QUESTION 6
(a) State three changes that take place after chopped forage has been compressed and covered in silage preparation. [3 marks]
(b) Give two reasons each for carrying out each of the following practices in pasture
management:
(i) weeding;
(ii) controlled burning;
(iii) irrigation;
(iv) fertilizer application;
(v) liming. [10 marks]
(c) State two functions of phosphorus in animal nutrition. [2 marks]
(d) Complete the table below by ticking (√) the appropriate column to indicate
the effect of low temperature on farm animals.
|
Parameter |
Increase |
Decrease |
Normal |
(i) |
Water intake |
|
|
|
(ii) |
Grazing time |
|
|
|
(iii) |
Milk yield |
|
|
|
(iv) |
Feed intake |
|
|
|
(v) |
Egg production |
|
|
|
[5 marks]
Observation
Question 6 was the least popular question in this paper and many candidates avoided it.
(a) Although many candidates who attempted this question had correct ideas on silage preparation and the fermentation process, they displayed lack of knowledge on the changes expected during silage preparation.
(b) Only few candidates were able to give reasons for carrying out the management
practices in Question 6(b).
(c) Most candidates seem not to understand the demands of Question 6(d) as some of them ticked two columns in a single row (parameter).
The expected answers include:
(a) Changes that take place after chopped forage has been compressed and covered
in silage preparation
- Oxygen is used up
- Carbon dioxide is increased
- Rise in temperature of ensiled mass
- Bacterial ferment carbohydrate to produce lactic acid
- Fruity smell⁄ alcoholic smell/esters produced
- pH is lowered
- Breakdown of fibre due to fermentation
- Gradual compression of ensiling material occurs⁄ reduction in bulkiness
- Colour changes to olive green
(b) Reasons for carrying out various practices in pasture management
(i) Weeding
- Reduces competition for air, water, nutrients and space
- For better growth of herbage/good yield
- Get rid of pests
- Get rid of diseases
- Removes poisonous plants⁄ obnoxious weeds
- Minimizes incidence of predators
- Enhances free movement
(ii) Controlled burning
- Kills eggs, larvae of parasites/kills parasites
- Destroys old herbage
- Promotes new growth of pasture grass
- Controls weed
- Controls vermin
- Control diseases
- Increase mineral content of soil
- Reduce soil acidity
- Control pests
- Eliminate predators
(iii) Irrigation
- Maintains good growth of herbage
- For good yield
- For all year-round production of pasture
- Availability of quality pasture
- Reduces dustiness
- Fertilizer application
- For good growth of herbage
- For high carrying capacity
- For higher yield
- For increased nutrient of pasture
- Neutralizes alkalinity
- Organic fertilizers improves soil structure
- Liming
- Neutralizes soil acidity/increases soil pH
- Improves soil structure
- Destroys the eggs of liver fluke
- Increases soil nutrient e.g. CaCO3
(c) Functions of phosphorus in animal nutrition
- For bone formation
- For teeth formation
- For egg shell formation
- For acid-base balance
- For metabolism of fats and carbohydrate
- For milk production
- Precursor for protein synthesis
(d) Parameters of farm animals when temperature is low
|
Parameter |
Increase |
Decrease |
Normal |
(i) |
Water intake |
|
√ |
|
(ii) |
Grazing time |
√ |
|
|
(iii) |
Milk yield |
√ |
|
|
(iv) |
Feed intake |
√ |
|
|
(v) |
Egg production |
|
|
√ |