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Analysis changes

LAMBPLAN 15 June 2012

MERINOSELECT 21 June 2012

LAMBPLAN

The June 15th LAMBPLAN analysis will introduce a number of updates and analysis changes that are all aimed at improving how information is captured and utilised to produce higher accuracy ASBVs.

This may lead to some re-ranking of animals however the ultimate outcome and aim of these changes is to provide ASBVs that can be utilised by the breeder with greater confidence to improve animal selection.

The changes are outlined below and further in depth support material is available for each.

New reproduction analysis

A new analysis has been developed to improve the way in which ASBVs for Number of Lambs Born (NLB) and Number of Lambs Weaned (NLW) are estimated.

The new reproduction analysis will only use information from flocks that are directly recording reproduction traits (mothering up and identifying DRY ewes)

If flocks are not directly recording reproduction traits, correlated information from weight and scrotal circumference will not be used to estimate reproduction ASBVS

Reproduction performance for yearling ewes will now be analysed under new traits

  • Yearling number of lambs weaned (YNLW)
  • Yearling number of lambs born (YNLW)

Combined maternal analysis

A new across breed maternal analysis is being introduced to allow direct comparison between Border Leicester, Coopworth, East Friesian and Composite Maternals breeds. The dual purpose breeds (Corriedales, SAMMs and Dohnes) will continue to be analysed within their own individual breed analyses.

The across breed maternal analysis will allow direct comparison between the included breeds. Information is analysed together and breeding values reported relative to a common base. The Border Leicester base will be used for the new analysis as it is the largest and most stable data set. All breeds included in the combined analysis will now have their figures derived relative to the Border base.

Updated Trade$ and Export$ indexes

The Trade$ and Export$ indexes have been updated to create two indexes that clearly identify high fat and low fat rams in terms of how well suited their progeny will be for different markets. The indexes now have a heavier optimisation on fat, while using the same weightings for WT and EMD as LAMB2020.

Weaning scans for the LAMBPLAN Maternal analysis

Weaning scan ASBVs (WEMD and WFAT) are now being produced in the LAMBPLAN maternal analysis. Genetic gains in growth rate have been made such that animals are reaching a stage of maturity where scanning is possible at an earlier age. Taking advantage of this will mean information on animal performance is known earlier thus allowing for earlier breeding decisions.

Merinoselect

Reproduction analysis

The key to producing accurate reproduction ASBVs is to capture and utilise direct reproduction data

  • The new reproduction analysis will only use information from flocks that are directly recording reproduction traits (mothering up and identifying DRY ewes)
  • If flocks are not directly recording reproduction traits, correlated information from weight and scrotal circumference will not be used to estimate reproduction ASBVS
  • Reproduction performance for yearling ewes will now be analysed under new traits
  • Yearling number of lambs weaned (YNLW)
  • Yearling number of lambs born (YNLB)

Indexes

With the current MERINOSELECT indexes all having a significant part of the index made up by NLW there will be significant re-ranking of animals on the Indexs based on animals no longer having NLW available.

To address this, the MERINOSELECT indexes have been updated to account for changes in meat and wool prices, and to create two types of indexes:- new ‘core’ indexes that only utilise the most commonly measured traits (WT, FD, FDCV, CFW), and ‘plus’ indexes that use additional traits, such as fertility, staple strength, eye muscle or worm resistance.

The recently completed Merino Breeding Review Survey showed that there are significant differences in how breeders place emphasis on traits based on their production system, wool type, current adult ewe fleece weight and current adult ewe fibre diamter. Examples of some traits that breeders valued higher include curvature, NLW, Staple Strength, Eye Muscle Depth and Worm Egg Counts.

There will be 6 new indexes with a core and plus index for the three major production systems. These are:

  • Wool Production, Wethers are maintained for wool production
  • Wool Production and surplus sheep, wethers are sold
  • Dual Purpose Wool and Meat Production, Wethers are sold & 25% of ewes are joined to a terminal sire.

The 6 new indexes are

  • Fibre Production (FP)
  • Fibre Production Plus (FP+)
  • Merino Production (MP)
  • Merino Production Plus (MP+)
  • Dual Purpose (DP)
  • Dual Purpose (DP+)

Their responses for fleece weight and fibre diameter are below.

 

 news-analysis-bodyweight.jpg

 

Their responses for body weight and fibre diameter are below.

 news-analysis-fleeceweight.jpg

Weaning Scans
Weaning scan ASBVs (WEMD and WFAT) are now being produced in the MERINOSELECT analysis.

Genetic gains in growth rate have been made such that animals are reaching a stage of maturity where scanning is possible at an earlier age. Taking advantage of this will mean information on animal performance is known earlier thus allowing for earlier breeding decisions.

Weaning scans, while still within the weaning age bracket, are likely to be taken after physical
weaning. There will therefore be a weight taken at physical weaning and a second taken at time of
scanning. This will result in two separate weights taken during weaning age, these repeated weaning
weights are both necessary and will both be utilised within the analysis to produce the most
accurate ASBVs possible.

The normal scanning requirements still apply; animals must all be above 30kg and minimum
average condition score of 2.