Slaughter of animals

29 important questions on Slaughter of animals

How are animals been handled up to the point of stunning? [ante-mortem inspection]

  • Held in special pens/areas in large
  • Animals rest & calm down --> fatigued/stressed by transport/uploading
    • easier handling
    • improve quality
    • improve welfare
  • Animals to rest adequately in unmixed groups (less stress)
    • stressed = more likely to be fractious, fall/bruise, danger to personnel handling them
  • Poultry transported in crates --> makes it impossible to provide food/water
  • Minimise lairage time

What is ante-mortem inspection?

  • Animals are inspected before slaughtered
  • Identification of clinical signs of diseases
  • Identification of pharmacological agents given / injuries

What can be looked for when doing an ante-mortem inspection

  • It is vital to detect some diseases early --> prevent further infection & contamination
    • e.g. Anthrax
    • e.g. Foot-and-mouth disease
  • Traceability (important - diseases)
  • Cleanliness (risk of carcass contamination)
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart

What is the foot-and-mouth disease

  • Virus = relatively hardly & highly infectious (rarely fatal)
  • Extremely rare that humans catch it
  • Reduced productivity (poor growth/less milk/abortions) --- economically serious

Name the 3 main types of methods used for stunning

  1. Use of mechanical instrument (e.g. Captive bolt pistol)
  2. Electrical current passed through brain
  3. Immersion in anaesthetic gas (e.g. CO2)

Which animal species are typically stunned by each type?

[mechanical, electrical, anaesthetic gas]

Mechanical

Electrical
  • Poulty, pigs & sheep
Anaesthetic gas

When is a free bullet used?

  • Generally, only used for large bulls & boars
  • Less easy to ensure safety, danger = bullet passing through body & ricocheting
  • Necessary if animal has very thick skull to use captive bolt pistol

What can you tell about captive bolt & concussive stunning?

  • Methods developed from use of pole-axe
  • Modern captive bolt / pneumatic stun gun (beef) much easier to use
  • To stun an animal --> not necessary to penetrate brain
  • concussion alone effective - some equipment give non-penetrating blow

What is the position of shooting?

  • Position of shooting --> maximum damage done to brain
  • Brain in different position to head shape --> different positions optimal for different species
  • Due to dangers of BSE spread --> captive bolt use in North America ceased

How is stunning/killing with gases go?

  • Pigs may be rendered unconscious & killed by CO2 (80-90% by volume)
  • Remain in gas for 90 seconds / more (longer =kill rather than stun)
  • CO2 = acidic & pungent at concentrations >30%
  • Potent respiratory stimulant - gasping & possible respiratory distress
  • CO2 works as carbonic acids formed when it dissolves in blood --> reduces pH of cerebra-spinal fluid that surrounds brain -> loses consciousness pH falls <7.1

What type of gas is used for chickens [stunning/killing]

  • Anoxia gas
    • relatively stress free
    • inert gas (argon or nitrogen) - reduce oxygen levels 2% or less
    • Tasteless & odourless = not detectable by animals
  • Argon's density - easy to confine in chamber
  • Duration of unconsciousness after removal not as long as with CO2
  • Add 30% CO2 to argon - benefits outweigh pungency perceived

What is the tonic phase and what is the clonic phase

Tonic phase
  • Effective percussion stunning leads to
    • Immediately collapsing
    • Stopping rhythmic breathing
    • Becoming rigid with head extended
    • Eyeball is fixed
    • Lasts 10-20 seconds

Clonic phase
    • 15-20 sec after stunning
    • Kicking /paddling movements
    • Not killed by exsanguination - will recover
Gradually animal relaxes
Rhythmic breathing returns followed by resumption of consciousness

How can you recognise an effective stun

  • Amount of clonic convulsions may be reduced by head-to body stunning
  • Most reliable & easiest way to recognise effective stunning in sheep, cattle & pigs = end of rhythmic breathing
  • Electrical stunning causes disruption of normal electrical activity in brain producing epileptiform (electro-lactic)
  • Large increase in release of glutamate & aspartate in sensory cortex (seizure)
    • act as neurotransmitters - over excite neurons = seizure
  • Characterised by initial tonic phase when animals become rigid, rhythmic breathing ceases & eyeball fixed

Effects of stunning methods on carcass & meat quality

  • Percussion stunning

Reduced chance of carcass bruising & bloodsplash

Effects of stunning methods on carcass & meat quality

  • Captive bolt stunning

Pigs leads to many convulsions - promote faster muscle acidification (--> PSE)

What are the advantages of kill poultry using gas?

  • Less haemorrhaging & broken bones
  • Birds killed by anoxia show increased pH fall in breast muscle --> less time post-mortem before portioning without risk of muscle shortening = tougher meat

What are the issues concerning religious slaughter? And what are the main religious slaughter methods?

  • Shechita used by Jews
  • Muslims to produce Halal meat
  • Jack used by Sikhs / Hindus


  1. Shechita & Jatka: animal not stunned prior to killing by exsanguination
    1. stunning not used in Halal slaughter but some methods may be acceptable to some adherents of Islamic faith
  2. Shechita & Halal: major vessels of throat severed by transverse cut
  3. Jatka: animal decapitated with single sword stoke

What is carcass dressing?

  • Carcass tissues & inside of body cavities microbiologically sterile
  • Skin, cavities, inside of gut contaminated with soil, dirt & bacteria


modern slaughter:
  • Animals hung by hind legs from overhead rial system & dressed
    • hygiene & throughput
  • Production line - each person carries out single job / one purpose
    • efficient & helps maintain carcass hygiene - no cross contamination

How goes carcass dressing with cattle & sheep

  • Oesophagus tied closed - prevent back flow of rumen contents
  • Head & feet removed
  • Carcass skinned
  • Feet removed below carpals (knee bones) in forelegs & tarsals in hind leg
  • Skin can be removed used mechanical hide-pullers (or manually)

How goes carcass dressing with pigs

  • Not skinned - except for making leather
  • Hair removed by scraping & scalding
    • hot water loosens hair & outer layer of skin, then scraped off by passing carcass through revolving metal tipped paddles
  • carcasses washed & cleaned with revolving brushes
  • Toenails removed
  • before washing carcasses may be singed (burn hair & tighten skin)
  • Scalding & singeing (burning) to some degree kill bacteria on surface - not sterilised
  • Feet left on carcass & head removed at later stage

What are the advantages of carcass dressing done by machines

  • Reduces manpower requirements
  • Improve carcass hygiene (meat safety)
  • Produce better hide & pelt quality
  • Higher yield of retail joints

How are chicken carcasses dressed?

  • After stunning blood vessels in neck severed = exsanguination
    • automatic - knife with rotating blade
  • Scalding: remove feathers --> low temp. 30 seconds (<55*C broilers)
  • Pucking: feathers removed mechanically by rotating rubbers

How is poultry been processed?

  • Evisceration separated from defeathering to reduce carcass contamination
  • Skin cut along back of neck & trachea & crop freed
  • Abdominal cavity is opened up by incision around vent to enable viscera to be pulled out
  • Lunge lie tight under vertebral column & need careful removal
  • Head, neck & feet are cut off
  • Carcass chilled either in cold air or iced water to 10*C
  • Poultry processing now highly mechanized

What is carcass washing?

  • After dressing washed with fine water spray to remove surface blood & bone dust
  • Effectiveness increased by using hot (80*C) water / by including low concentrations organic acids, chlorine / other agents in water
  • Traditional practice of wiping carcasses with cloths = unhygienic

What happens with post-mortem inspection?

Provide a few examples of diseases and/or conditions that can be identified during post-mortem inspections

  • Carcass & viscera inspected immediately after slaughter
  • ID abnormalities / disease that would make meat & edible offal unit for human consumption
  • Important that carcass retain identity with parts & viscera removed from it
  • Inspection carried out by specially licensed veterinarians / meat inspectors
  • Considerable attention given to lymph nodes to detect disease state

What can be found during a post-mortem inspection?

  • Pneumonia & tuberculosis (TB) have characteristic incisions
  • Parasitic disease (tapeworms) often manifested in cysts in heart, liver & muscles
  • Larval stage of roundworm forms cysts in pool muscle --> consume cause trichinosis
  • Larvae of nematode parasite, Ascaris scum, lodge in liver & result in small foci of connective tissue giving rise to milk spot liver
  • Inflammation of lining of thoracic or abdominal cavity indicate infection
  • Swine erysipelas produces red diamand shaped marks on pig skin

What are the modern production systems:

  • Emphasis on presenting only healthy animals for slaughter
  • Controlling levels of parasites & infectious diseases - farm
  • Risk assessment-based inspection - preventing carcass contamination

What are the most valuable and are edible by-products

  • Liver
  • Heart
  • Tongue
  • Kidneys
  • Spleen
  • Brains
  • Blood
  • Edible raw fat
  • Trotters
  • Cattle diaphragm
  • Parts stomach &. Intestines

What are the four main categories of by-product?

  1. Edible by-products (most valuable)
  2. Skins
  3. Production of pharmaceuticals ...?
  4. Animal feed...?


  • Value determined by handling
  • Most prone to rapid deterioration if handled incorrectly - downgrading
  • Critical part of handling = storage at low temperatures
  • Fat particularly liable to oxidation & development of rancidity

The question on the page originate from the summary of the following study material:

  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo