New Zealand Journal of Agricultural Research abstracts
Medullation and average fibre diameter vary independently in the wool of Romney
sheep
D. R. SCOBIE
A. R. BRAY
N. C. MERRICK
AgResearch
P. O. Box 60
Lincoln, New Zealand
Abstract The proportion of medullation was less in wool from
a line of Romney sheep selected for High staple tenacity (HST) than in one
selected for Low staple tenacity (LST) (1.15% versus 1.58% in 1991-born ram
hoggets, P < 0.076; 1.90% versus 3.10% in 1992-born ewe hoggets, P
< 0.001). This occurred despite the HST line having the greater mean
fibre diameter (ram hoggets 35.2 versus 33.1 um, P < 0.001; ewe
hoggets 35.1 versus 31.8 um, P < 0.001). Rams from the selection
lines were fed diets containing high and low levels of protein and energy.
During the treatment period, the high protein diets increased average fibre
diameter by 14% (P < 0.001) and the proportion of medullation to 5.6%
compared with 3.8% for the low protein diets (P < 0.001). During the
post-treatment period, fibre diameter was 12% higher in the groups fed the high
protein diet relative to the low protein diet (P < 0.001), but the
proportion of medullation fell to 4.9% for the high protein diets, increased to
4.4% for the low protein low energy diet, and fell slightly for the low protein
high energy diet (P < 0.067). The results of these experiments
indicate that the proportion of medullation in Romney wool can vary
independently of average fibre diameter.
Keywords nutrition; staple tenacity; selection lines;
multiple medullae
New Zealand Journal of Agricultural Research, 1998, Vol. 41: 101-110
0028-8233/98/4101-0101 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (1355K); (scanned from paper original: notes about this process)
This year's abstracts |
Journal home page |
All abstracts |
Publishing home page
