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The value of visual fleece assessment in addition to objective measurements in identifying Angora goats of greater clean mohair production

McGregor,BA and Butler,KL 2014, The value of visual fleece assessment in addition to objective measurements in identifying Angora goats of greater clean mohair production, Small Ruminant Research, vol. 120, no. 1, pp. 51-63, doi: 10.1016/j.smallrumres.2014.04.001.

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Title The value of visual fleece assessment in addition to objective measurements in identifying Angora goats of greater clean mohair production
Author(s) McGregor,BAORCID iD for McGregor,BA orcid.org/0000-0002-4574-4236
Butler,KL
Journal name Small Ruminant Research
Volume number 120
Issue number 1
Start page 51
End page 63
Total pages 13
Publisher Elsevier
Place of publication Amsterdam, The Netherlands
Publication date 2014
ISSN 0921-4488
Keyword(s) Animal assessment
Economic traits
Fleece assessment
Mohair quality
Objective assessment
Subjective assessment
Science & Technology
Life Sciences & Biomedicine
Agriculture, Dairy & Animal Science
Agriculture
GENETIC-PARAMETERS
ALLOMETRIC RELATIONSHIP
SUBJECTIVE ATTRIBUTES
FREE LIVEWEIGHT
WOOL PRODUCTION
FIBER DIAMETER
QUALITY TRAITS
MERINO SHEEP
BODY-WEIGHT
LIFETIME
Summary Visual assessment of the fleece of Merino sheep is an accepted method to aid genetic improvement but there is little evidence to support the use of visual assessment for improving mohair production. This paper examines the extent that visual traits, including staple length, character (staple crimp), staple definition, tippiness, style and staple entanglement, are related to clean fleece weight in animals of similar live weight and mean fibre diameter (MFD) from the same flock. Measurements were made over 9 shearing periods on a population of castrated Angora males (wethers) goats representing the current range and diversity of genetic origins in Australia, including South African, Texan and interbred admixtures of these and Australian sources (these different genetic origins are defined as Breed in this work). Data on genetic origin, sire, dam, lifetime characteristics (date of birth, dam age, birth weight, birth parity (single or twin), weaning weight), live weight, fleece growth and visual fleece attributes were recorded. A restricted maximum likelihood (REML) model was developed to relate clean fleece weight with age, MFD, average fleece-free live weight, lifetime characteristics and visual fleece attributes. There were separate linear responses of clean fleece weight to MFD and staple length for each age group, a quadratic response to the square root of average fleece-free live weight, an effect of sire breed and linear responses to dam age, staple definition score and character. Depending on age at shearing, the increase in clean fleece weight was between about 50 and 80. g for each increase of 1. μm in MFD. At similar MFD, clean fleece weight was generally greater at summer shearings compared with winter shearings. There was a strong increase in clean fleece weight with average fleece-free live weight up to around 50. kg but little response in clean fleece weight for animals larger than 50. kg. There was some evidence of a smaller increase in clean fleece weight as the age of dam increased. There was an effect of Breed in the model but this effect disappeared when a random sire effect was included in the model. There was a positive response to staple length at some age groups but the response did not differ from zero in other age groups. This response varied from negligible to about 70. g per 1. cm increase in staple length. Clean fleece weight increased about 40. g per unit increase in staple definition score and increased about 30. g for every 4 units increase in the number of staple crimps. There was no evidence that clean fleece weight was affected by staple style, staple tip score or staple entanglement score or lifetime factors such as birth weight, date of birth, birth parity, or weaning weight. The results show that using a combination of measuring MFD and visually assessing the fleece for staple length, staple definition and crimps can help identify the most profitable Angora goats. In this process, the objective measurement of MFD appears essential. Visual assessment will provide some extra benefit in identifying these animals above that provided by measuring MFD alone. Animal size should be considered by mohair producers when identifying more productive mohair producing animals. © 2014 Elsevier B.V.
Language eng
DOI 10.1016/j.smallrumres.2014.04.001
Field of Research 070203 Animal Management
070201 Animal Breeding
Socio Economic Objective 830304 Goats
HERDC Research category C1 Refereed article in a scholarly journal
ERA Research output type C Journal article
Copyright notice ©2014, Elsevier
Free to Read? Yes
Persistent URL http://hdl.handle.net/10536/DRO/DU:30069689

Document type: Journal Article
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Every reasonable effort has been made to ensure that permission has been obtained for items included in DRO. If you believe that your rights have been infringed by this repository, please contact drosupport@deakin.edu.au.