Ondersoek na seleksiemaatstawwe by Afrinoskape. Genetiese parameters van groei- en woleienskappe

Abstract

Investigation of selection criteria for Afrino sheep. Genetic parameters of growth and wool traits. The data used in this study were obtained from the Carnarvon Afrino stud. The genetic and phenotypic parameters for the various growth and wool traits were estimated by means of Henderson's Method III. The following traits were considered as possible selection criteria for ram selection: weaning weight (h² = 0,21 ± O,07), yearling weight (h² = 0,22 ± 0,07), ADG: weaning-year-old (h² = 0,22 ± 0,07), Kleiber: weaning-year-old (h = 0,23 ± 0,07), and eighteen-month mass (h² = 0,28 ± 0,08). However, the traits yearling weight, ADG: weaning-year-old and eighteen month mass cannot be considered as possible selection criteria because of their undesirable genetic correlations with birth mass and eighteen-month mass. Kleiber: weaning-year-old had a non-significant negative genetic correlation of -0,12 ± 0,22 with birth mass, a medium positive correlation with yearling weight (0,35 ± 0,21) and it is almost unrelated to eighteen-month mass (r_g = 0,10 ± 0,22). At 12 months of age, rams can be selected on the basis of the following selection index: I=3 X weaning mass -- 1 X Kleiber: weaning-year-old- 18 X fibre diameter.

Ondersoek is ingestel na geskikte seleksiemaatstawwe vir Afrino-skape. Data vanaf die Camarvonse Afrinokudde is vir hierdie ondersoek gebruik. Genetiese en fenotipiese parameters van die onderskeie groei- en woleienskappe is met behulp van Henderson se Metode III beraam. Die volgende eienskappe is as moontlike seleksiemaatstawwe vir ramseleksie oorweeg: speenmassa (h² = 0,21 ± 0,07), jaarmassa (h² = 0,22 ± 0,07), GDT: speen-jaar (h² = 0,22 ± 0,07), Kleiber: speen-jaar (h² = 0,23 ± 0,07), en agtienmaandemassa (h² = 0,28 ± 0,08). Jaarmassa, GDT: speenjaar en agtienmaandemassa is as gevolg van hul ongunstige genetiese korrelasies met geboortemassa en agtienmaandemassa as seleksiemaatstawwe geelimineer. Kleiber: speen-jaar het 'n nie-betekenisvolle negatiewe korrelasie van -0,12 ± 0,22 met geboortemassa, 'n matig-positiewe korrelasie van 0,35 ± 0,21 met jaarmassa en is feitlik onafhanklik van agtienmaandemassa (r_g = 0,10 ± 0,22). Ramme kan op 12-maande-ouderdom op grond van die volgende seleksie-indeks geselekteer word: I = 3 X speenmassa + 1 X Kleiber: speen-jaar - 18 X veseldikte.

Keywords: Afrino, genetic parameters, growth traits, Kleiber ratio.