October 25, 2010

Study shows better lighting improves broiler breeder performance

Getting the lighting right is absolutely crucial to maximise the egg laying performance of broiler breeders, according to Lindsay Broadbent of genetics company Aviagen.

Lighting for broiler breeders has traditionally been based on a knowledge of lighting for laying hens, Broadbent explained. But recent research has shown that this was not correct as broilers still exhibit some form of seasonal breeding.

"In nature, this is to prevent birds from breeding in the same season as they were hatched, to avoid adverse conditions and low food supply for the offspring in the winter," he explained. This inability to respond to lengthening hours of light is known as photorefractoriness.

He explained that typically broilers should have less than 10 hours of light for 19 or 20 weeks to become photoresponsive. Anything more and the breeders will take longer to reach sexual maturity and will produce fewer eggs.

To bring the birds into lay, Broadbent recommended increasing the day length to at least 11 hours, but no more than 14 hours, during weeks 20 to 22.

Exceeding 14 hours would have an adverse effect, he warned, resulting in the quicker onset of photorefractoriness, more energy going into body maintenance and poorer egg shell quality.

Body weight was also important, he added, noting that broiler breeders should be photostimulated when they are between 2kg and 2.2kg in weight. Underweight birds would take longer to become photoresponsive. Overweight birds would require more feed to reach sexual maturity.

He also explained that birds would reach sexual maturity at a minimum light intensity of seven lux, but recommended 30 to 60 lux, to minimise the incidence of floor eggs. There was no point in using anything other than white light, he added.