Reproductive performance of turkeys subjected to blackout versus brownout restricted light conditions. Poultry Sci

TH E increased demand in recent years for turkey poults throughout the year has stimulated a great deal of interest in light environment studies which might enhance out-of-season reproductive pro-formance. The reports of Albright and Thompson (1933) and Marsden (1936) showed that turkeys could be stimulated into early egg production through the use of supplementary artificial lights. As-mundson et al. (1946) stated a minimum of 21.5 lux was adequate to bring turkeys into production in the springtime while Garland et al. (1961) stated tha t as little as 5.4 lux was adequate and that 129.1 lux resulted in higher egg production than 21.5 lux or less. The length of light for optimum re-sponse as noted by Amundson and Moses (1950) was between 13 and 15 hours per day. Harper and Parker (1957) observed tha t Beltsville Small White turkeys, hatched during the winter months, be-came refractory to light; bu t that this con-dition could be overcome by restricting light to 8 hours per day for a 4-week peri-od. These results were supported by those obtained by Clayton and Robertson (1960), McCartney et al. (1961), and Leighton and Shoffner (1961a,b). Addi-tional information obtained by the latter two investigators, Wilson et al. (1962), Shoffner et al. (1962), Ogasawara et al. (1962), Marsden and Lucas (1964), Mars, den et al. (1966) and Wilson et al. (1967) suggested that light environment prior to sexual matur i ty had a profound effect on subsequent reproductive performance and that increment increases of light during the breeding season did not significantly improve egg production of turkeys. Another factor of ult imate importance in out-of-season reproductive performance is fertility and hatchability of the eggs produced. Fertility in particular could be markedly altered depending on the mat-ing scheme utilized. Fertility levels may be altered because of preferential mating on the par t of the female (Milby an