No abstract

Background: Natural mating colony cages for parent-stock layer breeders, instead of conventional cages with artificial insemination, have been widely adopted by many commercial farms in China. However, the fertility rate of this system is unstable and varies greatly among different cage tiers. We speculated that the difference in fertility rate might be caused by uneven illumination because vision appears to play a central role in hens’ behaviour, including mating, which is an important factor that affects the reproductive performance of hens. The objectives of this study was to investigate the effects of 4 LED light colours (white: WL, red: RL, yellow-orange: YO, blue-green: BG) with 2 light intensities (10 lux, 25 lux) in each colour on mating frequency and fertility for layer breeders in natural mating colony cages. Results: A total of 32 identical cages were involved in the 8 treatments, with 4 replicates for each treatment and 5 males and 45 females per cage. The results showed significant effects of age, light colour, light intensity and colour-intensity interaction on the frequency of mating behaviour, integrity of matings and fertility. Overall, flocks treated with WL and RL and a higher light intensity in natural mating colony cages during the laying period showed a more frequently mating behaviour, a large proportion of relatively complete matings and a higher fertility. All components of mating behaviour and fertility declined from 30 through 40 to 50 wks of age, but no significant correlation was found between fertility and mating behaviour. Conclusions: In summary, the results of this study illustrate that different LED light colour and light intensity influenced the mating behaviour and fertility of layer breeders. WL and RL and a higher light intensity could increase the frequency of mating behaviour, the proportion of complete matings and fertility. No significant correlation was found between fertility and mating behaviour. Such knowledge can help to understand mating behaviour in natural mating colony cages and provide a basis for the optimization of light environment regulation.