Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flock

Genetic evaluation systems require the accurate estimation of genetic parameters. The genetic, phenotypic and environmental parameters for live weight and objectively measured wool traits were estimated for a South African Merino flock. Records of the Tygerhoek Merino resource flock were used to estimate these parameters. The database consisted of records of 4 495 animals, the progeny of 449 sires and 1 831 dams born in the period 1989 to 2004. The pedigree records used have been collected between 1969 and 2004. Direct heritability estimates (h²a) for 16-month live weight (LW) and objectively measured wool traits ranged from 0.20 for staple strength (SS) to 0.68 for fibre diameter (FD). Maternal heritability estimates ranged from 0.05 for LW and FD, to 0.10 for clean fleece weight (CFW). The proportion of the total phenotypic variance due to the maternal permanent environment variance (c2pe) amounted to 5% for fleece weights. The genetic correlation between animal effects for LW, greasy fleece weight (GFW) and CFW were -0.28, -0.65 and -0.70 respectively. The genetic correlation between LW and CFW was positive, but low at 0.14. The other important genetic correlations among the wool traits ranged from low to high, and were variable in sign ((for GFW with CFW (0.87) and with staple length (SL - 0.18); CFW with clean yield (CY - 0.33) and with SL (0.29); FD with CY (-0.09), with SL (0.15), with SS (0.40) and with standard deviation of FD (SDFD - 0.38): CY with SL (0.33) and with SDFD (0.10); SS with coefficient of variation of FD (CVFD - -0.57) and with SDFD (-0.28); CVFD with SDFD (0.87)). These results suggested that worthwhile responses in the objectively measured traits can be achieved through direct and indirect selection.

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Main Authors: Matebesi,P.A., Cloete,S.W.P., van Wyk,J.B.
Format: Digital revista
Language:English
Published: The South African Society for Animal Science (SASAS) 2009
Online Access:http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892009000100008
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spelling oai:scielo:S0375-158920090001000082014-07-22Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flockMatebesi,P.A.Cloete,S.W.P.van Wyk,J.B. Direct heritability maternal effects correlations 16-months body and fleece weight fibre traits staple traits Genetic evaluation systems require the accurate estimation of genetic parameters. The genetic, phenotypic and environmental parameters for live weight and objectively measured wool traits were estimated for a South African Merino flock. Records of the Tygerhoek Merino resource flock were used to estimate these parameters. The database consisted of records of 4 495 animals, the progeny of 449 sires and 1 831 dams born in the period 1989 to 2004. The pedigree records used have been collected between 1969 and 2004. Direct heritability estimates (h²a) for 16-month live weight (LW) and objectively measured wool traits ranged from 0.20 for staple strength (SS) to 0.68 for fibre diameter (FD). Maternal heritability estimates ranged from 0.05 for LW and FD, to 0.10 for clean fleece weight (CFW). The proportion of the total phenotypic variance due to the maternal permanent environment variance (c2pe) amounted to 5% for fleece weights. The genetic correlation between animal effects for LW, greasy fleece weight (GFW) and CFW were -0.28, -0.65 and -0.70 respectively. The genetic correlation between LW and CFW was positive, but low at 0.14. The other important genetic correlations among the wool traits ranged from low to high, and were variable in sign ((for GFW with CFW (0.87) and with staple length (SL - 0.18); CFW with clean yield (CY - 0.33) and with SL (0.29); FD with CY (-0.09), with SL (0.15), with SS (0.40) and with standard deviation of FD (SDFD - 0.38): CY with SL (0.33) and with SDFD (0.10); SS with coefficient of variation of FD (CVFD - -0.57) and with SDFD (-0.28); CVFD with SDFD (0.87)). These results suggested that worthwhile responses in the objectively measured traits can be achieved through direct and indirect selection.The South African Society for Animal Science (SASAS)South African Journal of Animal Science v.39 n.1 20092009-01-01journal articletext/htmlhttp://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892009000100008en
institution SCIELO
collection OJS
country Sudáfrica
countrycode ZA
component Revista
access En linea
databasecode rev-scielo-za
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region África del Sur
libraryname SciELO
language English
format Digital
author Matebesi,P.A.
Cloete,S.W.P.
van Wyk,J.B.
spellingShingle Matebesi,P.A.
Cloete,S.W.P.
van Wyk,J.B.
Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flock
author_facet Matebesi,P.A.
Cloete,S.W.P.
van Wyk,J.B.
author_sort Matebesi,P.A.
title Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flock
title_short Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flock
title_full Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flock
title_fullStr Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flock
title_full_unstemmed Genetic parameter estimation of 16-month live weight and objectively measured wool traits in the Tygerhoek Merino flock
title_sort genetic parameter estimation of 16-month live weight and objectively measured wool traits in the tygerhoek merino flock
description Genetic evaluation systems require the accurate estimation of genetic parameters. The genetic, phenotypic and environmental parameters for live weight and objectively measured wool traits were estimated for a South African Merino flock. Records of the Tygerhoek Merino resource flock were used to estimate these parameters. The database consisted of records of 4 495 animals, the progeny of 449 sires and 1 831 dams born in the period 1989 to 2004. The pedigree records used have been collected between 1969 and 2004. Direct heritability estimates (h²a) for 16-month live weight (LW) and objectively measured wool traits ranged from 0.20 for staple strength (SS) to 0.68 for fibre diameter (FD). Maternal heritability estimates ranged from 0.05 for LW and FD, to 0.10 for clean fleece weight (CFW). The proportion of the total phenotypic variance due to the maternal permanent environment variance (c2pe) amounted to 5% for fleece weights. The genetic correlation between animal effects for LW, greasy fleece weight (GFW) and CFW were -0.28, -0.65 and -0.70 respectively. The genetic correlation between LW and CFW was positive, but low at 0.14. The other important genetic correlations among the wool traits ranged from low to high, and were variable in sign ((for GFW with CFW (0.87) and with staple length (SL - 0.18); CFW with clean yield (CY - 0.33) and with SL (0.29); FD with CY (-0.09), with SL (0.15), with SS (0.40) and with standard deviation of FD (SDFD - 0.38): CY with SL (0.33) and with SDFD (0.10); SS with coefficient of variation of FD (CVFD - -0.57) and with SDFD (-0.28); CVFD with SDFD (0.87)). These results suggested that worthwhile responses in the objectively measured traits can be achieved through direct and indirect selection.
publisher The South African Society for Animal Science (SASAS)
publishDate 2009
url http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0375-15892009000100008
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