Animal welfare is of increasing significance for European consumers and citizens. Previously, agricultural production focused mainly on supply, price and competition but consumers now expect their food to be produced and processed with greater respect for the welfare of the animals. Food quality is therefore determined by the welfare status of the animals from which it was produced as well as the nature and safety of the end product. Thus, practical welfare improvement strategies and reliable on-farm monitoring systems for assessing the animals’ welfare status and evaluating potential risks are urgently required to accommodate societal concerns and market demands. It is also of paramount importance to define the kind of information that consumers want about the final products and to develop effective strategies for communicating welfare standards to the public. Generating an intensified dialogue with all factions of society on welfare issues as well as appropriate labelling of animal products and farming systems that offer guarantees about welfare issues and production conditions will, in turn, promote transparency and the societal sustainability of European agriculture. Welfare is multidimensional. It cannot be measured directly but only inferred from external parameters. Therefore, the integration of the most appropriate specialist expertise in Europe is essential to develop, refine, standardise and intercalibrate welfare monitoring systems and to identify and validate remedial measures. We must establish a European standard for welfare assessment systems in order to facilitate intra-European trade and marketing. Only then can we harmonise labelling that is informative and relevant to all European consumers.

Human factors (attitudes, personality traits, self-esteem, job satisfaction) strongly determine our behaviour towards animals, animal production and animal welfare. Recent studies have emphasised positive human contacts as indicators of a stockperson's positive attitude towards animals and towards animal welfare in general. Stockmanship can be improved by careful selection of people and/or by training. However, little is known of the biological basis of the effect of stock handling procedures on the welfare of animals. The animal's perception of the stockperson (based both on emotional responses and cognitive aspects such as anticipation, recognition and categorisation), and the existence of sensitive periods in an animal's life, need to be explored in more depth, especially under farm conditions. We need to consider the complexity of human behaviour (eg husbandry practices, balance between positive and negative interactions, predictability, controllability) and its effect on animal welfare from the animal's point of view throughout its whole life. This paper identifies the importance of positive human contacts for both animals and stockpeople, and highlights the challenge to maintain such positive contacts despite the trend in modern agriculture to increase the number of animals per stockperson. This requires better knowledge of animal genetics, socialisation to humans during sensitive periods, and management of the social group. We emphasise the ethical importance of the human-animal relationship in the context of farm animal welfare and productivity.

Farmers' behaviour towards their animals could be improved by developing training programmes designed to decrease handling stress and improve animal welfare. This requires key preliminary work to collate farmers' beliefs concerning beef cattle and their knowledge of how to handle them easily. This paper reports the preliminary results of a survey conducted in 2004 among Limousin farmers. Fifty-five percent of the 300 French beef cattle farmers surveyed returned a questionnaire covering ease of handling, husbandry conditions, attitudes towards cattle, and behaviour during handling and husbandry practices. The results revealed that farmers' attitudes were generally positive. However, variability within each item indicated the potential for improvement. Temperament of heifers or cows is the first trait considered in decisions on culling an animal. Principal Component Analysis (PCA) showed a relationship between positive attitudes towards animals and towards contact with the animals. Attitudes towards negative behaviour (hitting, shouting) during handling are independent of attitudes towards animals. Most farmers underline human contact followed by quality of the facilities for improving ease of handling. Surprisingly, 28% of the farmers surveyed did not recognise the genetic traits as an important factor in ease of handling. Farmers seem open to improving handling, in particular through positive human contact. These results combined with existing scientific knowledge and additional observations of handling will be useful in defining future training programmes for improving the welfare of beef cattle.

The concept of quality of life in animals is closely associated with the concepts of animal sentience and animal welfare. It reflects a positive approach that inquires what animals like or prefer doing. The assessment of farm animal welfare requires a good understanding of the animals' affective experience, including their emotions. However, affective experience in animals is difficult to measure because of the absence of verbal communication. Recent studies in the field of cognitive psychology have shown that affective experience can be investigated without using verbal communication by examination of the interactions between emotions and cognition. On the one hand, appraisal theories provide a conceptual framework which suggests that emotions in humans are triggered by a cognitive process whereby the situation is evaluated on a limited number of elementary criteria such as familiarity and predictability. We have applied these appraisal theories to develop an experimental approach for studying the elementary criteria used by farm animals to evaluate their environment and the combinations of those criteria that trigger emotions. On the other hand, an increasing body of research, first in humans and then in other animals, suggests that emotions also influence cognitive processes by modifying attention, memory and judgement in a short- or long-term manner. Cognitive processes could therefore be manipulated and measured to provide new insights into how not only emotions but also more persistent affective states can be assessed in animals. Further work based on these cognitive approaches will offer new paradigms for improving our understanding of animal welfare, thus contributing to ‘a life of high quality’ in animals.

Whereas physiological and behavioural responses to acute stressors are well documented, chronic stress remains difficult to assess in farm animals. The aim of the present paper is to investigate whether calves’ behavioural reactions to acute events are modified during chronic intermittent stress. Thirty-two calves housed in pairs were used. For half of the calves the partner and the pen were changed once a week for 14 weeks (regrouped calves) while the others remained unchanged (controls). Four behavioural tests were performed to assess calves’ reactivity to novel or sudden events, to predator cues and to restraint. In the water spray test, regrouped calves were startled more often. In the umbrella test, regrouped calves took a longer time to feed in front of the closed umbrella but no differences between the two treatments were observed on opening the umbrella. In the dog test, regrouped calves moved more and looked at the dog more often. In the restraint test, regrouped calves were more agitated. These differences disappeared when the tests were repeated. In conclusion, repeated changes in the social and physical environment of calves enhances their behavioural reactivity to novelty. This is likely to make them more adaptive to potential changes in their environment.

In this study, we analysed the effects of social and human contact on calves ‘ behaviour and stress responses. We also measured the effect of this contact on calves ‘ reactions to novel conspecifics and novel humans. Sixty-four calves were housed either alone or in pairs and received either minimal human contact or ‘additional’ human contact (stroking and talking). At six, 10 and 14 weeks of age, the behaviour of the calves was recorded in their home pens. Calves were then tested in an unfamiliar arena either alone, with an unfamiliar calf, or with an unfamiliar man, and in a Y-maze with one arm leading to a calf and the other to a man. An adrenocorticotrophic hormone (ACTH) challenge was performed in order to assess chronic stress responses. Compared with individually housed calves, pair-housed calves were more active and made fewer contacts with their neighbours when in their home pens; they were also less active in the arena, spent more time near the calf in the Y-maze, and had lower Cortisol responses to ACTH. Calves that had received additional human contact interacted more with the man in the arena and had lower mean heart rates than those that had received minimal contact. This study confirmed that calves feel a need for social contacts and that pair-housing can lower the stress felt by calves separated from their conspecifics. Additional contact from stockpersons increases calves ‘ likelihood of approaching humans but cannot compensate for their lack of social partners. Hence, when calves are separated, the duration of the separation should be limited, and visual and physical contact with other calves should be provided.

Welfare is multidimensional, comprising good health, comfort, expression of behaviour, and so on. Its overall assessment therefore requires a multicriteria evaluation. The set of criteria shall be exhaustive (no missing item), minimal (only necessary items), agreed by stakeholders, and legible (a limited number of criteria). Furthermore, the interpretation from one criterion shall not depend on that from another. We propose a set of 12 subcriteria grouped into four criteria: feeding, housing, health and optimised emotional states. This work will assist in developing measures to be used on-farm to form a European standard for overall assessment of animal welfare.

Animal welfare is multidimensional; its assessment relies on complementary measures covering all dimensions. Welfare Quality® constructed a multicriteria evaluation model for its assessment at unit level (farms, slaughterhouses). Four welfare principles are distinguished (‘Good feeding’, ‘Good housing’, ‘Good health’, and ‘Appropriate behaviour’). An animal unit receives four principle scores (expressed on a 0-100 value scale). These scores are aggregated together to form the overall assessment by sorting animal units into predefined welfare categories boundaried by reference profiles. A unit is assigned to the welfare category above the profile it is considered at least as good as. Several assignment procedures were tested on a set of 69 dairy farms and compared with observers’ general impressions. The welfare categories, reference profiles and assignment procedure were defined in consultation with social scientists, animal scientists and stakeholders. Four welfare categories were defined: ‘Excellent’, ‘Enhanced’, ‘Acceptable’, and ‘Not classified’. The reference profiles were set at 80, 55 and 20, corresponding to aspiration values for Excellent, Enhanced and Acceptable. The assignment procedure resulted from a compromise between theoretical opinion on what should be considered excellent, enhanced or acceptable, and what can realistically be achieved in practice: to be assigned to a given category, a unit must reach its aspiration value on 2 or 3 of the 4 principles, and not score below the aspiration value for the next lowest category on the other principle(s). The model can be used for several purposes, including identifying welfare problems on a farm to advise farmers, or checking compliance with certification schemes.

In the European Union, at least 1% of farms are inspected every year and sanctions are applied to those that do not comply with the legislation on animal welfare. These on-farm inspections can result in measures to correct welfare problems detected. They can also highlight major risks that will require a focus of efforts and help prevent further non-compliances. Here, we analysed the reports from inspections of French cattle farms between 2010 and 2013 to check whether inspection stimulates improvement and to propose ways to improve how animal welfare legislation is implemented through the cross-compliance system. French inspectors use 32 items to assess overall compliance of farms inspected. We found that compliance improves on farms that are re-inspected but not in other farms (8% of severely non-compliant farms). Nine items do not influence the overall assessment whereas eight have a huge impact. The importance attributed to items varies from the first to the second visit to a farm. The major risks are absence of farm records, lack of basic care (practices or enclosures likely to harm animals, insufficient feeding) and inadequate skills (no veterinarian consulted, insufficient qualified staff). To improve compliance with EU animal welfare legislation and the efficiency of the inspection system, we suggest organising consultation between inspectors, ministry central services and welfare experts to: (i) refine the checklist and harmonise interpretations of item compliance; (ii) make sure all farmers are aware of the legislative requirements and the major risks of non-compliance; and (iii) define plans for a step-wise improvement of non-compliant farms.

Over the past decade there has been huge growth in the implementation of animal welfare assessments and audits in a variety of animal applications around the world. These include quality assurance programmes for meat, milk and eggs, certification for specialty brands or food-labelling programmes, accreditation of zoos, laboratories and animal shelters, and proofs of compliance with animal welfare standards required by regulatory agencies. Assessing animal welfare in such practical settings poses challenges at many levels. The animal welfare measures chosen for an assessment must be valid, repeatable and robust, and the sampling techniques must provide accurate representations of the overall welfare status of large groups of animals. Animal welfare assessors can come from a range of backgrounds with varying skill levels and experience and need to receive adequate training to ensure reliability. Although automated measures for animal welfare assessments can reduce potential for assessor error and bias, save time and reduce costs they must be sufficiently validated.

Animal welfare concerns stem from recognition of the fact that animals can experience emotions such as pain or joy. Nevertheless, discussion of animal emotions is often considered anthropomorphic, and there is a clear need to use explanatory frameworks to understand animals' emotions. We borrowed appraisal theories developed in cognitive psychology to study sheep emotions. Emotions are viewed as the result of how an individual evaluates a triggering situation, following a sequence of checks, including the relevance of the situation (its suddenness, familiarity, predictability, and intrinsic pleasantness), its implications for the individual (including consistency with the individual's expectations), the potential for control, and both internal and external standards. We assumed that if the outcome of checks has an impact on the animal's emotional responses, then animals do not only show emotional responses but also feel emotions. We showed that sheep use similar checks to those used by humans to evaluate their environment, ie suddenness, familiarity, predictability, consistency with expectations, and control. Furthermore, this evaluation affects their emotional responses (behavioural responses, such as startle, ear postures, and cardiac activity). It is concluded that sheep are able to experience emotions such as fear, anger, rage, despair, boredom, disgust and happiness because they use the same checks involved in such emotions as humans. For instance, despair is triggered by situations which are evaluated as sudden, unfamiliar, unpredictable, discrepant from expectations, and uncontrollable, whereas boredom results from an overly predictable environment, and all these checks have been found to affect emotional responses in sheep. These results have implications for animal welfare: although a completely invariable and totally predictable environment should be avoided to prevent boredom, sudden events should probably be minimised, the animals should be offered the possibility to control their environment, and care should be taken to ensure a degree of predictability concerning the various events.

Emotions are now largely recognised as a core element in animal welfare issues. However, convenient indicators to reliably infer emotions are still needed. As such, the availability of behavioural postures analogous to facial expressions in humans would be extremely valuable for animal studies of emotions. The purpose of this paper is to find out stable expressive postures in sheep and to relate these expressive postures with specific emotional contexts. In an initial experiment, we identified discrete ear postures from a comprehensive approach which integrates all theoretically distinguishable ear postures. Four main ear postures were identified: horizontal ears (P posture); ears risen up (R posture); ears pointed backward (B posture); and asymmetric posture (A posture). In a second experiment, we studied how these ear postures were affected by specific emotional states elicited by exposing sheep to experimental situations in which elementary characteristics (ie suddenness and unfamiliarity, negative contrast and controllability) were manipulated. We found that: i) the horizontal P posture corresponds to a neutral state; ii) sheep point their ears backward (B posture) when they face unfamiliar and unpleasant uncontrollable situations, hence likely to elicit fear; iii) they point their ears up (R posture) when facing similar negative situations but controllable, hence likely to elicit anger; and iv) they expressed the asymmetric A posture in very sudden situations, likely to elicit surprise. By cross-fostering psychological and ethological approaches, we are able to propose an interpretation of ear postures in sheep relative to their emotions.

Animal welfare enhancement requires that problems are reliably identified and ranked in order to prioritise corrective actions. Welfare problems vary with the conditions in which animals are maintained. The objectives were to highlight major welfare problems for dairy cows on farms in France, and find out how farm characteristics (housing and milking systems, breed) could impact specific welfare aspects on these farms. We conducted a cross-sectional survey on 131 French dairy farms. We used the Welfare Quality® protocol, which addresses all aspects of welfare, and yields scores for principles and criteria that represent how well farms meet welfare requirements (from 0 for a very adverse situation to 100 for an excellent one). We used descriptive statistics to highlight low welfare scores, and variance analyses to compare farms. Most farms were found ‘Acceptable’ according to the Welfare Quality® classification. Principles scores for Health, Feeding and Behaviour ranged from 33 to 39. The median score for eight of the welfare criteria was below 50 (‘Pain’, ‘Integument alterations’, ‘Diseases’, ‘Comfort around resting’, ‘Social behaviours’, ‘Human-animal relationship’, ‘Positive emotional state’, ‘Hunger’), while the median score was above 50 for the four other criteria (‘Thirst’, ‘Lameness’, ‘Expression of other behaviours’, ‘Ease of movement’). The scores varied widely between farms, within and between systems. Farms with cubicles obtained lower scores for ‘Comfort around resting’, ‘Injuries’; farms with Holstein cows obtained lower scores for ‘Hunger’; farms using an automatic milking system obtained lower scores for ‘Expression of other behaviours’ and ‘Diseases’ in Holstein herds. This survey yields information on bottlenecks in dairy cow welfare with all dimensions of welfare considered together. The results can be used by stakeholders to prioritise corrective actions in welfare plans, focusing either on the whole population of farms or on farms with characteristics that are at high risk for specific welfare problems.

All systems of scoring animal units (groups, farms, slaughter plants, etc) according to the level of the animals’ welfare are based inevitably on normative decisions. Similarly, all methods of labelling, in terms of acceptability, are based on choices reflecting ethical values. The evaluative dimension of scoring and labelling does not mean that we should reject them, but it does mean that we need to make the normative and ethical background explicit. The Welfare Quality® scoring system is used as a case study in order to highlight the role of underlying value-based decisions. In this scoring system, which was designed in accordance with assessments and judgments from experts in animal and social sciences and stakeholders, we identify value-based decisions at the following five levels. First, there are several definitions of animal welfare (eg hedonist, perfectionist, and preferentialist), and any welfare scoring system will reflect a focus upon one or other definition. In Welfare Quality®, 12 welfare criteria were defined, and the entire list of criteria was intended to cover relevant definitions of animal welfare. Second, two dimensions can structure an overall evaluation of animal welfare: the individual animals and the welfare criteria (here 12). Hence, a choice needs to be made between the aggregation of information at the individual level (which results in a proportion of animals from the unit in a good vs bad state) and the aggregation at criterion level (which results in a proportion of criteria to which the unit complies vs does not comply). Welfare Quality® opted for the second alternative to facilitate the provision of advice to farmers on solving the welfare problems associated with their farms. Third, one has to decide whether the overall welfare assessment should reflect the average state of the animals or give priority to worse-off animals. In the Welfare Quality® scoring system the worse-off animals are treated as much more important than the others, but all welfare problems, major or minor, count. Fourth, one has to decide whether good scores on certain criteria can compensate for bad scores on others. In the opinion of most people, welfare scores do not compensate each other. This was taken into account in the Welfare Quality® scoring system by using a specific operator instead of mere weighted sums. Finally, a scoring system may either reflect societal demands for high levels of welfare or be based on what can be achieved in practice — in other words, an absolute assessment or a relative one may be proposed. Welfare Quality® adopted an intermediate strategy: absolute limits between welfare categories (Not classified, Acceptable, Enhanced, or Excellent level of welfare) were set, but the rules governing the assignment of an animal unit to a category take into account what had been observed on European farms. The scientists behind Welfare Quality® are keen to make the value-based choices underlying assessments of animal welfare transparent. This is essential to allow stakeholder groups to understand the extent to which their views are acknowledged and acted upon.

Farm animal welfare has become an important issue for the European public, especially in the last two decades when a number of crises (eg Bovine Spongiform Encephalopathy and Avian Influenza) have affected farm animal populations. Public concern about this issue led the European Union to fund the Welfare Quality® project. This project aimed to develop a protocol for assessing animal welfare on farms and at slaughter plants, to identify the main animal welfare problems, and to address possible welfare improvement strategies. In fulfilling these aims, the Welfare Quality® project incorporated inputs from both science and society. This was crucial, as the public perception of what constitutes ‘animal welfare’ sometimes differs from animal science-based definitions. Furthermore, these differences are often interwoven with broader variations in ethical- and value-based understandings about human/non-human animal relationships. This paper presents the steps that we adopted to establish a dialogue between science and society during the construction of the Welfare Quality® assessment protocols. This dialogue involved numerous interactions between animal scientists, social scientists and members of the public. These interactions took several forms, including: meetings, conferences, workshops, websites, newsletters, interviews, focus groups, and citizen and farmers juries. Here, we address four key moments within this dialogue: the development of the initial list of twelve welfare criteria; the consumer focus groups; the development of the Welfare Quality® scoring system; and the citizen juries. In particular, we focus on the results of the focus groups and citizen juries. The focus groups were conducted in France, Italy, Sweden, The Netherlands, the United Kingdom, Norway, and Hungary and the citizen juries were carried out in Italy, the United Kingdom, and Norway. Drawing on this research, we highlight the similarities and differences between societal understandings of farm animal welfare and the views of scientific experts. Furthermore, and crucially, we outline how the animal scientists took account of societal opinion when developing their farm animal welfare assessment tools.

Cortisol is often used as a stress indicator in animal behaviour research. Cortisol is commonly measured in plasma and can also be measured in saliva. Saliva contains only the free form of cortisol, which is biologically active, and saliva sampling is not invasive and may therefore be less stressful. Our study aims to guide the choice between the measurements of cortisol in plasma v. saliva depending on experimental conditions. We analysed the effect of the level of cortisol in plasma on the concentration of cortisol in saliva compared to plasma and the effect of saliva sampling v. jugular venepuncture on the cortisol response. In Experiment 1, blood and saliva were collected simultaneously under conditions in which the expected cortisol release in blood varied: in an undisturbed situation or after the isolation of lambs from their pens or the administration of exogenous ACTH (six animals per treatment). In Experiment 2, we subjected lambs to saliva sampling, venepuncture or neither of these for 8 days to evaluate how stressful the sampling method was and whether the animals habituated to it by comparing the responses between the first and last days (four animals per treatment). All animals were equipped with jugular catheters to allow regular blood sampling without disturbance. Samples were collected 15 min before any treatment was applied, then at various time points up to 135 min in Experiment 1 and 45 min in Experiment 2. In Experiment 1, we observed a strong correlation between salivary and plasma cortisol concentrations (r = 0.81, P < 0.001). The ratio between salivary and plasma cortisol concentrations was 0.106 on average. This ratio was higher and more variable when the cortisol concentration in plasma was below 55 nmol/l. In Experiment 2, venepuncture induced a larger cortisol response than saliva sampling or no intervention on day 1 (P < 0.02); this difference was not observed on day 8, suggesting that sheep habituated to venepuncture. We recommend the measurement of cortisol in saliva to avoid stressing animals. However, when the expected concentration in plasma is below 55 nmol/l, the cortisol in saliva will reflect only the free fraction of the cortisol, which may be a limitation if the focus of the experiment is on total cortisol. In addition, if cortisol is measured in plasma and blood is collected by venepuncture, we recommend that sheep be habituated to venepuncture, at least to the handling required for a venepuncture.

The design of self-locking barriers can affect cows’ skin injuries and impair welfare. This study aimed to propose and refine recommendations, expressed relatively to the cows’ dimensions, for self-locking barrier design to reduce risks for skin injuries on the neck/shoulder/back and on carpus of dairy cows. We recorded individual body dimensions and the dimensions of self-locking barriers (e.g. top rail height) and assessed skin injuries on 3801 cows from 131 loose-housing dairy farms. We explored the significant associations between presence/absence of skin injuries and self-locking barrier dimensions using weighted multivariable logistic regression, taking into account the diversity of feeding barriers within each farm. The robustness of the models was assessed by cross-validation. Cows had skin injuries mainly on the neck/shoulder/back (29.0%) and, to a lesser extent, on the carpus (14.0%). The final multivariable logistic regression models comprised 13 factors for skin injuries on the neck/shoulder/back, and 11 factors for skin injuries on the carpus. Skin injuries were significantly reduced when the self-locking barriers were inclined (neck/shoulder/back) and when the cows used a feeding table (i.e. flat) instead of a feeding manger or cribs (i.e. hollow) (carpus). A top rail height >1.05 × cow height (measured at withers) was significantly associated with fewer skin injuries on the neck/shoulder/back and on carpus. Skin injuries on the neck/shoulder/back and carpus were significantly reduced when the bottom rail was on the food side relative to the wall, and at a height <0.39 of cow height. Skin injuries were significantly less frequent when the separation wall had no sharp edges on the food side (neck/shoulder/back), was >0.4 of cow height (carpus), was thinner than 15 cm (neck/shoulder/back and carpus) and when the height of the feeding step was 0.04 to 0.1 of cow height (neck/shoulder/back) and the length of the feeding step was <0.2 of cow length (carpus). A headlock articulation nut positioned between 0.62 and 0.78 of cow height significantly reduced skin injuries on the neck/shoulder/back. Here, by combining the diversity of on-farm self-locking barriers and their respective dimensions, we were able to refine the International Commission of Agricultural and Biosystems Engineering recommendations for self-locking barrier design and to propose new ones. This information now needs to be confirmed on other datasets, but can already help farmers and dairy industry stakeholders improve the design of self-locking barriers to improve dairy cow welfare.

This study aims to determine whether sheep modify their feeding and general behaviour when they undergo acidosis challenge, whether these modifications are maintained when acidosis challenges are repeated and whether yeast supplementation affects these modifications. Twelve rumen-cannulated wethers fed concentrate (wheat) and forage (hay) were exposed to three 28-day periods consisting of a 23-day recovery phase (20% of wheat) followed by a 5-day acidosis challenge (60% of wheat). Both diets limited food intake to 90% of ad libitum intake. Six sheep received a daily supplementation of a live yeast product, six received a placebo. Ruminal pH was recorded continuously. Daily consumption of wheat, hay, water and weekly consumption of salt were monitored. Behavioural observations were performed twice in each period: once under the recovery phase and once under acidosis challenge. These observations included video recordings over 24 h (time budget), social tests (mixing with another sheep for 5 min) and nociception tests (CO2 hot laser). As expected, sheep spent more time with a ruminal pH below 5.6 during challenges than during recovery phases (12.5 v. 4.7 h/day). Sheep drank more water (3.87 v. 3.27 l/day) and ingested more salt (16 v. 11 g/day) during challenges. They also spent more time standing than during recovery phases, adopting more frequent alarm postures and reacting more slowly to the hot stimulus. More severe behavioural modifications were observed during the first challenge than the two other challenges. Significant concentrate refusals were observed during challenge 1: from days 3 to 5 of this challenge, sheep ate only half of the distributed concentrate. Sheep were also more active and more aggressive towards each other in challenge 1. These behavioural modifications disappeared as the challenges were repeated: no behavioural modifications were observed between challenges and recovery phases during periods 2 and 3, and furthermore, sheep rapidly ate all the concentrate distributed during the third challenge. Focusing on the effects of yeast, the only differences registered between the two groups concerned ruminal pH, that is, mean ruminal pH values in the supplemented group were lower during the first challenge (5.11 v. 5.60) but higher during the third challenge (5.84 v. 5.28). In conclusion, our experiment suggests sheep can adapt to acidosis challenges, especially with yeast supplementation. Otherwise, ruminal pH values remained low during challenges, indicating that the modifications of general and feeding behaviour in subacute ruminal acidosis situations are not due exclusively to low ruminal pH values.