Medullated fibres and fleece characteristics in Corriedale hoggets from two flocks in Uruguay
I. Sienra A C , K. Neimaur A , R. Kremer A and J. I. Urioste BA Departamento Ovinos, Lanas y Caprinos, Facultad de Veterinaria, UDELAR, Lasplaces 1550, Montevideo, Uruguay.
B Departamento Producción Animal y Pasturas, Facultad de Agronomía, UDELAR, Garzón 780, Montevideo, Uruguay.
C Corresponding author. Email: isienra@hotmail.com
Animal Production Science 51(11) 1034-1038 https://doi.org/10.1071/AN11031
Submitted: 3 March 2011 Accepted: 7 September 2011 Published: 25 October 2011
Abstract
The incidence of medullation in 549 Corriedale hoggets from two experimental flocks, its association with other characteristics of the fleece, and the sire effect were evaluated. The investigation was carried out during 2005–06 in hoggets from the Faculty of Agriculture and Faculty of Veterinary Science experimental flocks. Fleeces were weighed and samples were taken at shearing by picking 104 staples from fleeces to measure medullation. A mid-side wool sample was taken to determine wool characteristics (fleece weight, wool yield, mean fibre diameter, staple strength and length). A Dark Fibre Detector was used to identify total medullated fibres and fibre type: medullated fibres (med) and kemp, which were confirmed by light microscope. Mean total medullated fibres, med and kemp content per 10 g of clean wool were 4.2 ± 11.2; 2.0 ± 8.9 and 2.3 ± 4.9, and median values were 0.9, 0.0 and 0.7, respectively, in 549 fleeces. A high variability between samples and a higher proportion of hoggets with kemp fibres than those with med were observed. There were significant differences between sire families for total medullated fibre content/10 g, med fibre content/10 g and kemp fibre content/10 g, but there were no significant effects between flocks, years or interaction between them. Phenotypic correlations between medullated fibre content and wool characteristics were generally low (less than 0.19). In conclusion, medullated fibre content was highly variable between samples and was not strongly correlated with other fleece characteristics. Medullation varied between sire groups, suggesting genetic variation, which could be exploited to improve wool quality.
Additional keywords: fibre diameter, kemp, medullation, wool.
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