Controlled feeding of the breeding bird - A comparative approach

Feed restriction enhances egg production in broiler and duck but not turkey breeders. Feed restriction controls multiple ovulation in broiler breeders and ducks and leads to enhanced rate and persistency of lay. In contrast, feed restriction in turkeys does not control multiple ovulation, reduces ovulation rate and leads to poor persistency of lay. The results of a series of experiments in broiler breeders are summarised from which a theory of the effects of feed restriction on egg production in broiler breeders was developed. The theory was used to create a stochastic computer model to predict egg production in broiler breeders. In silico simulation experiments with the model showed that total egg production was very sensitive to changes in body weight at photostimulation and body weight gain during the first 10 weeks of lay whereas changes in body weight gain after peak rate of lay showed only minor effects on egg production. Increasing variability (CV) of initial body weight was associated with a linear decrease in mean and increased variability of egg production. Higher variability in age at first egg had little effect on the mean number but was associated with increased variability of egg production. The results were in line with experimental data and commercial experience and support the conclusion that the model will be useful for predicting the outcome of changes to the management of broiler breeders. Similar outcomes are expected in feed restriction of ducks but feed restriction is contraindicated in turkey breeders. In principle the model could be adapted for ducks and turkeys and linked to nutritional data as a comprehensive management tool for breeding birds.