Genetische Analyse des individuellen Wachstums- und Futteraufnahmeverlaufs von Jungebern während der Eigenleistungsgruppenprüfung

Abstract

Abstract. Title of the paper: Genetic analysis of the course of individual growth and feed intake of group-penned Performance tested boars Objective of the study was to analyse the course of feed intake and growth of 661 boars of three lines (259, 208, and 194 animals of lines 3, 4, and 8, respectively) during an age dependent Performance test between the 100th and 170th day of age. Individual feed intake of the group-penned animals was recorded by electronic feeding stations during the first, third, fifth, seventh, and ninth week on test. Additionally, each animal was weighted in biweekly intervalls. A second order polynomial and a third order polynomial were individually fitted on feed intake and live weight. From these curves, individual information about daily feed intake, daily gain, and food conversion ratio were derived for five periods of 12 days and for the entire period. Genetic parameters were estimated simultaneously using a multiple trait animal model. Heritabilities of h2 = .50, .55, .40, and .39 for traits of entire test period were found for backfat thickness, daily gain, daily feed intake, and food conversion ratio, respectively. Estimated heritabilities for each test period from one to five were h2 = .50, .56, .54, .50, and .37 for daily gain, h2 = .18, .43, .46, .45, and .38 for daily feed intake, and h2 = .34, .42, .46, .44, and .39 for food conversion. The genetic correlation between daily gain and food conversion in period one (rg = −.84) was significantly different from correlations between these traits in the following periods (rg = −.32 to −.51). Genetic correlations between daily gain and daily feed intake in each period were rg = .56 to .42 from first to last period. Except of first period (rg = −.11), the genetic associations between food conversion and daily feed intake for periods were similar (rg = .52 to .56). The genetic associations indicate, that a high feed intake in the beginning of the fattening period is desirable, while afterwards a more reduced feed intake should be achieved to improve efficiency of fattening Performance. In order to optimise fattening Performance, the use of part test information from growth rate and feed intake is necessary.