Title page for ETD etd-09042012-164739


Document Type Doctoral Thesis
Author Molapo, Setsumi Motsoene
URN etd-09042012-164739
Document Title Effects of season and restricted feeding during rearing and laying on productive and reproductive performance of Koekoek chickens in Lesotho
Degree PhD
Department Animal and Wildlife Science
Supervisor
Advisor Name Title
Prof E C Webb Supervisor
Keywords
  • reproduction and egg laying performance
  • carcass characteristics
  • meat chemical composition
  • Lesotho
  • Koekoek chickens
  • growth
  • restricted feeding and season
Date 2012-09-07
Availability unrestricted
Abstract
This research project consisted of five experiments. The main objective of this study was to determine the effects of restricted feeding and season on growth, carcass characteristics, meat chemical composition, reproduction and egg laying performance of Koekoek chickens. Feed restriction lowered the body weight, weight gain, feed intake and improved the feed conversion efficiency during the rearing phase. During the laying phase, chickens that were in the RA treatment had higher body weights, weight gains and lower FCR. Chickens that were reared in summer had a higher body weight, weight gain and FCR, while total feed intake and mortality rates were high in winter. Feed restriction reduced the slaughter weight, defeathered weight, dressed weight, skin weight, breast muscle weight, shank width, chest width and heart girth during the rearing phase. The intestine, liver and abdominal fat pad weights were higher in chickens that were fed ad libitum. Chickens that were reared in summer had higher shank width, slaughter weight, defeathered weight, chest width, heart girth, breast muscle weight, skin weight, abdominal fat pad weight, intestine weight, liver weight and the relative skin percentage at the age of 18 weeks. During the laying phase, abdominal fat pad weight, abdominal fat pad percentage, intestine percentage, liver weight, gizzard weight and gizzard percentage were higher in the ad libitum fed chickens. Unrestricted feeding during the rearing phase increased the development of combs, wattles, pubic bones, ovaries and oviducts more than restricted feeding while at the age of 32 weeks, enhanced growth of the reproductive organs was seen in chickens that were fed ad libitum only during the laying phase (RA). The cold winter conditions hindered the growth of the combs, wattles, pubic bones, oviducts and ovaries. Restricted feeding during the laying phase reduced the laying percentage, egg weights and improved the hatching percentage. Ad libitum feeding during the rearing phase resulted in the attainment of puberty at an earlier age in chickens. Chickens that were produced in summer reached puberty first as well as 20%, 50% and 80% egg production, and had a higher average laying percentage and egg weights.

2011 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.

Please cite as follows:

Molapo, SM 2011, Effects of season and restricted feeding during rearing and laying on productive and reproductive performance of Koekoek chickens in Lesotho , PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-09042012-164739/ >

D12/9/99/ag

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