Effect of Light Duration and Variation on the Growth and Reproductive Performance in Breeder Geese

This study aims to investigate the effects of time and light variation on the growth and reproductive performances of breeder geese. A total of 32 ganders and 96 dames in their first laying season, with an average age of 10 months, were assigned to eight rooms, each containing four ganders and twelve dams. A split-plot design was used, incorporating two prelay photoperiod treatments: a 7-hour light period (P7H), in which the photoperiod was maintained at seven hours for the first six weeks, and a gradually decreasing light (GDL) group, in which the light duration was initially set at 12 hours and then reduced by one hour per week during the prelay period. Two variable photoperiod schedules were applied as sub-treatments and randomized across the rooms. In one treatment, the egg production rate in breeder geese decreased to an average below 30%, after which the photoperiod increased by 15 minutes each week (change time, CHP). A fixed photoperiod of nine hours was maintained (fixed time, FIXP) until the end of the egg-laying period. Geese in the GDL light group had a longer laying duration than P7H light group (243.75 vs 191.75 days; p<0.01). Number of eggs per goose in the GDL light group showed a trend toward higher values than P7H light group. However, the fertility and hatchability in GDL light group were significantly lower than the P7H light group at all periods, respectively. Geese exposed to a 12-hour light (12L:12D) regimen during the pre-laying period exhibited a longer laying duration and higher egg production per bird. However, maintaining a fixed lighting schedule of 9 hours of light and 15 hours of darkness (9L:15D) after the peak laying period is recommended to optimize production profitability by supporting better fertility and hatchability.