UNIVERSITY OF KWAZULU-NATAL SCHOOL OF AGRICULTURAL SCIENCES & AGRIBUSINESS DISCIPLINE OF ANIMAL AND POULTRY SCIENCE EXAMINATIONS: NOVEMBER 2010

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1 DURATION: 3 HOURS TOTAL MARKS: 100 External Examiner: Prof M Chimonyo Internal Examiner: Dr NC Tyler STUDENTS ARE REQUESTED, IN THEIR OWN INTERESTS, TO WRITE LEGIBLY NOTE: THIS PAPER CONSISTS OF FIVE (5) PAGES, PLEASE SEE THAT YOU HAVE THEM ALL ANSWER ALL QUESTIONS QUESTION 1 (total 10 marks) A chicken is hatched with an abnormality in which the flow of air through the lungs is reversed. a) Describe the route of a pocket of air in such a chicken. (2) b) Assuming there is no change in the direction of blood flow in the capillaries; do you think it will be possible for such a bird to survive? Explain your answer. (8) QUESTION 2 (total 6 marks) Slow-feathering (K) is dominant over fast-feathering (k) and is sex-linked. a) What is the best mating strategy to allow feather sexing in the offspring (show your punnet square). b) What is the importance of feather sexing in the poultry industry? 1

2 QUESTION 3 (total 16 marks) Are the following statements true or false? Provide a brief explanation for each. a) Older pigs may deposit fat more easily than younger pigs. (2) b) The more feed a sow eats during gestation, the greater her appetite will be during lactation. (2) c) The halothane gene is responsible for pale, soft and exudative meat in pigs (2) d) All colours, observed in the plumage of birds, are due to 3 pigments. (2) e) The best egg producers can be selected by their moulting patterns. (2) f) Gizzard size, to a certain extent, is dependent on the type of feed a chicken eats. (2) g) More cracked eggs could be a result of hot weather conditions. (2) h) It is possible to determine if an egg is fertile before incubation (2) QUESTION 4 (total 7 marks) a) Farmer Joe would like to wean early in order to improve the number of litters per sow per year. Explain why he needs to be cautious in this decision. (5) b) Other than possibly improving the number of litters per sow per year, what are the other potential benefits of practicing early weaning? (2) 2

3 QUESTION 5 (total 10 marks) a) Describe how artificial insemination has allowed for improvements in pig breeding. b) How soon after farrowing would you check for oestrus, and how would you do it? c) Describe the relationship between the number of piglets born alive and the number of inseminations/oestrus. (2) d) With the information from c), what other considerations need to be accounted for in a decision of how many times to inseminate a sow in oestrus? (2) QUESTION 6 (total 6 marks) Explain what the differences are between the 2 pigs in Figure 1, and give possible reasons for the differences. (6) Figure 1: The gains of fat and lean of 2 different pigs at 50 kg liveweight 3

4 QUESTION 7 (total 10 marks) A hatchery manager has asked for your opinion on the lower-than-expected hatchability he is experiencing at his hatchery. Describe the route of investigation you would follow to pinpoint the problem, and identify target figures for each potential problem area. (10) QUESTION 8 (Total 10 marks) a) Copy this table in your answer book, and complete it: (1) Date Time of oviposition 23/11/10 10:00 24/11/10 12:00 25/11/10 26/11/10 27/11/10 28/11/10 29/11/10 30/11/10 01/12/10 b) On which of these dates did the hen not ovulate? (1) c) What is the expected sequence/clutch length of this particular hen? (1) d) Show (with calculations) how you could improve the production of this hen with the use of an ahemeral cycle? (5) e) Would you recommend the use of ahemeral cycles in practice? (Provide reasons) (2) QUESTION 9 (total 10 marks) A recent survey at a supermarket has shown that a large proportion of their consumers do not like the idea that laying hens are kept in wire cages. However, the egg sales of the premium product barn eggs are very low. Discuss your view on the balance between keeping production costs low and ensuring welfare of the birds. (10) 4

5 QUESTION 10 (total 15 marks) A farmer with 10 laying sheds is trying to market his own eggs and establish a customer base and needs to be able to forecast how many eggs, as well as the numbers of eggs in each size category, will be produced on any given day in the future. a) What information will he need in order to do this? Explain. (7) b) What advice could you give him in order for his egg production and egg size variation to remain as constant as possible from the farm? (2) c) Comment on how the management of birds on this farm will be different to a broiler breeder operation. (6) 5