This question was fairly attempted by the candidates.  In 6(a)(i-ii), most of the candidates could neither define culling nor state the reasons why culling is practised in cattle production.  Furthermore, most of the candidates could not mention the major function of ptyalin, rennin and pepsin during digestion of feed in rabbits as required in 6(b).   However, most of them were able to state the advantages of castrating farm animals as required in 6(c).  Finally, majority of the candidates were able to state the sources and the functions of carbohydrate in farm animal diet as required in 6(d).

The expected answers include:

(6)  (a)  (i)        Definition of culling as used in cattle production
                        Culling is the removal of animals from the flock for specific reasons  
                    
(ii)        Reasons for culling

-           For immediate financial gain
-           To avoid the spread of diseases
-           To prevent animals with undesirable trait from
            reproducing
-           To remove unproductive animals
-           To reduce competition for feed
-           To reduce competition for space
-           To reduce competition for water

      (b)  Major function of ptyalin, renin and pepsin during digestion
            of feed in rabbit
           
            Ptyalin

            It is an amylase/enzyme which converts/digests starch to maltose/dextrin in the mouth
                                   

            Renin 

            It is an enzyme which helps in the coagulation/curdle of milk protein in the stomach
            OR
            Digestion of casein to casinogen in the stomach                   
            Pepsin
            It is an enzyme which converts proteins to peptones and or polypeptides in the stomach