# Effect of light duration and variation on the growth and reproductive performance in breeder geese

## TL;DR

This study found that varying light exposure affects geese's egg production and fertility, with gradual light reduction increasing laying duration but lowering fertility.

## Contribution

The study introduces a split-plot design to evaluate the effects of different photoperiod treatments on breeder geese's reproductive performance.

## Key findings

- Geese under gradual decreasing light had longer laying duration but lower fertility and hatchability.
- A 12-hour light regimen during pre-laying improved egg production, while a 9-hour fixed light schedule post-peak improved profitability.
- Income over feed cost was higher in the gradual decreasing light group compared to the fixed 7-hour light group.

## Abstract

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), and a gradually decreasing light (GDL) group. 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). A fixed photoperiod of nine hours was maintained (fixed time) 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 (81.82 vs 55.45 egg/bird; p = 0.0779). However, the fertility and hatchability in GDL light group were significantly lower than the P7H light group at all periods, respectively (48.35 vs. 62.57% and 42.80 vs. 53.17%; p<0.05). Income over feed cost for the GDL and P7H light groups was 3,069.6 and 2,535.5 NT$/bird, 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.