Sire Reference Scheme 2005

Seven bucks were selected from grower’s nominations and were used in the artificial insemination (AI) program in the first year of the project.

Laparoscopic artificial insemination was carried out over two days in the beginning of March. Does AI’d to each sire were randomised on the basis of age and previous years cashmere production. Two weeks after the AI the does were drafted into two mobs and single sire mated to one of two bucks. One of these bucks (UWA 78) had been used in the AI program, so the second buck (UWA T272) was able to be included in the evaluation as there was a genetic link to the AI mating.

Prior to kidding does were drafted into sire groups and moved into fox proof kidding paddocks. At birth kids were tagged and litter size and weight recorded. As soon as kidding finished all does and kids were run as one mob. Monthly weighing of kids was carried out until weaning and at weaning individual faecal samples were taken from all kids and worm egg counts done. A test was also carried out to assess temperament of the newly weaned kids. This test is based on one used in the sheep industry and gauges each animals reactions to being isolated from its flock mates.

From weaning body weighing is being carried out on a three monthly basis to show possible differences in growth rate and mature body weight.

Shearing is due to take place in the third week of June.

Estimated Breeding Values of Sire Groups 2005

Growth

There is a marked difference in growth rate of progeny between the top performing sire UWA 272 and the slower growing progeny of sire Rix. The mean difference in weight at 7months of age between these two sires was 5.5kg. The WA (UWA 272 & 78) and Qld (James) sired progeny had the fastest growth rate compared to progeny sired from bucks located in the eastern states region (Fig 1).

Figure 1. Mean growth rate of progeny for each sire group from birth to 16 months.

Based on the estimated breeding values (EBV) calculated for birth weight UWA sire 272 performed the best at (0.26kg). James and Muirhead where the only other sires that produced progeny with a birth weight EBV greater than flock mean (Fig 2.).

Figure 2. Estimated breeding values of birth weight for each sire group.

The EBV for weaning weight shows that UWA sire 272 is the best performer again at (1.3kg). The UWA sire 72 that had the lowest EBV for birth weight is now the second top performing sire (0.27kg). The Bell sire now has a positive EBV where as the Muirhead sire EBV has shifted to below the flock mean (Fig 3.).

Figure 3. Estimated breeding values of weaning weight for each sire group.

Worm resistance

The average faecal worm egg count of kids sampled was 828 with a standard deviation of 645 eggs per gram (epg). These figures indicate that the kids received a satisfactory challenge during the test period. The top sire’s with a lower worm egg count (fewer epg than the flock mean) was Rix (-234) and Esson (-87). UWA 78, Murihead and Bell all had a worm egg count greater than 240 epg.

Figure 4. Estimated breeding values of faecal worm egg count for each sire group.

Temperament

Temperament is described as the emotional reactivity to a novel environment or stressor. The isolation box test isolates the animal from its flock/herd mates for a period of 1 minute. During this time the animals response to isolation (level of agitation exhibited while in the box) is measured. The more “calm” or less agitated the animal the lower number of counts conversely, the more “nervous” the higher number of counts is measured. Temperament has been studied extensively in cattle and more recently sheep temperament has been under investigation, with studies showing calmer mothers have an increased lamb survival rate.

Sires Bell and James are the most calm sires with lower than average agitation scores while, Adamson and Rix were the most nervous (Fig 5.). It is interesting to note that the four most calm, sires where the same four sires that had the highest weaning weight EBV’s.

Figure 5. Estimated breeding values of the isolation box test for each sire group.