Question 5
(a) A farmer observed twisting of neck and head as well as paralysis of the legs among the chickens on a poultry farm.
(i) Name the disease that the chickens are most likely infected with. (1 mark)
(ii) What is the causative organism of the disease named in 5(a)(i)? (1 mark)
(iii) State three factors that could predispose chickens to the disease named in 5(a)(i).
(3 marks)
(iv) Mention three ways of preventing an outbreak of the disease named in 5(a)(i)on a poultry farm. (3 marks)
(b) State three functions each of the following organs in farm animals:
(i) liver;
(ii) kidney. (6 marks)
(c) Mention four effects of high wind velocity on growing crops. (4 marks)
(a) Although many candidates could not state the disease associated with the observed
symptoms (Newcastle disease) but were mentioning Gumboro and fowl pox, they were able
to identify viruses as the causative organism of the disease.
(b) Most candidates were able to state the functions of the kidney and liver in farm animals but
faltered in mentioning the effects of high wind velocity on growing crops.
Observation
The expected answers include:
(a) (i) Name of disease the chickens are most likely infected with
- Newcastle disease
(ii) Causative organism of Newcastle disease
- Virus
(iii) Factors that could predispose chickens to Newcastle disease
- Age of the birds - Poor nutrition
- Overcrowding/poor housing - Poor sanitation
- Unfavourable weather/ High temperature - Health status of the birds
- Low body resistance/low immunity
(iv) Ways of preventing an outbreak of Newcastle disease on a poultry farm
- Good feeding - Regular vaccination
- Proper stocking - Good housing
- Good sanitation/good hygienic conditions/disinfecting poultry pens
- Interval stocking/ Resting poultry house before restocking
(b) Functions of organs in farm animals
(i) Liver
- Deamination of proteins
- Storage of iron for the manufacture of red blood cells
- Regulation of blood sugar
- Regulation of body temperature
- Fat metabolism
- Detoxification of poisonous substances
- Manufacture of plasma proteins
- Storage of vitamins and glucose
- Production of bile
- Conversion of excess glucose to glycogen
(ii) Kidney
- Excretion of wastes
- Detoxification of poisonous substances
- Removal of excess glucose
- Maintenance of acid/base balance
- Osmoregulation
- Conservation of useful substances
- Regulation of salt concentration
(c) Effects of high wind velocity on growing crops
- Aids in seed and fruit dispersal
- Aids in spread of diseases
- Causes lodging of plants
- Affects evapo-transpiration
- Causes premature shedding of fruits
- May cause wind erosion
- Aids in pollination