title: Illuminance, sexual maturation, and early egg production in female broiler breeders.
abstract: 1. Broiler breeders were reared at an initial illuminance of 13, 21 or 44 lux and transferred at 20 weeks and a mean body weight of 2.06 kg to floor pens at 25, 55 or 71 lux, or to individual cages at various intensities between 3 and 138 lux. 2. Rate of sexual maturation was not significantly affected by the light intensity experienced during the rearing period, but was progressively accelerated by the provision of a brighter illuminance after 20 weeks, up to a ceiling of about 14 lux. There was no interaction between the pre- and post-20-week illuminance. 3. Cumulative egg numbers to 39 weeks were unaffected by illuminance in the rearing period, positively correlated with illuminance post 20 weeks up to an asymptote at about 8 lux, and highly correlated with age at sexual maturity. Peak rate of lay was both delayed and depressed at 3 lux. 4. It is concluded that the minimum light intensity required at bird-head height to achieve satisfactory photostimulation and an optimal peak rate of lay in broiler breeders is 10 lux, but that a higher illuminance would be prudent for broiler breeders kept in floor pen facilities to maximise nest-box usage.
authors.affiliation: Animal and Poultry Science, University of KwaZulu-Natal, Pietermaritzburg, South Africa. pdlewis@dsl.pipex.com
authors.forename: P D
authors.initials: PD
authors.lastname: Lewis
authors.forename: R
authors.initials: R
authors.lastname: Danisman
authors.forename: R M
authors.initials: RM
authors.lastname: Gous
mesh_terms: D000818:Animals; D001947:Breeding / Q000379:methods; D002645:Chickens / Q000254:growth & development* / Q000502:physiology; D052284:Clutch Size / Q000528:radiation effects*; D005260:Female; D006799:Housing, Animal; D008027:Light; D010063:Ovum / Q000254:growth & development / Q000528:radiation effects*; D017440:Photoperiod