Die herhaalbaarheid van reproduksie-eienskappe in die Tygerhoek- Merinokudde – voorlopige waarnemings

Author: S.W.P. Cloete, H.J. Heydenrych & J.J. du Plessis
Year: 1984
Issue: 1
Volume: 14
Page: 29 - 33

The repeatability of reproduction characteristics in the Tygerhoek Merino flock – preliminary observations. The repeatability of lambs born and weaned per mating was estimated using data from 145 ewes of a control group and 260 ewes of four selection groups. By relating the reproduction of ewes at two years of age to their average subsequent reproductive performance, repeatability estimates and standard errors were calculated at 0,201 ± 0,018 and 0,065 ± 0,134 for lambs born per mating in the control group and the selection groups respectively. Corresponding estimates for lambs weaned per ewe mated were 0,187 ± 0,077 and 0,067 ± 0,122. By relating the reproduction of ewes at three years to their average subsequent reproductive performance, estimates of 0,286 ± 0,014 and 0,214 ± 0,062 were calculated for lambs born per mating in the control group and the selection groups respectively. Corresponding estimates for lambs weaned per ewe mated were 0,181 ± 0,110 and 0,152 ± 0,126. Reproduction at three years of age is thus a better indicator of reproductive performance in subsequent years than at two years of age, especially in the selection groups

Keywords: regression-methods, Repeatability, reproduction characteristics
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