1
Q
Why is the poultry industry so important?
A
- Wide variety of species and systems
- Over 90 million broiler chicks placed in the UK and nearly 90 million broiler chickens slaughtered per month.
- 140,000 tonnes of chicken meat per month.
- 2.4 million commercial laying hen chicks placed in the UK. (Lot less as they have a longer lifespan than broiler chicks).
- 11.3 billion eggs produced in the UK in 2021
2
Q
Why is the poultry industry important to vets?
A
- Commercial companies are very large and tend to have their own vets.
- But independent farms, particularly free range laying eggs, may use independent vets.
- Birds are rarely treated individually.
- Backyard poultry and very common and you are likely to come across them in practice.
- Individual birds are more visible.
- Important safety impacts with relate to the production system are food safety, disease control and environmental impact.
3
Q
Why is the poultry industry unique?
A
- Contains the most intensively housed livestock in agriculture – the first animal based agri-business.
- Most highly mechanised.
- Requires high level of financial capital.
- Labour requirements are low.
- Individual bird performance has increased year on year bringing down the relative unit cost.
- Chickens are efficient converters of feed, but feed is most important unit cost.
4
Q
Briefly describe broiler chicken production.
A
- Slaughtered around 5/6 weeks old
- Mostly loose housed, indoor barn
- Often white birds, with very large breasts and legs
5
Q
Briefly describe laying hen production.
A
- Slaughtered 80-100 weeks old
- Mostly free range, with some barn and cage
- Mostly brown with a few white laying flocks in the UK
- Not as substantial build
6
Q
What are the life stages of laying hens?
A
- Males and females grandparent flock
- Eggs
- Males and females breeding flock
- Eggs
- Day old chicks – a pullet
- Become the female only laying flock
- Produce eggs for sale
7
Q
What are the life stages of broiler chickens?
A
- Male and female grandparent flock
- Eggs
- Male and female breeding flock
- Eggs
- Chicks
- Male and female table birds at 5-6 weeks
8
Q
What are the life stages of turkeys?
A
- Male and female breeding flock
- Eggs
- Poults – day old chicks
- Chicks
- Male and female table birds at 18-20 weeks
9
Q
What are the life stages of ducks?
A
- Male and female breeding flock
- Eggs
- Chicks
- Male and female table birds at 42-56 days old
10
Q
Describe the laying hen market.
A
Major egg packers control the market and have developed brands. Mixture of contract production and company owned farms. Pullet rearing separate.
11
Q
Describe the broiler chicken market.
A
Processors control the market. Nearly all contract production. Lots of further processing.
12
Q
Describe the turkey market.
A
2 large integrators control the intensive market. Significant traditionally produced Christmas market. Lots of further processing.
13
Q
Describe the duck market.
A
2 large integrated companies produce meat, 3 produce eggs.
14
Q
Describe the laying hen breeding pyramid.
A
- 6 genetics companies
- Each with their own lines for different markets, for example, colonoy vs free range, white eggs vs brown eggs.
- 3 breeds of layer dominate the UK market – Hyline. Lohmann and Novogen
15
Q
Describe the broiler chicken pyramid.
A
- 4 genetic companies
- Each with their own lines
- 2 breeds of broiler dominate the UK market – Ross (Aviagen) and Cobb (Cobb breeding company)
16
Q
Describe laying hens furnished cage systems.
A
29%
- Stocking density: 750cm2 per hen (~13 birds/m2), 600 cm2 must be usable are (45cm high)
- Group size: 60-80 birds per cage
- Facilities: perch, nest box, scratch mat
- Access to outdoors: no
17
Q
Describe laying hen barn systems.
A
- Stocking density: 9 birds per metre squared usable area
- Group size: 32,000 birds (RSPCA)
- Facilities: 1 m2 nest space per 120 birds, litter
material to dustbathe and forage in, perches - Access to outdoors: no
- Other information: some systems multi-tier/aviary, providing additional levels to use above the ground
18
Q
Describe laying hen free range systems.
A
- Stocking density: 9 birds/m2 usable area
- Group size:16,000 birds (RSPCA)
- Facilities:1 m2 nest space per 120 birds, litter material to dustbathe and forage in,15 cm perch space per bird
- Access to outdoors: yes (from 21
weeks (RSPCA), adequate outside area, appropriate for the size of the flock (size
of the popholes: 2m per 1000 birds). - Other information: some systems multi-tier/aviary, providing additional levels to use above the ground
19
Q
Describe laying hen organic systems.
A
- Stocking density: 6 birds/m2 usable area
- Group size: 2000 (Soil association), 3000 EU legislation
- Facilities: 120 cm2 per bird in a communal nest, 18 cm perch per bird, 50% of floor area solid covered with litter
- Access to outdoors: yes, from 12 weeks, 1000 birds per ha
20
Q
Describe standard indoor broiler chicken systems.
A
- Large, closed buildings
- Temperature, artificial lighting, ventilation, food and water carefully controlled
- 25,000-50,000 birds
- Variable stocking density, depending on management on farm
21
Q
Describe improved indoor broiler chicken systems.
A
- Natural daylight through windows
- Reduced sticking densities environmental enrichment, such as straw bales
22
Q
Describe broiler chicken free range systems.
A
5%
Access to an additional outdoor range area for part of their lives via popholes in the side of the building
23
Q
Describe broiler chicken organic systems.
A
- Must have access to range 2/3 of life
- Suggest use of enrichments like perches inside the house
24
Q
Describe turkey standard indoor systems.
A
95%
- Reared on the floor of large, purpose built sheds or converted farm buildings
- Up to 25,000 birds may be housed in one building
25
Describe turkey pole barn systems.
Upper part of the house walls are open, allowing natural light and air
26
Describe turkey free range systems.
5%
Similar to indoor or pole barn systems but eth turkeys also have access to an outdoor range area
27
What are the stocking densities of laying hen systems in birds/m2?
Enriched cage = 13
Barn = 9
Free range (indoor) = 9
Free range (outdoor) =1
Organic (e.g. soil association) = 6
28
What are the stocking densities of broiler chicken systems?
Standard = 13-15 (33-39 kg/m2, assuming adult bird weighs approx. 2.5kg)
Improved indoor = 12 (RSPCA – 30 kg/m2)
Free range (indoor) = 11 (RSPCA – 27.5 kg/m2)
Free range (outdoor) = 1
Organic (e.g. soil association) = Fixed housing: 8 (21 kg/m2); mobile housing:12 (30 kg/m2)
29
Describe geese.
Mainly derived from the greylag goose/Anser anser but also from Anser cynoides may be kept.
- Annual moult
- Fully webbed front feet
- Tend to fee don land and eat forage
- Males and females tend to be the same colour
30
Describe ducks.
Domesticated ducks are derived from the wild mallard and the Muscovy duck.
- Moult twice
- Dimorphic plumage – multi-coloured with difference between the sexes
- Tend to feed on water
31
Describe indoor housing systems for ducks.
- Typically several thousand birds reared on the floor of a large building/barn
- Should have access to a water trough big enough to dunk their heads
32
Describe free range housing systems for ducks.
- Similar to indoor, but with access to an outdoor range area
- 2500 ducklings per hectare
33
Why is lighting important for poultry?
- Important for all poultry
- Extended day lengths to bring birds into lay
- Low light levels and dawn and dusk dimming to keep birds calm
34
What are the dark hours of day needed for poultry?
Broilers = 6 hours
Laying hens = 8 hours
Turkeys = 8 hours
35
What are the effects of intermittent and natural daylight on poultry?
To mimic natural rearing environment – intermittent lighting and dark brooders.
Natural daylight as they can see much more in the lower end of the wavelength spectrum and can detect up to 90-100 Hz of light flickering. So artificial light may affect behaviour.
36
What are the weights of laying and broiler chickens, ducks, geese and turkeys?
Lay hens = 1.9kg
Broiler hens = 2.3kg
Duck = male 5kg, female 3kg
Goose = 4.5kg
Turkey = female 7kg, male 10(-18)kg
37
When are broilers, ducks, geese and turkeys slaughtered?
Broilers = 32-40 days
Duck = male 84 days, female 68 days
Goose = 70 days
Turkey = female 110 days, male 130 days
38
What are the factors affecting the performance of poultry?
* Genetics
* Nutrition
* Sex
* Age
* Water quality and availability
* Temperature
* Environmental pollution, such as ammonia
* Stockmanship, such as management and use of enrichments
* Stocking density: indirectly through effects on the above
* Disease and welfare
39
What is the house temperature for laying and broiler chickens?
Laying = 17-25˚C depending on system of production
Broiler = not more than 3˚C above the outside temperature when the outside temperature exceeds 30˚C.
40
What is the humidity of laying and broiler chickens?
Laying = 40-60%, up to 70-75% for short periods
Broiler = must not exceed 70% when the outside temperature is below 10˚C
41
What is the light intensity in laying and broiler chicken housing?
Laying = at least 10 lux. Nest boxes less than 1 lux
Broiler = at least 20 lux. Photoperiod: at least 6 hours of dark each day, 4 of which must be continuous
42
What is the ammonia concentration in laying and broiler chicken houses?
Less than 20 ppm
43
What is the carbon dioxide concentration in laying and broiler chicken housing?
Less than 3000 ppm
44
Define thermal comfort zone.
Conditions in which a bird is likely to be able to maintain body temperature and not have to work excessively hard to do so by shivering (cold) or panting (hot).
45
Describe the anatomy of egg laying.
22-26 hours
1. Yolk released by the ovary
2. Enters the oviduct where fertilisation would take place
3. Albumen forms around the yolk in the oviduct
4. Held together by a thin membrane
5. Shell added by the shell gland in the uterus
6. Liad via the cloaca
46
Describe the characteristics of the eggs produced.
- Eggs for breeding – egg is an incubator for a chick for 21 days
- Eggs for eating are when the egg is not fertilised
- Pores in the eggs shell allow movement of water vapour and gas exchange
- The yolk is 33% lipid and 17% protein
- Albumen is 10% protein
47
What is beak trimming and the methods?
- Blunts the tip of the beak to make it less damaging
- It involves the removal of part (less than 33%) of the beak before chicks are 10 days old
- Methods: hot or cold blade, robotic, chemical, laser
- Welfare implications: acute and chronic pain, behaviour change
48
What are the issues of hot blade trimming?
- Possible formation of neurones
- Shorter beaks
- Scar tissue
49
What are the advantages of infrared trimming?
- No open wound
- Reduction in operator error
- Gradual change in beak shape
- Reduced stress
- Reduced feather pecking
- Improved feather conditions
- Improved feeding behaviour
50
What is the legislation on beak trimming?
Infrared method must be used and the tip of the beak falls off 10 days after treatment. There is a move to ban beak trimming, which is considered a mutilation.
51
What are the production and welfare concerns of broiler chickens?
- Rapid growth rate – heart defects and lameness
- Space allowance and facilities – performance of normal behaviour of mating, space and environmental enrichment
- Foot pad dermatitis/pododermatitis/hock burn
- Breeding flocks – mating injury and hunger
52
How is lameness assessed in poultry and the consequences of lameness?
Assessed by gait scoring
Lameness is painful and reduced production – birds may not be able to reach food, reducing growth and increasing mortality
53
What is the solution to lameness is heavy birds?
Heavy birds simply cannot hold their weight: broken limbs, rickets.
Solutions: breeding and keeping active by enrichments and perches
54
What is foot pad dermatitis/hock burn?
Lesions on the feet and legs. Possible caused by poor litter quality.
Use wood shavings, maintain dry litter for good drainage or litter replacement or appropriate ventilation to control humidity.
55
What is the consequence of high humidity?
Wet litter and increases heat stress as it makes it more difficult for birds to thermoregulate
56
What is the consequence of poor air quality?
Poultry houses are dusty. Total maximum 5.5 mg/m3 and 84.5 mg/m3
57
When is a substance classed as hazardous to health?
Defined as dust of any kind when present at a concentration in air ≥ 10 mg/m3 8-hour of inhalable dust (COSHH).
58
What is the consequence of dust and ammonia?
Ammonia levels are often high (particularly when litter is wet)
Combination of dust and ammonia: particularly prone to respiratory diseases, such as infectious bronchitis, mycoplasma, infectious Coryza
59
Why is ventilation important?
- Minimum ventilation must supply fresh air for oxygen and remove sufficient carbon dioxide, moisture and aerial pollutants.
- Rule-of-thumb, minimum ventilation for all classes of poultry is 2 m3 air per second per tonne of feed consumed daily.
60
What are the stages of red jungle fowl courtship behaviour?
1. Feather ruffling
2. Waltzing
3. Crowing
4. Tidbitting
5. High step advance
6. Wing-flapping
61
Why is feed restricted in broiler chickens?
Broilers are selected for fast growth and weight gain. This can lead to lameness, reduced reproductive performance, and high mortality. So, feed is restricted in order to achieve:
- Good reproductive performance
- Good health and low mortality of the female breeder
- Satisfactory growth of the offspring
62
What are the consequences of restricting broiler chicken feed?
Chronic hunger; contravenes five freedoms (freedom from hunger)
63
How is hunger and stress shown in feed restricted broiler chickens?
- Hyperactivity
- Pacing
- Stereotypic (object/spot) pecking
- Overdrinking
- High feeding motivation
- Increased plasma corticosterone levels
- Increased Heterophil / Lymphocyte ratio in the blood
64
What are some solutions to hunger in broiler chickens?
- Environmental enrichment
- Scattering of food
Both increased time spent engaged in foraging behaviour; however, neither reduced the signs of stress or hunger.
- Feeding diluted feed (e.g. with oat hulls) has been successful in some studies
65
Explain the production and welfare concerns in turkeys.
Lack of space
- Foot pad lesions
- Heat stress
- Solutions: litter management, good ventilation, ‘thinning’ – females removed at about 18 weeks, gives more room for bigger males
Performance of normal behaviour
- Injurious pecking
- Frustration, stress
- Solutions: provide enrichments, beak trim, low light levels (welfare implications)
Handling and transport
- Risk of bone fractures, dislocated hips and bruising
66
Explain some production and welfare concerns in ducks.
Access to open water
- Perform normal behaviour
- Clean feathers and eyes
- Provide water source (UK legislation states ducks must be able to immerse their heads); open water required by RSPCA
Performance of normal behaviour
- Injurious pecking
- Access to open water and other enrichments for foraging; beak trim
Litter management is particularly important, as ducks flick water around
- Wet litter can have impacts on health as for broiler chickens
Falling over onto their back and not being able to right themselves
- Body shape/lack of muscle strength
- Nutrient deficiency/disease
67
What is the role of a vet in poultry?
- Disease prevention – biosecurity
- Flock health planning
- Vaccination
68
What are the zoonoses in poultry?
- Salmonella
- Campylobacter
- E. coli
- Listeria
- Clostridium
- Erysipelas
- Ornithosis
- Cryptococcosis
- Cryptosporidiosis
- Arcobacter butzleri
- Helicobacter pullorum
- MRSA
- Staphylococcus
- Avian influenza and Newcastle disease: notifiable diseases in the UK
Controlled by good biosecurity and/or vaccination.
69
Describe Newcastle disease.
- No cure
- Water birds can be silent carriers
- Rare in UK
- Pneumotrophic; neurotrophic; viserotrophic
- Notifiable due to high mortality rate
70
Describe avian influenza.
- Caused by an orthmyxovirus (group includes human and swine influenza viruses)
- Rapid mutation rate makes vaccination almost impossible
- Spread through direct contact, or contact with contaminated bodily fluids, such as faeces
71
Distinguish the low and high pathogenic strains of avian influenza.
Low pathogenic AI strains will only cause mild respiratory signs such as sneezing, runny nose, runny eyes and lethargy.
High pathogenic AI strains will cause your birds to appear very sick: swollen head; blue discolouration of neck and throat; loss of appetite; respiratory distress such as gaping beak, coughing, sneezing, gurgling, rattling; diarrhoea; fewer eggs laid; increased mortality.
72
What happens in the case of a notifiable disease?
APHA must be informed. They will take care of testing, serological tests and exclusion zones around affected farms and movement restrictions.
73
Describe biosecurity used when working with poultry.
- Taking care with movements of people on/off farm (48h exclusion)
- Clean overalls, footwear; provide foot baths (showering on some larger units)
- Clean and disinfect housing between flocks
- Rotate/rest pasture
- Clean feed and water; sterilised bedding
- Regular health checks
- All in/all out system
- Vaccination
74
Define backyard poultry.
Non-commercial – exhibition birds, pets, egg laying, raised for meat rescue birds. May compromise any poultry species, as a number of breeds and species may all be kept together.
75
Why are backyard poultry important?
- 750,000 backyard poultry in the UK
- Lack of access to specialist poultry vets
- Inexperience
- Poor biosecurity and is potentially an important source of disease transmission
- Investment: time, money and emotion
- As a vet, one of the most commonly seen groups of animals. Not simply treating diseases as they arise and providing advice on where to start and how to look after poultry.
76
What must be considered when obtaining birds?
* What humans, pets or wildlife have they been exposed to?
* Are different batches kept separate?
* If delivered, how are they transported?
* What vaccinations have they received?
77
What are the vaccinations and initial health for newly obtained birds?
- If buying chicks, they need to be vaccinated. Some suppliers do this for you.
- A few veterinary practices bulk buy and break into smaller lots.
- Buy birds all at once. If only part of the flock is replaced, place in quarantine for a minimum of 14 days, 30-60 preferable.
- Round worm cycle is 6 weeks, if roundworm egg is picked up on the day of purchase positive test 6 weeks after.
78
Describe egg production in rare and hybrid breeds.
Rare breeds lay few and fewer as the years go on.
Hybrids:
- 6-7 per week in 1st year
- 5-6 per week 2nd year
- 3-4 per week 3rd year
Recued layers may go off lay initially due to stress of moving and change of environment. May lay off for a year and often develop egg abnormalities or reproductive complications.
79
What should poultry housing provide?
* Shelter from wind and rain or direct sunlight
* Ventilation
* Protection from predators
* Dry safe area to sleep
* Secluded area for laying
* Perching fir chicken sand turkeys
* Enough space for birds to move around and perform normal behaviours
80
Why is litter important?
- Hens need to be able to ground peck and litter should promote this, especially if they are prevented from ranging.
- Hens prone to respiratory problems should have dust extracted shavings or carefully sourced straw and hay to ensure they do not contain fungal spores.
81
What is the consequences of wet litter?
- Wet litter causes fungal respiratory problems, frustrations of dustbathing and foraging behaviour, and foot and leg issues.
- Wet litter caused by defection, drinker spillage and leaks. Spot clean daily or change entire litter regularly.
82
Describe how water should be managed in poultry housing.
- Waterfowl require water to dunk their head in to wash their eyes and bathe to keep feathers in good, watertight and condition.
- Open water inside the house is too messy. Use an open trough, paddling pool or pond liner outside the house for just a few waterfowl.
- Static water is emptied and container cleaner and sanitised every other day due to the risk of botulism.
- All poultry need fresh cold water daily
- A variety of types of drinker are available
- Drinkers should be cleaned and disinfected regularly
- In cold weather drinkers should be checked to ensure not iced over
83
Describe the feed given to poultry.
- Commercial feed is fed in the morning ad lib.
- Whole grain in the afternoon and stays in the crop longer to keep birds full overnight. Do not feed until 12 weeks old as the gizzard is fully developed.
- Vegetable matter but not kitchen waste, which is illegal.
- Avocado is poisonous to chickens
- Oystershell and flint grit is commercially bought
- Do not make sudden changes to feed and gradually change over a week.
- Obese chickens: fatty liver could get haemorrhagic and die, heat stroke in warm weather, reduced diet
- Waste feed attracts rodents and/or wild birds, who pose an avian influenza risk
84
What are the routine treatments for poultry?
- Wing clipping to prevent escape – not pinioning: clip 1 wing only, use quality scissors, annually, use assistant
- Beak tipping for overgrown beaks – top beak clipped back to meet with the lower beak, not painful or a mutilation, distinct from beak trimming.
- Claw trimming for long claws in permanently housed poultry – nail clippers for smaller birds and larger clippers/sheep foot shears for larger birds.
- Spurs of cockerels should also be trimmed and filed, as they may cause injury during fighting or mating.
- Bareback – hens may lose feathers and suffer injury caused by continual treading during mating. canvas and leather saddles for chickens and turkey available.
85
What are broody hens?
Hens have a natural instinct to sit on a clutch of eggs and hatch them. May be useful if breeding. Silkies and bantams particularly useful for this purpose. Commercial hybrids have had the tendency mostly bred out of them, though will occasionally go broody.
- Sits for 21 days, lose condition, stop laying
- Fluffs up feathers to exaggerate size
- May be aggressive and ‘nest hog’
Treat with a broody coop. Wire bottoms – hens cooled from underneath.
86
Describe Marek's disease.
- Often fatal
- Herpes type virus, causes limb paralysis as one symptom – easily spread
- Can vaccinate: do so early as strikes young birds
- Diagnosis by PME and histopathology
87
Describe E.coli in poultry.
- Can lead to Colispeticaemia
- Yolk sac infection in chicks during the first week of life
- Egg peritonitis
- Diagnosis by PME
88
Describe gumboro disease.
- Infectious bursal disease –IBD
- Highly contagious viral infection
- High mortality in rearing birds (before 16 weeks)
- Rare in backyard flocks, but vaccination (via drinking water) may be advisable for high value birds
89
What are the symptoms of worm infestation in poultry?
Weight loss
Depression
Loss of condition/poor growth
Can be fatal
Lameness in waterfowl
90
How are worm infestations prevented?
- Routine worming – Flubenvet / Elanco
- Resting of land to avoid build-up of worm and eggs
- Runs and paddocks should not be overloaded with too many birds
91
What are the symptoms of red mite?
Visible mites
Irritation/restlessness
Anaemia
Reduction in condition and production
Blood spots on eggs
Injurious pecking
Increased mortality
92
What are the clinical signs of red mite?
Damaged plumage, feather loss
Tired, irritated, cannibalism
Reduced egg numbers and loss of egg quality
Anaemia, mortality
93
How is red mite diagnosed?
Hand lens – magnifying glass. Microscope.
Lice bigger than mites, lice 6 legs, mites 8 legs
94
What is the life cycle of red mite?
Mite life cycle on host: lice > norther fowl > scaly leg > depluming
Mite life cycle in environment: red mite > egg > larvae > protonymph > deutonymph > adult
95
How is red mite infection spread?
Bought in birds
Wild birds
Feed
Second hand equipment
Visitors dirty clothing
96
How can husbandry be altered to prevent red mite?
- Materials: metal and plastic with minimal joints make smites unfriendly. Wood makes mites friendly.
- Disinfection programmes: attention to detail, insecticide, terminal and routine
- Monitoring: routine inspections, mite traps, specific inspection at night in warm weather
- Intermittent lighting: 3 hours light, 3 hours dark, illegal in UK
97
How are flocks treated for red mite?
- Flock treatment: oral Exzolt. 0 egg withdrawal but 14 days for eat and offal.
- Backyard treatment: topical or injection. Egg withdrawal at least 7 days after the last treatment and 28 days for meat.
- Treatment for both: oral Exzolt 50ml or 1L bottle or 0.2ml per 2kg hen. Oral garlic, homeopathic or herbal, with withdrawal eggs 0 days.
98
How is red mite environmentally controlled?
- Powders (silica, diatomaceous earths)
- Insecticide/acaricide (spot treatments, must have a use for when birds housed, terminal and routine)
- Plant extraction (garlic and vegetable oil)
- Cellulose (harmonix)
- Biological (predator mites)
- Heat (raise house temperature over 56˚C)
99
What food safety must be considered with red mite?
- Flock treatment: must have 0 egg withdrawal
- Backyard treatment: forbidden to use small animal exemption products, products for food producing animals (oral, injection), ivermectin, moxidectin. Statutory withdrawal periods.
100
What does coccidiosis cause?
- Enteric disease; poor growth; mortality
- Mild exposure – protective immunity
- Severe exposure – intestinal damage
101
What is the life cycle of coccidiosis?
Oocysts consumed → cell walls broken down → infective sporocysts released → change into sporozoites → invade cell walls → merozoites produced → cause more cell damage → new oocysts produced & excreted
102
How is coccidiosis diagnosed?
- Wet, watery droppings which may contain blood
- Anaemia
- Faecal oocyst counts
- May see blood poisoning if damage to the gut is severe
103
How is coccidiosis controlled and treated?
- Infection treated with coccidiocide: Toltrazuril; Amprolium
- Control with regular removal of bedding and droppings
- Vaccination available
104
Describe normal and abnormal poultry faeces.
Normal: firm and brown with a white top (urates)
Abnormal – yellow foamy or bloody
105
What are the possible causes of diarrhoea in poultry?
Coccidiosis
Worms
Viruses (rotavirus, adenovirus)
Bacterial diarrhoea (Brachyspria infection)
Feed too high in protein – causes chicken to drink more
106
What is the advice and treatment for diarrhoea?
- Check for coccidia and worms and use coccidiostat or wormer
- Microscopic examination of fresh droppings or gut contents for spirochetes; medication with tiamulin
- Add Biostop to the water – equivalent of human Imodium, firms up faeces * Ensure that drinking water is fresh and clean
- Check quality of feed, dry, not old, free of mould
- Cut down on treats
- Remove wet bedding and replace
- Monitor weight loss, adjust feed appropriately
107
Describe duck virus enteritis.
- Muscovy and Indian Runner ducks particularly susceptible
- Seasonal – April-June
- Contracted after contact with wild/feral species (carriers)
- Symptoms: reduced apetite; ataxia; watery, bloody diarrhoea; increased mortality
- Diagnosis by PME and histopathology
108
Describe goose parvovirus.
- Highly contagious and fatal
- Rapid progression with anorexia, prostration and death
- Diagnosis by PME, histopathology, virus isolation and or serology
109
Describe the symptoms of rickets in poultry.
Lameness
Hock swelling
Reluctance to stand or walk
Limp bones and pliable weak
Slayed legs
Poor growth and weight loss
Squat when resting
Treat with vitamin D in water
110
What are the symptoms and treatments for footpad dermatitis?
Pus filled abscess on foot. Swollen, hot and painful to touch.
Antibiotic injection and hot poulticing. Severe case may be treated with surgery but euthanasia may be preferable.
111
Name 4 egg problems.
Blind layer - egg layed internally
Egg bound - eggs not fully formed
Egg peritonitis - ectopic yolk caused infection in coelomic cavity
Prolapsed oviduct
112
What may pale, poorly shelled eggs be caused by?
* Respiratory disease causing damage to the oviduct
* Bright sunlight during the summer
* Time of the laying cycle (start/end)
* Calcium, phosphorus or vitamin D3 deficiency
* Stress
* Genetics – may be normal for breed
113
What are some behaviour and welfare issues of poultry?
Bullying
Injurious pecking
Not having all behavioural needs met:
- Foraging
- Dustbathing
- Nesting
- Perching
- Shelter
114
How do nutritional requirements of poultry vary?
- Affected by physiology
- Vary between chickens, turkeys, ducks and geese
- Change with age
- Vary according to purpose: breeders, broilers and laying hens
115
What are the nutritional requirements for feathers?
Methionine and cysteine
116
What are the nutritional requirements for egg and shell health?
Calcium, phosphorus, trace elements, canthaxanthin (a carotenoid) for red/yellow yolk colour
117
What are the specific requirements for bone health in laying hens?
Calcium, phosphorus, omega-3 and omega-6
118
How is poultry nutrition linked to behaviour?
- Dietary deficiencies associated with abnormal behaviours, such as injurious pecking
- Foraging is an important behavioural need
- For example, jungle fowl spend 60% of their time engaged in foraging behaviour
- Disruption of foraging behaviour can cause behavioural problems
119
What happens when energy concentration increases?
Poultry adjust feed intake according to energy density in their feed.
As energy concentration of feed increases, feed intake decreases. This leads to a decreased intake of other nutrients. So diets must be adjusted to ensure that nutrient content is appropriate for energy intake at each age, species and management system.
120
What are the negative effects of non-starch polysaccharide fibres?
Water soluble increases digesta viscosity, leading to reduced nutrient absorption and loose faeces/colitis. Water insoluble – entrap nutrients.
121
What are the positive effects of non-starch polysaccharides?
Viscosity of the digesta is decreased, allowing better absorption of nutrients. Overall better feed conversion and allows managers to feed less.
122
How do poultry digest insoluble fibre?
1. Decreased small intestine and proventriculus and increased gizzard weight, indicative of improved GI tract function.
2. Increase in gizzard weight associated with increased secretion of HCL and digestive enzymes.
3. Amylase production in the pancreas is increased for improved starch digestibility.
4. Bile acid content in the jejunum increased for improved fat digestion.
5. Some farmers also feeing a whole wheat portion, reporting a reduction in oocysts count.
6. Accumulates in the gizzard and slows feed passage rate, increasing time for nutrient uptake and increased period of satiety.
This may reduce motivation to forage. Dilution of diet decreases energy concentration. Increases time spent foraging, which is associated with decreases in injurious pecking.
123
Describe the function of the gizzard.
- Gizzards are in all birds but the wall are especially thick and muscular in ducks and gallinaceous birds (chickens and turkeys).
- Grinding organ, helps to break down hard items such as seed and nuts, and so aids digestion.
- Should be provided with grit which is consumed and collects in the gizzard.
- Proper functioning of the gizzard may affect satiety, gut transit time, gut pH microflora
- May disrupt oocysts (coccidia)
124
What are some benefits of dietary fat?
Higher percentage of metabolizable energy is utilised from fats compared with carbohydrates: broiler chickens showed better performance where oils included in starter diets. Laying hens supplemented with dietary fatty acids show higher egg weights, but also increased proportion of yolk compared with albumen.
125
What are the effects of vitamins A, B, D, E and K?
A = bone metabolism
B = embryo development
D = calcium absorption
E/selenium = meat quality and fertility
K = blood clotting, protective against coccidiosis
126
How do birds obtain fatty acids?
Birds are not able to synthesise all fatty acids so some must be obtained through the diet:
- Linoleic and linolenic acid/omega-6 and omega-3
- Soya oil high in linoleic acid
127
What are the effects of a linoleic acid deficiency in poultry?
Zero hatchability
Respiratory infections
Poor egg production
Small egg size
Low fertility
128
Why is the ratio of omega-6 and omega-3 important?
- Natural diet of a laying hen has relatively high levels of omega-3 through consumption of green leaves
- Commercial diets have relatively high levels of omega-6 and low levels of omega-3 due to grain content
- Diets supplemented with omega-3 have been associated with reduced keel bone breakage in laying hens and is a major problem is loose-housed laying hens.
129
What are the essential amino acids that must be supplied in poultry feeds?
Methionine
Lysine
Threonine
Tryptophan
Isoleucine
Leucine
Valine
Phenylalanine
Arginine
130
Which synthetic acids can be added where lacking?
DL methionine
L lysine
L threonine
L tryptophan
L valine
131
What percentages of the diet are required for different poultry diets?
Pullets = 14-18%, decreases with age to 1st egg
Laying hens = 15-18g per day, stepped up at lay peak, decreases with age
Broilers = 18-23%
Turkeys = 16-28%
Ducks = 16-22%
Geese = 15-20%
132
What happens to poultry in protein deficiency?
- Reduced growth in all species, as well as reduced egg size/production
- Feather abnormalities in chickens with arginine deficiencies
- Loss of pigment in wing feathers of turkeys with lysine deficiency
- Deficiency of methionine and cysteine have been associated with injurious pecking in laying hens
- Deficiency of a single essential amino acid limits performance, irrespective of supply of other amino acids
133
What happens to poultry in protein excess?
- Catabolism so wastage or protein, an expensive part of the diet
- Poor performance
134
How does poultry nutritional requirements affect the environment?
- Feed production and transport – 70% of the global warming potential of poultry system - soya
- Manure management – 40-60% eutrophication
- Replace south American grown soya with locally grown protein crops and potentially insects
135
How does calcium affect poultry nutrition?
- Important constituent of bone and eggs
- Deficiency: weak bones, poor egg numbers, and soft/broken egg shells
- Excess can also reduce eggs numbers
- Also for cells and tissue fluid, as well as activity of enzyme systems involved in the nervous system and muscle contraction
136
Describe the calcium requirements of laying hens.
Have extremely high calcium requirements:
- Calcium required to produce egg shells, sequestered from the bones
- Needs to be replaced otherwise results in thin/absent shells, bone weakness and osteoarthritis
- May also be associated with keel damage
137
Describe the calcium requirements of broiler chickens.
Broiler chickens have a high incidence of leg problems (fast growth, heavy birds), which are associated with decreased productivity, increased carcass rejections, and impact upon the welfare of the birds. Calcium promotes proper bone formation.
138
Why does calcium need to be balanced with vitamin D and phosphorus?
- Deficiencies of Ca, P or vitamin D can cause rickets – chicks cannot stand and have soft beaks.
- Ca:P must be appropriate, as abnormal ratios can lead to bone deformations in the feet of broiler chicks. Ratio is 2:1 except in laying hens, where it is much higher.
- Ca supplemented in the form of CaCO3 and oystershell
- Too much Ca makes food unpalatable
139
What are the functions of phosphorus and what happens when there is deficiency?
- Bone growth
- Phospho-proteins
- Phospholipids
- Nucleic acids
Deficiency causes reproductive failure and suboptimal growth.
140
What are chelated minerals?
- Attaching inorganic minerals to a substrate (typically an amino acid complex) to help overcome potential poor bioavailability
- For example, organic selenomethionine made by feeding selenium to growing yeast cultures vs inorganic sodium selenite
- Mode of absorption/utilisation not fully understood but tends to be more efficient
- Higher cost per active unit of mineral
- Use in monogastric diets limited to date due to limited data and added cost
141
How are broiler chickens reared?
- Feed quantity restricted/controlled to achieve breeders standard liveweight at POL
- Pattern of growth through rearing is important
- Frame/skeleton size
- Body composition (fat vs muscle vs skeleton)
142
Describe how broiler hens and cockerels are fed separately.
- Hens fed in feeder track with ‘toast rack’
- Only hens can access feed
- Cocks fed in separate tube feeders
- Peak feed intake (hens) 165-170 g/hen/d; reduce hen feed allowance post peak for best performance
143
Describe how laying hens are reared.
- Age of maturity is the first egg at 16-17 weeks of age
- Right diet during rear impacts liveweight, uniformity and physiological age/maturity
- Liveweight at POL duet to laying performance, egg size and persistency
- Consequently it is important to manage the diet correctly during rearing
144
Describe laying in laying hens.
- Feed intake is important for breed and environment
- Variation on age/stage of production, egg size demand, egg price
- POL liveweight determines egg size, which is initially small and increases with age
- Egg size determines chick size
145
What happens with excess liveweight in laying hens?
- Reduced egg laying performance
- Possible mortality of embryos
- High egg size in late lay
- Egg shell quality and hatchability may be reduced
- High specification vitamin and trace element premix required because of high demand from egg production
146
Describe broilers and turkey systems.
- Meat birds relatively short lived at 30-42 days
- Importance for high energy, high protein feeds to eb consumed as early as possible to sustain high growth rate
147
How are broilers and turkeys limited by early digestive capacity?
- Feed consumption stimulates development of digestive tract
- Enzyme supply limits digestive processes for 3-5 days
- Bile supply limits fat digestion in first 7 days
- There is a requirement for high protein, easily digested starter feed
148
Describe the changing physical requirements due to rapid growth rate in broilers and turkeys.
- Physiological tissue demand changes
- Digestive capacity increases with age
- Requirement for a high energy, lower protein finisher feed
149
What are the consequences of optimising feed intake in turkeys and broilers?
Maximise feed conversion ratio and growth rate would be ideal. However thus can lead to:
- Leg weakness and mortality
- Modern broiler on a slow growing system reduced from 11% to 0% mortality
150
When should poultry be fed?
- Though feeding ‘ad lib’ e.g. chain feeders run multiple times each day
- Don’t want to constantly call birds in from the range
- Need to make sure whole ration is eaten (esp. mashed feed)
- Feed so that birds will be sated overnight (wholewheat?)
151
Outline the order of events from hatching chicks to beak trimming of laying hens.
1. Eggs come from a breeder farm
2. Placed in setter trays – constant movement/tilting to stimulate being under a laying hen
3. Hatching trays and incubated for 21 days
4. Dry out
5. Sexing
6. Travel through hatchery
7. Eggs put in hatching trays. Do not all hatch at once. May be up to 2 days old when they arrive on the farm.
8. Some companies feed in the hatchery.
9. Movement through the hatchery – fast conveyer belts and drops.
10. Exposure to dirt
11. Beak trimming of laying hens
152
What are 3 methods of sexing chicks?
- Cloacal or vent sexing – sucks and turkeys
- Colour sexing – females red, males white in laying hens
- Feathers sexing – shape and rate of development of feathers in broilers
153
How are the sexes separated?
- In theory, could be a genetic test but in practice in unlikely.
- Males carry two full genes for colour and females carry the sex-determining gene and a gene for colour
- Different colour genes are dominant or modify other colour genes
- Most common sex link cross: red sex link
154
What are the genotypes of males and females?
- ZW sex determination system
- Ovum determines the sex of the offspring. Males homogametic ZZ, females heterogametic ZW
- Z chromosome is larger and has more genes
155
How are broiler chicks sexed?
Female = primary feathers are longer than the covert feathers
Male = if the coverts and primaries are the same length, or the primaries are shorter than the coverts
156
What is the layer breeding pyramid?
1. 6 genetic companies
2. Each with their own lines for different markets
3. 3 breeds of layer dominate the UK market – hyline, Lohmann and novogen
157
What are the welfare concerns linked to broiler growth rates?
- Skeletal disorders
- Contact dermatitis
- Ascites
- Sudden death syndrome
- Rearing period: severe feed restriction causing hunger and stress
- Laying period: fear and skin damage to the hens due to rough mating behaviour of the males
- Mutilations in males and females to prevent excessive damage to the hens
- Health, mortality and selection (males)
Animal Management Y2
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