GROWTH IN SWINE - COMPARISONS OF FUNCTIONS AND THE COURSE OF DAILY GAIN, FEED-INTAKE AND THEIR RELATION TO CARCASS COMPOSITION

Data from pigs in a testing station were taken to compare different growth functions. The accuracy was good for cubic polynomials and a function proposed by LISKI (1987). Functions defined by PETERSEN (1920) and LEHMANN (1975) were not acceptable. Due to the short testing period (30-100 kg liveweight) no nonlinear functions were approximated to the observations. Depending on the coefficients signs from the polynomial regression, different patterns (typical and atypical) were found for the course of daily gain and feed intake. A typical course in daily gain and feed intake was shown by 69% and 81%, resp, of the animals. The negative genetic correlation between bodyweight at the turning point (y*) and lean meat content (r(g) = .28) is mainly based on the reduced feed intake during the last growing period (78-100 kg liveweight). A turning point at lower bodyweight is correlated with lower feed intake in the later fattening period.