Comprehensive Notes: Principles of Humane Slaughtering of Animals (Module 2)

Animal Welfare Act and Legislative Framework

  • Module 2: Principles of humane slaughtering of animals covers humane slaughter, transport, fasting, and a deep discussion of the Animal Welfare Act (RA 8485).

  • Specific objectives: 1) know humane slaughter of food animals; 2) understand benefits of humane slaughter practices.

  • Lesson proper focuses on the Animal Welfare Act of 1998 as amended by RA 10631, under the Humane Slaughter Act of 1978, requiring that all animals be rendered insensible to pain before harvest.

  • Purpose of the Act: to protect and promote welfare of all terrestrial, aquatic and marine animals in the Philippines by supervising and regulating facilities for breeding, maintaining, keeping, treating or training animals, whether for trade or as household pets. Pet animals include birds.

  • Animal welfare: physical and psychological well-being of animals; includes avoidance of abuse, maltreatment, cruelty and exploitation; maintaining appropriate standards of accommodation, feeding and general care; prevention and treatment of disease; freedom from fear, distress, harassment and unnecessary discomfort and pain; allowing animals to express normal behavior.

  • The Act governs transport, lairage, restraint and slaughter to avoid undue stress; implements that cause pain should not be used; controls handling of livestock in holding pens and chutes, restraints, and use of mechanical probes.

Definitions and Core Concepts in Animal Welfare

  • Ante-mortem and post-mortem considerations are covered; all animals entering accredited slaughter facilities are inspected while in motion (ante-mortem) and at rest to ensure welfare during pre-slaughter and slaughter processes until death.

  • Historical development: 20th century saw refined definitions of animal welfare; Five Freedoms are a foundational concept for basic animal needs, later supplemented by the life-worth-living concept.

  • Five Freedoms (conceptual reference):

    • Freedom from hunger and thirst

    • Freedom from discomfort

    • Freedom from pain, injury and disease

    • Freedom to express normal behavior

    • Freedom from fear and distress

  • Life Worth Living (British Farm Animal Welfare Council): assesses welfare over the animal’s entire life, including life and death; balance of experiences should be positive over the lifetime; pain or distress should be necessary or unavoidable and minimized; care should meet basic needs and animal preferences while ensuring positive overall welfare.

  • Relevance of the life-worth-living concept: evaluation of whether a system or practice induces severe negative mental states, frustrates normal behavior, or precludes positive experiences; ensures physiological and mental needs are met. Examples of life not worth living include untreatable severe disease, severe starvation or dehydration, or chronic, intense pain, fear or distress; humane handling implies prompt treatment or humane euthanasia when necessary.

Quality of Death and Whole-Process Approach

  • Quality of death emphasizes minimizing pain, suffering, distress across the entire process, not only the killing step.

  • The final stressor (killing method) is often preceded by other stressors (transport, handling, unloading, inspection, restraint).

  • In 2003, Farm Animal Welfare Council (UK) broadened welfare at slaughter to include the whole process, not just the killing method. Basic principles include:

    • Pre-slaughter handling methods and facilities that minimize stress

    • Competent, well-trained, caring personnel

    • Appropriate equipment fit for purpose

    • An effective process that induces immediate unconsciousness/insensibility, or an induction to unconsciousness without distress; and non-recovery until death

  • This framework ensures assessment considers the entire slaughter system, not just the killing method.

  • Practical pre-slaughter considerations for slaughter animals:

    • Access to clean water while waiting for slaughter

    • Avoid mixing hostile animals in groups

    • Restraint that prevents turning during stunning/shooting

    • Fly/insect control during slaughter

    • Proper shearing (unshorn lambs under necks, briskets, front legs)

    • Proper containment to facilitate pre-slaughter inspection by NMIS personnel

  • Animal factors that affect welfare: breed, sex, temperament, age, rearing history influence behavior and welfare outcomes.

  • Benefits of humane slaughter practices: reduced animal suffering, economic benefits, reduced waste (meat and hides), improved worker and meat safety.

  • Effects of brutal/slaughter methods: immense animal suffering, economic losses (bruised meat, damaged hides, worker injuries), potential disease spread and meat contamination.

  • Key reminder: Pre-slaughter conditions influence meat quality and yield.

Two Main Factors in Humane Slaughter

  • A. Animal Factors

    • Stress arises when animals experience extreme physical/behavioral changes in new environments.

    • Individual animals, breeds and species cope with stress differently; pigs are particularly sensitive to heat stress.

    • Stress outcomes in meat quality:

    • DFD (Dark Firm Dry) meat (dark color, dry, sticky texture in cattle)

    • PSE (Pale, Soft, Exudative) meat (pale color, soft, watery in swine)

    • Animal behavioral patterns include flight zone and point of balance guiding movement and handling.

    • Flight Zone: the area around an animal that, when intruded, triggers flight/escape behavior; tameness reduces flight zone; wild/unbroken animals have larger zones. Movement can be prompted by skirting the flight zone.

    • Point of Balance: typically at the shoulder; body-wide vision defines the control line; movement decisions depend on handler position relative to this point.

    • Handling guidelines: avoid crowding, harsh movements, loud noises, sharp edges, and excessive restraint; non-slip floors; calm, controlled movements.

  • B. Human Factor

    • Emphasizes humane handling, calm, confident and patient behavior by handlers; being one step ahead reduces stress.

    • Handlers should use a small number of people for aversive procedures; others handle routine tasks to reduce cross-trauma and fear.

Cattle: Behavior, Evolution, and Social Dynamics

  • Cattle origins: Bos primigenius (aurochs) in Europe, Asia, Africa; domestication in India led to Bos indicus (zebu, hump and dewlap) and Bos taurus (hump-less cattle).

  • Diet and grazing: naturally grazing on grasses; extensive systems involve 9 hours of grazing daily; rumination ~75% of grazing time; water intake ranges from 25\ \text{to}\ 80\ \text{L} daily depending on diet and environment.

  • Social nature: cattle form groups for predator protection and efficiency; extended group living enhances survival and reduces attack risk.

  • Social organization: individuals recognize up to ~70 herd members; social hierarchies form through dominance fights but are stabilized by post-conflict retreat and posture cues.

  • Mixing unfamiliar cattle increases fighting; avoid mixing unfamiliar animals to minimize injuries and stress.

  • Leadership vs dominance:

    • Lead animal: followed by group when moving to resources; usually mature females, though leadership can vary by context.

    • Dominance vs leadership distinction: the lead follows the group to water; the dominant displaces others to access resources.

    • Leadership patterns: high-ranking animals tend to lead; low-ranking become independent; movement patterns during grazing reflect leader influence.

  • Learned vs innate behavior:

    • Innate behavior: pre-programmed, species-specific responses; e.g., calves show innate reactions.

    • Learned behavior: depends on experiences; affects handling and response to humans and procedures.

  • Sensory influence on behavior and handling: cattle rely on vision, olfaction, and hearing to interpret stimuli; environment and handler actions influence stress and welfare.

Innate and Learned Behavior, Imprinting, and Rearing Environments

  • Innate behavior details:

    • Cattle are ruminants; extensive grazing involves ~9 hours of grazing, 6-7 hours of rumination (roughly 75%), with water intake 25\text{ to }80\text{ L} daily.

    • Social animals; group living provides predator protection and improved survivability.

  • Learned behavior details:

    • Cattle memorize handling routines and respond to positive or negative human cues.

    • Early positive handling reduces fear responses at the slaughterhouse; imprinting during calfhood affects adult behavior.

    • On-farm handling quality strongly influences welfare during transport and at the plant.

    • Herds from different farms may exhibit different handling challenges even for similar breeds.

    • Key findings (summarized): aversive handling increases future difficulty; early positive handling yields calmer cattle; imprinting effects may be time-bound; minimal staff should perform aversive tasks; calibration of handling practices improves welfare and production.

  • Rearing environment effects:

    • Animals raised in extensive systems tend to be more reactive than those from enclosed systems.

    • Calves require positive stimuli after birth to foster calm adult behavior (imprinting period).

    • Mixed groups of cattle from different herds can complicate handling; familiarity reduces aggression and stress.

  • Practical implications for handling:

    • Use few handlers for aversive tasks; many handlers for routine tasks to minimize negative associations.

    • Positive, gentle handling from birth reduces long-term fear and improves welfare.

    • Recognize that some breeds (e.g., Brahman/Zebu) are more reactive but can be docile with gentle handling; temperament is heritable but heavily influenced by rearing.

  • Behavioral indicators of reactivity and welfare:

    • High-reactive cattle show behaviors such as constant ear movements, head lifting, tail flicking, flinching, etc.

    • Mixing leaders into groups can improve overall handling if managed carefully.

  • Learned behavior: a concise set of research findings:

    • Aversive procedures hinder future handling

    • Early gentle handling yields calmer cattle

    • Imprinting times influence later responses but are not fully established

    • Animals recognize individuals who treated them well or poorly

    • Fewer individuals should perform most aversive procedures

    • Heart rate recovery after intensive handling is ~ 30\ \text{min} for a cow

    • Cattle adapt to repeated non-painful procedures but resist repeated painful events

    • Temperament is heritable; excitable genetics require gradual introduction to novel experiences

    • Highly reactive herds exhibit certain overt behaviors; mixing known calm leaders improves handling

Sensory Modalities in Cattle

  • Vision:

    • Cattle have slit-shaped pupils and weak eye muscles; limited ability to rapidly focus on objects.

    • They are dichromats: see two of the three main retinal colors; they distinguish long wavelengths (yellow, orange, red) better than blue/green; may aid in survival and movement during attack events.

    • Binocular vision is limited to a small forward angle (roughly 30^{\circ}-50^{\circ}); eyes are lateral, giving wide panoramic view but with poor depth perception in most of the field.

    • Depth perception is limited; cattle often lower heads to inspect objects; they may balk at shadows or drains due to depth perception challenges.

    • Unloading ramps and flooring affect perception; diffuse lighting aids movement.

  • Monocular vision:

    • Panoramic lateral vision of 300^{\circ}-320^{\circ}, with a blind spot directly behind and a small area in front of the nose.

    • Lack of depth perception in broad view; movement detection remains strong even with heads lowered.

    • Uniform wall and floor colors in high-traffic areas facilitate handling.

  • Olfaction:

    • Smell helps identify calves; social recognition and identification of individuals through pheromones are involved in social hierarchy signaling.

    • Alarm situations trigger pheromone-based signaling (urine, saliva) that can alert others and influence fear reactions.

  • Hearing and communication:

    • Cattle are sensitive to high-frequency sounds; they orient ears toward sound sources and use ear position to gauge attention and intent.

    • Vocalization is generally limited in open fields but increases at slaughter or during aversive handling; excessive noise in plants should be minimized (e.g., high-pitched compressor noise).

  • Behavior and genetics:

    • General differences: Bos taurus indicus (zebu) more reactive than Bos taurus taurus; crossbreeds vary in reactivity; Brahman cattle may be inquisitive and follow people; with gentle handling they can be quite docile.

    • Reactive breeds tend to approach novel objects but may freeze under forced movement toward unfamiliar stimuli.

  • Behavior and age:

    • Beef cattle are typically under 30 months; dairy cattle typically older (often >5 years); bulls’ ages vary by production purpose.

    • Younger cattle are typically more easily socialized; older cattle may be more set in routine and stress-prone when moved to unfamiliar environments.

Social Structure and Handling Considerations

  • Social behavior in cattle can be complex: dominance hierarchies, leadership, and group dynamics influence stress and welfare during handling.

  • Leadership tends to be tied to mature females; movement tendencies in grazing and water-seeking scenarios correlate with hierarchy ranks.

  • When mixing groups, fights can occur to reestablish hierarchy, increasing stress and injury risk; familiar groups that have lived together should be transported together when possible.

  • Handling implications: avoid isolating animals; maintain social groups to reduce distress and promote smoother movement through handling facilities.

Transport, Handling, and Care of Animals

  • Transport purposes: marketing, slaughter, restocking, drought transfers, changes of ownership; modes include on-foot trekking, road vehicle, rail, ship, and air.

  • Transport is the most stressful stage in the chain and has significant welfare and production implications.

  • Effects of transport and movement include:

    • Stress leading to DFD beef and PSE pork

    • Bruising and meat waste

    • Trampling and potential fractures

    • Suffocation and heart failure in overfed pigs

    • Heat stress, dehydration, sunburn, and bloat (especially in ruminants and elderly animals)

    • Poisoning from plants, predation risk, and general fatigue

  • Vehicle design and loading considerations:

    • Adequate ventilation; non-slip floors with proper drainage; protection from sun and rain; smooth sides; no protrusions; no total enclosure for most species.

    • Ventilation: avoid accumulation of ammonia; floor-level air movement is essential; pigs particularly susceptible to heat and respiratory stress.

    • Floors: non-slip surfaces are essential; cross-slatted grids (50{-}60\ \text{cm} per head) may be used; partitions help stabilize animals; floors should align with unloading platforms to prevent injury.

    • Sides: high enough to prevent jumping; padding at hip level can reduce bruising; avoid gaps that can cause limb injury; narrow entry doors increase bruising risk.

    • Rail trucks: spring couplings cushion movement; roofs are not always required, but pigs in hot weather benefit from roofs; poultry require protection from sun/rain; cages/crates recommended for birds to prevent injury; ventilation must be adequate.

  • Pre-loading precautions:
    1) Pre-mixing cattle or pigs increases familiarity and reduces stress; mix 24 hours before loading; identify and remove victimized animals.
    2) Most animals can be fed and watered before transport; pigs should not be fed just before transport due to gas buildup and potential heart strain.
    3) Do not mix horned and hornless animals; avoid mixing different species; small animals may be transported in loose sacks; avoid tying feet; do not turn animals every 30 minutes; pigs should not travel with other species unless partitioned.
    4) Diseased, injured, emaciated, or heavily pregnant animals should not be transported; unfit animals should not travel far.
    5) Vehicles should be equipped with portable ramps for emergency offloading.

  • Unloading and calm handling: unload and move animals calmly; patience and knowledge of animal behavior in unfamiliar environments facilitate smooth directing into stockyards.

  • Transport operations: multiple factors must be considered to minimize suffering and injury.

    • Trekking: cattle, sheep and goats can be moved on foot; plan journeys with grazing and watering opportunities; maximum trekking distances depend on weather, body condition, age; table values below.

    • Time of day: cooler periods reduce heat stress (especially for pigs).

    • Duration: journeys should be short and direct; frequent stops for water when long journeys; cattle and sheep/goats should not travel more than 36\ \text{hours}; offload after 24 hours for feed and water if travel time is within 24 hours; pigs require frequent water during long journeys; some regions seek to limit transport durations to 8\ \text{hours} or less.

    • Driving: smooth driving with minimal jerks; two-person operation to monitor downer animals.

    • Wind chill: wind cooling on wet animals in cold weather increases losses and stress.

  • Holding and care after transport:

    • Fitted animals that will be slaughtered within 24 hours should be moved directly to lairage; resting areas should be kept calm and quiet; feed should be withheld for last eight hours prior to slaughter while clean fresh water remains available.

    • Ante-mortem inspection should occur during resting or approximately twelve hours before delivery to killing floor.

    • Rest allows gut to empty, reducing viscera size and facilitating evisceration; reduces contamination risk and off-flavor development; heavy gut fill can impede evisceration and cleanliness.

  • Effects of improper handling and care:

    • Nervous, tired, excited animals may have higher body temperature, resulting in imperfect bleeding.

    • Muscular fatigue reduces glycogen in blood, converting to lactic acid post-mortem, promoting spoilage and bacterial growth.

    • Fatigue and excitement can enable gut bacteria to penetrate meat; holding animals without adequate litter/drainage increases fecal contamination of the skin.

Practical Assessment (Summary Items for Review)

  • True/False practice (from Activity 2):

    • 1. Animals have access to clean water while waiting for slaughter. \text{True}

    • 2. Mixed animals that are hostile to each other in a group situation should be mixed. \text{False}

    • 3. Animals should be restrained in a manner preventing them from turning. \text{True}

    • 4. Fly/insect control methods are required during slaughter. \text{True}

    • 5. Humane slaughter induces animal suffering prior to slaughter. \text{False}

    • 6. Worker and meat safety is a requirement. \text{True}

    • 7. Humane slaughter has significant economic impact. \text{True}

    • 8. Bruising of the meat renders it unfit for human consumption. \text{True}

    • 9. Damages to the hides causes loss of product. \text{True}

    • 10. Worker injuries result in decreased productivity. \text{True}