On-farm estimation of pig growth parameters from longitudinal data of live weight and feed consumption and the use of a mathematical model

Experimental data of feed consumption and composition, recorded over 5 consecutive short periods of growth from 30 crossbred male pigs divided 2 two groups and fed two restricted feeding regimes from 25 to 160 kg LW, were used to run a model in which a set of theoretical values, to describe the potential chemical growth of the pig, was preliminarily assumed. Simulated values of average daily gain (ADG) and feed conversion ratio (FCR) were the outputs. Estimates of protein mass at maturity (Pm, kg) and relative growth rate (B, d(-1)) for each feeding regimes where successively obtained through an optimization procedure which has minimized the coefficients of variation of the differences between the estimates and the measurements of ADG and FCR. The very similar values of Pm (33.7 and 33.2 kg), and B (0.0104 and 0.0105 d(-1)), obtained for the two feed treatments suggested that these values can be used as operational data to describe the growth parameters of the experimental pigs used.