The effect of supplementation of daylight with artificial light from various sources and at two intensities on the egg production of two lines of geese.

Three light sources: Cool-White (C), Vita-Lite (V), and tungsten (T), each at two intensities (20 or 50 lx), were used to supplement light to 16 hr in a 24-hr cycle for geese maintained in open-shed pens. Two lines of mixed breeds of geese, white and grey, were used and egg production was followed from the 27th week of age through 6 months of the laying period. A significant increase in egg production was found under the C light illumination. At 20 lx, egg production was significantly higher than at 50 lx. No difference in egg production was found between the two lines of geese; however, significant interactions were found between light sources, intensities, and geese lines, as exhibited by different patterns of egg production. Light intensity had the greatest effect until peak egg production had been reached; thereafter, egg production was influenced mainly by the light source.