI and DG in the late finishing phase and a higher FCR overall compared with both IM groups. Gilts showed a higher lean meat content compared with both IM groups. Earlier vaccination increased dressing percentage, which could partly be explained by the lower weight of the gastrointestinal tract, but not by testes weight. Meat quality traits and palatability did not differ significantly between IM-6 and IM-4. Vaccination of immunocastrates at 6 compared with 4 weeks before slaughter improved the calmness in the stable and the dressing percentage, while maintaining performance and carcass characteristics.     

Consequences of the Ban of By-Products from Terrestrial Animals in Livestock Feeding in Germany and The European Union: Alternatives,Nutrient and Energy Cycles,Plant Production,and Economic Aspects

Consequences of the ban of meat and bone meal (MBM) and animal fat with regard to livestock feeding, cropping, ecology and economy where investigated with an inter-disciplinary approach for Germany and the European Union. Calculations were made for different production systems with pigs and poultry on the basis of statistical data for the production and for the feed markets as well as from requirement data for the respective species and production system. (1.) The ban of MBM from feeding caused a need for alternative protein sources. If all the amount of protein from MBM is to be replaced by soybean meal, in Germany and the EU about 0.30 and 2.30 · 10⁶t would be needed each year (supplementary amino acids not considered). Alternatively, doubling the grain legume acreage in Germany to about 420,000ha would supply a similar amount of protein. A wider application of phase feeding with adjusted dietary amino acid concentrations, however, would allow for saving protein to an extent which is similar to the amount of protein that was contributed by MBM in recent years. Thus, the ban is a minor problem in terms of ensuring amino acid supply. (2.) However, alternative plant ingredients cannot compensate for the gap in P supply that is caused by the ban. An additional demand for inorganic feed phosphates of about 14,000 and 110,000t per year is given in Germany and the EU, respectively. So far, this gap is filled almost completely by increased mining of rock phosphates. Alternatively, a general application of microbial phytase to all diets would largely fill this gap. Until the ban, MBM contributed to 57% of the supplementation of P that was needed for pigs and poultry. The ban of MBM makes large amounts of P irreversibly disappearing from the food chain. (3.) Energy from slaughter offal and cadavers can be utilized in different technologies, in the course of which the efficiency of energy utilisation depends on the technology applied. It is efficient in the cement work or rotation furnace if heat is the main energy required. In contrast, the energetic efficiency of fermentation is low. (4.) Incineration or co-incineration of MBM and other by-products causes pollution gas emissions amounting to about 1.4kg CO₂ and 0.2kg NO_x per kg. The CO₂ production as such is hardly disadvantageous, because heat and electrical energy can be generated by the combustion process. The prevention of dangerous gaseous emissions from MBM burning is current standard in the incineration plants in Germany and does not affect the environment inadmissibly. (5.) The effects of the MBM ban on the price for compound feed is not very significant. Obviously, substitution possibilities between different feed ingredients helped to exchange MBM without large price distortions. However, with each kg MBM not used in pig and poultry feeding economic losses of about 0.14¢ have to considered. In conclusion, the by far highest proportion of raw materials for MBM comes as by-products from the slaughter process. Coming this way, and assuring that further treatment is safe from the hygienic point of view, MBM and animal fat can be regarded as valuable sources of amino acids, minerals and energy in feeding pigs and poultry. Using them as feedstuffs could considerably contribute to the goal of keeping limited nutrients, phosphorus in particular, within the nutrient cycle and dealing responsible with limited resources.