02633naa a2200229 a 450000100080000000500110000800800410001910000180006024501130007826000090019152019580020065000120215865000160217065000210218665300270220765300180223465300270225270000150227970000200229470000290231477300600234315307372004-09-24       2002    bl uuuu     u00u1 u    #d1 aPORTOLANO, B.  aEstimation of the genetic and phenotypica variance of several growth traits of the Sicilian Girgentana goat.  c2002  aThe possibility of increasing the age at slaughter of kids, from 25 to 45-60 days, without affecting meat quality, led to this study of the source of variation of several growth traits in the Girgentana goat. Data used in this study were collected between 1998 and 2000 from a total of 276 kids (118 males and 158 females), the progeny of 23 sires and 109 dams. For each individual the identification number, pedigree, sex, body weight at birth and every 15 days up to the age of 60 days and the individual's maternallitter size were recorded. A sire model was used in order to estimate genetic parameters and correlations between all traits considered, including, in total, 94 animals from 23 sires. This data-set was made up of nine generations. As fixed effects, the mixed sire model included year of birth, age of dam at birth of the offspring and individual' s maternal litter size. Sire within year of birth and the residuals were used as random effects. The genetic correlations between body weight at birth (BW0)/body weight at 30 days (BW30) and body weight at 60 days (BW60) showed the possibility of indirect selection for BW60, by selecting for BW0 or BW30. These genetic correlations with BW60 were 0.86 and 0.90, respectively for BW0 and BW30. Furthermore, body weight heritability ranged from 0.20 to 0.49 at different ages. Average daily gain (ADG) was also considered in four successive 15 day periods starting at birth and up to 60 days (ADG1-4). The ADG heritability estimates were very low and ranged from 0.06+0.026 (ADG2 and 3) to 0.16+0.040 (ADG4). The genetic correlations between ADG1 with 2-4 were negative and tended to zero with increasing age. The phenotypic correlations, on the contrary, increased (from 0.33 to 0.82) with the increase of age. The genetic correlations between BW and ADG traits ranged from -0.32 to 0.93; the phenotypic correlations were lower than the genetic correlations, but showed an analogous trend.  aCaprino  aCrescimento  aGenética Animal  aCorrelação genética  aHerdabilidade  aMelhoramento genético1 aTODARO, M.1 aFINOCCHIARO, R.1 aVAN KAMM, J. H. B. C. M.  tSmall Ruminant Researchgv. 45, n. 3, p. 247-253, 2002.