A case control study of on-farm risk factors for tail biting in pigs

Social stress as a cause of diseases in farm animals: Current knowledge and future directions

Over the past 50 years, biomedical research has established a strong linkage between psychosocial stress and disease risk in humans, which has transformed the understanding of stress and the role it plays in human lives. This research has led to personalized medicine where a reduction in daily life stress is a main goal for many people with debilitating illnesses. This review describes the supporting evidence that social stress also plays a critical role in farm animal disease prevention, and may be a mediator by which common management practices can increase disease risk. There is evidence that social factors, including deprivation of social contact ('social isolation'), reducing space allowance ('crowding') and disturbing social order ('social instability') trigger physiological and behavioral indicators of stress in livestock. Less research exists, however, linking management practices that trigger social stress with higher disease risk. Suggestions are offered for future research opportunities, and practical, evidence-based recommendations are made for reducing the negative effects of social isolation, instability and crowding. The current evidence that social factors contribute to disease risk in farm animals is not as convincing as the human literature, but remains a promising and important area for future research.

Animal welfare towards sustainability in pork meat production

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

Save the pig tail

Tail biting is a common problem in modern pig production and has a negative impact on both animal welfare and economic result of the farm. Tail biting risk is increased by management and housing practices that fail to meet the basic needs of pigs. Tail docking is commonly used to reduce the risk of tail biting, but tail docking in itself is a welfare problem, as it causes pain to the pigs, and facilitates suboptimal production methods from a welfare point-of-view. When evaluating the cost and benefit of tail docking, it is important to consider negative impacts of both tail docking and tail biting. It is also essential to realize that even though 100% of the pigs are normally docked, only a minority will end up bitten, even in the worst case. In addition, data suggests that tail biting can be managed to an acceptable level even without tail docking, by correcting the production system to better meet the basic needs of the pigs.

Welfare implications of invasive piglet husbandry procedures, methods of alleviation and alternatives: a review

Iron administration, teeth clipping, tail docking and castration are common invasive husbandry procedures performed on piglets on commercial farms, generally within the first week of life. These procedures are performed to prevent potential health and welfare problems of piglets and/or the sow, or, with respect to castration, to enhance meat quality. The objectives of this review were firstly, to provide the rationale and scientific evidence for performing these procedures, secondly, to describe the welfare implications of these procedures, and lastly, to describe mitigation strategies or alternatives that can be used to eliminate or reduce the pain caused by these procedures. Administering supplementary iron is necessary to prevent anaemia in piglets and the procedure has a low welfare impact. The stated benefits of teeth clipping to prevent udder lesions do not appear to outweigh the risk from injury and infection in piglets following the procedure. Tail docking reduces the prevalence of tail biting, but does not eliminate this behaviour and the practice of tail docking can cause acute pain. Castration is primarily performed to reduce the occurrence of boar taint, but alternatives are now available that negate the need to perform this procedure. Teeth clipping, tail docking and castration all cause behavioural and physiological changes indicative of acute pain and can have potentially long-term negative consequences such as causing abscesses, lesions and the formation of neuromas. Therefore effective pain mitigation strategies (e.g. analgesia, local or general anaesthesia) that markedly alleviate the pain caused by these procedures are necessary to improve the welfare of piglets. Alternatively, if management practices are available that eliminate the need for performing these procedures altogether, then they should be adopted.

Injurious tail biting in pigs: how can it be controlled in existing systems without tail docking?

Tail biting is a serious animal welfare and economic problem in pig production. Tail docking, which reduces but does not eliminate tail biting, remains widespread. However, in the EU tail docking may not be used routinely, and some 'alternative' forms of pig production and certain countries do not allow tail docking at all. Against this background, using a novel approach focusing on research where tail injuries were quantified, we review the measures that can be used to control tail biting in pigs without tail docking. Using this strict criterion, there was good evidence that manipulable substrates and feeder space affect damaging tail biting. Only epidemiological evidence was available for effects of temperature and season, and the effect of stocking density was unclear. Studies suggest that group size has little effect, and the effects of nutrition, disease and breed require further investigation. The review identifies a number of knowledge gaps and promising avenues for future research into prevention and mitigation. We illustrate the diversity of hypotheses concerning how different proposed risk factors might increase tail biting through their effect on each other or on the proposed underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible, manipulable natural materials can be of considerable benefit. Further comparative research is needed into materials, such as ropes, which are compatible with slatted floors. Also, materials which double as fuel for anaerobic digesters could be utilised. As well as optimising housing and management to reduce risk, it is important to detect and treat tail biting as soon as it occurs. Early warning signs before the first bloody tails appear, such as pigs holding their tails tucked under, could in future be automatically detected using precision livestock farming methods enabling earlier reaction and prevention of tail damage. However, there is a lack of scientific studies on how best to respond to outbreaks: the effectiveness of, for example, removing biters and/or bitten pigs, increasing enrichment, or applying substances to tails should be investigated. Finally, some breeding companies are exploring options for reducing the genetic propensity to tail bite. If these various approaches to reduce tail biting are implemented we propose that the need for tail docking will be reduced.

Acoustic-reward learning as a method to reduce the incidence of aggressive and abnormal behaviours among newly mixed piglets

The aim of the study was to test whether aggressive actions among piglets could be redirected by an automatically generated sound signal followed by a sweet food reward. Per round, four litters of 25-day-old piglets (BHZP breed) were trained 5 times per day over 8 days to expect a sweet feed reward from a dog feeder after hearing a specific sound. In total 144 piglets in 14 entire litters were trained in five trials. At the end of the training 71% of the piglets were around the feeder 5 s after the feeder sound. After the training period, the piglets were weaned and mixed in two pens, 12 piglets per pen. During 2 days (3 h/day) after mixing two observers (one per pen) hidden behind a wooden wall activated the feeder when aggressive or abnormal behaviour started. A total of 616 aggressive events and 31 incidences of abnormal behaviour (ear biting) were used for the analysis. The logistic regression showed that the type of behaviour had a significant effect on the piglets’ response to the feeder sound (P < 0.001). The results showed the possibility of interruption of the aggressive behaviours such as head thrust [odds ratio (OR) = 0.43], jump on other (OR = 0.56) or attack with bite (OR = 0.61). Ear biting was very unlikely to continue (OR = 0.55). The risk of continuing elevated aggression level behaviours was doubled in the event of chasing (OR = 2.16) and the risk that fight would continue after the feeder sound was released was 7 times higher (OR = 7.89). Categorical analysis showed a significant effect (<0.001) of the time intervals t ≤ 1 s and 1 s < t ≤ 3 s on interruption of aggression by the feeder sound release. The piglets’ response to the feeder sound differed significantly between the experimental days (P < 0.001). On the second day of mixing, the feeder sound interrupted 74.9% of aggressive events, compared with 33.7% on the first day. The results suggest that acoustic-reward treatment can distract pigs from performing certain aggressive behaviours and ear biting in piglets when properly applied in time.

Animal Health and Welfare Issues Facing Organic Production Systems

Simple Summary

The demand for organically grown, animal derived produce is increasing due to a growing desire for consumer products that have minimal chemical inputs and high animal welfare standards. Evaluation of the scientific literature suggests that a major challenge facing organic animal production systems is the management and treatment of health-related issues. However, implementation of effective management practices can help organic animal producers achieve and maintain high standards of health and welfare, which is necessary to assure consumers that organic animal-based food and fibre has not only been produced with minimal or no chemical input, but under high standards of animal welfare.

Abstract

The demand for organically-grown produce is increasing worldwide, with one of the drivers being an expectation among consumers that animals have been farmed to a high standard of animal welfare. This review evaluates whether this expectation is in fact being met, by describing the current level of science-based knowledge of animal health and welfare in organic systems. The primary welfare risk in organic production systems appears to be related to animal health. Organic farms use a combination of management practices, alternative and complementary remedies and convenional medicines to manage the health of their animals and in many cases these are at least as effective as management practices employed by non-organic producers. However, in contrast to non-organic systems, there is still a lack of scientifically evaluated, organically acceptable therapeutic treatments that organic animal producers can use when current management practices are not sufficient to maintain the health of their animals. The development of such treatments are necessary to assure consumers that organic animal-based food and fibre has not only been produced with minimal or no chemical input, but under high standards of animal welfare.

Tail docking and the rearing of heavy pigs: the role played by gender and the presence of straw in the control of tail biting. Blood parameters, behaviour and skin lesions

This study evaluated whether the specific heavy pig rearing context allowed the fattening of undocked pigs without an outbreak of tail biting. At the same time, gender and straw availability (small amounts) were considered to understand their possible interactions with tail presence in the display of tail biting. A 2 × 2 × 2 factorial design was adopted to test the effects of these factors on blood parameters, behaviour and tail/ear lesions. Few interactions among factors were detected. Undocked pigs showed lower cortisol (P<0.02), lying behaviour (P<0.001), and higher risk of tail/ear biting (weeks 3 and 9), but lower risk of tail lesions (week 14). Straw increased the motivation for exploring (P<0.001), reduced serum haptoglobin (P<0.001) and the risk for tail biting (weeks 3, 9, 18) and ear biting (weeks 3, 9). Results highlight the importance of straw as an environmental enrichment and seem to indicate that fattening undocked heavy pigs is possible.

Behavioural and Brain Gene Expression Profiling in Pigs during Tail Biting Outbreaks - Evidence of a Tail Biting Resistant Phenotype

Abnormal tail biting behaviour is a major welfare problem for pigs receiving the behaviour, as well as an indication of decreased welfare in the pigs performing it. However, not all pigs in a pen perform or receive tail biting behaviour and it has recently been shown that these 'neutral' pigs not only differ in their behaviour, but also in their gene expression compared to performers and receivers of tail biting in the same pen. To investigate whether this difference was linked to the cause or a consequence of them not being involved in the outbreak of tail biting, behaviour and brain gene expression was compared with 'control' pigs housed in pens with no tail biting. It was shown that the pigs housed in control pens performed a wider variety of pig-directed abnormal behaviour (belly nosing 0.95±1.59, tail in mouth 0.31±0.60 and 'other' abnormal 1.53±4.26; mean±S.D) compared to the neutral pigs (belly nosing 0.30±0.62, tail in mouth 0.13±0.50 and "other" abnormal 0.42±1.06). With Affymetrix gene expression arrays, 107 transcripts were identified as differently expressed (p<0.05) between these two categories of pigs. Several of these transcripts had already been shown to be differently expressed in the neutral pigs when they were compared to performers and receivers of tail biting in the same pen in an earlier study. Hence, the different expression of these genes cannot be a consequence of the neutral pigs not being involved in tail biting behaviour, but rather linked to the cause contributing to why they were not involved in tail biting interactions. These neutral pigs seem to have a genetic and behavioural profile that somehow contributes to them being resistant to performing or receiving pig-directed abnormal behaviour, such as tail biting, even when housed in an environment that elicits that behaviour in other pigs.

Minimising pain in farm animals: the 3S approach - 'Suppress, Substitute, Soothe'

Recently, the French National Institute for Agricultural Research appointed an expert committee to review the issue of pain in food-producing farm animals. To minimise pain, the authors developed a '3S' approach accounting for 'Suppress, Substitute and Soothe' by analogy with the '3Rs' approach of 'Reduction, Refinement and Replacement' applied in the context of animal experimentation. Thus, when addressing the matter of pain, the following steps and solutions could be assessed, in the light of their feasibility (technical constraints, logistics and regulations), acceptability (societal and financial aspects) and availability. The first solution is to suppress any source of pain that brings no obvious advantage to the animals or the producers, as well as sources of pain for which potential benefits are largely exceeded by the negative effects. For instance, tail docking of cattle has recently been eliminated. Genetic selection on the basis of resistance criteria (as e.g. for lameness in cattle and poultry) or reduction of undesirable traits (e.g. boar taint in pigs) may also reduce painful conditions or procedures. The second solution is to substitute a technique causing pain by another less-painful method. For example, if dehorning cattle is unavoidable, it is preferable to perform it at a very young age, cauterising the horn bud. Animal management and constraint systems should be designed to reduce the risk for injury and bruising. Lastly, in situations where pain is known to be present, because of animal management procedures such as dehorning or castration, or because of pathology, for example lameness, systemic or local pharmacological treatments should be used to soothe pain. These treatments should take into account the duration of pain, which, in the case of some management procedures or diseases, may persist for longer periods. The administration of pain medication may require the intervention of veterinarians, but exemptions exist where breeders are allowed to use local anaesthesia (e.g. castration and dehorning in Switzerland). Extension of such exemptions, national or European legislation on pain management, or the introduction of animal welfare codes by retailers into their meat products may help further developments. In addition, veterinarians and farmers should be given the necessary tools and information to take into account animal pain in their management decisions.

Brain gene expression differences are associated with abnormal tail biting behavior in pigs

Knowledge about gene expression in animals involved in abnormal behaviors can contribute to the understanding of underlying biological mechanisms. This study aimed to explore the motivational background to tail biting, an abnormal injurious behavior and severe welfare problem in pig production. Affymetrix microarrays were used to investigate gene expression differences in the hypothalamus and prefrontal cortex of pigs performing tail biting, pigs receiving bites to the tail and neutral pigs who were not involved in the behavior. In the hypothalamus, 32 transcripts were differentially expressed (P < 0.05) when tail biters were compared with neutral pigs, 130 when comparing receiver pigs with neutrals, and two when tail biters were compared with receivers. In the prefrontal cortex, seven transcripts were differently expressed in tail biters when compared with neutrals, seven in receivers vs. neutrals and none in the tail biters vs. receivers. In total, 19 genes showed a different expression pattern in neutral pigs when compared with both performers and receivers. This implies that the functions of these may provide knowledge about why the neutral pigs are not involved in tail biting behavior as performers or receivers. Among these 19 transcripts were genes associated with production traits in pigs (PDK4), sociality in humans and mice (GTF2I) and novelty seeking in humans (EGF). These are in line with hypotheses linking tail biting with reduced back fat thickness and explorative behavior.

Health parameters in tail biters and bitten pigs in a case-control study

Health in relation to tail-biting behaviour was investigated on a problem farm. Quartets (n = 16) of age- and gender-matched fattening pigs including a tail biter (TB, n = 16), a victim (V, n = 16), a control in the same pen (Ctb, n = 10) and a control in a pen where no tail biting was observed (Cno, n = 14) were chosen by direct behavioural observation. Haematological and clinicochemical analyses, autopsy and histological examination of 16 different tissues were carried out. Tail lesion severity was evaluated both macroscopically, on the basis of inspection, and histologically, in the sagittally cut tail. Category effects were tested using Friedman's ANOVA by Ranks, Cochran's Q or a repeated-measure GLM and, if significant, pair-wise tests were conducted using Wilcoxon Signed Ranks or McNemar's Test. The number of received tail bites correlated better with histological than with macroscopic tail lesion scoring because of deep inflammation beneath healthy skin in some cases. Most individuals had mild inflammatory lesions in internal organs suggestive of generalized activation of the immune system, and 30% of the animals were anaemic, possibly because of systemic spread of infectious agents. V had more severe respiratory organ lesions and higher serum protein concentrations than all other categories of pigs. Liver- and muscle-specific enzymes (alanine aminotransferase, alkaline phosphatase and creatine kinase) differed between categories. In conclusion, most animals had signs of generalized activation of the immune system, possibly because of systemic spread of infectious agents. V pigs suffered from more severe inflammatory lesions than TB, Ctb or Cno. Deep infections may exist under healthy skin in the tail of bitten pigs.

Evaluating the prevalence of tail biting and carcase condemnations in slaughter pigs in the Republic and Northern Ireland, and the potential of abattoir meat inspection as a welfare surveillance tool

Despite extensive utilisation in epidemiological investigations of animal health, to date there has been little consideration of the value of abattoir meat inspection as a pig welfare surveillance tool. This study measured the prevalence of tail-docking, tail biting, carcase condemnations and associated financial losses of the latter (Northern Ireland only) in 36,963 pigs slaughtered in six abattoirs from the Republic of Ireland and Northern Ireland in July and August 2010. Over 99 per cent of inspected pigs had been tail-docked, while 58.1 per cent and 1.03 per cent had detectable and severe tail lesions, respectively. Producer losses resulting from carcase condemnation were estimated to be €0.37 per pig slaughtered. Enhanced capture and utilisation of meat inspection data for use in animal welfare surveillance schemes has the potential to drive improvements in production efficiency and animal welfare. However, significant differences were detected in the prevalence of carcase condemnation conditions between abattoirs and judiciaries (Republic and Northern Ireland). This reflects variation in the criteria and methods of data capture used in meat inspection in different abattoirs. Thus, the meat inspection process needs to be standardised and reformed before it can be reliably utilised in large-scale pig welfare surveillance schemes.

Influence of tail biting on weight gain, lesions and condemnations at slaughter of finishing pigs

The present study assessed the association of tail-biting lesions in finishing pigs with weight gain, occurrence of locomotion or respiratory disorders and abscesses during finishing period, and carcass condemnation at slaughter. The study was carried out on 4 different farms. For each animal with a tail biting lesion, two control pigs were selected. The total number of animals in the study was 312, with 104 of them being tail-bitten. Tail lesions were classified according to the degree of severity into four scores: score 0 -normal tail withou lesion; score 1-3 - increasing lesion severity, and score 4 - healed lesions. Overall, the occurrence of severe tail lesions (score 3) varied from 55 to 73% of tail-bitten pigs among farms. On all farms, healing of tail lesions was observed in 95% to 100% of the animals at the evaluation performed within 41-43 days after the commencement of the study. In two out of the four evaluated farms, pigs with score of 3 showed lower weight gain (P<0.05) compared with score 0 pigs. Before slaughter, the occurrence of locomotion problems and nodules/abscesses was associated (P<0.05) with the presence of tail-biting lesions. At slaughter, tail-biting lesions were associated (P<0.05) with the presence of abscesses, lung lesions (pleuritis and embolic pneumonia) or arthritis in carcasses. Carcass condemnation was associated with the presence of tail-biting lesions (P<0.05). Overall, carcass condemnation rate was 21.4%, of which animals with tail-biting lesions accounted for 66.7% of condemnations. Among the animals diagnosed with cannibalism at farm level, only two had not healed their lesions at slaughter. The fact that there were a lot of carcass condemnations, despite the fact that tail-bitten animals had no more active lesions, suggests that different situations may be observed between the field and slaughter, reinforcing the need to analyze pigs both at farm and slaughter to allow proper assessment of losses related to tail biting. Collectively, the observations of the present study show that complications associated with tail-biting found in slaughterhouses are probably underestimating field prevalence.

Good animal welfare makes economic sense: potential of pig abattoir meat inspection as a welfare surveillance tool

During abattoir meat inspection pig carcasses are partially or fully condemned upon detection of disease that poses a risk to public health or welfare conditions that cause animal suffering e.g. fractures. This incurs direct financial losses to producers and processors. Other health and welfare-related conditions may not result in condemnation but can necessitate 'trimming' of the carcass e.g. bruising, and result in financial losses to the processor. Since animal health is a component of animal welfare these represent a clear link between suboptimal pig welfare and financial losses to the pig industry.Meat inspection data can be used to inform herd health programmes, thereby reducing the risk of injury and disease and improving production efficiency. Furthermore, meat inspection has the potential to contribute to surveillance of animal welfare. Such data could contribute to reduced losses to producers and processors through lower rates of carcass condemnations, trimming and downgrading in conjunction with higher pig welfare standards on farm. Currently meat inspection data are under-utilised in the EU, even as a means of informing herd health programmes. This includes the island of Ireland but particularly the Republic.This review describes the current situation with regard to meat inspection regulation, method, data capture and utilisation across the EU, with special reference to the island of Ireland. It also describes the financial losses arising from poor animal welfare (and health) on farms. This review seeks to contribute to efforts to evaluate the role of meat inspection as a surveillance tool for animal welfare on-farm, using pigs as a case example.

Prevalence of risk factors for tail biting on commercial farms and intervention strategies

A husbandry advisory tool (HAT) was devised to help pig producers and their advisors identify and minimise possible risk factors for tail biting in finishing pigs. The prevalence of 83 risk factors identified from the literature and expert opinion was recorded on 65 commercial pig farms in England between May 2007 and July 2009. Those considered most important were associated with atmosphere/environment, environmental enrichment, the provision of food/drink and animal health factors. Forty-six farms received advice on minimising these risks and, of these, 27 also received a financial incentive to encourage the uptake of advice. A reduction in risk factors was observed on 42/57 farms visited at the end of the study, with the greatest reduction occurring on the farms that had been incentivised. However, farms not receiving advice also had reduced risk factors associated with atmosphere/environment and stocking density over the course of the study. In conclusion, while some risk factors are structural and require substantial capital investment to change, a significant reduction in the risk of tail biting can be achieved on many farms through the systematic evaluation and modification of management practices.

Comparison of pig behaviour when given a sequence of enrichment objects or a chain continuously

Tail biting is a major problem in modern pig (Sus scrofa) production and results in a reduction of animal welfare and productive performance. Biting behaviour has been shown to be decreased by the use of enrichment objects. In this study, 108 pigs housed in a room with 12 pens were observed and a sequence of seven different enrichment materials was tested. Gilts and barrows were housed together and received a new enrichment object each week starting from three different points in the fattening period, ie 20, 40 or 70 kg bodyweight. Toy-contact and biting-penmate behaviour were observed during one hour at day of introduction and five days later. A continuous sequence of seven enrichment objects reduced biting-penmate behaviour and the number of wounds compared to providing only a single toy (chain). This study also confirmed that not every object was feasible as an enrichment object for growing pigs. Generally, the highest toy contact was observed together with the highest biting-penmate behaviour. Most toy-contact and biting-penmate behaviour was observed between 20 and 40 kg bodyweight and was decreasing over age. Providing a sequence of toys for the first time induced toy-contact behaviour while reducing bitingpenmate behaviour but decreased after applying the same sequence for the second or third time. The presence of a single chain or a sequence of different toys had no effect on growth and feed conversion. The ideal sequence should maintain toy-contact behaviour without competition in order to avoid biting-penmate behaviour and reduced animal welfare.

Tail-biting: a new perspective

Tail-biting data from different studies are difficult to compare because a range of definitions of tail-biting behaviour and tail-biting lesions are used. Although records from abattoirs provide a large database, their usefulness is restricted as tail-biting is under-recorded and environmental and husbandry factors associated with the behaviour are unlikely to be known. Both farm and abattoir data provide no information on the number of pigs biting, only those bitten. Studying individual animals that tail-bite should give a better understanding of the pig's motivation to tail-bite and which of the components of its environment should be adjusted to improve welfare. This review examines the existing literature on tail-biting in pigs but considered from a new perspective using three different descriptive behavioural types, namely, 'two-stage', 'sudden-forceful' and 'obsessive', each of which may have different motivational bases. The article also considers the different environmental and husbandry factors which may affect each type of behaviour and discusses why this is such a complicated field and why it is often difficult to draw conclusions from available research.

Postnatal piglet husbandry practices and well-being: the effects of alternative techniques delivered separately

The aim of this study was to evaluate stress responses evoked by 2 alternative methods for performing the following processing procedures: 1) teeth resection-clipping vs. grinding; 2) tail docking-cold vs. hot clipping; 3) identification-ear notch vs. tag; 4) iron administration-injection vs. oral; 5) castration-cords cut vs. torn. Eight to 10 litters of 8-, 2-, and 3-d-old piglets were assigned to each procedure. Within each litter, 2 piglets were assigned to 1 of 4 possible procedures: the 2 alternative methods, a sham procedure, and a sham procedure plus blood sampling. Blood was sampled before processing and at 45 min, 4 h, 48 h, 1 wk, and 2 wk postprocedure and assayed for cortisol and beta-endorphin. Procedures were videotaped and analyzed to evaluate the time taken to perform the procedure and the number of squeals, grunts, and escape attempts. Vocalizations were analyzed to determine mean and peak frequencies and duration. Piglets were weighed before the procedure and at 24 h, 48 h, 1 wk, and 2 wk afterward. Lesions were scored on a scale of 0 to 5 on pigs in the identification, tail docking, and castration treatments at 24 h, 1 wk, and 2 wk postprocedure. For teeth resection, grinding took longer than clipping and resulted in greater cortisol concentration overall, poorer growth rates, and longer vocalizations compared with pigs in the control treatment (P<0.05). For tail docking, hot clipping took longer, and hot-clipped piglets grew slower than cold-clipped piglets (P<0.05). Hot clipping also resulted in longer and higher frequency squealing compared with pigs in the control treatment (P<0.01). For identification, ear notching took longer than tagging, and ear-notched piglets had worse wound scores than tagged piglets (P<0.05). Cortisol concentrations at 4 h also tended to be greater for ear-notched piglets (P<0.10). Ear notching evoked calls with higher peak frequencies than the control treatments. For iron administration, oral delivery took numerically longer than injecting, but there were no significant differences between injecting and oral delivery for any of the measures. For castration, tearing took longer than cutting the cords (P<0.05), but beta-endorphin concentrations at 45 min postprocedure were greater for cut piglets. When measures of behavior, physiology, and productivity were used, the responses to teeth resection, tail docking, and identification were shown to be altered by the procedural method, whereas responses to iron administration and castration did not differ. The time taken to carry out the procedure would appear to be an important factor in the strength of the stress response.

A population-based on-farm evaluation protocol for comparing the welfare of pigs between farms

The variability of animal-based parameters was studied within a population of 41 farrow-to-finish farms. Data were collected during three visits, each corresponding to a different season within a two-year period. The largest between-farm variability was observed for stereotypic behaviour by pregnant sows, and for skin, ear and tail lesions, dirtiness and respiratory problems in growing pigs. Relationships with housing and management parameters were established to formulate advice on how to improve pigs' welfare. Group-housed sows performed less oral stereotypic behaviour than individual housed sows (18.7 versus 44.1%), but a higher proportion of skin lesions was observed in group-housed sows (15.4 versus 2.0%). Prevalence of tail-biting behaviour varied between 0 and 21%. The risk for tail biting was higher in cases of reduced levels of floor space per pig, and ear-biting behaviour occurred more often when tails were docked short. Coughing was not correlated directly with the occurrence of lung lesions, but the risk was higher in instances of reduced space availability per pig. Farms could be ranked according to these welfare parameters, ie either according to the score of each individual parameter or based on the summation of all scores. Hence, welfare status was defined in relation to farm-specific information, allowing formulation of advice on housing and management to ultimately improve pig welfare through the matching of a predefined benchmark.

Tail and ear biting lesions in pigs: an epidemiological study

Tail and ear biting lesions have a negative effect both on the animal welfare status of pigs (Sus scrofus) and the economical revenue of the pig farm. Tail biting behaviour is an unpredictable, abnormal behaviour that is thought to have a multifactorial origin. On-farm factors influencing tail biting have been described, but the real triggers are poorly understood. Much of the research into tail biting has been done on a small scale within a well-controlled environment and small sample sizes. This well-controlled environment is not always representative of the contemporary commercial conditions. Therefore, an observational epidemiological approach at farm level was adopted to gain a better insight into the factors influencing the occurrence of tail and ear biting lesions. Tail and ear biting lesions were observed at pen level three times a year on sixty farms across Belgium. A questionnaire was conducted to build a multifactorial model indicating different risk factors concerning the lesions scored. The temperature and the number of feeding places per animal in the nursery, the percentage of floor space covered with slats in the farrowing unit, the feed type in the growing unit and the overall hygiene policy were the most important indicators for the appearance of tail and ear biting lesions during fattening. The leave-one-out cross validation of the model demonstrated an intraclass correlation coefficient of 0.55 between the predicted model outcomes and the observed data. This epidemiological study provides important potential risk factors in relation to the incidence of tail and ear biting lesions. However, experimental and/or longitudinal studies have to confirm that the correlations found in this work are causal factors.