Agriculture Paper 2, WASSCE (PC), 2022

Question 5

 

(a)        State two roles each of the following hormones in animal reproduction:
(i)         oestrogen;
(ii)        testosterone;
(iii)       oxytocin;
(iv)       progesterone.                                                                                  (8 marks)


(b)        A poultry farmer bought 1,000 point-of-lay pullets for egg production.
(i)         Recommend the most suitable intensive management system for easy collection
of eggs.                                                                                                         (1 mark)
(ii)        State:
I.    three advantages of the management system recommended in 5(b)(i);       
                                                                                                                                            (3 marks)
II.   three disadvantages of the management system recommended in 5(b)(i).       
                                                                                                                                            (3 marks)


(c)        Mention three ways by which plant nutrients are lost from the soil.                    (3 marks)

Observation

Question 5 was not popular among candidates.
(a)  Many candidates could not state the roles of the reproductive hormones in farm animals;
(b)  Most candidates do not understand Question 5(b) and  many of them avoided it.

 

The expected answers include:

 

(a)        Roles of hormones in animal reproduction

  1. Oestrogen

-   Stimulates the development of female secondary sex characteristics
-   Brings about ovulation/heat in female animals
-   Promotes the production of eggs through oogenesis
-   Prepares the uterus lining for the reception of the fertilized ovum
-   Increases the blood supply as well as the water content of the uterus
-   Stimulates the growth of the duct system in the mammary glands (udder)
-   Increases ciliary activities and mucous secretion in the oviduct
-   Induces the rapid multiplication of epithelium in the vagina
                                                                                                                       

  1. Testosterone

-   Initiates spermatogenesis/production of spermatozoa
-   Responsible for the development of male secondary sex characteristics
-   Maintains sex drive (libido)
-   Enhances muscular and skeletal growth
-   Reduces fat deposition
-   Promotes the growth of accessory sex glands
-   Sustains the life of sperms in the epididymis


  1. Oxytocin

-   Aids in the contraction of the female uterine muscles during parturition
-   Affects mammary gland after birth by causing milk-let down
-   Promotes the transport of spermatozoa in the female genital tract
                                                                                          

  1. Progesterone

-   Ensures the development of the uterus and implantation of the fertilized ovum
-   Inhibits oestrus/prevents heat period in female animals
-   Causes the development of the alveoli in the mammary gland
-   Ensures the continuance/maintenance of pregnancy       

                                          
(b)        (i)         Most suitable intensive management system for easy collection of eggs
-   Battery cage system                                                           

(ii)  I    Advantages of the battery cage system
-   The rate of feed consumption can easily be determined
-   Makes collection of eggs with clean shells possible
-   Makes record keeping easy
-   Easy access to feed and water
-   Birds are protected from predators
-   Low labour requirement
-   Feed wastage is minimized
-   Facilitates culling of unproductive/sick birds
-   Cannibalism/ egg pecking is reduced
-   Egg production is high
-   Aids easy administration of drugs and vaccines
-   Egg collection is easy
-   Stealing of eggs/birds is reduced
-   Birds are protected from adverse weather conditions

  II       Disadvantages of the battery cage system
-   Diseases can spread easily
-   Birds do not exercise which can lead to incidence of metabolic disorders
-   Cost of establishment is high
-   Requires high level of farm sanitation/biosecurity
-   Could result in lameness
-   High cost of maintenance of battery cages
-   Requires technical skill to establish


            (c)                    Ways by which nutrients are lost from the soil
-   Land clearing                                             
-   Crop removal
-   Soil erosion/Flooding
-   Leaching as a result of water percolation and infiltration
-   Oxidation and reduction reactions            
-   Volatilization
-   Poor tillage practices
-   Continuous cropping
-   Burning
-   Overgrazing