Poultry exam short

1.Health problems in intensive egg-productive poultry farming

Intensive farming: high number of birds, confined housing system, no access to outside, high production. Leads to a lot of health problems, metabolic, overcrowding, stress, rapid spread.

Examined and treated at flock basis (not individually).

Behavior:

• Feather plucking: Stress, overcrowding, boredom, poor-protein diet

• Cannibalism: overcrowding/stress

Skeletal:

• Rickets: young/growing birds, vitamin D3/Ca/P deficiency. Poor nutrition or malabsorption, weak and soft bones.

• Osteomalacia: old birds.

• Cage-layer fatigue: nutritional, result in soft bones. Ca+ exercise deficiency, occur after peak egg output.

Reproductive:

• Egg-drop syndrome: Adenovirus, pale-soft shelled, shell-less eggs in otherwise healthy hens

• Egg peritonitis: problem with oviduct → egg does not form properly → yolk is deposited internally in abdomen → risk for E.Coli infection

Metabolic:

• Fatty liver hemorrhagic syndrome: incorrect protein - energy balance in caged birds. More energy intake than exercise. Results in fatty liver + hemorrhage. Give proteins and antioxidants - prevents vascular damage.

Infectious:

- fowl pox, Newcastle disease (NCD), salmonellosis, coccidiosis, fowl cholera, avian influenza etc.

2.Health problems occuring in intensive fattening flocks

Short production lifespan: 42 days, reaching 2.5 kg body weight.

• Generally affected by fewer disease types than hatchery birds, but rapid growth predisposes them to several health disorders.

Growth-Related (Locomotory) Disorders

Rapid weight gain places excessive stress on the skeletal system, leading to:

• Rickets

• Tibial dyschondroplasia

• Degenerative joint disease (DJD; including viral arthritis)

• Tibial rotation

Circulatory Disorders

The cardiovascular system may not develop proportionally to body growth, meaning heart remains too small, insufficient capillary development.

Consequences: sudden death syndrome (SDS) & ascites syndrome

Foot Lesions

Bumblefoot (pododermatitis)

• Constant pressure on the feet causes local ischemia → damaged tissue becomes susceptible to bacterial infection - pododermatitis.

Metabolic Disorders

• can occur due to extremely rapid growth and high production demands.

Environmental and Management-Related Problems

• High stocking density + poor ventilation - increased exposure to airborne pathogens, rapid spread of diseases

• Overcrowding + stress - cannibalism, suffocation/crushing of birds

• deep-litter housing systems - poor ventilation → ammonia accumulation & intoxication. Increased risk of fungal infection.

When locomotory or circulatory disorders become evident:

• Feed lower-energy/poorer-quality diets to slow growth.

• Reduce daily light exposure to decrease feed intake and growth rate.

3.Health problems in extensive poultry farming

Extensive systems: Low bird density, lower meat and egg production, and less veterinary supervision (often only annual visits). Disease risk is increased due to lower biosecurity and greater contact with the environment, wildlife, and intermediate hosts.

General Problems

• Pododermatitis

• Nutritional deficiencies (vitamins and minerals)

• Intoxications: excess nutrients (e.g., salt), soil toxins (e.g., Clostridium spp.), and mycotoxins (aflatoxins in feed)

• Wildlife predation

Parasitic Diseases - Greater exposure to intermediate hosts increases parasite burden.

Endoparasites:

• Capillaria spp. (IH-earthworm) - weight loss, dysphagia

• Ascaridia spp.

• Heterakis gallinarum

• Histomonas meleagridis

• Syngamus trachea

• Eimeria spp.

Ectoparasites:

• Lice

• Mites (Dermanyssus gallinae, air sac mites)

• Ticks

Treatment: flubendazole, levamisole, prevent my limiting IH, biosec.

Viral Diseases

• Marek's disease (from vaccinated poultry, cause paralysis, high mortality)

• Newcastle disease (paramyxovirus, resp. sudden death, airborne)

• Avian influenza (zoonotic risk)

Bacterial Diseases

• Chlamydia psittaci (systemic - resp. + GIT, often asymp).

• Mycoplasma synoviae & Mycoplasma gallisepticum (chronic resp. disease)

• Salmonella pullorum/gallinarum

Fungal Diseases

• Aspergillosis (Aspergillus spp. - lungs, airsac)

• Dermatophytosis (Microsporum spp., Trichophyton spp.)

4.Specific immunoprophylaxis and serodiagnostics

Immunoprophylaxis: Prevention of disease by inducing active immunity (vaccination, recovery from infection) or passive immunity (maternal antibodies). Goal: Prevention of infectious diseases.

Important points:

• Vaccinate only healthy birds.

• Do not use chlorinated water for vaccines administered via drinking water.

• Live vaccines are mainly used in housed poultry.

• Killed vaccines are preferred for outdoor birds.

• Vaccinating breeder hens provides maternal antibodies to offspring.

Vaccine administration methods: Injection (SC/IM), Wing web (fowl pox/avian encephal.), Water (NCD, IB, IBD), spray (IB, NCD), Eye drop/intranasal.

Biosecurity/hygiene: All-in-all-out system, cleaning + disinfection bw. flocks, black and white hygiene zones, egg disinfection (dipping), probiotic feed.

Vaccination scheme (Strek = means nothing)

Breeders

• same as layers + vaccination against mycoplasma, ILT, salmonella

• Avian encephalomyelitis is important in breeders to protect offspring - given at 10-12w. (!not in layers!).

Serodiagnostics: Diagnosis & monitoring of disease using serum Ab detection. Serology after 2-3w to look for titers (vaccination give elevated titers).

• Uses: assess vaccine efficacy (Ab titers), determine timing of revaccination, investigate outbreaks + increased mortality.

• Test - ELISA, HIT (Hemagglutination inhibition test - for NCD), VNT (virus neutralization test), AGID (Agar gel immunodiffusion), PCR (not Ab-based but for detecting pathogen DNA/RNA).

5.Diseases caused by incorrect nutrition, avitaminosis, malabsorption syndrome

Incorrect nutrition:

Avitaminosis:

• Primary: exogenous - lack in feed

• secondary: endogenous - high demand or disorders in absorption/utilisation (enteritis)

Vitamin deficiencies are most commonly caused by a lack of complete vitamin premix fromt he bird`s diet (exogenous). In some cases, endogenous deficiencies can be seen, caused by incr. demands, stress, infection etc. Multiplke signs of deficiency can be seen, generally, signs of B-vit. deificiencies appear first as there are some stores of fat-soluble vitamins in the body.

Malabsorption syndrome

• Disease complex (avian reovirus + enterovirus, other, bacteria)

• May affect GIT → nutritional deficiency + lesions

• diarrhea, malpositioned beak, rickets, foamy undigested particles in droppings

• NO treatment! May vaccinate. Good hygiene.

• Common in broilers.

Bone problems → think Calcium/P/Vit D3 or perosis

Neuro signs → think Vit. E or B vitamins

Skin/epithelium → vit. A/biotin

Bleeding → vit K

6.Feather disorders - etiology, symptoms, diagnostics, dif. dg,  therapy and prevention.

Ectoparasites (major causes of feather damage and anemia)

• Bed bug (Cimex lectularius) - anemia, feather loss, decr. production.

• Biting lice (Mallophaga) - irritation, scabs, anemia, crusty egg masses attached to feather bases.

• Red mite (Dermanyssus gallinae) - Pruritus, anemia, restless, decr. production. Feeds on birds at night - disease vector - fowl cholera.

Treat by pyrethroids.

• Northern fowl mite (Ornithonyssus sylviarum) - Soiled feathers, anemia. Vent crusts/scabs, blood-sucker. Treat by ascaricidal sprays. Resistance is common (pyrethroids - ineffective).

• Burrowing mites (Knemidocoptes spp.) - depluming itch → self-plucking, Pruritus, weight loss. Species: K.mutans, K.gallinae, K.pilae. Treat by ascaricides.

• Ticks (Ixodes, Dermacentor) - can transmit systemic disease, anemia, skin lesions. Treat by acaricides.

Non-parasitic Feather Disorders

Feather plucking

• Causes: Stress, Overcrowding, High environmental temperature, Boredom/lack of enrichment, Low-protein diet, High stocking density.

• Signs - feather loss, skin damage

• treat by enrichment, reduce light intensity, incr. dietary protein, sedation if needed, beak trimming.

Viral Feather Diseases

1) Reticuloendotheliosis virus (Retrovirus)

• Signs: Abnormal feather development, Anemia, Enlarged nerves & Thymic atrophy

• Diagnosis by PCR, diff.dx: Marek`s disease (also causes nerve enlargement). NO treatment available.

2) Psittacine Beak and Feather Disease (PBFD) - circovirus

• Infects rapidly dividing cells, esp. thymus, feather follicles, crop epithelium

• Primarily affects pet birds, parrots.

• Signs: Abnormal feather growth, Immunosuppression, Feathers may be: Pinched or club-shaped at the base & Hemorrhagic (bleeding within the feather shaft)

Nutritional Causes

Niacin (Vitamin B3) deficiency

• Signs: Feather loss & Perosis ("slipped tendon" deformity of the legs)

• Treat by B-complex vitamin supplements.

7. Skin diseases – etiology, signs, diagnosis, DDx, therapy, prevention

Inflammation of skin = dermatitis.

Causes can be:

• Infectious: bacteria, viruses, fungi, parasites

• Non-infectious: trauma, chemicals, frostbite

Diagnosis: Flock history, CS, necropsy (PM), bacteriology/PCR if needed

Bacterial diseases

1) Gangrenous dermatitis (“malignant Edema”)

• by clostridium perfringens, C.septicum

• Signs: Red to black moist necrosis, feather loss, cellulitis, skin sloughing, gas crepitiation (crackling under skin)

2) Bumblefoot (Pododermatitis)

• By Staphylococcus aureus, S.epidermidis, S.gallinarum

• Signs: plantar abscess (bumble), lameness

3) Erysipelas - Zoonotic!

• By erysipelothrix rhusiopathiae

• Signs: scabby skin lesions, depression, enteritis, endocarditis, pericarditis

• Dg: culture (blood agar), PCR. Diff.dx - salmonellosis/pasteurollosis

4) Cellulitis

• By E.Coli, staphylococcus aureus

• Signs: subcutaneous exudate, often seen at slaughter, may have a few CS

• diff.dx: fowl cholera

Treatment by ATBs (tetracyclines), penicillin. Prevent: hygiene, good litter, reduce skin trauma, stress. Vaccine in erysipelas.

Viral Diseases

1) Avian pox (avipoxvirus)

• dry form: skin nodules on head, neck, legs, vent

• wet form: diptheritic plaques in mouth and upper resp. tract

• diff.dx: marek. Usually self-limiting. Prevent by vaccine/vector control.

2) Marek`s disease (herpesvirus)

• cutaneous nodules, nerve enlargement, ocular lesions, visceral tumors

• NO treatment, prevent by vaccine.

Fungal Diseases

Favus (microsporum gallinae) - crusty/scaly lesions on head, white oral membranes. In severe case → spread to lungs + GI tract. Treat by antifungals.

Parasitic causes: ectoparasites (lice, mite, ticks) - skin irritation, feather loss, anemia. Trichomoniasis → skin nodules.

Other skin conditions: Hock burn (contact pododermatitis) → by wet or dirty litter, by black skin → erosions → fibrosis → inflammation → lameness. NO specific treatment. Prevent by dry litter.

Other causes: trauma, tumor, cannibalism, skin emphysema, breast blisters.

8.Non-infectious, bacterial and parasitic diseases with ocular changes/8. Ocular diseases – etiology, signs, diagnosis, DDx, therapy, prevention

Non-infectious

- keratoconjunctivitis (ammonia blindness)

- Avitaminosis A

- Hypervitaminosis A

Bacterial

- chlamydiosis (chlamydia psittaci)

- infectious coryza (avibacterium paragallinarum)

- mycoplasmosis (mycoplasma gallisepticum)

- salmonellosis (salmonella typhimurium)

Parasitic

- eye fluke (philoptalmus gralli)

- eye worm (oxyspirura mansoni)

- Trichomas gallinae

Viral and mycotic diseases with ocular changes

Viral

- Avian pox (avipoxvirus) - nodules on eyelid

- Marek´s disease (G-alpha-HV-2): ocular lymphomatosis (grey eye)

- Infectious laryngotracheitis(GHV-1) - bloody cough

- Avian rhinotracheitis (metapneumovirus): swollen head syndrome

- Newcastle Disease (avian paramyxovirus)

- Avian influenza (orthomyxovirus)

- Duck viral enteritis (herpesvirus)

Fungal

- Aspergillosis (A.fumgitaus, A.flavus) - plaques in eye

- Favus/ringworm (microsporum gallinae)

- Candida spp

Non-infectious diseases of circulatory system

Mainly in broilers due ot rapid growth (hypoxia, nutrition, toxins, stress)!

main diseases

- ascites syndrome (pulmonary hypertension syndrome)

- sudden death syndrome (arrhythmia + metabolic stress)

- enzootic heart failure/exudative diathesis (low vitE+Se)

dystrophic changes of heart:

- parenchymatous degeneration (toxins)

- gout (pericarditis uricosa)

- fatty degeneration (toxins)

- hyaline degeneration

vascular disorders:

- aortic rupture (hypovit E, thrombi, genetics)

- arteriosclerosis (cholesterol)

inflammations

- myocarditis (toxins)

- pericarditis (uricosa)

Infectious diseases of circulatory system

1. Myocarditis

- infections, toxins, systemic diseases

2. Endocarditis (endocarditis vulvaris -> ascites syndrome)

- staph, strepto, pasterurella, E.coli, erysipelopthrix

3. Pericarditis

- fibrinous (mycoplasma)

- exudative (strepto, enterococcus)

- purulent (foreign body injury)

- uricosa (gout)

- hemorrhagic (fowl cholera)

4. Hydropericardium (nutritional/cardiac edema, toxins, infections like inclusio body hepatitis)

5. Viruses:

- AI (internal hemorrhages),

- Mareks (systemic form, tumor in heart), - reticuloendotheliosis (neoplasia),

- CIA,

- IBH (hydropericardium)

6. Parasites: Plasmoidum (chicken malaria), Hemoproteus, Leucocytozoon

Anemia associated with infectious and non-infectious diseases of poultry

Infectious cause of anemia

- Chicken infectious anemia (CAV, circovirus) -> BM destruction and T cell damage

- Inclusion body hepatitis (adenovirus)

- Lice, mites -> hemorrhagic anemia

- plasmodium gallinaceum, hemoproteus, leukocytozoon

Non-infectious cause of anemia

- intoxications: warfarin, aflatoxins (haemolytic/hemorrhagic anemia)

- hypovitaminosis K (low prothrombin -> delayed clotting -> bleeding)

Hemorrhagic diathesis associated with infectious and non-inefctious diseases

Hemorrhagic diathesis is caused by

1. Vasculopathies (vessel wall defects)

- exudative diathesis (Vit E+Se def)

- vasculitis/septicemia (IBH, IB, Mareks, Fowl cholera, salmonellosis, ILT, Duck viral hepatitis, IBD)

2. Coagulopathies (clotting factor disorder)

- hypovit K

- warfarin

- aflatoxins (liver damage)

- hypovit B9 (macrocytic anemia + bleeding)

3. Thrombocytopathies (platelet disorders)

- CIA (bone marrow atrophy)

- IBH (adenovirus -> anemia, hemorrhages, hydropericardium)

- Mycotoxicosis (fumonisin, ochratoxin, satratoxin)

- Drugs: sulfonamide overdose -> pancytopenia

Bacterial diseases of the respiratory system

-Mycoplasmosis (mycoplasma gallisepticum + meleagridis: CRD, airsacculitis, fibrin, cheesy exudate. Vertical transmission!)

- Infectious coryza (avibacterium paragalllinarum: acute URT disease in chickens, facial swelling, infraorbital sinus edema)

- Fowl cholera (Pasteurella multocida: acute with white diarrhea, resp. distress and death, or chronic with swelling and torticollis)

- Avian chlamydia (Chlamydia psittaci: zoonosis, facial swelling, dyspnea)

Viral diseases of the respiratory system

- Infectious Bronchitis (coronavirus. most contagious in chickens! 70% decreased egg production, poor quality, shell less eggs and misshapen)

- Fowl pox (avipoxvirus. cutaneous and diptheric)

- Newcastle Disease (paramyxovirus. velogenic, mesogenic, lentogenic. respiratory/nervous/digestive form. Zoonotic. Pigeons most affected > torticollis, falling, incoordination etc.)

- Avian influenza (orthomyxovirus. LPAI -> mild resp signs, sinusitis, HPAI (H5N1)-> systemic hemorrhagic disease)

- ILT (gallid herpesvirus 1. cheesy exudate in trachea -> suffocation, severe dyspnoe, death)

- Avian rhinotracheitis (metapneumovirus. swollen head syndrome, swelling of sinuses, frothy eyes)

Parasitic and mycotic diseases of the respiratory system

Parasites

1. Syngamus trachea (in free-range birds, gaping, coughing, head shaking, resp distress. Ivermectin. Paratenic host is earthworm, insect. Only use flubenazole in meat producing animal1)

2. Cytodites nudus (air sac mite, rare in commercial poultry, PM white spots in air sacs/lungs)

3. Sternostoma tracheocolum (air sac mite, in cage birds, rare in poultry)

4. Cryptosporidium baileyi/meleagridis (resp tract and bursa. no treatment)

Fungi

1. Aspergillus fumigatus, A.flavus, A.niger (opportunistic, not from bird-bird. grey/green granulomas in lungs/airsacs. acute in youngs first 3weeks ->high mortality, CNS signs. Chronic -> dyspnoe, weight loss. Not as important in poltry, no airsacculitis as in retiles/exotic birds)

Non-infectious, infectious and parasitic diseases of beak, beak cavity and crop

Non-infectious

- beak deformities (congenital: brachygnathia superior/inferior, acquired: rickets/osteomalacia)

- beak necrosis (fine feed accumulation -> pressure necrosis)

- vit A def (metaplasia of crop epithleium)

- foreign bodies (crop obstruction)

- chemicals/trauma (high fiber feed and chemicals -> ingluvitis.

- nervus vagus damage -> pendulous crop (enlagred, fluid filled)

Infectious

1. Pasteurella (ingluvitis)

2. Pseudomonas (stomatisis)

3. Klebsiella (stomatitis)

4. Fowl pox (diptheric form -> stomatitis and ingluvitis)

5. Candida albicans (stomatitis and ingluvitis. white plaques in crop -> sour crop. crop stasis and regurgitation in youngs)

Parasites

1. Trichomonas gallinae (stomatitis, ingluvitis. yellow plaques in oral cavity, blocks the esophagus -> starvation)

2. Capillaria anulata, contorta (ingluvitis)

3. Gongylonema ingluvicola

Non-infectious, infectious and parasitic diseases of the proventriculus and gizzard

Proventriculitis

1. Candida albicans

2. Newcastle disease (hemorrhages)

3. Mareks (lymphoma)

3. Macrorhabdus ornithogaster (rare in poultry)

4. Fusarium toxins (fusarium fungi -> necrosis and ulceration of oral mucosa, GI reddening, visceral hemorrhages)

5. Cyclopiazonic acid (aspergillus flavus -> lesions in proventriculs with enlargement, ulceration and thick mucosa)

6. Proventricular dilation syndrome (high fibre and mash feed diet -> enlarged, thin walls, gizzard atrophy)

7. Tetrameres Americana (in proventricular glands -> red spots in serosa. Thick oedematous, possible partial obstruction)

Diseases of gizzard

1. Impaction (litter ingestion in turkeys -> early sudden mortality)

2. Dilation (soft feed, lack of grit -> inflam + dysfunction)

3. Amidostomum anseris (waterfowl, hemorrhage and necrosis -> anemia)

4. Clostridium spp. (necrosis in proventriculus-gizzard junction)

5. Adenovirus -> gizzard erosion and ulceration

6. Macrorhabdus (mainly in pet birds, weight loss)

Non-infectious and infectious diseases of intestines and cloaca

ENTERITIS

Bacterial enteritis

1. Necrotic Enteritis (Clostridium perfringens due to diet change, coccidiosis or gut damage -> infection -> necrosis of SI -> death, diarrhea, ruffled feathers, liver lesions)

2. Pullorum disease (Salmonella pullorum in chicks, vertical and horizontal -> unabsorbed yolk sac + white nodules in organs -> death, diarrhea)

3. Fowl typhoid (Salmonella gallinarum, older birds)

4. Colibacillosis (E.coli -> enterocolitis and coligranulomas)

5. Avian tuberculosis (M.avium, granulomas in intestine, liver -> weight loss, lameness if in bone)

6. others: Pasterurellosis, campylobacter jejuni (no CS in poultry, hidden disease - contamination in slaughterhouse), yersinia

Parasitic enteritis

1. Eimeria -> coccicdiosis with bloody diarrhea

2. Ascaridia -> obstruction

3. Capillaria -> enteritis

4. Histomonas meleagridis -> blackhead disease. LIVER lesions - then too late to treat (toltrazuril).

5. Trichomonas (upper GIT, sometimes small intestine)

Viral enteritis

1. NCD (velogenic viscerotrophic strain -> severe hemorrhagic enteritis. PM: petechial hemorrhages in proventriculus!!)

2. Avian influenza (HPAI -> hemorrhagic enteritis and necrosis)

3. Coronavirus (turkey coronavirus, infectious bronchitis)

4. Reovirus, Rotavirus, adenovirus, parvovirus, astrovirus (-> malabsorption syndrome)

Intoxications

1. CuSO4 overdose -> catarrhal enteritis

2. Mercury -> caustic burns, ulcers

3. Phosphorus -> diarrhea, weakness, anorexia

Others

- poor nutrition, sudden diet change, stress, dysbiosis, hypomotility (nervous origin), volvulus (gas -> obstruction)

CLOACA

- cloacal prolapse (enteritis and egg-laying problems)

- cloacitis (infection, irritation or enteritis -> dirty vent, foul odour, ulceration, stop egg laying)

Protozoan diseases of the GIT

1. COCCIDIOSIS (-> secondary clostridial infection)

- Eimeria tenella (ceca -> bloody diarrhea)

- Eimeria necatrix (small intestine -> severe hemorrhage)

- Eimeria acervulina (poor growth)

- Eimeria brunetti (lower intestines -> necrosis)

(T; toltrazuril, ionophores, sulfonamides 3-3-3)

2. HISTOMONIASIS (black head disease)

- Histomonas meleagridis (vector: heterakis gallinarum egg)

-> ceca + liver, yellow diarrhea, cyanotic head. Thick cecal wall with ulcers and cheesy core. Round necrotic lesions in liver. Perforation -> peritonitis possible. T; flubendazole against heterakis

3. TRICHOMONIASIS (trichomonas gallinae)

- yellow caseous plaques in upper GIT, death in pigeons. T; metronidazole

Helminthoses of the GIT

Nematodes

1. Ascaridia galli (obstruction of duodenum/jejunum, migrate to cloaca)

2. Capillaria spp (C.annulata in crop, C.obsignata in SI, C.anatis in ceca. Inflm and thickening of intestine. Catharral enteritis if severe. Some need earthworm as IH)

3. Heterakis gallinarum (Direct LC. Ceca. vector histomons. usually mild with poor growth and depression.

4. Trichostrongylus tenuis (ceca)

5. Amidostomum spp. (gizzard)

T; flubendazol

Cestodes

1. Davainea proglottina (hemorrhagic enteritis in duodenum)

2. Raillietina tetragona ( iluem. indircet LC - snails etc)

T; praziquantel

Trematodes (flukes)

1. Prostogonimus ovatus (IH: snail + dragonfly. intestine -> oviduct. rupture -> peritonitis)

Diseases of bursa of Fabricius

1. Infectious bursal disease (Gumboro disease)

- etiology: Birnavirus, serotype 1 (pathogenic to chickens), serotype 2 (non-pathogenic). Destroy B cells -> severe immunosuppression. subclinical in chicks under 3 weeks, clinical in older: watery dirrhea, soiled vent, infl of cloaca and incoordination. Enlarged, edematous, hemorrhagic bursa in acute case. Atrophy in chronic case. Core vaccine week 3-5!

2. Lymphoid leukosis (avian leukosis virus - retrovirus)

- affect birds older than 14-16weeks due to slow tumor development. Infect B-cells -> tumor formation in liver, spleen and bursa. Weakness, weight loss, diarrhea. Vertical transmission!

3. Marek´s disease (GHV-2)

- spread via feather dander (resistnat in environment). Infect T-cells -> lymphoma formation. Tumors and nerve lesions -> paralysis, ocular change, skin lesions. Atrophy of bursa rather than tumor! Core vaccine day 1!!

4. Histomonas meleagridis (transmitted from heterakis gallinarum egg) -> infects the cecum -> spreads to liver and bursa -> atrophy -> immunosuppression

5. Prostagonimus spp.

Non-infectious and parasitic diseases associated with changes in the liver

Non-infectious

1. Fatty liver hemorrhagic syndrome (in caged birds with positive energy balance and no excercise. Obese birds, low egg prod., pale, sudden death)

2. Aflatoxicosis (aspregillus, penicillium -> convulsions, ataxia, opistotonus, anorexia, death. PM: large yellow liver)

3. Heavy metals (Lead, Mercury -> degeneraiton + atrophy of liver)

Parasitic

1. Histomonas melagridis (transmitted from heterakis eggs, spread from cecum to liver -> severe necrosis. Sulphur-yellow diarrhea, cyanotic head (blackhead disease), high mortaility. Round necrotic foci in liver. Caseous cores in cecum. Flubendazole.)

2. Trichomonas gallinae (necrotic lesions in liver, weight loss, weakness, upper GIT lesions)

Infectious diseases asociated with changes in the liver

1. Pullorum disease (Salmonella pullorum, vertical + horizontal. young chicks acute, diarrhea, grey necrotic foci in liver and organs.

2. Fowl typhoid (Salmonella gallinarum. older birds, diarrhea, pale and dehydrated. hepatomegaly, congestion, necrosis. T; only eradication due to carriers)

3. Salmonella typhymurium (liver congestion+necrosis)

4. Avian tuberculosis (mycobacterium avian -> grnaulomas in liver, spleen, intestine. chronic weigh loss, emaciation, lameness. T; culling)

5. Duck viral hepatitis (picornavirus, young ducklings under 7 weeks show signs like sudden death, neutrological signs: ataxia, opistotonus. Hepatomegaly with focal haemorrhages. T; no therapy, vaccinate breeders! 95% mortality)

6. Inlcusion body hepatitis (avian adenovirus, liver damage with intranuclear inclusion bodies -> sudden death, pale comb, icterus may be. T; no therapy, control IBD and CIA)

7. Aspergillus fumigatus (respiratory -> spread -> granulomas in airsacs, lungs and LIVER

8. Lymphoid leukosis (avian leukosis virus - tumors in chicks over 14-16 weeks in liver, spleen and bursa. Differential diagnosis is Histomoniasis!)

Non-infectious and infectious diseases of the female reproducitve organs

Non-infectious diseases of the ovary (only left ovary and oviduct is functional in birds!!!)

1. Cysts (fluid filled incidental finding due to endocrine imbalance or chronic inflammation)

2. Degeneration (toxins, vit A def, fowl typhoid -> misshapen dark follicles)

3. Hypoplasia (congenital small underdeveloped -> low egg production)

4. Neoplasia (adenocarcinoma, lymphosarcoma (mareks)

Infectious diseases of the ovary

1. Salmonellosis (-> misshapen follicles with caseous content)

2. Fowl cholera (inflammation of ovary)

3. Infectious bronchitis (70% less egg prod., thin, soft shells, water albumen.

Diseases of the oviduct

1. Salpingitis (multifactorial -asending infection from cloaca, trauma, spread from airsacs, e.g: E.coli, Mycoplasma gallisepticum, Salmonella, Pasteurella multocida. CS: soft/misshapen/shell less eggs, cloacal discharge, penguin posture! see picture)

2. Egg peritonitis (backflow of egg material + E.coli infection -> distended abdomen, penguin posture, low egg prod)

3. Egg binding (caused by large/deformed eggs, Ca deficiency or oviduct dysfunction. Distended abdomen, swollen vent. Oviduct rupture -> peritonitis. T; lubricate, massage, surgery)

4. Egg drop syndrome (adenovirus -> sudden drop, and soft or shell-less eggs)

5, Prolapse (egg retention, salpingiits or inflam of cloaca. T; clean, disinfect, reposition)

6. prostogonimus ovatus (fluke in oviduct -> low egg prod and soft shelled eggs, may rupture oviduct -> peritonitis. T; limited, control IH.

Non-infectious and infectious diseases of the male reproductive organs

Diseases of the testicles:

1. Orchitis (Salmonella, E.coli -> testicle enlargement -> atrophy later with fibrosis and calcification

2. Atrophy (age, nutrition, chronic disease, vit def -> low fertility and decreased size)

3. Hypoplasia (congenital -> small non-functional)

4. Neoplasia (rare, more in older birds)

Diseases of the penis (phallus in waterfowl)

1. Trauma during mating (on land -> microinjuries -> secondary infections -> hyperemia, edema, prolapse, necrosis if severe. Clean, ATB, reposition)

Venereal diseases

- infections transmitted during mating caused by bacteria (mycoplasma, neisseria, pasteruella), fungi (candida, aspergillus), protozoa (trichomonas) -> catarrhal, crupous and necrotic inflammation of RT in males and females -> weight loss and cloacal inflammation. AI reduces the spread!

Artificial insemination

- common in male turkeys (heavy males cant mate efficiently), massage abdomen + back and apply pressure pushing the tail forward-> semen release. Use extenders to maintain fertilizing ability of sperm. Pressure on abdomen on left side to evert cloaca and and oviduct, then apply semen. Once per week)

Egg-output disorders, the factors and diseases influencing egg-output, and management of egg-output disorders in poultry farming

Egg output abnormalities

- soft-shelled or shell-less eggs (rapid passage through shell gland)

- thin or poorly calcified shells (nutrition, virus, genetics)

- small/misshapen eggs (Infectious bronchitis)

- double yolk eggs (2 follicles ovulated simultaneously)

- factors: E.coli, Proteus, micrococcus, pseudomonas contamination of RT. Aspergillus and Penicillium penetrating shell and contamiante

Bird related/reproductive diseases

- Salpingitis and oophoritis (E.coli, salmonella, mycoplasma)

- ovarian cysts, degeneration, hypoplasia, prolapse, rupture of oviduct, neoplassia, egg peritonitis, venereal infections

Important production diseases

1. Egg drop syndrome (adenovirus -> soft shelled eggs in healthy birds)

2. Caged layer fatigue (calcium depletion -> thin shells, weakness, anorexia, bone fragility)

3. Fatty liver hemorrhagic syndrome (ovefed birds -> fatty liver -> hemorrhage -> death)

Factors influencing egg output

1. Age and genetics (start egg laying at 5months, peak first 8 weeks, then decline 65% after 12months. No egg prod during moulting!)

2. Nutrition (energy:protein balance, Ca + vit D3 for shell, methionine + lysine (protein synthesis), Vit E+Se (repro and antioxidant function), water intake!!)

3. Light (increasing day length -> stimulate egg laying. Commercial flocks have 14-16h light per day)

4. Stress (heat, overcrowd, trnasport, feed change, vaccine and management)

5. Infections (IB, Marek, NCD, AI, Lymphoid leukosis, salmonella, strepto, aspergillus.(IB and NCD -> wrinkled egg shell and malformed eggs. IB has affinity to highly metabolic active cells such as those in reporducitve tract)

Management and prevention

- nutrition, body condition, light (30-40lux 3 days, then 10lux at 15 days), temperature (30 chicks, 25 adults), humidity (60%), ventilation, biosecurity, vaccination, all-in-all-out

Hatching of eggs in poultry and its control

Egg formation: yolk from ovary -> captured by infundibulum (fertilization by sperm) -> magnum (albumen formed) -> isthmus (shell membranes) -> shell gland -> vagina

Veterinary control of hatching

- hatchability is influenced by egg quality, storage duration, ventilation, breeder nutrition (def Se+vit E -> myodystrophy -> low embryo development and reduced hatchability)

Handling and storage

- Collect eggs frequently (not dirty eggs -> contamination risk) and fumigate with formaldehyde to reduce microbes

- very small eggs -> insufficient nutrients for embryo

- very large eggs -> navel defects

- Storing temp: 10-12 °C and 70-75% humidity

- Equilibration at 18-22 °C before incubation! to avoid sudden temperature shock!

- Too long storage (>7 days ) -> embryo age before incubation -> increaed mortaility

Incubation conditions

- Blunt end UP to ensure correct air cell position (first breath during internal pipping)

- Temp: 37.8 °C

- Humidity: 50-60%

- CO2 and O2 exchange (proper ventilation essential)

- Egg rotation: turn every 2-3 h to prevent embryo adhesion and ensure normal development

- Critical phases: early (organogenesis - sensitive) and late (air cell pipping)

Candling and monitoring

- Day 5-6 (white eggs - fertility check/embryo viability

- Day 7-8 (brown eggs)

- Day 18 (embryo development and viability - see if it moves)

- remove infertile or dead embryos

Hatching phase

Day 19: transfer eggs to hatcher

- temp: 37 C

- humidity: 70-75%

- hatching: day 21

- check chick quality, remove weak chicks

- evaluate hatchability %, chick quality scoring, and culling weak

Sexing

- commercial layers: cloacal sexing (japanese method)

- broiler systems: sex separation may be performed

The causes of embryonal mortality and growth disorders in poultry and waterfowl

Two critical phases during incubation:

1. Early mortality (day 4 -> peak lactic acid prod and CO2 exchange)

2. Late mortality (day 19 -> oxygen demand increase)

Causes of embryonal mortality

1. Nutrition (vit A, B, E and minerals Ca, P, Mn, Zn. Protein and lipid. Vit E+Se -> muscle weakness + poor hatchability)

2. Management factors (temp, RH, ventilation, long storage, contamination, inadequate turning, cracked shells, improper incubation conditions)

3. Infections (salmonella, strepto, NCD, IB, Mareks, IBD, aspergillus. Mycoplasma synovia with vertical transmission1)

4. Genes (lethal genes)

Age-related:

0-7days: hygiene, trauma, vit def, toxins

7-14 days: malnutrition, infections

14-21: malposiiton, low O2, improper incubation

Metabolic growth disorders (CVS and MSS)

1. Sudden death syndrome (fast growing broilers, metabolic imbalance+arrhthmias -> healhy bird suddenly collapse and die)

2.Muscular dystrophy (Se+vit E -> perioxidative damage -> muscle degeneration -> weakness, no standing, sudden death if cardiac muscle)

3. Rickets

Infectious growth disorders

1. Malabsorption syndrome (multifactorial affecting intestinal absorption -> poor uneven growth, diarrhea, poor feathering (helicopter wings), undigested feed in droppings

Metabolic diseases of bone

1. Rickets (disorder of endochondral ossification in growing bones due to def. in Ca, P, Vit D3/incorrect Ca:P ratio -should be 1.2:1. Lack of sunlight. Renal/GI disorders. Enlarged joints and epiphyses, soft beak+claws, bone deformities)

2. Osteomalacia (adult rickets affecting bone remodelling -> fragile bones, fractures, spinal deformities, thin/soft eggshells)

3. Osteoporosis (reduction of total bone mass due to high Ca depamand during egg laying and low Ca + vitD3 intake + protein deficiency -> cage layer fatigue -> unable to stand, fragile bones, drop in egg prod., soft shelled eggs)

4. Cage layer fatigue (severe form of osteoporosis caused by demineralisation of bones to get Ca to egg production -> cortical bone thinning -> cage paralysis, fragile bones -> tibia and femur fractures, low feed intake)

Infectious diseases of bones

1. Osteopetrosis (Avian leukosis virus -> infect osteoblasts -> excessive bone formation -> bilateral symmetrical thickening of long bones, tibiotarsus and tarsometatarsus -> lameness, cant reach food/water, weakness, recumbency)

2. Osteomyelitis (staphylococcus aureus, streptococcus, E.coli, salmonella, M.synovia -> septicemia -> infection of epiphyseal region of bone -> lysis, necrosis -> caseous exudate -> sclerosis and deformity in chronic case. Lameness, swollen joints. Poor response to ATB)

3. Femoral head necrosis (FHS in fast growing broilers. Mechanical stress + rapid growth -> weakness at growth plate -> separation of GP from articular cartilage -> FHS -> bacterial infection by staph, strept, e.coli -> thrombosis of damaged vessels -> ischemia -> FHN. Severe lameness -> wings for support. ATB not recommended - will not fix the developmental disorder.

4. Avian tuberculosis (M.avium -> granulomas in liver, spleen and bone marrow -> chronic weight loss, lameness. Common in backyard chickens, not in farms)

Muscle disorders in poultry

1. Muscle atrophy (malnutrition, decreased BW, chronic systemic disease e.g. Marek´s -> decrease size and function of muscle -> muscle wasting)

2. Muscle dystrophy/nutritional myopathy (vitE+Se deficiency -> lipoperoxidation -> degeneration + calcification of muscle cells -> stiffness, inability to stand, acute heart failure and death)

3. Deep pectoral myopathy/green muscle disease (excessive wing flapping in heavy broilers/turkeys -> muscle overuse -> swelling of muscle inside tight fascia -> vascular compression -> ischemia, hypoxia, necrosis. PM: pale and swollen muscles, later becomes green with fibrous capsule)

4. Capture myopathy (rare, stress -> anaerobic glycolysis -> lactic acidosis + hyperthermia -> pale skeletal muscle on legs, sometimes cardiac muscle)

5. Toxic myopathy (ionophores overdose -> increase cation transport -> increase intracellular Ca -> distruption of ionic balance -> muscle cell death -> incoordination, diarrhea, dyspnoe, low feed intake. Increased toxicity with ATB!)

Diseases of the joints

1. Chondrodystrophy (genetic disorder of cartilage development -> skeletal malformation. Lethal chondrodystophy -> inherited -> shortened cartilaginous bones -> non-viable chicks if severe (Bones cannot support body -> lethal). Embryonal form -> skull deformities (brachycephaly, parrot beak)

2. Tibial dyschondroplasia (rapid growth in broilers, genes, vitD metabolism disorder, Ca:P imbalance, mycotoxins -> failure of chondrocyte maturation -> avascular cartilage plug in the growth plate of proximal tibiotarsus. Lameness, not moving, and fractures.

3. Perosis (slipped tendon. Mn + choline deficiency -> tendon slips from the condyle -> joint instability -> larger hock joint, tendon displacement, lameness)

4. Viral arthritis (Reovirus transmitted vertically+horizontally -> arthritis + tenosynovitis of gastocnemius tendon + possble rupture. cs: lameness, swollen hocks. Vaccinate breeders!)

5. Articular gout (high uric acid due to renal dysfunction, high protein diet, dehydration, vit A def. -> uric acid crystals deposits in the joints -> swelling and inflammation. T; alkalisation of water with sodium bicarbonate.)

6. Infectious synovitis (Mycoplasma synoviae -> respiratory -> systemic spread -> synovitis + tendinitis -> yellow exudate in joints, lameness, swollen hocks and footpads, recumbency -> breast blisters)

7. Leg deformities (valgus/varus, caused by rickets, chondrodystrophy, rapid growth. CS: lateral and medial deviation, lameness)

8. Spondylolisthesis (kinky back caused by rapid growth, development disorder with rotation of TV -> vertebral displacement -> spinal cord compression -> posterior paralysis, abnormal posture

9. Secondary bacterial arthritis (secondary to reovirus and mycoplasma with staph, e.coli, strept, Pasteurella)

10. Degenerative joint disease (older and heavy birds -> chronic lameness)

Diseases of the tendons

1. Slipped tendon (perosis. poultry under 6 weeks old. manganese deficuency -> deforming leg weakness -> flatted, enlarged hock joint -> displacement of achilles -> lateral deviation of leg + lameness.

2. Valgus/varus deformities (lateral deviation; valgus cowboy stance. Varus deviation; knock-knees) -> predispose to slipped tendon and fractures.

3. Crooked toe (deviation of phalanges -> toe curls inward due to weak tendons -> crab-like appearance)

4. Curled toe paralysis (riboflavin vit B2 def and poor flooring)

5. Infectious synovitis with tendon involvement (mycoplasma synovia infect joint and tendon sheats)

6. Viral arthritis (reovirus -> tenosynovitis and even rupture of gastrocnemius tendon, especially in broilers)

7. Tendon rupture (severe cases like reovirus may lead to rupture. birds are culled).

Infectious and non-infectious diseases of the central nervous system in poultry

Non-infectious

1. Encephalomalacia (crazy chick syndrome: deficiency of vit E+Se and rancid feed -> lipid peroxidation -> neuronal damage -> cerebellar edema, hemorrhages, liquefactive necrosis -> ataxia, falling, tremors, paralysis)

2. Thiamine (vit B1) deficiency (vit B1 def -> impaired carbohydrate metabolism -> decreased ATP in neurons -> cerebrocortical necrosis -> incoordination, opistotonus, paralysis, blue comb. T; vit B1 injection or in feed)

4. Aflatoxicosis (Aspergillus flavus -> aflatoxins -> depression, incoordination, paralysis. Affect intestinal lining -> less nutrients absorbed. Put adsorbants in food to absorb toxins and remove them or buy new food.)

5. Lead intoxication (Most important and frquent intoxication! Birds of prey eathing shot pigeon with bullet. -> opistotonus, CNS disturbances)

6. Botulism (intoxication by toxins from C.botulinum in decaying organic matter or in maggots -> neurotoxins blocking acetylcholine release -> flaccid paralysis, unable to walk or fly, limber neck/flaccid neck, drowning in waterfowl, mydriasis)

Infectious

1. Newcastle disease (paramyxovirus -> velogenic strain -> severe resp distress, tremors, paralysis, toricollis, high mortaility, drop in egg prod.)

2. West nile fever (West Nile virus transmitted by mosquito -> neutrotrophic -> encephalitis -> subclinical, or tremors, weakness, paralysis, convulsions, death)

3. Avian encephalomyelitis (vertical+ horizontal. Virus -> neuronal degeneration -> ataxia, tremors of head/neck, leg weakness, recumbency -> paralysis in youngs. Low egg production in adults. Vaccinate breeders!)

Infectious and non-infectious diseases of the peripheral nervous system

Non-infectious

1. Curled toe paralysis (vit B2 riboflavin deficiency -> degeneration of peripheral nerves, especially the sciatic nerve)

2. Vit B5 pantothenic acid deficiency (degeneration of peripheral nerves -> ataxia, goose stepping gait)

3. Organophosphate poisoning (inhibit acetylchlesterase -> overstimulation of PNS + CNS -> SLUD signs + tremors, paralysis. T; atropine

4. Botulism neurotoxins -> block neuromuscular transmission -> flaccid paralysis

5. Lead, mercury, arsenic (weakness, paralysis)

6. Trauma/neoplasia (compress peripheral nerves)

Infectious

1. Marek´s disease (Gallid alphaherpesvirus 2 -> infect lymphocytes -> tumors. Infiltrates peripheral nerves -> enlargement and dysfunction). Clinical forms of mareks

a) Classical (neurolymphomatosis): asymmetrical paralysis of legs and wings -> split leg posture, sciatic nerve enlargement, crop dilation due to n.vagus)

b) acute form: depression, paralysis, death

c) ocular form: grey iris, unequal pupils, death

d) cutaneous form: nodules at feather follicles

e) immunosuppresion: T-cell damage -> low immunity

f) atherosclerosis

2. Newcastle disease (mostly CNS but can cause paralysis of peripheral nerves)

Mycotoxicosis

= diseases caused by toxins produced by fungi growing in feed (grains). Not infectious, cause chronic production loss.

Mechanisms of action: oxidative stress and lipid peroxidation -> membrane damage and cell death -> inhibition of protein and DNA synthesis, and disruption of cellular metabolism

- systemic effects: immunosuppression, liver and kidney injury, hematopoietic damage, GIT disturbance, nervous signs -> reduced growth, poor feed efficiency, low egg prod., mortality.

1. Aflatoxicosis (Aspergillus, Penicillium -> targets liver -> immunosuppression and liver damage -> anorexia, ataxia, convulsion, opistotonus, death)

2. Fusariotoxicosis (Fusarium -> trichothecenes, fumonisin, zearalenone toxins -> GIT + immune system -> feed refusal, oral lesions, dermatitis, bone marrow suppression. Zearalenone -> estrogenic effect -> reproductive disorders -> low hatchability)

3. Ochratoxicosis (Aspergillus, Penicillium -> nephrotoxic -> poor growth, immunosuppression, hypothermia, low production)

4. Ergotism (claviceps spp. -> nervous system (convulsions), vascular system (vasoconstriction, gangrene), endrocrine disruption)

diagnosis: chromatography, lab tests to detect toxin (samples from feed, feeders and recently dead birds)

Aflatoxicosis, ochratoxicosis

AFLATOXICOSIS

- etiology: Aspergillus flavus, A.parasiticus growing in high moisture and temperature feed -> aflatoxin B1. Ducks, turkeys highly sensitive.

- primary target: liver -> inhibit protein synthesis, immunosuppresion, mutagenic, carcinogenic, teratogenic effects

- Acute case: hepatocellular necrosis and death

- Chronic: hepatomegaly, poor growth, immunosuppression

- CS: low feed intake, low growth, low production, poor hatchability, depression, hemorrhages, and in severe cases ataxia, convulsions and death

- Diagnosis: moldy feed, cs, necropsy: hepatomegaly, pale or fatty, necrosis, visceral hemorrhages. Chromatography.

OCHRATOXICOSIS

- etiology: Aspergillus ochraceus, Penicillium viridicatum -> ochratoxin A in corn, rice, peanuts

- primary target: kidney, also liver, immune system, bone marrow (chornic -> anemia)

- CS: low growth and egg prod., hypothermia, diarrhea, weakness, depression, death in severe case

- Diagnosis: necropsy shows enlarged pale kidneys

NB: unit for mycotoxins in feed: ppb (parts per billion)

Other mycotoxicoses (fusariotoxicosis, F2-toxicosis, T2-toxicosis)

FUSARIOTOXICOSIS

- Fusarium species produce several toxins (T-2, F2, fumonisin, moniliformin) which generally presents as feed refusal and poor growth.

1. F2-toxicosis (Zearalenone)

Estrogenic mycotoxin -> hyperestrogenism -> reproductive disorders, oviduct enlargement, decreased egg production, infertility, poor egg shell quality

2. T2-toxicosis (Trichothecenes)

Strong cytotoxic and immunosuppressive effect -> feed refusal, oral necrosis and ulceration, dermatitis, intetinal irritation -> diarrhea, low egg production, immunosuppression (bone marrow damage), mottle liver, atrophy of spleen and lymphoid organs, visceral hemorrhages

3. Fumonisins

- poor feed conversion. no clear lesions in poultry. high doses -> tibial dyschondroplasia in turkeys

4. Moniliformin

- cardiotoxic and nephrotoxic

- feed refusal, oral lesions, poor growth, immunosuppression, low production, sudden death in severe cases

other mycotoxicosis:

1. Ergotism (claviceps spp.): vascoconstriction -> ischemia -> necrosis of extremities (toe gangrene), neuro and endocrine effects, cyanosis of comb/wattles + lameness. vesicles on legs and toes.

2. Rubratoxicosis (Penicillium spp. rare. -> hemorrhagic syndrome, liver damage, neurosigns.

Intoxications caused by drugs

Drug toxicosis caused by overdose, wrong route of administration, prolonged use, drug combination interactions and species sensitivity differences.

1. IONOPHORE toxicity (monensin, salinomycin, narasin) Prevention and treatment of coccidiosis. Narrow range of safety -> intoxications. Disrupt ion transport -> increase intracellular Ca -> muscle degeneration + cell death. CS is weakness, ataxia, dyspnoe, diarrhea, decreased feed intake.

Monensin (backward leg paralysis), Salinomycin (paralysis, low egg production), Narasin (flaccid paralyisis of wings and legs). TURKEYS -> salinomycin and narasin TOXIC. Toxicity increases with ATB (Tiamulin and Erythromycin due to interfering with its metabolism)

2. Sulfonamide toxicity (hot weather -> increased water intake -> overdose -> folate metabolism inhibition, bone marrow suppression -> anemia, hemorrhages on legs, pectorals, in abdominal organs, pale bone marrow, poor clotting. T; Vit K)

3. Nitrofurans (neurotoxicity, convulsions. Banned in many countries)

4. Hypervitaminosis A (eye lesions -> crusts, edema, blindness)

5. General toxic substances in high doses: Se, NaCl and CuSO4.

Differential diagnosis: NCD, Mareks, mycotoxicosis, nutritonal defi., heavy metal poisoning.

Intoxications caused by chemical compounds and toxic gases

1. Anticoagulant rodenticides (inhibit vit K -> decrease synthesis of clotting factors -> coagulopathy and hemorrhages -> sudden weakness, pale comb and mm, dyspnoe, bloody droppings, sudden death. T; vit K)

2. Organophosphates pesticide (inhibit acetylcholinesterase -> SLUD + tremors, seizures, paralysis, death. T; atropine)

3. Lead intoxication (contaminated environment, paint, batteries -> inhibit enzymes -> gametotoxic, teratogenic, neurotoxic and nephrotoxic -> green droppings, ataxia, paralysis)

4. Mercury intoxication (from disinfectants and fungicides -> ulceration of MM of the oral cavity and GIT -> visceral hemorrhages, incoordination, diarrhea)

5. Ammonia gas (decomposition in uric acid in litter + poor ventilation -> respiratory tract irritation -> keratoconjunctivitis, corneal ulcers, blindness)

6. Zinc (cage wire ingestion -> neuro signs, green droppings. T; CaEDTA)

7. Nitrates/nitrites (from fertilizers -> methemoglobinemia -> cyanosis, hypoxia)

8. Copper sulfate -> catharal enteritis

9. NaCl excess -> neuro signs, edema, seizures

10. Carbon monoxide (-> carboxyHb -> block O2 transport -> hypoxia -> sudden death, cyanosis, weakness. PM: bright pink/red tissues)

Metabolic and mycotic diseases in pigeons

Metabolic diseases

1. Fatty liver (high energy intake + low activity in cage birds -> obesity -> fatty liver -> liver dysfunction and hemorrhage risk. PM shows enlagred friable yellow liver. T; vit E + choline)

2. Gout (multifactorial: high protein, kidney disease/failure, vit A deficiency, dehydration -> uric acid levels increase and deposit in organs and joints -> weakness, anorexia, joint swelling. T; sodium bicarbonate in water, allopurinol)

3. Rickets (soft, bowed bones)

4. Vit A deficiency (eye lesions, blindness, poor growth)

Mycotic diseases

1. Candidiasis (white plaques in crop and GIT -> mild signs in adults with weight loss, lethargy, dull plumage, and in youngs anorexia, crop stasis, regurgitation, weight loss)

2. Aspergillosis (A.fumgatus -> air sac and lung granulomas -> dyspnoe, high mortaility in youngs. Inhalation of spores froom contaminated litter or feed. Acute case -> high morbidity and mortaility, gasping, anorexia, convulsions, death. Chronic -> gasping, loss of BW, dyspnoe, tail bobbing, excercise intolerance)

Parasitic diseases of the feathers and skin in pigeons

Lice

1. Columbicola columbae (host-specific lice located on the underside of feathers on upper wing feathers, feeding on keratin, NOT blood -> minimal signs, mild feather damage. T; pyrethrins

Mites

1. Dermanyssus gallinae (red mite, most common mite in pigeons, blood-sucking nocturnal feeder, leave host during the day. Feather picking, pruritus, anemia. T; pyrethroids

2. Knemidocoptes spp. (burrowing mites; K.gallinae-> depluming itch, K.mutans -> scaly leg, K.pilae -> scale face/beak. Burrow into feather shafts and skin -> severe pruritus, pain -> self-trauma, reduced feed intake, weight loss. Diagnosed by skin scraping. T; ivermectin + repeat after 7-10 days.

Fleas

1. Ceratophyllus columbae (common in feral pigeons "norsk: bydue", blood-feeding -> irritation, stress, anemia if many. T; ivermectin + environmental control).

Others

1. Bed bug Cimex lectularis (blood sucking, primarily on humans, but also pigeons, poultry, and mammals -> irritation, anemia, swelling and itching at bite site. Loft infestations can be heavy. T; pyrethroids + again after 7-10 days)

2. Ixodes ticks (-> anemia, vector for borrelia)

3. Pseudolynchia canariensis (louse fly, vector for Hemoproteus columbae -> anemia, weakness)

4. Harpyrhynchus (feather base -> hyperkeratotic epithelial cysts)

5. Cheyletiella (rare in pigeons -> burrowing mange -> dermatitis and secondary fungal infection)

Protozoan diseases in pigeons

1. Trichomoniasis ("Canker", Trichomonas gallinae -> transmitted directly when mother feeds their young -> small white/yellow lesions in oral cavity, pharynx, esophagus, crop, proventriculus -> progress to ulceration and inflammation forming large masses -> obstruction. Can spread to liver and organs -> death in 8-10 days. Wet mount microscopy. T; metronidazole, control carriers)

2. Coccidiosis (Eimeria columbanum, E.labbeana -> catarrhal enteritis with mucoid and bloody diarrhea, ruffled feathers, hunched posture, weight loss, if severe, also paralysis and death. T; sulphonamides. P: toltrazuril, ionophores, hygiene)

3. Toxoplasma gondii (birds IH, cats FH. Cell necrosis, cyst formation in organs, inflammatory lesions -> anorexia, conjunctuvitis, neuro signs. Avoid contact with cat feces. Histopathology and PCR to diagnose.

In blood:

4. Hemoproteus columbae (-> avian malaria. D: blood smear giemsa stain. T; sulphonamides., not effective. Vector: Pseudolynchia canariensis (pigeon lice fly) carries the protozoa)

5. Leukocytozoon spp (Vector: blackflies Simuliidae. Liver invasion -> cell destruction -> anemia, leukocytosis, diarrhea, CNS signs, emaciation, death in 7-10 days or survive with organ damage. D: blood smear giemsa)

Helminthoses in pigeons

Cestodes (tapeworms)

1. Hymenolepis columbae (IH: earthworm, snails, insects, usually asymptomatic, but heavy infections -> decreased performance and diarrhea. D: Necropsy -> worms. T; praziquantel, flubendazole)

2. Davainea proglottina (very small, IH is molluscs, scolex penetrates deep in duodenal villi -> necrosis, hemorrhagic inflammation. Heavy infections can lead to death)

3. Raillietina tetragona -> enteritis

Nematodes

1. Syngamus trachea (adult worms (Y-shape) in trachea -> irritation -> mucus production -> airway obstruction -> coughing, sneezing, dyspnoe, gasping, open-mouth breathing, head shaking, anorexia. D: fecal flotation. T; flubendazole.

2. Ascaridiae columbae (intestinal damage -> hemorrhagic enteritis -> decreased feed intake, weight loss, poor growth)

3. Capillaria spp. (C.caudinflata, C.obsignata -> inflamamtion and thickekning og GIT, severe thickening and catarrhal enteritis in heavy infections -> anorexia, drooping wings, ruffled feathers, anemia, diarrhea, mortaility)

Trematode

1. Echinostoma revolutum -> hemorrhagic enteritis

Bacterial diseases in pigeons

1. Chlamydia psittaci (PARROT FEVER. infect sinuses, conjunctiva, trachea, possble spread to liver and spleen. Asymptomatic carriers or severe -> ocular + nasal discharge, anorexia, dyspne, dehydration, diarrhea, biliverdinuria -> green urates. D: PCR, serology, X-ray -> hepatomegaly, splenomegaly, airsacculitis. T; doxycycline (reduce Ca if given orally)

2. Mycoplasma avium, M.columbinum (colonise URT early in life -> immunosuppression-> sec.infections common. Fatigue, panting, rhinits, tracheitis, sinusitis. T; ATP, vaccination

3. Mycobacterium avium (intestinal granulomas, weight loss. D: necropsy, acid-fast staining, PCR. T; culling)

4. Fowl cholera (pasteurella multocida, peracute -> sudden death. Acute -> fever, anorexia, resp.signs, diarrhea, cyanosis, death. Chronic -> joint swelling, tendonitis, wattle/footpad swelling, resp.disease.. T; sulfonamides, ATB. vaccination)

5. Salmonellosis (joints and organs -> arthritis common in pigeons -> lameness, diarrhea, torticollis. P: vaccine)

7. Clostidiosis (clostridial necrotic enteritis -> sudden death, diarrhea. T; penicillin)

7. Avian spirochetosis (Borrelia, vector borne: Argas ticks. Fever, sudden death, green/yellow feces. D: giemsa blood smear. T; tetracyclines.

8. Avian colibacillosis (E.coli -> septicaemia, enteritis, toxemia -> diarrhea, dehydration. T; ATB)

Viral diseases in pigeons

1. Avian pox (avipoxvirus, cutaneous form with nodules on unfeathered skin like eyelids, beack, legs, and diptheric form with caseous plaques on mouth, pharynx, larynx, trachea, interferes with feeding and respiration. Mixed form. Vaccinate with attenuated vaccine in wing web)

2. Newcastle disease (paramyxovirus. same as in poultry with neurological, respiratory and high mortaility)

3. Avian influenza (orthomyxovirus, same as poultry with systemic hemorrhagic disease. more common in poultry)

4. Pigeon herpesvirus (transmitted during feeding -> replicates in oropharynx -> viremia -> depression, anorexia, conjunctivitis, oral and pharyngeal ulcers, dyspnoe, diarrhea)

5. Inclusion body hepatitis (adenovirus -> liver necrosis -> pale swollen friable liver -> sudden death is most typical, depression shortly before death, pale comb/wattles, sometimes icterus. Necropsy and histopathology showing inclusion bodies. No treatment or vaccine.

6. Pigeon circovirus (destory lymphoid tissue -> immunosuppression and feather abnormalities -> chronic wasting and secondary infections. No treatment).

The tasks of the field practitioner in the poultry farming

1. Preparation of poultry house before arrival

a) cleaning and disinfection: mechanical cleaning and chemical disinfection to remove the mealworms. Control by bacterial swabs.

b) deep litter management: disinfect deep litter using an aerosolator with Virkson S. Bedding can be hay, special pellets, or wood shavings.

c) environment: temp 30C, RH 50%,

2. Arrival of chicks

- take random samples from a few chicks to confirm health status, including checking antibody titers

- during the first days: add probiotics and plant extracts to increase appetite and water intake

3. Feed control

- check composition of food (if it adheres to recommended dietary levels)

- check for presence of mycotoxins

- coccidiostatic drugs can be added to control parasites

4. Vaccination progam

a) Infectious bursal disease: take blood and evaluate maternal Ab titers (last up to 3 weeks). Vaccination timing based on the Ab levels.

b) Infectious bronchitis: Vaccinate in hatcheries, often combined with NCD and revaccinate at 2-3 weeks of age.

5. Regular veterinary visits and monitoring

- first 3 weeks: vet should visit farm 2x per week to collect carcasses and check protocols/records.

- Daily mortality rate max 3%.

- signs of disease is change in feed intake and change in weight (malabsorption or disease).

- peform necropsy in dead chickens

- take samples of sick animals and treat

6. Salmonella monitoring

- salmonella sampling is performed 3 weeks before birds leave

- shoe cover sampling system: vet walks through the halls with shoe covers and fecal samples are collected from the show covers.

- S.pullorum, S.gallinarum, S.copenhagen

7. Blood sampling (ulnar vein/wing vein, medial metatarsal vein or right jugular vein. hematoma common. thin skin - do not press.

8. Common health problems in broilers: locomotor, resp, E.coli infection

Welfare and its influence on health status and productivity of poultry

1. General concept of welfare

- all birds should be inspected twice daily to ensure housing conditions are good and welfare requirements are met

- preventative health work: good infection control and good hygiene routines -> good animal welfare

2. Five freedoms of animal welfare

I. Freedom from hunger and thirst: ready access to fresh water, appropriate diet to prevent nutrional deficiencies, reduced productivity and disease susceptibilty

II. Freedom from discomfort: appropriate housing environment, shelter and resting areas

III. Freedom from pain, injury and disease: prevention of diseases, rapid diagnosis and treatment. Prevention better than treatment!!

- Enriched cages: high welfare in terms of mortaility and health because of good hygiene, feces fall onto belt system, lower infection pressure

-Broiler systems: all-in-all-out system to reduce infection pressure

IV. Freedom to express normal behavior: sufficinet spaces proper facilities, same species, stocking density is max 39kg/m2 or 42kg/m2.

- poor stocking densities -> heat stress (->possible death), changes in temp, RH, ammonia levels, pathogen load. Increased RH -> microbial survival and increased transmission

- Temp: 35C in youngs, 25C in adults

- RH: 60-65% (ventilation to prevent ammonia and fungi)

- Light imortant for egg prod, growth, mortality, feed intake, behavior (blue is calming, red reduce cannibalism, blue/green for growth, organs/red for repro.

- Enriched cages: must have nest, sand bath, perch, and limited group size maintains the stable hyerarchy

- Free-range system: more natural behavior, but higher infection

V. Freedom from fear and distress: proper handling, environmental condition, minimize stress, humane treatment practices