Author/Editor		Curk, A
Title		Piglet production modelling using a dynamic simultaneous equation system
Type		članek
Source		Zb Vet Fak Univ Ljublj
Vol. and No.		Letnik 31, št. 1-2
Publication year		1994
Volume		str. 109-16
Language		eng
Abstract		When studying simultaneous cause-effect relationships in animal production systems, the ordinary least squares is not an appropriate estimation tool, because the resulting parameter estimates would be biased and inconsistent. In this study a dynamic simultaneous equation system was used to model a piglet production process. The model consisted of three equations explaining the number of liveborn piglets per sow per year, the weaning to conception interval and the number of non-productive days per litter. Iterative weighted 3-stage least squares were applied to estimate the system parameters. The fitted mode can easily be used for the dynamic simulation, which makes it possible to perform what-if type simulations.
Descriptors		SWINE BREEDING ANIMALS, NEWBORN FERTILIZATION MODELS, STATISTICAL ANIMALS, DOMESTIC POPULATION SEASONS