Poultry Pathology Flashcards
Deficiency in vit D, Ca, Ph
- Affects all GPs -> evenly thickened GP -> accumulation of non-mineralised cartilage
- Tibial dyschondroplasia = proximal tibia, uneven GP, plug of non-mineralised cartilage
- HypoCa in laying hens -> reduction in lay / whole bird paralysis
Water deprivation
- Gout
- Due to back up of urates (kidney issues/water deprivation) -> go into viscera first then joints
Vitamin B2/riboflavin deficiency
- Clubbed down + curled toe paralysis
- CS - poor growth, reluctance to stand or walk, sitting on hocks, toes curl inwards
Egg production
- Lights on 6 am -> egg laid
- Chickens eat, then drink
- After few hours, ovulates again
- Shell forms last in evening + overnight - require stillness + quiet during this time
- 9 h after lighters out -> lays another egg
(Only left ovary is developed)
https://www.thepoultrysite.com/publications/egg-quality-handbook/2/formation-of-the-egg
Trauma to growth plate infection
- Reovirus
- Mycoplasma synoviae
- Osteomyelitis
Cause swelling around the hock joint
Rickets
- Metabolic disorder in young growing birds
- Thickening and poor mineralisation of the
growth plates and the bone - Dietary Ca, P and vitamin D3 deficiency; disturbed Ca/P ratio, or impaired absorption of one of these elements
- High dietary phosphorous levels have a similar
effect as low Ca levels - Hypocalcaemic rickets = accumulation of proliferating chondrocytes
- Hypophosphataemic rickets = accumulation of
hypertrophic chondrocytes
Tibial dyschondroplasia
- Macroscopically, hypocalcaemic rickets are
hardly distinguished from tibial dyschondroplasia because the latter condition may be a consequence of the former in its etiological aspect - TD can follow rickets as a result of the lowered hypertrophy of chondrocytes when birds try to adapt to the low calcium diet
- Histopathology: Abnormal masses
of prehypertrophic cartilage occupy
the entire metaphysis and disrupting
the blood supply. No distinct border is
present between the proliferating and
hypertrophic cartilage.
Biotin deficiency
- Leads to dermatitis
- Skin is not a healthy -> prone to ulcerations + pododermatitis
Common viral infectious causes of splenomegaly
- When spleen > ½ length of proventriculus = splenomegaly
- Viral infections causing tumours on spleen – Marek’s disease virus + Avian leucosis virus
- Diffuse = spleen grossly attached
- Nodular = diff parts attached = overall enlargement
Bacterial organisms that cause splenomegaly
- E. coli
- Salmonella
- Pseudomonas
- Staphylococcus
Feathering abnormalities caused by mating damage
Mating damage
- Neck
- Back of female bird
Mutilation/over-preening
- Self-mutilation - other feathered part of the body – depends where parasites are
- Pull out their feathers when pulling out eggs, parasites, over-preening, pull out feathers
- Mutilation – bullying, depending on type of environment
Ensure have 1 : 10 male to female ratio
Types of vacc / vacc protocol
Live – short duration, when want to boost immunity, admin several times
- IBC, Mycoplasma, Newcastle disease
- Given SC
Inactivated – longer duration + higher immune response, only need to admin once
- Primed w/ live vacc – stimulates memory cells e.g. for IBV
- Attenuated vacc – primed w/ live vacc
- IBD
- If all ages affected - vacc early
- Site/region-specific
- Stabilising agent in water prior to vacc - to neuralise chlorine effects (used to kill microorgaisms)
Pathogens free-range birds are commonly exposed to (Resp)
- Bacteria = mycoplasmosis
- Virus = IBV
- Parasite = Syngamus trachea
Difference between non-starters, starve-outs + hypoglycaemia
- Non-starters + starve outs used interchangeably
- Caused by poor management of feeders, drinkers
o Collapse of
o Correct amount of feed given - Biodegradable paper on floor for easy access to feed
- Chicks could be hypoglycaemic when they don’t feed
Challenges during life of broiler - stress/impact on production
Stress/impact on production during:
- Brooding
o Temperature
o Feed
o Water available – nipple drinkers are at the correct level, not too high
- Transfer crumb to pellet
o Crumbs have smaller particle size than pellets
o Don’t give too large pellets, will start to starve-out
o Crumbs 1 – 7 d
o When transferring – mix crumbs + pellets e.g. have on diff sides of building
o Water available – helps dissolve feed in crop
- Vacc
o Shouldn’t starve birds for > 1 h, especially broilers, esp during in summer
o Be gentle
- Feathering up – protects them, keeps warm
o Need to give right quantity of feed + to maintain body temp
o Vitamins – give to build-up feathers
- Coccidiosis challenge
o Layers – vacc
o Broilers – incorporate coccidiostats in feed
o Make sure litter is dry – no host for coccidia to sporulate
o Don’t reuse litter – should start on new ground
- Various feed changes throughout life
o Correct particle size
o Correct feeders
o Change gradually
- Thinning
o Dim lights, dec lighting, close curtains
o Raise feeders + drinkers
o Withdraw feed prior
