Please use this identifier to cite or link to this item:
https://hdl.handle.net/1959.11/8185
Title: | Estimates of genetic and phenotypic parameters for production, haematological and gastrointestinal nematode-associated traits in Australian cashmere goats | Contributor(s): | Olayemi, Muyiwa (author); Bolormaa, Sunduimijid (author); Van Der Werf, Julius H (author) ; Baillie, Neil (author); Le Jambre, Leo (author); Walkden-Brown, Steve W (author) | Publication Date: | 2011 | DOI: | 10.1071/AN10035 | Handle Link: | https://hdl.handle.net/1959.11/8185 | Abstract: | The present study was designed to estimate genetic parameters of 17 production, parasite-associated and haematological traits in Australian cashmere goats. It comprised 796 records of female progeny of 532 dams sired by 29 bucks over a 4-year period. Measurement of haematological and parasite-associated traits was carried out on female kids during low-level natural gastrointestinal nematode challenge at 3 and 5 months of age and at 28 and/or 35 days after artificial challenge with 10 000 infective larvae of 'Trichostrongylus colubriformis' administered 1 week after the 5-month measurement. Production traits were measured up to 18 months of age. Year of birth significantly affected all traits apart from cashmere diameter (CSD). Twin kids had significantly lower liveweight (up to 10 months), packed cell volume and mean corpuscular volume (at 3 and 5 months) but higher specific IgG levels and mean corpuscular haemoglobin content at 3 months. Paddock of birth and early rearing and its interaction with year of birth had significant effects on worm egg count (WEC) during natural challenge, on IgG at both natural and post-artificial challenge measurements and on liveweight at early ages. The level of gastrointestinal nematode challenge in the nine different paddocks clearly influenced both WEC and IgG during natural and subsequent artificial challenge. Maternal permanent environmental effects were important only for liveweights at 3 month of age and for IgG at 5 months of age. For other traits, a simple animal model without maternal permanent environmental effects gave the best fit. Estimates of heritability (h²) of WEC and IgG were low (0.06–0.22) with the highest h² estimates occurring after 5 months of natural infection or 35 days after artificial challenge. The majority of fleece traits were moderately to highly heritable, ranging from 0.38 to 0.78. The h² estimates for mean fibre curvature are novel for cashmere goats and were moderate, varying from 0.32 to 0.48. Heritability estimates for erythrocyte traits were uniformly high (0.49–0.98) while those for leukocyte traits varied from low to moderate (0.09–0.43). Strong genetic and phenotypic correlations existed between major production traits. Due to the comparatively small dataset, the standard errors of genetic correlations were relatively high. CSD was positively correlated with cashmere weight and yield, an unfavourable direction. CSD was negatively correlated with fibre curvature, indicating that animals producing finer fibres produce cashmere with a higher crimp count. No phenotypic relationships were observed between WEC and fleece traits. Liveweight was weakly but negatively correlated with WEC and circulating neutrophils, while it was positively associated with eosinophils, lymphocytes and packed cell volume. This study has shown that selection for increased resistance to gastrointestinal nematode infection cashmere goats is possible but progress will be slow. WEC should remain the phenotypic marker of choice and the additional cost of alternative measures of resistance is not justified. Many of the parasite-associated traits appear to under independent genetic control. | Publication Type: | Journal Article | Source of Publication: | Animal Production Science, 51(2), p. 123-134 | Publisher: | CSIRO Publishing | Place of Publication: | Australia | ISSN: | 1836-5787 1836-0939 |
Fields of Research (FoR) 2008: | 070201 Animal Breeding 070708 Veterinary Parasitology |
Socio-Economic Objective (SEO) 2008: | 830304 Goats | Peer Reviewed: | Yes | HERDC Category Description: | C1 Refereed Article in a Scholarly Journal |
---|---|
Appears in Collections: | Journal Article |
Files in This Item:
File | Description | Size | Format |
---|
SCOPUSTM
Citations
5
checked on Jun 29, 2024
Page view(s)
1,374
checked on Jul 7, 2024
Download(s)
2
checked on Jul 7, 2024
Items in Research UNE are protected by copyright, with all rights reserved, unless otherwise indicated.