Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
46 Cards in this Set
- Front
- Back
|
Diseases of the hen associated with Egg Production NB not one factor responsible; requires balanced overall health |
Infertility; not a PH problem Infectious Bronchitis, Pasteurellosis, Salmonellosis, Collibacillosis, Egg Drop Syndrome NUTRITIONAL deficiencies Stress |
|
|
Vitelline Membrane |
Membrane surrounding the yolk; fresh egg should have a strong vitelline membrane NB, germinal disk is a depression in the surface of the yolk; entry site for fertiisation |
|
|
Albumen layers |
Thick and thin albumen; water, high quality protein, some minerals - 2/3 egg weight Contains antimicrobial elements Fresh eggs; thick albumen stands up around the yolk |
|
|
Chalaza |
Pair of spiral bands, hold the yolk in place, prominent when egg is fresh but not visible when egg is cooked |
|
|
Air Cell |
Forms wide end of egg, as it cools from bird body temp to ambient temp Small in a fresh egg |
|
|
Reproductive Tract (Oviduct) |
Mature ovum at ovulation travels; Infundibulum - Magnum - Isthmus - Tubular Shell Gland, Shell Gland Pouch (Uterus) - Vagina - Cloaca - Vent Ovaries produce yolk + vitelline membrane; vascularised for production but recedes before release |
|
|
Public Health risks associated with Egg |
Vertical transmission of Salmonella enteritidis (control at FARM LEVEL) Contamination by microorganisms in the environment, esp with compromised shell RESIDUES; pesticides, PCB, anthelmintics, coccidiostats, antibiotics |
|
|
Pre-existing antimicrobial defences in shell eggs |
glycoprotein Cuticle covers shell pores calcium carbonate Shell Inner and Outer membranes; thin layers of protein fibres Albumen is at pH9.2, contains antimicrobial proteins and is highly viscous, impeding microbial movement |
|
|
Antimicrobial proteins present in Egg Albumen |
Avidin - binds with biotin Lysozyme - active against gram-positive bacteria Ovotransferrin/Conalbumin - used as antimicrobial agent in food production Ovoinhibitor; inhibits fungal proteases |
|
|
Salmonella cases attributable to eggs and egg products (EU, 2013) |
44.9% (Mostly S. enteriditis, some S. typhimurium, and others) Sweets/chocolate; 10.5% Pig meat/products; 8.9% |
|
|
UK Salmonella stats |
2005: 8% layer flock holdings positive for Salmonella (enteritidis/typhimurium) - aim to reduce by 10% per year 2009: eggs from Salmonella flocks not sold as table eggs - have to be heat treated 2008-2013: prevalence well below 2% target, esp for regulated serovars (~0.1%), some fluctuation in all Salmonella prevalence (1%, 2013) |
|
|
Salmonella risk factors on farm |
Lack of attention to Biosecurity, Rodent Control * no protective clothing (for each flock) * no footbaths outside poultry houses * live/dead/evidence of rodents |
|
|
Routes of Egg Contamination |
Surface; faecal/environmental Content; vertical transmission/damaged shell and cuticle/storage conditions/time of storage Eggs stored at 6 degrees; limited/decreased growth of Salmonella serovars - high levels of growth if stored at 25 degrees At 20 degrees, lag phase until egg is 3 weeks old, then exponential growth; minimal lag phase at 30 degrees |
|
|
Chemical changes within an egg (stored at 20 degrees); |
Glucose starts at 5mg/ml, drops to <0.5mg/ml by day nine pH starts at 7.5. sharply rises and reaches plateau of pH 9 by day five |
|
|
Eggs that go for further processing (NOT sold as table eggs) |
from Infected Farms damaged dirty old (stored at 20 degrees for no longer than 28 days) |
|
|
Egg Marketing Inspectors; EMIs; (part of Animal Health); roles and responsibilities |
Inspect packers, wholesalers, retailers (alongside Trading Standards), producers, hatcheries, auction markets, collectors, egg processors etc Run Candling courses |
|
|
Class A Eggs; |
Normal/clean/undamaged shell/cuticle Air space <6mm and stationary Clear albumen, no foreign bodies, gelatin consistency Yolk seen as shadow in candling, stays in center of egg on rotation, no foreign bodies Imperceptible germ cell development No foreign smell, no cleaning permitted |
|
|
Class B Eggs; *naturally dirty shelled and washed |
Dirty/damaged/treated cuticle but undamaged shell
Air space <9mm and mobile Clear albumen, no foreign bodies Yolk seen as shadow in candling, no foreign bodies Imperceptible germ cell development No foreign smell, cleaning permitted |
|
|
Class C Eggs; *shell faults and dry cracked eggs |
Dirty/damaged/treated cuticle and cracked/misshapen/rough/abnormal shell (membranes unbroken)
Air space >9mm and/ordamaged Clear albumen, no discolouration/turbidity, small foreign bodies allowed Yolk is distinct in candling, small foreign bodies but no discolouration Imperceptible germ cell development No foreign smell, cleaning permitted |
|
|
Council Regulation (EC) 5/2001 relating to egg marking and labelling rules: |
Compulsory stamp with individual producer code and method of production; 0: organic 1: free range 2: barn 3: caged hens *eggs from third country also stamped and labelled prior to retail |
|
|
Double Yolked Eggs |
from young, highly productive laying hens; double ovulation |
|
|
Blood Spots |
in/around the yolk, due to tiny blood vessels in ovary breaking as egg is released - more likely with high levels of activity/disturbance eggs from free-range layers partially protected from this due to rooting |
|
|
Meat Spots |
brown and associated with albumen rather than the yolk, more likely in brown laying hens likely small pieces of body tissue e.g. internal wall of oviduct (magnum) |
|
|
Watery Whites |
eggs from older birds, older eggs, or may indicate viral disease, including infectious bronchitis |
|
|
Green Yolks |
excess green herbage consumed by hen |
|
|
Mobile/Bubbly Airspace |
due to shell structure fault/abnormality airspace in albumen indicates ruptured inner membrane |
|
|
Bacterial/Fungal Contamination |
pass through shell and multiply within egg; black, red, or green rots |
|
|
Misshapes |
e.g. 'crinkled' shell associated with certain viral diseases |
|
|
Coated Shells |
additional calcium deposits; calcium splashing/pink or lilac coloured eggs; eggs remains in shell gland for extended period - commonly seen in young flocks |
|
|
Rough Shelled Eggs |
e.g. if two eggs enter the shell gland at the same time |
|
|
Pale Shelled |
brown laying hens/older hens in free range flocks - may be due to disease |
|
|
Cracked Eggs (downgraded) |
due to inadequacy of the shell, or due to poor/rough handling e.g. during collection, grading or transport |
|
|
Dirty Shells |
Affects the egg after laying; contamination with faecal material, dust, mud, litter, blood and other egg contents |
|
|
Why does the Air Space get bigger? |
Egg cools - contents contract, air space forms between inner and outer membranes moisture and carbon dioxide lost through pores as egg ages |
|
|
How does the Albumen change over time? |
jelly like, slightly cloudy in fresh egg - becoming more transparent and watery over time water migrates out of albumen into shell and yolk; both become mottled, yolk enlarges/flattens on breakout quality indicated by height of thick albumen |
|
|
Egg Pasteurisation; |
reduces initial bacterial load 69 degrees for 100 seconds gives 5 day shelf life in standard packing; 21 days in 'ultra clean' then dried to reduce water activity |
|
|
Ostriches |
reach 90kg slaughter weight by 9-12 months ostrich feathers come from 20-30 year old male birds (ratites) slaughtered on farm or licenced rem meat slaughterhouses (need suitable unloading facility - non-slip, minimum incline) * kept CALM, not separated but led individually to point of slaughter (hooded to reduce stress) or moved in groups through pre-stun race wide enough for one, solid 2m walls |
|
|
Signs of an effective stun in an Ostrich NB 400 mA for 3 seconds, may restrain legs during stunning so can be rapidly shackled, hoisted and bled |
Loss of posture, short initial kicking phase; Becomes rigid, legs flexed beneath, neck arches over body before falling forward (tonic) Followed by kicking; varied intensity (clonic) NO SIGNS OF RHYTHMIC BREATHING (would indicate recovery) |
|
|
Processing of Ostrich |
Feathers hand plucked, then skin carefully removed Evisceration through the vent Deboning and cutting |
|
|
Ducks |
Less than 70 days at slaughter Feathers are valuable and so more sophisticated plucking required 130 mA to stun ducks/geese Ducks (aquatic evolution) resistant to raised carbon dioxide so can take a long time to die with gas - argon, or argon/carbon dioxide mixtures may be used |
|
|
Duck Plucking methods |
Dry Plucking machine - finished by hand Wax finishing; parrafin wax at 60 degrees in tanks, carcases removed, sprayed with/immersed in cold water - wax stripped off by hand or rubber-fingered drum plucking machine |
|
|
Disease/disorders in Turkey production |
Leg disorders indicate reduction in level of Welfare Turkeys show more deep muscle myopathy and infections |
|
|
Transportion of Turkeys |
Walked on/walked off straw covered trailers, good for small numbers of birds travelling short distances Modular crating systems; common for large numbers of birds |
|
|
Stunning Turkeys - risk of pre-stun shocks NB 150 mA used |
Wings hang lower than heads; enter the water bath first OR ramp at entrance can become electrically live by water splashing out of the stunner Shocked turkeys flap wings, rise upwards; may miss stunner alltogether New ramp system being developed to prevent |
|
|
Gas Stunning of Turkeys |
Required prolonged exposure time - acceptable for Animal Welfare? |
|
|
Bleeding time, and further inspection of Turkeys |
2 minutes stun-bleed; whereas only 90 seconds for other bird species Also undergoes post mortem inspection, the same as for chicken Evisceration is delayed, or birds are 'new york dressed' (head, feet, viscera left in) |
