BVMCh V Semester Test (Supplementary) 24.08.01 (Memorandum)
2. Discuss the role of lighting programs in the management of commercial
laying hens from day old to death.
(10)
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0-7 days – 23 hours good intensity (25 lux), to find feed (1.5)
Rearing 1-18 w – about 8-10 hours, low intensity about 10 lux at
bird level (1.5)
Early lay 19-30 weeks increase by ½ hour per week to 16 hours
(1.5)
Late lay maintain to cull at 65 –75 weeks. (1)
Rapid increase in light intensity and photoperiod is used with
correct body weight to stimulate onset of lay at around 20 weeks.
NB birds come into production together and not too early to
ensure good peaks and limit weight loss in lay. (3)
Used to increase overall production (0.5)
Lowered light intensity reduces incidence of vices such as
cannibalism (0.5)
Never increase light duration during rearing, never decrease light
duration during lay (2)
Comments on stimulation of the pineal gland by light. (0.5)
2. Define minimum ventilation.
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(3)
The minimum ventilation required to maintain birds at full
production potential by ensuring an adequate supply of oxygen
and removing waste gases such as CO2, ammonia and excess
dust and water vapour.
3. Discuss omphalitis in broiler chicks under the following headings :
causative organisms, source of infection, post mortem findings and
treatment.
(10)
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Cause : bacterial – E.coli, Pseudomonas general
Source – egg or unhealed navels
PM – distended abdomen with inflamed and vascularised yolk sac,
congestion and peritonitis, inflamed navel
Rx – none advised, control by hatchery and farm hygiene
4. List five viruses that are vertically transmitted through the egg in chickens.
(5)
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EDS, AE, leucosis/sarcoma group, reovirus, avian influenza, CAV,
reticuloendotheliosis virus
5. List the most important post mortem lesions you would expect to find in
broilers infected by virulent Infectious Bursal Disease.
(6)
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Haemorrhages in muscles
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Haemorrhages in proventriculus
Haemorrhages in bursa
Oedematous swollen bursa
Nephrosis
Congested carcass
6. How would you confirm a suspected diagnosis of Newcastle disease?
(2)
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Virus isolation (in eggs)
7. Name the main method of control of EDS 76 in commercial layer flocks.
(1)
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Oil vaccination
8. Name the viral diseases which are specifically associated with a decrease
in egg quality and egg shell abnormalities.
(3)
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EDS, IB, ND
9. Discuss Infectious Bronchitis briefly under the following headings:
etiology, transmission, symptoms, treatment and prevention. (14)
Aetiology:
 Coronavirus
Transmission:
 Droplet,
 Not egg transmitted
Symptoms:
 Layers: mild respiratory
 Severe drop in egg production
 Egg shell changes
 High % culls with oophoritis
 Young chicks and broilers: respiratory infections
 Reduced appetite
 Poor growth
Prevention and treatment:
 Treat secondary E coli
 Evaluate and rectify management
 Vaccines: live attenuated – H120
 Inactivated
10.Which Salmonella is responsible for Fowl Typhoid?
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Salmonella gallinarum
(14)
(1)
11. Which organisms are most likely to be involved in “Chronic Respiratory
Disease”?
(2)
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MG and E. coli
12. Is Coryza (Haemophilus paragallinarum) an upper or lower respiratory
tract infection? Where should samples/swabs be taken from for bacterial
culture?
(2)
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Upper respiratory
Infraorbital sinuses
13. What advice would you give to a broiler producer experiencing high
mortalities due to ascites, to prevent the condition in future flocks? (7)
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Associated with rapid growth – slow growth by:
o reducing feed intake by reducing lighting, especially in 2nd
and 3rd week of life
o changing from pellets to mash feeding.
Associated with respiratory disease – check management esp.
ventilation and ammonia levels also resp. pathogens
Associated with altitude – aware certain incidence on Highveld is
normal
Males more susceptible due to rapid growth – difficult to solve.
14.Name two treatments (active ingredients) for roundworms in chickens: (2)
Levamisole
Piperazine
Fenbendazole
Ivermectin
Hygromycin B
15. How would one confirm a diagnosis of Aspergillosis: (3)
Culture - on Saborauds dextrose agar
Microscopy – using material = 10% KOH and heat – visualise
hyphae
Histopathology – hyphae seen
16. a) Indicate which of the 4 most important coccidia are medium pathogenic
species and which are high pathogenic species. (4)
Medium pathogenic:
E. acervulina and E. maxima
High pathogenic:
E. tenella, E. necatrix
b) Compare the clinical symptoms seen in medium pathogenic species
and high pathogenic species. (6)
Medium pathogenic:
Diarhhoea (mucoid)
Poor Growth
Poor FCR
High pathogenic:
Listless, ruffled, huddle together
Dysentry (haemorrhagic diarrhoea)
Mortality
17. Name the fat-soluble vitamins and list 1 of the most important deficiency
symptoms/ post mortem signs/ syndromes of each in chickens (4):
Vit A:
White faeces due to excessive urate formation, nephrosis
and renal failure (before skin esions) erosions in mouth and
tongue, hyperkeratosis of cornea, oesophagus, eyelids,
hyperkeratosis with secondary infection in respiratory
system, GIT and ureters, poor appetite and growth, usually
4- 8 weeks.
Vitamin D3:
Rickets, osteomalacia, fractures, soft shelled eggs, cracked
eggs,
Vit E:
Crazy Chick disease –encephalomalacia, Exudative
diathesis, early embryonic mortality, Nutritional muscular
dystrophy
Vit K:
Widespread haemorrhage
18. There are 3 main manure management systems in caged layer hen units.
Describe each briefly and indicate how frequently the manure is removed in
each of the systems. (6)
1. Manure accumulates under cages and is removed once per
week.
2. Manure accumulates on conveyor belts under cages and is
removed daily from the house.
3. Deep manure system (hi-rise) – manure removed when the
flock is culled.