SELECTION INDEX FOR WOOL IMPROVEMENT IN BARKI SHEEP | ||||
| Journal of Animal and Poultry Production | ||||
| Article 4, Volume 7, Issue 1, January 2016, Page 33-38 PDF (416.44 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2016.48265 | ||||
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| Authors | ||||
H. M El-Gabbas  1; Salwa I. El-Wakil2
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| 1Wool Production and Technology Dept., | ||||
| 2Animal and Poultry Breeding Dept., Desert Research Centre, El-Matareya, Cairo, Egypt | ||||
| Abstract | ||||
| The present study was carried out to estimate genetic and phenotypic parameters for some subjective and objective wool traits to develop a suitable selection index for wool improvement in Barki sheep. Over 937 fleeces were obtained from three Barki sheep flocks along the north western coastal belt of Egypt together with full pedigree information for those 937 animals descended from 74 sires and 896 ewes. After the first shearing, a composite wool sample was collected to represent the entire fleece of each animal. The greasy wool samples were subjectively assessed for kemp score, KS, greasy colour grade, GCG, handle grade, HG, lustre grade, LG, bulk grade, BLG and measured for staple length, STL. After scouring, the scoured colour grade, SCG was also assessed. SAS and MTDFREML statistical programs were used to generate analysis of variance and estimating genetic and phenotypic parameters as well as constructing selection indexes. Results indicated that Barki wool had higher than average kemp content (2.45), slightly softer handle (3.20) and lustrous (3.48) and of average compressibility (2.41) with an average staple length of 10.31cm. Barki wool appeared to be slightly less than average of whiter greasy colour (2.02) and slight improvement occurred after scouring (2.83). Flock had highly significant effect on all studied traits while sire within flock showed highly significant effect on KS, HG, LG and STL. Heritabilities were estimated for KS (0.73), GCG (0.03), HG (0.62), LG (0.47), BLG (0.13), SCG (0.09) and STL (0.58). KS had highly significant and positive genetic correlations with all studied traits, while phenotypically it was significantly associated with harsher and lustrous wool. Estimates of genetic and phenotypic parameters were used to construct selection indices using different combinations of the studied traits for wool improvement. The maximum accuracy of selection (RTI = 1.10) was obtained using the full index incorporating all studied traits. The present study recommended the utility of selection index included GCG, LG and STL (RTI = 0.84 with relative efficiency of 76.4%) since selection based this index would be adequate for wool improvement and its application would lead to maintain low level of kemp content and reasonable level of harshness, improve greasy and scoured colour with marked increase in wool luster and staple length which could be contributed to enhance wool quantity produced. | ||||
| Keywords | ||||
| Barki sheep; subjective wool traits; Genetic and phenotypic parameters; selection indexes | ||||
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