Observation

Question 5 (a) was not popular among candidates and responses were poor. Candidates misconstrued the question by relating it to effects of temperature, light and relative humidity on crop production. Thus, they were writing ‘it aids germination of seeds’, ‘it assists in photosynthesis’ etc.

The expected answers include:

5. (a)    Effects of changes in climatic factors on egg production

• Temperature

High temperature

• Causes reduction in feed intake, leading to low egg production
• Reduces spermatogenesis and libido in males thereby reducing production of fertilized egg
• Causes heat stress, thus reducing egg production
• May result in death of birds, particularly chicks and layers
• Increases water intake and reduces water intake in cold weather
• Is necessary for incubation of eggs
• Leads to decrease in feed efficiency, leading to low egg production
• Reduces the shelf life of eggs/storage of eggs
• Reduces hatchability of eggs
• Extremely high or low temperature can reduce egg production

• Relative humidity
• Very important during incubation of eggs
• High humidity compounds heat stress
• Low humidity induces rapid water loss from the birds’ body and thus increases their water intake
• High humidity encourages the spread of diseases thereby reducing egg production
• High humidity cause feed to go mouldy (rancid)

• Light
• Controls egg laying in hens
• Duration of lighting controls time spent at feeding which regulates growth and rate of feathering
• Direct light of high intensity causes stress to the eyes
• Bright light makes birds active
• Light makes object visible                

(b)        Benefits that can be derived by the farmer using the deep litter system of rearing Chickens

• Increases efficiency in chicken management
• Maximizes the use of land
• Increases poultry production
• Reduces loss of eggs to predators/thieves
• Protects the chickens from harsh weather conditions
• Maximizes the use of labour
• Makes identification of sick chickens easier
• Makes drug administration to the chickens easier
• Increases the farmers’ profit
• Promotes the rate of growth of birds
• Makes the management of large flock possible

            (c)        Uses of sugarcane

• Production of molasses
• Manufacture of sugar
• Manufacture of ethanol, acetone, citric acid, glycerol
• Wastes are used as animal feed
• Production of bagasse for biofuel
• Used as substrate for the production of brewers and baker’s yeast
• Used in pharmaceutical industry
• For human consumption
• Wastes can be used for mulching