title: Evaluation of breeding objectives for purebred and crossbred selection schemes for adoption in indigenous chicken breeding programmes.
abstract: 1. The aim of the study was to evaluate the genetic and economic breeding objectives for an indigenous chicken (IC) breeding programme in Kenya. 2. A closed three-tier nucleus breeding programme with three breeding objectives and two selection schemes was simulated. The breeding objectives included IC dual-purpose (ICD) for both eggs and meat, IC layer (ICL) for eggs and IC broiler (ICB) for meat production. 3. Pure line selection scheme (PLS) for development of IC pure breeds and crossbreeding scheme (CBS) for the production of hybrids were considered. Two-and three-way crossbreeding strategies were evaluated under CBS and the impact of nucleus size on genetic gains and profitability of the breeding programme were investigated. 4. Males were the main contributors to genetic gains. The highest genetic gains for egg number (2·71 eggs) and growth traits (1·74 g average daily gain and 57·96 g live weight at 16 weeks) were realised under PLS in ICL and ICB, respectively. 5. The genetic response for age at first egg was desirable in all the breeding objectives, while that for fertility and hatchability were only favourable under ICL and PLS in ICD. Faecal egg count and immune antibody response had low, but positive gains except under PLS where the later was unfavourable. ICB was the most profitable breeding objective, followed by ICD and ICL under all the selection schemes. 6. Although PLS was superior in genetic gains and profitability and recommended in breeding programmes targeting ICL and ICB, a three line CBS should be considered in development of a dual-purpose breed. 7. Increasing the nucleus size beyond 5% of the IC population was not attractive as it resulted in declining profitability of the breeding programme.
authors: Animal Breeding in the Tropics and Sub-Tropics, Department of Crop and Livestock Sciences , Humboldt Universität zu Berlin, Philippstraße 13, Berlin, Germany.
authors: T O
authors: TO
authors: Okeno
authors: A K
authors: AK
authors: Kahi
authors: K J
authors: KJ
authors: Peters
mesh_terms: D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D001947:Breeding / Q000379:methods*; D002645:Chickens / Q000235:genetics* / Q000254:growth & development; D003433:Crosses, Genetic; D004531:Eggs; D005260:Female; D005838:Genotype; D007630:Kenya; D008297:Male; D008460:Meat; D010641:Phenotype