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References describing the theories on which the EFG models are based

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Emmans, G.C. A Model of the Growth and Feed Intake of Ad Libitum Fed Animals, Particularly Poultry. In: Computers in Animal Production. Occasional Publication No 5.-British Society of Animal Production, edited by Hillyer, G.M., Whittemore, C.T., and Gunn, R.G.Thames Ditton: BSAP, 1981, pp. 103-110.

An early discussion of the problems of nutritional modelling and a description of the Edinburgh Growth Model - a forerunner to the EFG Model

Emmans, C.G. Computer simulation in poultry nutrition. In: Proceedings 3rd European Symposium on Poultry Nutrition. pp. 91-103. World’s Poultry Science Association, UK Branch, 1981, pp.91-103.

 Discussion of ideas relating to the development of nutritional models

Emmans, G.C. and Fisher, C. Problems in nutritional theory. In: Nutrient Requirements of Poultry and Nutritional Research, edited by Fisher, C. and Boorman, K.N. London: Butterworths, 1986, pp. 9-39.

A fairly complete statement of the ideas and equations underlying the EFG Broiler Growth Model.

Emmans, G.C. Growth, body composition and feed intake. World's Poult Science J. 43:208-227, 1987.

Formal statements of relationships and equations.

Emmans, G.C. The genetic variables and efficiency constants. Proceedings International Poultry Breeders Conference, Ayr, UK., 1987.

A discussion of the genetic components of growth models.

Emmans, G.C. Genetic components of potential and actual growth. In: Animal Breeding Opportunities Occasional Publication No. 12 - British Society of Animal production, pp.153-181, 1988.

Similar discussion to previous paper

Emmans, G.C. and Oldham, J.D. Modelling of growth and nutrition in different species. In: Modelling of Livestock Production Systems, edited by Korver, S. and van Arendonk, J.A.M.Amsterdam: Kluwer Academic Publishers, 1988, pp. 13-21.

A wider ranging and more general discussion of modelling issues. Covers farm species in general.

Emmans, G.C. The growth of turkeys. In: Recent Advances in Turkey Science, edited by Nixey, C. and Grey, T.C. London: Butterworths, 1989, pp. 135-166.

Equations and parameters for modelling the growth of turkeys using a similar set of ideas to those used for broilers.

Gous, R.M., Emmans, G.C., Broadbent, L.A., and Fisher, C. (1990) Nutritional effects on the growth and fatness of broilers. British Poultry Science 31:495-505.

Description of an experiment which tests the underlying ideas concerning the theory of food intake.

Kyriazakis, I. and Emmans, G.C. The effects of varying protein and energy intakes on the growth and body composition of pigs.1. The effects of energy intake at constant, high protein intake. British J. of Nutrition 68:603-613, 1992.

Description of a pig experiment which explores the effect of diet composition on protein utilisation.

Kyriazakis, I. and Emmans, G.C. The effects of varying protein and energy intakes on the growth and body composition of pigs. 2. The effects of varying both energy and protein intake. British J. of Nutrition 68:615-625,1992.

As above

Emmans, G.C. Effective energy: a concept of energy utilisation applied across species. British J. of Nutrition 71:801-821, 1994.

A formal description of the energy system used in the EFG Broiler Growth Model

Kyriazakis, I., Dotas, D., and Emmans, G.C. The effect of breed on the relationship between feed composition and the efficiency of protein utilization in pigs. British J. of Nutrition 71:849-859, 1994.

Further pig experiments concerned with the effect of diet composition on protein utilisation. Effect of breed.

Emmans, G.C. Problems in modelling the growth of poultry. World’s Poultry Science Journal 51:77-89,1995.

An update on the underlying ideas and equations used in the EFG Broiler Growth Model

Hancock, C.E., Bradford, G.D., Emmans, G.C., and Gous, R.M. The evaluation of the growth parameters of six strains of commercial broiler chickens. British Poultry Science 36:247-264, 1995.

Description of an experiment concerned with the genetic parameters of growth.

Kyriazakis, I. and Emmans, G.C. The voluntary feed intake of pigs given feeds based on wheat bran, dried citrus pulp and grass meal, in relation to measurements of feed bulk. British J of Nutrition 73:191-207, 1995.

An attempt to tackle the difficult question of diet bulk.

Kyriazakis, I., Emmans, G.C., and Anderson, D.H. Do breeds of pig differ in the efficiency with which they use a limiting protein supply? British J. of Nutrition. 74:183-195, 1995.

A discussion of the utilisation of protein and genetic variation in protein utilisation. Description of an experiment using two very different breeds of pig.

Emmans, G.C. A method to predict the food intake of domestic animals from birth to maturity as a function of time. Journal of Theoretical Biology. 186:189-199, 1997.

A general model of food or energy intake under non-limiting conditions.

Gous, R.M., Moran, E.T Jr., Stilborn, H.R., Bradford, G.D. and Emmans, G.C.Evaluation of the Parameters Needed to Describe the Overall Growth, the Chemical Growth, and the Growth of Feathers and Breast Muscles of Broilers. Poultry Science 78: 812 - 821, 1999.

Description of an experiment concerned with the genetic parameters of growth 

Ferguson, N.S., Arnold, G.A., Lavers, G. and Gous, R.M. (2000).  The response of growing pigs to amino acids as influenced by environmental temperature.  1. Threonine.  Animal Science, 70: 287 – 297.

An experiment to corroborate the theory of food intake regulation incorporated into the EFG pig growth model

Ferguson, N.S., Arnold, G.A., Lavers, G. and Gous, R.M. (2000).  The response of growing pigs to amino acids as influenced by environmental temperature.  2. Lysine.  Animal Science, 70: 299 - 306.

As above

Ferguson, N.S. and Gous, R.M. (2002).  The response of growing pigs to amino acids as influenced by environmental temperature: tryptophan.  Animal Science 74: 103 – 110.

As above

Johnston, S.A. and Gous, R.M. (2003)  An improved mathematical model of the ovulatory cycle of the laying hen.  British Poultry Science, 44: 752 – 760.

First paper  in a series to model the potential laying performance of hens, with a view to predicting food intake

Gous, R.M. and Morris, T.R. (2005) Nutritional interventions in alleviating the effects of high temperatures in broiler production.  World’s Poultry Science Journal, 61: 463 – 466.

Making use of the broiler growth model to demonstrate that there is little benefit in improving the amino acid balance at high temperatures

Gous, R.M. and Berhe, E.T. (2006).  Modelling populations for purposes of optimisation, in: Mechanistic Modelling in Pig and Poultry Production, R.M Gous, T.R Morris and C. Fisher (Ed’s), pp 76 – 96, CAB International, Wallingford, U.K.

A discourse on the need for stochasticity when modelling broiler production

Johnston, S.A. and Gous, R.M. (2006).  Modelling egg production in laying hens,  in: Mechanistic Modelling in Pig and Poultry Production, R.M Gous, T.R Morris and C. Fisher (Ed’s), pp 188 - 208, CAB International, Wallingford, U.K.

Description of a mechanistic model of egg production in a laying flock

Blanco, O.A. and Gous, R.M. (2006).  Considerations for representing the micro- environmental conditions in simulation models for non- sweating livestock, in: Mechanistic Modelling in Pig and Poultry Production, R.M Gous, T.R Morris and C. Fisher (Ed’s), pp 76 – 96, CAB International, Wallingford, U.K.

Description of the difficulties involved in determining the effective temperature of broilers

Nonis, M.K. and Gous, R.M. (2006) Utilisation of synthetic amino acids by broiler breeder hens.  South African Journal of Animal Science 36: 126 - 134.

First paper in a series that addresses the issue of modelling the effect of nutrition on broiler breeder performance

Gous, R.M. (2007) Predicting nutrient responses in poultry: future challenges.  Animal 1: 57 – 65.

Some nutritional issues that need to be addressed in the future

Johnston, S.A. and Gous, R.M. (2007) A mechanistic, stochastic, population model of egg production.  British Poultry Science, 48: 224 – 232.

Part of a series of papers describing a model that predicts flock laying performance

Johnston, S.A. and Gous, R.M.  (2007)  Modelling the changes in the proportions of the egg components during a laying cycle. British Poultry Science, 48: 347 – 353.

As above

Johnston, S.A. and Gous, R.M. (2007) Extent of variation within a laying flock: attainment of sexual maturity, double-yolked and soft-shelled eggs, sequence lengths and consistency of lay. British Poultry Science 48: 609 – 616.

As above

Lewis, P.D., Gous, R.M. and Morris, T.R. (2007) A model to predict sexual maturity in broiler breeders given a single increment in photoperiod. British Poultry Science 48: 625-634.

As above, for broiler breeders

Nonis, M.A. and Gous, R.M. (2008). Threonine and lysine requirements for maintenance in chickens.  South African Journal of Animal Science 38:75 – 82.

Addresses the issue of modelling the effect of nutrition on broiler breeder performance

Gous, R.M. and Nonis, M.K. (2010) Modelling egg production and nutrient responses in broiler breeder hens. Journal of Agricultural Science, 148: 287 - 301.

The basis on which the broiler breeder simulation model is being developed by EFG Software

Danisman, R. and Gous, R.M. (2011) Effect of dietary protein on the allometric relationships between some carcass portions and body protein in three broiler strains.  South African Journal of Animal Science 41: 194 - 208.

Evidence that the allometric relationships between body protein and the different physical components is the same for all genotypes

Gous, R.M., Emmans, G.C. and Fisher, C. (2012).  The performance of broilers on a feed depends on the feed protein content given previously.  South African Journal of Animal Science 42: 63 – 73.

An important issue when optimising the feeding of broilers.  Performance overall is the key; not that within each phase.

Nonis, M.K. and Gous, R.M. (2012) Broiler breeders utilise body lipid as an energy source. South African Journal of Animal Science 42: 369 - 378.

Evidence that the lipid content of broiler breeders is labile and can support energy requirements when energy intake is below that required by the bird

Danisman, R. and Gous, R.M. (2013) Effect of dietary protein on performance of four broiler strains and on the allometric relationships between carcass portions and body protein. South African Journal of Animal Science 43: 25 – 37.

Further evidence that the allometric relationships between body protein and the different physical components is the same for all genotypes

Nonis, M.K. and Gous, R.M. (2013) Modelling changes in the components of eggs from broiler breeders over time.  British Poultry Science 54: 603-610.

Useful information for the broiler breeder simulation model

Mlaba, P.P, Ciacciariello, M. and Gous, R.M. (2015) The effect of dietary protein on breast meat yield of broilers reared on different daylengths.  South African Journal of Animal Science 45: 39 - 48.

Evidence that the reduced breast meat yield under 12-h light cannot be overcome by feeding higher dietary protein levels