Research note: an amendment to the model for predicting age at sexual maturity for growing pullets of layer strains given two opposing changes in photoperiod

British Poultry Science

2010

1. Individually-caged Ross 308 broiler breeders were transferred temporarily at 147 d from 8 to 14-h photoperiods and back to 8 h at 5-d intervals from 5 to 25 d and at 32 d. Control birds were maintained on 8 h or transferred permanently to 14 h. 2. Five long days had minimal effect on age at first egg, between 10 and 25 long days progressively accelerated sexual development, and maximum advance was achieved by 32 long days. However, a model involving the ogive of a normal distribution with a mean of 14 long days and an SD of 5.3 indicated that 28 long days would be sufficient to maximise sexual development. 3. The similarity of this model for broiler breeders with one previously produced for egg-type pullets suggested a common physiological mechanism for photosexual responses to two opposing changes in photoperiod.

Temporary exposure of prepubertal, somatically-mature broiler breeder females to stimulatory photoperiods

Danisman

British Poultry Science

2010

The rewards of using a modelling approach in directing poultry research

British Poultry Science

2016

The purpose of this paper was to demonstrate the advantages of using a good theory as the basis for designing and conducting research, using personal experience of developing a simulation model to predict food intake in laying hens and broiler breeders. To develop such a model, research projects were designed to measure, among others, the effect of lighting programmes on age at sexual maturity, changes in internal cycle length, egg and body component weights over time, effects of temperature on performance, and to determine whether these birds would make use of body lipid reserves as an energy source. Most of the experiments described here were conceived and conducted only because they were seen as a means of collecting information required for the development of empirical and mechanistic models, both of which have contributed to a better understanding of the birds themselves, as well as to the basis for predicting food intake in broiler breeders and laying hens. For those researchers seeking ideas for further study, there is no better way of generating such ideas than by first developing a theory of the subject to be studied, the greatest benefit from this approach being that such targeted research is bound to be new, innovative and useful.

Modeling as a research tool in poultry science

2014

Poultry Science

The World's Poultry Science Association (WPSA) is a long-established and unique organization that strives to advance knowledge and understanding of all aspects of poultry science and the poultry industry. Its 3 main aims are education, organization, and research. The WPSA Keynote Lecture, titled "Modeling as a research tool in poultry science," addresses 2 of these aims, namely, the value of modeling in research and education. The role of scientists is to put forward and then to test theories. These theories, or models, may be simple or highly complex, but they are aimed at improving our understanding of a system or the interaction between systems. In developing a model, the scientist must take into account existing knowledge, and in this process gaps in our knowledge of a system are identified. Useful ideas for research are generated in this way, and experiments may be designed specifically to address these issues. The resultant models become more accurate and more useful, and can be used in education and extension as a means of explaining many of the complex issues that arise in poultry science.