Veterinary · Pre-clinical and foundation · also Ethology, Animal Welfare Science
Normal and abnormal behaviour by species, how pain and stress show, and how welfare is assessed on farm, in transport, at slaughter and in the home.
In the exams: NAVLE animal welfare 6%; BCSE animal welfare 6-7 items; SAVC Paper 4 welfare 15; EAEVE and WOAH Day One competences
Ethology is the scientific study of animal behaviour: what animals do, how the behaviour is produced, how it develops, what it is for and how it evolved. Animal welfare science asks a related question: how is this animal faring, in its body and in its experience, in the conditions in which it lives and dies? The two belong together, because behaviour is the most direct window a veterinarian has into how an animal feels. A sow chewing an empty mouth for hours, a cat that has stopped grooming, a heifer that will not walk into a crush and a dog that bites without growling are all telling you something, and you need the vocabulary of ethology to read them.
In practice this subject decides whether a lame cow is found early, whether a post-operative cat gets enough analgesia, whether cattle reach the abattoir calm or bruised, whether a stun is effective, and whether a family keeps an anxious dog. The World Organisation for Animal Health (WOAH, formerly OIE) lists animal welfare among the Day 1 competencies of every graduating veterinarian, and its Terrestrial Animal Health Code sets welfare standards for transport, slaughter and killing for disease control. National law adds detail that differs a great deal between countries.
NAVLE gives welfare about 6% of its content, the BCSE has 6 to 7 welfare items, the South African registration exam gives welfare 15 marks, and the RCVS examination, the Australasian Veterinary Examination and the EAEVE Day One competences expect a new graduate to handle animals safely, recognise pain and judge fitness for transport. National postgraduate entrance, research-fellowship and government veterinary officer examinations in many countries ask behaviour and welfare within livestock production management and physiology papers. Where law or standards differ by country, this manual says so.
Niko Tinbergen proposed that any behaviour can be explained at four levels, and a full explanation needs all four. Causation (mechanism) asks what internal and external factors trigger the behaviour now: hormones, neural circuits, stimuli. Development (ontogeny) asks how the behaviour appears over the animal's lifetime through genes, experience and learning. Function (adaptive value) asks how the behaviour helps survival and reproduction. Evolution (phylogeny) asks how it arose in the ancestors of the species. A cow seeking isolation before calving can be explained by rising hormones and the cues of labour (causation), by its appearance only in mature females (development), by its protection of a hidden calf from predators (function) and by its presence in wild bovids (evolution). Mixing these levels is a common source of confused argument in welfare debates.
Lorenz and Tinbergen described fixed action patterns: stereotyped sequences that, once started by a sign stimulus (a releaser), run to completion, as when a greylag goose keeps rolling an egg after it is removed. For welfare the lasting lesson is that some behaviours, such as nest building in sows and dustbathing in hens, are motivated from inside and are performed even when their functional outcome is already provided.
Many behaviours develop through sensitive periods, windows in which particular experiences have an unusually large and lasting effect. Filial imprinting in precocial birds such as ducklings and chicks, described by Lorenz, makes the young follow the first conspicuous moving object they meet soon after hatching. Sexual imprinting shapes later mate preference. In mammals the socialisation period is the time when the young learn which other species are safe social partners. In puppies it runs from about 3 weeks to about 12 to 14 weeks of age; in kittens it is earlier and shorter, about 2 to 7 weeks. The exact limits vary between individuals and breeds and are best treated as approximate. Animals that miss positive exposure to people, other animals and everyday environments during this window are more likely to be fearful later, and that fear is hard to undo. Hand rearing without contact with conspecifics can produce the opposite problem: an animal that directs social and sexual behaviour at people, a recognised hazard with hand-reared bull calves and male llamas and alpacas, which may become dangerous to handlers as adults.
Habituation is a decline in response to a repeated stimulus that has no important consequence, such as cattle ceasing to react to traffic beside their field. Sensitisation is the opposite: an increase in response after an intense or aversive stimulus, so a dog frightened by one firework may react more to later, quieter bangs. Classical (Pavlovian) conditioning pairs a neutral stimulus with an unconditioned stimulus (US) that already produces an unconditioned response; the neutral stimulus becomes a conditioned stimulus (CS) that produces a conditioned response. Cats that hide when the carrier appears and dogs that tremble in the clinic car park have learned fear this way. Operant (instrumental) conditioning, studied by Thorndike and Skinner, links a behaviour to its consequence. Reinforcement makes a behaviour more likely and punishment less likely; positive means something is added and negative means something is removed. Positive reinforcement adds a reward; negative reinforcement removes an aversive stimulus, as when pressure on a horse is released the moment it steps forward; positive punishment adds an aversive stimulus; negative punishment removes something wanted, such as ending play when a puppy bites.
Continuous reinforcement gives the fastest learning; intermittent schedules make behaviour more resistant to extinction, and a variable-ratio schedule is the most resistant of all, which is why a dog occasionally fed at the table begs persistently. When reinforcement stops, the behaviour often first intensifies, an extinction burst; owners who give in then teach the animal to try harder. A conditioned (secondary) reinforcer, such as a click, gains value by pairing with food and marks the exact moment of a correct response.
Systematic desensitisation exposes the animal to a feared stimulus at an intensity low enough that it does not react and raises the intensity in small steps. Counterconditioning pairs the stimulus with something pleasant so that its emotional meaning changes. The two are normally combined. Flooding, prolonged exposure to a full-intensity stimulus with no escape, can worsen fear and is not recommended in clinical behaviour practice. Learned helplessness, described by Seligman, is the passive state that follows repeated exposure to aversive events the animal cannot control; an animal that has stopped responding is not necessarily calm.
Cattle are social grazing prey animals. They form stable dominance hierarchies, and regrouping causes fighting until a new order is settled, which is one reason frequent regrouping of dairy cows costs feed intake and milk. Their wide panoramic vision leaves a blind spot directly behind, and their depth perception is poorer than ours, so they balk at shadows, drains and sudden contrasts on the floor. Dairy cows typically lie roughly 10 to 14 hours a day and ruminate several hours more, though values vary with diet, housing and production. Lying is a high priority: cows deprived of lying time give up eating time to recover it. A fall in rumination time is an early sign of disease.
Before calving the cow usually becomes restless and, at pasture, seeks a secluded site. Calves are 'hiders': in the first days they lie concealed while the dam grazes and returns to suckle. Buffalo share most of these traits but rely heavily on wallowing or water for cooling, because they have relatively few sweat glands and dark skin that absorbs heat. Bulls of dairy breeds are among the most dangerous animals on farms, and bulls reared in isolation or hand-fed as calves are particularly so.
Sheep have the strongest flocking instinct of the farm species. A sheep separated from its flock shows marked distress, vocalisation and escape attempts, so sheep should be handled in groups and never isolated unnecessarily. They follow a leader, move readily uphill and towards other sheep, and resist moving into dark or confined spaces. Lambs are 'followers': they stay close to the ewe from birth. A ewe forms a selective bond with her lamb within a few hours of birth, recognising it mainly by smell at first; this sensitive period is triggered by vaginocervical stimulation at birth, and shepherds exploit it when fostering a lamb onto another ewe.
Goats are browsers, preferring leaves, shrubs and tree material to grass, and they climb, rear on their hind legs and explore objects with their mouths. Kids are 'hiders' in the first days of life, like calves. Goats are more independent than sheep, less inclined to flock tightly and more likely to escape enclosures. Both species are stoical prey animals that show pain and disease subtly, a point that matters for every welfare assessment.
Pigs are intelligent, social omnivores with a strong motivation to explore and root. Under semi-natural conditions they spend much of the day foraging, and in barren pens this motivation is redirected to pen-mates, which is a major cause of tail and ear biting. Pigs have few functional sweat glands and cool themselves by wallowing in mud or water; they keep the dunging area apart from the lying area when the pen design allows it, and a pen fouled throughout is a sign of poor design, overcrowding or heat stress. Mixing unfamiliar pigs produces fighting that settles a hierarchy, usually within a day or two.
About a day before farrowing the sow becomes restless and builds a nest. The motivation is hormonally driven and strong: sows in crates without material still perform nest-building movements, pawing and rooting at the floor. Piglets establish a teat order within the first days, each piglet suckling from its own teat, and the anterior teats are generally the most productive. Nursing is a coordinated sequence of grunting, massage, a brief milk let-down lasting only seconds, and further massage.
Horses are grazing prey animals adapted to move and eat for much of the day. Free-living horses spend more than half of each day foraging, eat many small meals and live in stable family bands. They are flight animals: sudden movement, noise or unfamiliar objects can trigger a powerful escape response, and a frightened horse is dangerous. The stay apparatus allows a horse to doze standing, but rapid-eye-movement sleep requires lying down, so a horse that cannot or will not lie down, because of pain, lack of space or social insecurity, may become sleep deprived and collapse while standing. Horses communicate through ear and tail position, facial expression and mutual grooming, and they show the flehmen response, raising the upper lip to draw odours to the vomeronasal organ, which is also seen in cattle, sheep, goats and cats. Foals are followers.
The domestic fowl descends from the red jungle fowl and keeps most of its ancestor's behavioural repertoire. Hens form a pecking order, first described by Schjelderup-Ebbe, which is stable in small groups but cannot be maintained as individual recognition breaks down in very large flocks. Hens are highly motivated to dustbathe, which maintains plumage condition, to forage by scratching and pecking at the ground, to perch at night and to find an enclosed nest site before laying. Pre-laying behaviour includes searching and a strong preference for an enclosed nest; hens denied a nest show restless pacing and stereotyped escape movements. Feather pecking is best understood as redirected foraging pecking. Broiler chickens are much less active than laying strains because of their rapid growth, and leg weakness further reduces walking.
The domestic dog descends from wolf ancestors and has been selected for life with people for many thousands of years. Dogs are social, attach readily to human caregivers and read human gestures such as pointing well. They communicate through body posture, tail carriage, ear position, facial expression, vocalisation and scent. A relaxed dog has a loose body and soft face. Signs of mild anxiety or appeasement include lip licking, yawning out of context, turning the head away, lifting a front paw and showing the white of the eye ('whale eye'). Fear escalates through lowering the body, tucking the tail, pinning the ears back, freezing and then growling, lip lifting, snapping and biting. This sequence is often taught as a 'ladder' of aggression: when early signals are ignored or punished the dog may skip them and bite with little warning. The play bow, front end lowered and rear end up, signals that what follows is play.
Raised-leg urination is typical of adult males. Breeds differ in traits selected for work, but variation within breeds is large and breed alone predicts an individual dog's behaviour poorly.
The domestic cat descends from the African wildcat, a solitary hunter of small prey. Cats are not obligately solitary: free-living cats with enough food form colonies built around related females, which groom each other (allogrooming), rub against each other (allorubbing) and cooperate in rearing kittens. Unrelated cats forced to share a house may never form a social group, and much feline stress comes from living with cats they do not regard as companions. Cats greet with the tail held vertically, signal relaxed trust with a slow blink, and mark their surroundings by facial rubbing, which deposits facial pheromones, and by scratching, which leaves both visible marks and scent from interdigital glands. Scratching also conditions the claws and is normal behaviour, not a problem in itself.
Cats naturally eat many small meals a day, often hunting even when fed, and they are most active at dawn and dusk. They bury urine and faeces in loose substrate and prefer a clean toileting site away from food and water. Urine spraying, a standing posture with a raised quivering tail that deposits small volumes on vertical surfaces, is a marking behaviour distinct from toileting, which is done squatting on horizontal surfaces. Cats hide when frightened, and a hiding place is one of their most important resources; a cat with nowhere to hide in a cage or a clinic is under greater stress.
Rabbits are social prey animals, active mainly at dawn and dusk, that live in groups and dig burrows. They are highly motivated to graze and need a diet based on hay or grass both for their teeth and gut. They produce caecotrophs, soft faecal pellets eaten directly from the anus, which is normal behaviour and essential for nutrition. Pet rabbits do best in compatible pairs or groups, with room to hop, stand up on the hind legs and hide. Like other prey species, rabbits and rodents tend to hide pain and illness, and reduced food intake or faecal output is often the first sign of disease.
Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Animals cannot report it in words, so we infer it from behaviour and physiology, and pain goes untreated mainly because nobody recognised it. Prey species, including cattle, sheep, goats, horses, rabbits and rodents, are adapted to hide weakness from predators and may show few signs while a person is watching. Cats also tend to hide pain. The most useful approach is to watch the animal undisturbed first, then interact with it and palpate the painful area, and to compare its behaviour with its own normal behaviour.
General signs across species include changes in posture (hunched back, tucked abdomen, abnormal weight bearing), reluctance to move or lie down, guarding a body part, altered gait, reduced appetite, reduced grooming or excessive licking of one area, changes in social behaviour such as withdrawal or new aggression, restlessness, and vocalisation. Teeth grinding (bruxism) is seen with pain in cattle, sheep, goats and horses.
In cattle, signs include an arched back, low head carriage, reduced rumination and feed intake, reduced milk yield, kicking at the abdomen and, for lameness, shortened stride and uneven weight bearing. In sheep, pain may be shown only by isolation from the flock, lip curling or abnormal posture. Pigs may show reduced activity, trembling, huddling and changes in tail posture, and piglets after castration show prostration, trembling and tail wagging. In horses, colic pain produces pawing, flank watching, lying down and rolling, and sweating; foot pain in laminitis produces a characteristic stance with the weight rocked back onto the heels and frequent weight shifting. Dogs in pain may be restless, pant, whine or be unusually quiet, adopt a 'prayer' position with abdominal pain, and resent handling. Cats in pain often sit hunched and still at the back of the cage, half close their eyes, stop grooming and eating, and may hide; the absence of activity is easily misread as calm.
Facial action coding, first applied to animals as the Mouse Grimace Scale, records changes in a few facial 'action units' that accompany pain. Validated grimace scales now exist for several species, including rats, rabbits, horses, sheep, piglets and cats. The Feline Grimace Scale scores five action units, ear position, orbital tightening, muzzle tension, whisker change and head position, each from 0 to 2, giving a total of 10; a total of 4 or more is the published threshold at which analgesia should be considered. Typical pain faces show orbital tightening (narrowed eyes), tension around the muzzle and changed ear position. Grimace scales are quick, need little handling and can be taught to nurses and stock people, but each is valid only for the species and type of pain it was validated in.
Composite scales combine several behaviours and responses to interaction. The short form of the Glasgow Composite Measure Pain Scale (CMPS-SF) for acute pain in dogs scores posture, demeanour, mobility, vocalisation, attention to the wound and response to touch; a total of 6 or more out of 24, or 5 or more out of 20 when mobility cannot be assessed, is the recommended threshold for giving analgesia. For cats, the UNESP-Botucatu multidimensional composite scale and the Glasgow feline composite scale are validated for acute post-operative pain. WSAVA's Global Pain Council guidelines summarise these tools.
Chronic pain, especially from osteoarthritis, changes behaviour slowly: dogs become reluctant to jump, climb stairs or play, and cats stop jumping onto high surfaces, groom less, sleep more and may toilet outside a high-sided tray. Owners notice these changes before vets do, so owner questionnaires such as the Helsinki Chronic Pain Index and the Canine Brief Pain Inventory for dogs, and the Feline Musculoskeletal Pain Index for cats, are used to detect and monitor chronic pain. A useful diagnostic test is response to analgesia: improvement in activity after a trial of an analgesic supports pain as the cause. Pain should be reassessed at regular intervals, because a single score cannot capture a changing state.
Stress is the biological response to a perceived threat to homeostasis. Two systems act together. The sympathetic-adrenomedullary (SAM) axis releases adrenaline and noradrenaline within seconds, raising heart rate, blood glucose and alertness for fight or flight. The hypothalamic-pituitary-adrenal (HPA) axis acts over minutes: corticotropin-releasing hormone from the hypothalamus stimulates adrenocorticotropic hormone (ACTH) from the anterior pituitary, which stimulates glucocorticoid release from the adrenal cortex. The main glucocorticoid is cortisol in most mammals and corticosterone in birds and rodents. Hans Selye described a general adaptation syndrome of alarm, resistance and exhaustion. Gary Moberg's model adds the idea of biological cost: stress becomes distress when coping diverts resources from other functions such as growth, reproduction and immunity, so that the animal enters a pre-pathological or pathological state.
Cortisol is released in pulses, follows a daily rhythm, rises with sampling itself and rises with positive arousal such as mating, so a high value does not prove a negative experience. Less invasive samples include saliva, faeces (metabolites reflecting hours to a day or more earlier, depending on gut transit) and hair (weeks to months). In birds the heterophil to lymphocyte ratio rises with chronic stress.
Acute stress produces vigilance, freezing, attempts to escape, alarm calls, defecation and urination, trembling, panting and, in some animals, aggression. Displacement activities, behaviours that seem out of context such as grooming, scratching or yawning during conflict, appear when an animal is torn between competing motivations. Chronic stress tends to show as reduced activity and exploration, apathy, altered feeding, poor coat or feather condition, reduced play, abnormal behaviours and increased susceptibility to disease. Some animals in chronically poor environments become unresponsive, which may represent a state close to learned helplessness or depression rather than contentment.
Fear of humans is a measurable form of stress with practical costs. Paul Hemsworth and colleagues showed that aversive handling of pigs and dairy cows raised fear of people and reduced growth, reproduction and milk yield. In dairy cows adrenaline released during fear inhibits milk ejection, which depends on oxytocin, so fearful cows leave milk behind in the udder.
A stereotypy is a repetitive behaviour with an invariant pattern and no obvious function. Georgia Mason's definition adds the cause: repetitive behaviours induced by frustration, repeated attempts to cope, or central nervous system dysfunction. Classic examples are crib-biting and windsucking, weaving and box-walking in stabled horses; bar-biting and sham-chewing in confined, food-restricted sows; tongue-rolling in cattle, particularly veal calves fed milk without solid feed; pacing in zoo carnivores; and route-tracing in caged birds. Stereotypies are strongly associated with barren environments, restricted feeding of animals selected for high appetite, early weaning and social isolation. In horses, crib-biting is associated with low-forage, high-concentrate diets, early abrupt weaning and limited social contact.
Three points matter clinically. First, a stereotypy signals that the environment is, or once was, inadequate, but it may persist as a 'scar' after conditions improve, so it does not always mean the animal is suffering now. Second, within a poor environment the animals that stereotype may sometimes be coping better than those that do not. Third, physically preventing the behaviour, for example by fitting a cribbing collar, without changing the cause may increase frustration. The aim is to remove the cause: more forage, more space, social contact and enrichment.
Redirected behaviours are directed at an inappropriate target when the proper one is missing. Tail biting in pigs is multifactorial, linked to lack of rooting material, crowding, poor air quality, competition for feed and water, and health problems; tail docking reduces it but does not remove the causes, and EU rules forbid routine docking. Feather pecking in laying hens is redirected foraging behaviour and can progress to cannibalism; beak trimming reduces damage and is restricted or banned in some countries. Cross-sucking in calves is redirected suckling, reduced by feeding milk through teats and letting calves suck after the meal. Wool pulling in housed sheep and belly nosing in early-weaned piglets are further examples. In each case the most effective control is to give the animal a better outlet for the underlying motivation.
Modern farm animal welfare policy began in the United Kingdom with the Brambell Committee report of 1965, written in response to public concern about intensive systems. The committee said animals should at least have the freedom to stand up, lie down, turn around, groom themselves and stretch their limbs. The Farm Animal Welfare Council (FAWC), set up in 1979, developed these into the Five Freedoms: freedom from hunger and thirst; freedom from discomfort; freedom from pain, injury or disease; freedom to express normal behaviour; and freedom from fear and distress. The Five Freedoms are written into many codes of practice and laws and into WOAH's general principles. Their limitations are that they describe ideals that cannot be fully achieved, focus on the absence of negative states, and say little about positive experiences.
David Mellor and Cam Reid introduced the Five Domains model in 1994 to grade the severity of procedures in research animals, and Mellor and colleagues have since extended it to all animals, most recently in the 2020 version. Four physical or functional domains, nutrition, physical environment, health, and behavioural interactions, describe the conditions and internal states that generate feelings. The fifth domain, mental state, is where those feelings are experienced and is what welfare finally consists of. In the 2020 update the fourth domain was renamed behavioural interactions and now explicitly includes interactions with the environment, with other animals and with humans. It is now widely used in welfare assessment, policy and teaching, including in Australia and New Zealand.
David Fraser and colleagues described three overlapping ways people think about welfare: biological functioning (health, growth, reproduction and normal physiology), affective state (feelings such as pain, fear and pleasure) and natural living (being able to live a reasonably natural life and perform natural behaviours). Each captures something real, and disagreements about welfare, for example between a producer and a campaigner, often come from emphasising different conceptions.
WOAH's Terrestrial Animal Health Code defines animal welfare as the physical and mental state of an animal in relation to the conditions in which it lives and dies. The Code's guiding principles recognise the Five Freedoms and the Three Rs, state that the use of animals carries an ethical responsibility to ensure their welfare to the greatest extent practicable, and favour outcome-based (animal-based) criteria when standards are compared. The Three Rs, Replacement, Reduction and Refinement, were set out by Russell and Burch in 1959 for animal research and are now applied more widely.
Welfare science has shifted from avoiding suffering towards promoting positive experiences. In 2009 FAWC proposed that animals should have at least 'a life worth living' and, increasingly, 'a good life'. Positive indicators include play, affiliative behaviour such as allogrooming, exploration, relaxed postures and some vocalisations. Methods for studying affective state include preference tests, which show what an animal chooses; motivation tests, which measure how hard an animal will work for a resource, where a resource for which demand stays high as the price rises (inelastic demand) is regarded as a necessity; and judgement (cognitive) bias tests, in which animals in better welfare interpret an ambiguous cue more optimistically.
A welfare assessment can measure what the animal is given, what is done to it, or how the animal is. Resource-based (input) measures include space allowance, number of drinkers, bedding type and ventilation. Management-based measures include feeding routines, colostrum management, pain relief at castration and staff training. Animal-based (outcome) measures are taken on the animals themselves: body condition, lameness, lesions, cleanliness, injuries, mortality, disease prevalence and behaviour. Resource measures are easy to audit and suit legislation, but the same resources produce different outcomes on different farms. Animal-based measures reflect the result and are favoured by WOAH and the EU's scientific bodies, but they take skill and time. Most modern protocols combine both: animal-based measures to judge welfare, and resource and management measures to explain the cause and guide improvement.
The Welfare Quality protocols, developed by a large EU-funded project and published in 2009 for cattle, pigs and poultry, are built on four principles and twelve criteria. Good feeding covers absence of prolonged hunger and absence of prolonged thirst. Good housing covers comfort around resting, thermal comfort and ease of movement. Good health covers absence of injuries, absence of disease, and absence of pain induced by management procedures. Appropriate behaviour covers expression of social behaviours, expression of other behaviours, a good human-animal relationship and a positive emotional state. Measures include body condition, lameness, integument alterations, cleanliness, an avoidance distance test of the human-animal relationship and Qualitative Behaviour Assessment (QBA), in which trained observers rate the demeanour of a group with descriptive terms such as relaxed, fearful or playful. The AWIN project later produced protocols for horses, donkeys, sheep, goats and turkeys.
A good welfare measure must be valid (it measures what it claims to measure), reliable (repeated observations agree) and feasible (it can be done on a real farm in the time available). Reliability is tested between observers (inter-observer) and within one observer over time (intra-observer). Percentage agreement overstates reliability because observers agree by chance; Cohen's kappa corrects for this. Kappa is calculated as the observed agreement minus the agreement expected by chance, divided by one minus the agreement expected by chance. Values above about 0.6 are usually taken as substantial and above 0.8 as almost perfect, though cut-offs are conventions. Lameness scoring, for example, often has good reliability only after observers are trained together on reference videos.
Body condition scoring uses a scale defined for each species, typically 1 to 5 for cattle and sheep and 1 to 9 (or 1 to 5) for dogs and cats, and indicates long-term nutrition. Locomotion or mobility scoring in dairy cattle, using scales such as a 5-point locomotion score or the 4-point (0 to 3) mobility score used in UK schemes, detects lameness, which is among the most important welfare problems of dairy cows worldwide. Lesion and injury scoring includes hock lesions in cows, tail and ear lesions in pigs, and footpad dermatitis and hock burn in broilers, which reflect litter quality. Mortality, culling and disease records are valuable but reflect only the severe end of welfare. Some measures act as 'iceberg indicators', single outcomes that reflect many underlying problems, such as lameness in dairy cows or footpad dermatitis in broilers.
Good handling uses the animal's own behaviour. The flight zone is the area around an animal that, when a person enters it, makes the animal move away; its size depends on tameness, previous handling and the approach, being small in hand-reared or regularly handled stock and large in extensively reared stock. The point of balance is usually at the shoulder: a handler standing behind the point of balance, at the edge of the flight zone, moves the animal forward, and a handler in front of it makes the animal back up. Pressure is applied by entering the flight zone and released by stepping back as soon as the animal moves the right way, which is negative reinforcement. Temple Grandin's work showed that animals balk at distractions that people overlook: shadows, reflections on wet floors, dangling chains, moving objects ahead, air blowing into their faces, sudden changes in floor colour or texture, high-pitched noise and people visible ahead. Animals move more readily from dark into light, but not into blinding light. Curved single-file races with solid sides work because animals cannot see the handler or the activity ahead and because cattle tend to go back towards where they came from.
WOAH guidance limits electric goads to extreme cases, on the hindquarters of adult cattle and pigs that refuse to move, never on sensitive areas such as the eyes, mouth, ears, anogenital region or belly; national rules are often stricter.
Cattle should be moved in small groups at a walk, through well-designed races to a crush (chute) with a head bail; good facilities are safer for people as well as animals. Sheep move as a flock and follow a leader, so a few sheep moving ahead pull the rest; for examination a sheep can be set up on its rump, which makes most sheep stop struggling. Pigs are best moved in small groups with boards or hurdles; a snout snare restrains an adult pig for a short procedure but is aversive and should be brief. Poultry should be caught and carried gently and supported; holding birds by one leg causes injury, and WOAH and many codes prefer upright carrying. Horses are traditionally approached from the near (left) side at the shoulder and restrained with a headcollar; a nose twitch has a calming effect that appears to involve more than distraction, possibly including endogenous opioid release, but the mechanism is debated and the twitch should be used briefly. Lifting a leg reduces kicking with the opposite hind limb. Sedation is often safer and more humane than prolonged physical restraint.
Low-stress, fear-reducing handling is now standard in small animal practice. It includes calm, quiet waiting areas separated by species, letting the animal approach, using the least restraint that is safe, giving food rewards, examining cats in the bottom half of their carrier, wrapping cats in a towel, and stopping and rescheduling when an animal becomes highly distressed. The 2022 AAFP/ISFM Cat Friendly Veterinary Interaction Guidelines advise against scruffing and suspending cats. Basket muzzles allow a dog to pant and take treats and are preferable to tight fabric muzzles for anything but brief procedures; a dog in a tight muzzle cannot pant and can overheat. Chemical restraint, including pre-visit anxiolytic medication given at home, is used when an animal is too fearful for safe handling; drugs commonly used in this way are often used off-label, so check national rules and confirm any dose against the product label and your national formulary.
Every forced restraint is also a learning trial: an animal held down while struggling learns that the clinic is frightening. Hemsworth's studies showed that brief positive daily contact reduces fear of people in pigs and cows, and the same logic underlies cooperative care training of pets.
Transport is one of the most stressful events in a farm animal's life. It combines handling and loading, mixing with unfamiliar animals, novelty, vibration and motion, noise, restricted space, thermal extremes, and deprivation of feed and water, often ending at an unfamiliar market or abattoir. WOAH's Terrestrial Animal Health Code includes chapters on transport by sea, by land and by air. Their principles include planning the journey, competent handlers, fitness of animals to travel, appropriate vehicle design and space, provision of water, feed and rest according to species and journey length, contingency plans for delays and breakdowns, and clear allocation of responsibility among owners, transporters, drivers, market operators and veterinarians. Regional and national law sets the detail. The EU's Regulation (EC) No 1/2005 sets journey times, rest intervals and space allowances; in the United States the Twenty-Eight Hour Law limits confinement of livestock in interstate transport without unloading for feed, water and rest. Exact limits differ widely and must be checked locally.
The single most important welfare decision before a journey is whether each animal is fit to travel. WOAH lists animals that should not be transported, and national rules are similar. They include animals that are sick, injured, weak, disabled or fatigued; animals unable to stand unaided or bear weight on each leg; animals blind in both eyes; animals that cannot be moved without causing additional suffering; newborn animals with an unhealed navel; females in the final 10% of gestation at the time of planned unloading; and females that have given birth very recently (within 48 hours under WOAH, within the previous week under EU rules) travelling without their young. Animals in poor body condition, or with large prolapses or open wounds, are also at risk. When an animal is unfit, it should be treated on the farm or killed humanely there, not loaded in the hope it survives the journey. Veterinarians are often asked to certify fitness, and the certificate is a professional responsibility.
Space allowance must let animals stand in a natural position, lie down when the journey is long enough for them to want to, and allow air to circulate. Too little space causes injuries and falls; too much on rough roads also causes falls. One scientific approach expresses floor space as an allometric function of body weight, area in square metres equals a coefficient k times body weight to the power 0.67, where k depends on the posture the animals need to adopt; the coefficients and resulting legal allowances differ between jurisdictions. Heat stress is a major cause of death in transport, especially for pigs and poultry, and is worse when vehicles are stationary because airflow depends on movement. Cold and wind chill affect newly shorn sheep and young animals. Feed and water deprivation cause dehydration and weight loss ('shrink'); young unweaned animals are particularly vulnerable because they cannot drink from ordinary drinkers.
Transport welfare can be judged by animal-based outcomes at unloading: dead on arrival, non-ambulatory animals, injuries, bruising, slipping and falling during unloading, panting and shivering. Bruising on carcasses is often traceable to rough handling, horned animals mixed with polled ones, and poor vehicle design. Meat quality records stress. Long-term stress before slaughter depletes muscle glycogen, so less lactic acid forms after death and the ultimate pH stays high, producing dark, firm and dry (DFD) meat, typical of bulls mixed with strangers or held long without feed. Acute stress immediately before slaughter, especially in pigs carrying the stress-susceptibility (halothane, RYR1) mutation, makes pH fall rapidly while the carcass is still warm, producing pale, soft and exudative (PSE) meat. These links mean that good transport welfare also has a direct economic value.
WOAH's Terrestrial Code chapter on the slaughter of animals covers the arrival of animals, lairage, handling, restraint, stunning and bleeding, and a separate chapter covers killing animals for disease control. The principles are that slaughter should be carried out by trained, competent staff; animals should be moved calmly without unnecessary force; lairage should provide water at all times, protection from weather, enough space to lie down, and feed if animals are held for longer periods; and that stunning, when used, should render the animal immediately unconscious, or unconscious without avoidable pain, distress or suffering, until death. Unfit or injured animals should be slaughtered or killed without delay on arrival. Restraint should be appropriate to the species and size, applied only when the operator is ready to stun, and should not cause pain, so that the time between restraint and stunning is short.
Mechanical stunning uses a captive bolt. A penetrating captive bolt produces concussion and brain damage; a non-penetrating (percussive) bolt produces concussion alone and is used mainly for younger animals and poultry. For cattle the standard frontal site is the point where two lines drawn from each eye to the base of the opposite horn (or horn bud position) cross, aimed along the axis of the brain. For pigs the bolt is placed on the midline slightly above eye level, aimed towards the tail. For polled sheep the site is the top of the head aimed down towards the throat; horned sheep are shot behind the poll aimed towards the chin. Back-up stunning equipment must be immediately available.
Electrical stunning passes current through the brain. Head-only stunning produces a generalised epileptiform seizure and is reversible, so the animal must be bled quickly before it can recover. Head-to-body stunning also passes current through the heart, causing cardiac fibrillation, and so kills the animal. EU Regulation (EC) No 1099/2009 sets minimum currents for head-only stunning, for example 1.28 A for adult cattle, 1.00 A for sheep and goats and 1.30 A for pigs; other jurisdictions set their own values. High concentrations of carbon dioxide, used widely for pigs (at least 80% by volume under EU rules), are aversive: pigs gasp and try to escape before losing consciousness. Inert gases such as argon and nitrogen are less aversive. For poultry, controlled atmosphere stunning avoids shackling conscious birds, whereas electrical waterbath stunning requires live shackling and risks pre-stun shocks and missed birds.
After a captive bolt stun an effectively stunned animal collapses immediately, shows a tonic spasm, has no rhythmic breathing, no corneal or palpebral reflex, a fixed glazed stare, a relaxed jaw with the tongue hanging out, and makes no attempt to right itself or vocalise. Kicking movements may follow and are not by themselves a sign of consciousness. After an electrical head-only stun there is a tonic phase, with rigidity and no breathing, followed by a clonic phase of paddling. Signs of an ineffective stun or recovery include rhythmic breathing, vocalisation, eye movement and tracking, a returning corneal reflex, and attempts to raise the head or right the body; any of these requires immediate re-stunning.
Bleeding should follow quickly and completely. In cattle a thoracic stick severing the major vessels near the heart drains blood faster than a neck cut, because after a neck cut the vertebral arteries continue to supply the brain; in addition, the cut ends of the carotid arteries can occlude ('ballooning'), which delays brain death. Bleeding without prior stunning is permitted for religious slaughter in many countries under specific conditions, while some countries require stunning for all slaughter; WOAH addresses welfare considerations for both and leaves the decision to national authorities.
Outcome-based audits developed by Temple Grandin for the North American meat industry are widely used. Typical criteria are the percentage of animals effectively stunned with the first attempt (at least 95% for captive bolt), the percentage insensible on the bleed rail (100%), the percentage of cattle vocalising during handling and stunning (3% or fewer), the percentage falling (1% or fewer) and the percentage moved with an electric prod, with acts of abuse such as dragging conscious animals causing automatic failure. Thresholds differ between audit versions and certification schemes, but the method of scoring a defined sample of animals against numerical targets is the core lesson. Vocalisation in cattle during handling and stunning is a useful measure because it is associated with painful or frightening events such as missed stuns, prod use or excessive restraint pressure.
Environmental enrichment is a change to an animal's environment that improves its biological functioning or welfare, a working definition associated with Ruth Newberry. Adding objects is not enough: an enrichment works only if animals use it and if welfare measures improve, such as fewer stereotypies, less injurious behaviour, better health, more varied behaviour or positive affective indicators. Types include social (companions, or contact with people), occupational (puzzles, training, foraging tasks), physical (structures, substrates, space and complexity), sensory (visual, olfactory and auditory stimuli) and nutritional (novel foods, changed delivery). Animals habituate to unchanging objects, so items that are destructible, edible or rotated retain value longer. Enrichment must be safe, hygienic and sufficient for the group, because a single item in a pen can create competition and aggression.
Pigs need materials they can root, chew, manipulate and destroy, such as straw, hay, wood or other fibrous materials. Good standards (EU Council Directive 2008/120/EC is one example) require permanent access to such material; hanging chains alone are insufficient. Straw also reduces tail biting. Laying hens need perches, litter for scratching and dustbathing, and enclosed nest boxes. Conventional battery cages provide none of these; the EU ended them from 2012 (Directive 1999/74/EC) and New Zealand by the end of 2022. For furnished cages, EU rules, for example, require at least 750 cm2 of cage area per hen, of which 600 cm2 is usable, plus a nest, litter and perches, and limit barn systems to 9 hens per m2 of usable area. Broiler welfare is improved by lower stocking density, natural light, perches and bales, and slower-growing breeds; legal density ceilings are set in kg of live weight per m2, and EU Directive 2007/43/EC, for example, sets a maximum of 33 kg/m2, which may be raised to 39 and then 42 kg/m2 when additional conditions are met.
Sow stalls (gestation crates) restrict movement for most of pregnancy. Many jurisdictions now restrict or ban them: the United Kingdom and Sweden banned stalls, New Zealand and several US states restrict them, and in the EU sows must be group housed from four weeks after service until one week before expected farrowing. Calves benefit from social housing and from teat feeding; EU rules, for example, prohibit individual pens for calves older than eight weeks except on veterinary grounds. Dairy cows use mechanical brushes intensively. Horses benefit most from turnout, equine company and ad libitum forage. Elsewhere standards vary greatly, many countries rely on voluntary codes or assurance schemes, and WOAH's production-system standards are the common international reference.
Kennelled dogs benefit from regular human contact, exercise, food-dispensing toys and predictable routines; long-term kennelling without these increases repetitive behaviours and stress. Shelter cats provided with a hiding box adapt faster and show lower stress scores than cats without one. At home, cats need separate key resources, food, water, toileting areas, scratching posts, resting places and elevated perches, placed in several locations so that cats in a multicat household need not compete or pass each other. Indoor cats benefit from play that simulates hunting and from feeding puzzles. Rabbits need companions, hay, room to hop and stand upright, places to hide and opportunities to dig. Laboratory mice benefit from nesting material, which lets them control their microclimate, and from shelters; enrichment is part of the Refinement principle of the Three Rs and is required under many national laboratory animal rules.
Behaviour problems are a leading reason dogs and cats are relinquished to shelters or euthanased, and many are treatable. A behaviour consultation follows a medical model. Take a full history: signalment, the problem's onset and progression, a detailed description of typical episodes (what happened before, during and after), the household, routines, training methods used and what has been tried. Videos recorded by the owner are often more informative than observation in the clinic. Rule out medical causes, because pain, endocrine disease, neurological disease, sensory decline and urinary disease frequently cause or worsen behaviour change. Make a diagnosis based on the underlying motivation, for example fear-related aggression, rather than a description such as 'aggression'. Assess risk, especially bite risk to children. Then build a plan: safety and management first, behaviour modification, environmental change, medication where indicated, and follow-up.
Most canine aggression is fear-related or defensive; other motivations include pain, resource guarding, conflict with familiar people and inter-dog aggression. 'Dominance' explanations that urge owners to confront their dog are not supported for most problems, and confrontation raises fear and bite risk, as the American Veterinary Society of Animal Behavior (AVSAB) position statements set out. Treatment is to keep everyone safe (management, avoidance of triggers, basket muzzle training), stop punishment, teach alternative behaviours with reward, and change the emotional response by desensitisation and counterconditioning.
Separation-related problems show only when the dog is alone or separated from a particular person: vocalisation, destruction focused on exits, and elimination, often starting soon after the owner leaves. Treatment includes graded practice of short absences below the dog's threshold, avoiding leaving the dog alone beyond what it can tolerate while training, and in some cases medication. Noise aversion, especially to fireworks and thunder, is common; it is treated with a safe hiding place, management on high-risk days, desensitisation and counterconditioning to recorded sounds, and medication where needed. Prevention starts with puppy socialisation: AVSAB advises that puppies can begin well-run socialisation classes from about 7 to 8 weeks of age after their first vaccinations and deworming, rather than waiting until the vaccination course is complete.
House soiling is the most common feline behaviour complaint. First decide whether the cat is toileting outside the tray (squatting, normal volumes of urine or faeces, horizontal surfaces) or marking (spraying small volumes on vertical surfaces). Rule out medical causes: feline idiopathic cystitis, urinary tract infection, urolithiasis, renal and endocrine disease causing polyuria, constipation and osteoarthritis, which makes climbing into a high-sided tray painful. Toileting problems often reflect the tray: too few trays, trays that are too small, covered, dirty, near food or in busy or threatening locations, or an aversive litter. A common guideline is one tray per cat plus one, in separate locations, cleaned at least daily, with unscented fine-grained litter that many cats prefer. Spraying is associated with entire males, multicat households and outdoor cats nearby; neutering reduces spraying in most males, and reducing conflict and providing separate resources helps. Cleaning soiled areas with an enzymatic cleaner removes odour that attracts further marking.
Overgrooming leading to alopecia is far more often caused by allergic or other skin disease than by psychogenic factors, so dermatological causes must be ruled out first. Stress is also a known contributor to feline idiopathic cystitis, linking behaviour and urinary medicine.
Canine and feline cognitive dysfunction is a progressive neurodegenerative condition of older animals. Its signs are summarised as DISHAA: Disorientation, altered social Interactions, Sleep-wake cycle changes, House soiling and loss of learned behaviours, Activity changes, and Anxiety. Diagnosis is by exclusion of other diseases. Management includes environmental enrichment, routine, diets supplemented with antioxidants and medium-chain triglycerides, and medication; selegiline, a monoamine oxidase B inhibitor, is licensed for this use in dogs in some countries. Compulsive disorders include tail chasing, notably in Bull Terriers, flank sucking in Dobermanns, fly snapping and acral lick dermatitis, which is often combined with an underlying dermatological or orthopaedic cause.
Medication supports behaviour modification and does not replace it. Selective serotonin reuptake inhibitors (fluoxetine) and tricyclic antidepressants (clomipramine) are licensed in some countries for canine separation-related problems and are used for anxiety and compulsive disorders; they usually take about four to six weeks for full effect. Combining serotonergic drugs with monoamine oxidase inhibitors, including selegiline and the acaricide amitraz, or with tramadol, risks serotonin syndrome. Short-acting drugs given before predictable events, such as noise or veterinary visits, are often used off-label. Licensing, availability and doses vary by country; confirm any dose against the product label and your national formulary. Synthetic pheromone products are widely used, but evidence for their effect is mixed.
As a student you need to handle animals safely and calmly in practicals, read fear and pain signals in every species you meet, and know the core frameworks well enough to apply them: the Five Freedoms and Five Domains, Tinbergen's four questions and the four quadrants of operant conditioning. Learn the signs of an effective stun and the list of animals unfit to travel, because both appear in exams and in your first abattoir and farm placements. Practise scoring pain with the Glasgow and Feline Grimace scales on hospital patients and compare your scores with experienced staff; this is the fastest way to calibrate your eye.
Five years into practice, behaviour and welfare are part of most consultations. You score pain after surgery and adjust analgesia, use fear-reducing handling so patients do not become harder to examine each visit, and recognise when a 'behaviour problem' is pain, cystitis or osteoarthritis. On farms you assess lameness, body condition and housing, judge whether a casualty animal is fit to travel or must be killed on farm, and certify accordingly. You run first-line behaviour consultations, prescribe behaviour drugs with awareness of interactions, and refer complex aggression cases. You may give evidence in a neglect or cruelty case, which needs careful, objective records.
With 25 years of experience, you may lead a practice, an official veterinary team at an abattoir, or a welfare assurance programme. Your decisions concern systems: designing handling facilities and stunning procedures, setting audit criteria and corrective actions, training stockpeople and abattoir staff, advising on transport planning and contingency, and investigating welfare failures. You advise retailers, regulators and farmer groups on standards that must be both scientifically sound and achievable, and you handle conflict between economic pressure and welfare. You also mentor younger vets in difficult ethical decisions, such as euthanasia for welfare reasons when owners or farmers disagree.
A researcher with a PhD and 25 years of experience works on how to measure welfare validly: developing and validating animal-based indicators, grimace scales and composite pain scales, testing reliability across observers and countries, and using methods such as judgement bias, motivation testing and QBA to study affective states. Such a scientist contributes to WOAH ad hoc groups, EFSA-style scientific opinions and national standards, and must distinguish clearly between what evidence shows and what is policy choice. Current questions include positive welfare indicators, welfare of fast-growing broilers and fish, alternatives to CO2 stunning of pigs, and welfare in rapidly intensifying livestock systems in Asia and Africa.
This manual gives welfare and behaviour principles and standards in general terms. It does not reproduce national legislation in detail, and the EU, US and other figures it quotes are examples that must be checked against current local law. It does not cover welfare of fish, wildlife, zoo animals or working equids in depth, euthanasia methods for companion animals, or the detailed pharmacology and dosing of behaviour drugs, which belong in pharmacology and companion animal practice. Specific space allowances for transport, journey-time limits and religious slaughter rules by country are not tabulated because they differ widely and change often. Pain scale cut-offs are quoted only for the scales whose published thresholds are well established.
Original practice questions written to the syllabus and pattern of the exams named in each question's examTags. They are not past papers and do not reproduce any board's questions.
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