Page 9 - Stud Ram and Ewe Fair 2020
P. 9

For every analysis SIL sets 1995 as the benchmark year and the average genetic merit
       of lambs born in 1995 is set to zero. Therefore, eBVs are measures of genetic merit for a
       ram compared to the 1995 average for that evaluation. If two flocks had different average
       genetic merit in 1995 the eBVs would have to be adjusted for the difference to make them
       comparable.
       When selecting a ram that is high genetic merit it is important to first select the flock the ram
       was bred in. The ram should rank highly within that flock for the key traits you are interested
       in. Index values provide the best guide to overall genetic merit across traits.

       In summary, whichever flock you decide to buy a ram from, be sure to select one that is
       highly ranked by SIL. This will guarantee improved genetic merit in your flock compared to
       using rams selected without an accurate assessment of genetic merit.

       EXPLANATIONS FOR COMMONLY USED SIL DATA
        Abbreviations Definition

        eBV              eBVs (estimated breeding values) are expressed in the units the
                         trait is measured in, and are an estimate of the value of the ram’s
                         genetic merit for the trait.
        eBV Accuracy     Indicates the amount of information used in the prediction of the
                         eBV. Traits that are more heritable and more related to other traits
                         they are predicted from have higher accuracy.
        WWT eBV          Weaning weight – “lamb growth”

        LW8 eBV          Body weight at 8 months of age – rates animals for post-weaning
                         growth
        FATY eBV         (Whole carcass) Fat yield – kg per kg of carcass
        EMA eBV          Eye muscle area

        EMAc eBV         Eye muscle area corrected for carcass weight – a measure of
                         muscularity
        FAT eBV          Weight of fat in carcass

        FD eBV           Fat depth ‘C
        NLB eBV          Number of lambs born
        FW12 eBV         Fleece weight at 12 months of age
        NZTW index       New Zealand Terminal Worth is expressed in cents and is an
        (previously TSO)  estimate of genetic value for growth (TSG), meat yield (TSM)
                         and survival (TSS).
        NZMW index       New Zealand Maternal Worth is expressed in cents and is an
        (previously DPO)  estimate of genetic value for number of lambs born (DPR), lamb
                         survival (DPS), lamb growth + adult size (DPG+A), meat yield
                         (DPM), and wool production (DPW).

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