In May 2022 Sheep Genetics made some changes to the analysis. The link below is some documentation to add some clarity to the changes. Overall they have had very little effect on the ASBVs for Felix Rams. This is not the complete document – only the pages relevant to terminals have been included.
Our thoughts:
We have been scoring lambing ease since 2004, birthweights since 1996 and gestation length since 1998, and optimising birthweight in our internal selection index for 20 years.
Lambing ease ASBVs (LE_DIR) have been added to the terminal indexes. LE_DIR ASBVs are a combination of birthweight, lambing ease scores, and gestation length. Virtually every lamb in our flock is weighed at birth, however there are very few scores for lambing ease problems as we have selected for moderate birthweight for many years. Gestation length is only recorded on lambs where the conception date is known, such as AI or pen mated animals. Again only a small percentage in most flocks. Selecting for short gestation beyond an optimum will lead to increased lamb mortality. While there may be some merit in looking at LE_DIR ASBVs, due to the lack of lambing ease scores, and relative lack of gestation length records, we still believe that selecting for ASBVs for moderate birthweight is the best way to reduce lambing problems and increase lamb survival. The average accuracy for BWT ASBVs for our sale rams is 73%, while the average accuracy for LE_DIR is only 44.5%.
LE_DIR ASBVs are included in the XLS version of our catalogue, the AuctionsPlus catalogue, but not in the standard PDF version.
We believe the TCP, EQ and LEQ indexes provide only limited value to lamb producers because of their significant weighting on eating quality traits, particularly shear force. You will still see in our catalogue that about 95% of the offering are in the top 20% (many in the top 1%) for these indexes, but this is mainly because we target a balance of all the ASBVs, rather than using an index that has a heavy weighting on several traits. We firmly believe you need to look at the ASBVs that are important to you, rather than focusing on a generic index. The indexes are provided in our catalogues for reference because they are promoted by Sheep Genetics as an industry standard.
This DOES NOT mean we don’t see eating quality as being important, more so that it is very important for the good of the industry, but selection for these traits is a long haul. The accuracy and repeatability for these traits does not warrant lamb producers putting a lot of emphasis on them when selecting flock rams at this time. Producers will be better served by selecting a balance with other traits like growth, muscle and lean meat yield. Over 80% of our offering is above the terminal average of -0.46 for IMF.
Data Quality Scores – both our flocks are 5 Star for data quality.
