BVSc V Poultry Examination 10 June 2004
Question 1/ Vraag 1
a) What is the difference between minimum ventilation and summer
ventilation? (4)
Minimum ventilation : supply oxygen, remove waste gases viz. CO2,
H2O, dust, ammonia.
Summer ventilation : effects of minimum ventilation plus airflow to allow
cooling.
b) With the aid of annotated sketch diagrammes explain two different
ventilation systems that can be used in mechanically ventilated poultry
houses. (4) (1/2 x 8)
see drawings in notes
Question 2/ Vraag 2
What negative effects does an increase in stocking density have on broilers?
In view of these disadvantages, why do farmers still tend to overstock their
chicken houses? (6) (4+2)
Decreased growth
Worse FCR (higher FCR)
Higher condemnations at slaughter
Increased general stress and disease problems
Increased meat yield per square meter
Capital outlay determined by size of structure
Question 3/ Vraag 3
Cobb South Africa imports broiler great-grandparent (GGP) stock from the
USA as the basis for their South African breeding programme.
a) Cobb’s main breeding farms for GGP and GP flocks are near Carolina in a
remote part of the eastern Highveld. What is the main advantage of this
location for this nature of breeding operation? (2)
b) Rainbow Farms, the main client of Cobb SA, has broiler operations around
Rustenburg, about 100km west of Pretoria. What are the advantages of this
location for broiler farming? (2)
c) What major physiological problem is associated with broiler farming on the
Highveld? Why?
(3)
a) Remote from other chickens - > better biosecurity NB @ GGP
level
b) - close to big Gauteng market -> less transport costs
- close to maize growing areas -> less feed costs
c) broiler ascites syndrome high altitude -> low O2 ->predisposes
marks were also given for respiratory problems associated with cold
and dry winters
Question 4/ Vraag 4
With reference to broiler breeder management, please answer the following
questions.
a) At what age is de-beaking usually done? (1)
b) How is the growth rate of the birds controlled during rearing? (2)
c) What biosecurity measures should be applied on broiler breeder rearing
sites? (3)
d) Why is separate sex feeding applied when broiler breeders are in
production? (3)
a) 7-21 days
b) feed restriction based on weekly weights, feed composition
c) limit access, showers, change clothes, vehicle control
d) control relative growth rates, calcium levels, egg production,
competition between sexes
Question 5/ Vraag 5
Broilers:
a) What behaviour in young chicks would indicate that they are too hot?
(2)
b) Aspergillosis is a common problem in newly hatched chicks. Where is
the original source of this infection? What can be done to control the
infection at this point in the production cycle? (3)
c) Describe different types of drinkers used for broilers and explain their
correct use.
(6)
a) move away from heat source, pant & spread wings
b) litter in nestboxes, nestbox management, prillsetc.
c) fonts
young chicks, 1:100 chicks
bell
1:100, at height of back, clean &check H2O level
nipples
1:12-15, adj height to 60 degrees
troughs
not commonly used.
Question 6/ Vraag 6
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
Haemorrhages in proventriculus
Haemorrhages in bursa
Oedematous swollen bursa
Nephrosis
Congested carcass
Question 7/Vraag 7
Newcastle Disease.
a. Name the aetiological agent. (1)
b. Name the 3 organ systems affected by Newcastle disease. (3)
c. Describe the clinical picture in a flock of unvaccinated broilers
affected by velogenic Newcastle disease. (4)
d. Give the full name of a test used to differentiate the
pathogenicity of different types of Newcastle disease virus. (1)
e. Describe a typical vaccination programme against Newcastle
disease in broilers. (4)
a) Paramyxovirus
b) GIT, respiratory, nervous
c) >75% mortality, nervous signs, green diarrhoea, respiratory
signs incl haem tracheitis.
d) MDT or ICPI (in full)
e) Live vaccines at day old, boost between 10 and 21 days,
second booster
Question 8/Vraag 8
You are in practice near Kyalami, it is late in the summer and one of your very
important horse owners phones to tell you that her daughter’s bantams
recently hatched a clutch of eggs. The chicks did fine for the first few weeks
but have now developed “lumpy wart-like things” all over their faces and are
not doing at all well, in fact three of the chicks have already died and she is
worried the four survivors will soon die too.
a) Give the most likely viral aetiology for this problem. (1)
b) Which test can be used to confirm the diagnosis of this disease and what
will be observed? (3)
c) How would you advise control of the disease under the circumstances? (3)
d) How is this disease controlled in commercial poultry operations – please
give the control measure and its application. (3)
a) fowl pox
b) histopathology; intracytoplasmic inclusions (Bollinger bodies)
c) antibiotics, mosquito control, supportive care, consider vaccination
d) live vaccinationat 4-9 weeks, wing- web stab
Question 9/ Vraag 9
a) List three diseases caused by haemagglutinating viruses in chickens. (3)
b) Name the virus responsible for each of these diseases. (3)
c) Without going into the actual nature of how the test works; explain how the
haemagglutination inhibition test can be used to assist a veterinarian to make
a diagnosis in a disease outbreak in chickens. (3)
a) ND, AI, EDS
b) paramyxovirus, orthomyxovirus, adenovirus
c) test for antibodies in serum/blood, paired samples, increased titre
(this was very badly answered!)
some marks also given for HI use in virus isolation,but not for use of HA
Question 10/ Vraag 10
a) Name two moderately and two highly pathogenic coccidia species in
chickens and give their location in the gut. (4) (1/2 x 8)
b) You carry out a chicken post mortem at your veterinary practice. What
simple diagnostic test can you use to confirm a diagnosis of coccidiosis? How
would you use this test to differentiate coccidiosis from necrotic enteritis? (3)
c) What drugs would you use to treat an acute outbreak of coccidiossis and
what route of administration would you use? (2)
d) Give an example of a coccidiostat rotation programme used in the
prevention of coccidiosis. (5)
a) moderately: E. acervulina, E. maxima
highly: E. tenella, E. necatrix
b) wet scraping of gut, oocysts vs.gram positive rods
c) sulphonamides or diclazuril in water
d) see attached hand out as an example
Question 11/ Vraag 11
Fowl typhoid.
a) Name the causative agent. (1)
b) What age of birds are affected? (2)
c) Describe the characteristic post mortem lesions. (4)
a) Salmonella gallinarum
b) older birds, usually in lay
c) Bronze coloured , enlarged liver, splenomegally, grey coloured lungs,
catarrhal enteritis, anaemia,septicaemic carcass.
Question 12/ Vraag 12
Infectious coryza.
a) Name the causative agent. (1)
b) Give the growth requirements for the bacteria to be isolated in the
laboratory. (5)
c) Give your first choice drug for treatment in an outbreak. (1)
a) Haemophilus paragallinarum
b) Microaerobic and
high humidity,
1% chicken serum x-factor,
NAD (V) factor dependant or independent,
satellitism
c) Sulphonamides/Quinolones
Question 13/Vraag 13
Discuss the control of Mycoplasma gallisepticum in a broiler breeder flock
under the following headings: biosecurity, disease monitoring, treatment & its
aims and vaccination. (11)
Biosecurity: purchase MG free chicks
general access control to farm
Serology: ELISA/plate tests regular intervals
confirmation by PCR or culture
Treatment: slaughter (possibly)
treat chronically with acutely in water with quinolone, then
in-feed with macrolide or tetracycline
Aim of Rx: avoid egg prod. drop, avoid vertical transmission
Vaccination: live TS11, dead bacterin