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Estimated Progeny Differeces - Sire Reference Scheme 2005-2007
The results below are fleece characteristics, growth rate, faecal egg count and temperament measurements for progeny of sires selected in 2005, 2006 and 2007 for the Sire Reference Scheme. The results are expressed as Estimated Progeny Differences (EPD) which; is the measure of an animal's (the sire's) own breeding value passed onto the progeny. The breeding value can also be expressed as Estimated Breeding Values (EBV) however, this is calcualted using the genetic merit of both sire and dam. |
Estimated Progeny Differences of Selected Bucks
Fleece Characteristics – 1st shearing
There are large differences among sires in the ranking of fleece characteristics. DYNB50/4800 is ranked highest using the McGregor Index (23.05) – although its fibre diameter was not the finest (0.50 µm above the mean); the overall ranking was compensated for by its high down fleece weight (41.34 g). ATJU084 had the finest fleece (-0.50 µm). Both ATJW052 and Y1584 had a finer than average fibre diameter as well as a down fleece weight (20.04 g and 6.93 g respectively) that was above average (Table 1). Ideally, a sire will have a high positive EPD for down fleece weight and a more negative EPD for fibre diameter. However, the correlation between these two fleece traits is negative so selection is generally made in one direction (eg, down fleece weight) before the other (eg fibre diameter).
Sire/Rank Down Fibre diameter (µm) Down Fleece weight (g) McGregor Index DYNB50_4800 0.50 41.34 23.05 ATJW052 -0.08 20.04 13.69 Y1584 -0.11 6.93 5.57 RBGZ26 -0.43 -0.28 3.61 MACA005 0.22 9.18 3.40 UWA2002A078 0.14 4.51 3.32 MTAY40 -0.71 -4.82 2.95 ATJU084 -0.50 -5.34 0.71 DMR131 0.08 -1.80 -0.84 KABB39 0.27 -0.56 -1.64 UWA2002A272 0.15 -2.04 -1.81 DIA377 0.65 6.16 -2.83 BRB102 0.38 -0.18 -3.23 ATJ113 -0.45 -13.59 -3.56 DYNR205_1847 0.11 -8.66 -7.00 HTE23 0.18 -6.73 -7.52 BRB301 -0.32 -22.17 -12.61 KDCGZ158 -0.08 -21.98 -15.25 Table 1. Estimated progeny differences for fleece characteristics of the sire group kids 1st shearing. Fleece Characteristics – 2nd shearing
Large differences among sires are also seen in the ranking of fleece characteristics for the 2nd shearing. DYNB50/4800 is ranked highest using the McGregor Index (30.35) – again its fibre diameter was not the finest (0.78 µm above the mean); but the overall ranking was compensated for by its high down fleece weight (65.95 g). MTAY40 had the finest fleece (-0.83 µm) but was below the mean for down fleece weight. ATJW052 had a finer than average fibre diameter as well as a down fleece weight (39.97 g) that was above average (Table 2).  Table 2. Estimated progeny differences for fleece characteristics of the sire group kids 2nd shearing.
Growth
Birth to 12 months
The EPD for birth weight and growth are compared across sires from all 3 years 2005 - 2007, up until 12 months of age (Fig. 1). UWA2002A272 from Western Australia had the heaviest weight at birth (0.24 kg) above the mean. HTE23 (NSW) and UWA2002A272 were heaviest at weaning (0.20 kg and 0.19 kg) respectively. At 6 months kids of sire BRB102 from Victoria were heaviest (1.05 kg) above the mean. UWA2002A272, HTE23 and BRB102 kids by twelve months had lost weight whereas Y1584 had gained (1.28 kg) above the herd mean.
Figure 1. Estimated progeny differences for body weight from birth to 12 months of age for all sire groups, 2005-2007.
Worm resistance
The top sires with a lower worm egg count (more resistance) than the herd mean were DYNR2005/1847 (-815 epg) and MTAY40 (-652 epg). Sire Y1584 showed least resistance (1030 epg more than the average) followed by UWA2002A078 with (380 epg) (Fig. 2).
Figure 2. Estimated progeny differences for faecal worm egg count for each sire group from all years, 2005-2007.
Temperament
Temperament is the ‘emotional reactivity to a novel environment or stressor’. We used an ‘isolation box’ to isolate the animal from its flock/herd mates for a period of 1 minute, during which time we measured the level of agitation. ‘Calmer’ or less agitated animals have low counts whereas ‘nervous’ animals have high counts. Temperament has been studied extensively in cattle and sheep. In sheep, lamb survival rate is higher in calm mothers than in nervous mothers. Sire DMR131 had the calmest progeny whereas ATJU084 had the most nervous progeny (Fig. 3). However, these temperament tests have been developed for sheep and may not necessarily be the most suitable for goats. Measuring temperament in goats requires further development.
Figure 3. Estimated progeny differences for the results of the isolation box test for each sire group from all years (2005-2007). |
