Wool
Livestock
Exploit genetic differences for best sires
by
Trevor Pollard,
DEPARTMENT OF NATURAL
RESOURCES AND ENVIRONMENT,
VICTORIA
ibre diameter and fleece weight
differences vary significantly between and
within Merino bloodlines and producers can
use this to their advantage by becoming more
demanding of studs for genetic information.
Such information will enable producers
to identify the best genetic material for
ram selection.
Progeny testing showed the fibre diameter
and fleece weight differences among sires
resulted in an average difference in fleece
value of more than $7 per head and a
maximum of almost $20/head (see Table 1).
The average difference in fleece value
among the progeny groups of different
bloodlines was more than $2/head.
Objective information such as estimated
breeding values (EBVs) can be made available
for most of the economically important
wool traits.
Beth Field
F
On-farm progeny tests
Previous analysis of wether trials on a
national basis has shown a large range in
TABLE 2 Bloodline performance*
Maximum Mean
bloodline bloodline
difference1 difference
over all
sites
Fibre diameter (microns)
1.0
0.5
Fleece weight (kg)
0.55
0.21
Fleece value ($)2
5.62
2.20
* Differences in performance for 11 sites.
1. Site showing the largest difference in
performance between best and poorest
bloodlines. 2. Based on five-year average
wool prices.
Source: DNRE, Victoria.
Producers are encouraged to obtain estimated breeding values from studs before selecting sires to gain
the best genetic source for their purposes.
bloodline performance. The identification
and purchase of genetically superior sires
depends on the availability of comparative
data and its understanding by commercial
producers.
So, from 1997 to 2001, progeny testing
was carried out on 46 properties with
assistance provided to producers to set up
on-farm comparisons of individual sires
and bloodlines.
Ewes were allocated randomly to mating
groups, run in separate mobs for joining and
lambing and managed as one mob
throughout pregnancy.
All lambs were identified to their sire
group at weaning and then managed as
one mob.
sire relationships only with sex as a fixed
factor and animal as a random factor.
Acknowledgements: Mark Ferguson, Kon
Konstantinov, Lyndon Kubeil and Peter
Heazlewood, DNRE, Victoria.
For more information contact Trevor Pollard
by email on [email protected], phone
(03) 5573 0900 or fax (03) 5573 0900.
Comparing bloodlines
Table 2 shows the performance of 23
bloodlines from ram sources on 11 properties.
In these trials wool micron varied by up to
1µm between bloodlines and fleece weight
varied by more than 0.5 kilograms.
Fleece weight of the progeny was recorded
at hogget shearing with 10–12 months’
wool growth.
Mean fibre diameter was measured for
mid-side samples taken before shearing.
EBVs were calculated with the analysis using
TABLE 1 Differences in sire performance for 35 test sites
Estimated breeding value (EBV) fibre diameter (microns)
Estimated breeding value (EBV) fleece weight (%)
Fleece value ($)1
Maximum sire
difference*
Mean sire difference
over all sites
3.9
2.0
54
21
19.06
7.25
* Site showing the largest difference in performance between best and poorest rams.
The performance of 7668 progeny of 216 individual sires was measured. 1. Based on
five-year average wool prices.
Source: Department of Natural Resources and Environment, Victoria.
FA R M I N G A H E A D
No. 135
March 2003
61