Over the last three decades, LIC has invested more than $70 million to improve the accuracy of its animal evaluation system, with better predictions on breeding worth coming from improved data over time.
Differences can be seen between NZAEL BW, which does not include genomic information, and LIC’s genetic merit output (gBW), which has a component of genomic information included. The genomic component contributes throughout the lifetime of an animal, including for daughter proven bulls.
LIC’s Herd Improvement Technical Manager, Rachel Bloxham, says, “As more cows get genotyped, the more information we have, and the more accurate our predictions will become, to ensure we continue to support breeding profitable and efficient cows that will convert feed into profit for dairy farmers now and for the future. The new model is perhaps the greatest step forward in animal evaluations since Breeding Worth was introduced in 1996 – it’s an exciting development.”
FAQs about the Single-Step Animal Model
What is different about the new model?
A key feature is that the Single-Step Animal Model analyses the complete New Zealand dairy population (approx. 30 million deceased and current, genotyped and non-genotyped animals) simultaneously, allowing the benefit of genomic data to flow through a larger proportion of the population.
Why do bulls have a different BW on LIC’s website compared to NZAEL’s?
While both evaluation systems (NZAEL 2.0 and SSAM) utilise the same ancestry and phenotypic information, the Breeding Worth and Breeding Value figures shown by LIC contain genomic information, whereas NZAEL’s results currently don’t.
How can an animal’s values be affected by genomics if the animal hasn’t been genotyped?
Ancestry and all known relationships to an animal play a critical part in any animal evaluation system. This is no different with the inclusion of genomic data. The new Single-Step Animal Model uses all information (production, TOP, genomics, pedigree) for all animals (all breeds, historical, current, genotyped, non-genotyped) at the same time (in one single step), resulting in the flow of genomic information across multiple generations, up and down a pedigree.
Do you know if the new model is better than the previous model?
Validation of the 11-code, 12-code, 13-code and 14-code cohorts of LIC’s Sire Proving Scheme (these animals now have daughters with milk recording data) shows use of the new Single Step Animal Model has resulted in an 8% increase in genetic merit prediction accuracy (i.e. comparing genomic predictions to actual daughter proofs).
Does inclusion of genomic information make the gBW of bulls increase or decrease?
Genomic data is another piece of information used in the estimation of an animal’s genetic merit. The inclusion of genomics can result in an animal’s gBW moving, either up or down. The overall outcome is more reliable estimates for all genomic bulls.
Why does LIC still include genomic information in daughter proven bulls?
Inclusion of genomic information for bulls that are already daughter proven gives LIC additional information on the slow maturing traits like fertility and longevity
As the bull’s daughters complete additional lactations and we gain more phenotypic data, the amount of genomic influence decreases. For traits where the daughter phenotype is measured later in life, it takes longer for the information provided by genomics to be dominated by phenotypic data.
What measure is LIC marketing their bulls on?
LIC will be marketing their bulls on gBW, and will continue to select their bulls on a wide range of traits. The intention is to provide dairy farmers with the best bulls to meet their individual breeding objectives.
Was the earlier genomic information inaccurate?
No – the earlier models produced positive results. The success the breeding programme is reflected in the number of LIC bulls on the RAS List.
These bulls were bred and purchased on the previous genomic models. As the science advances and our dataset of genotyped animals keeps growing, we will continue to iterate the model to improve the accuracy of genomic selection.
How does genomic data improve accuracy of prediction of an animal’s genetic merit?
A reference population of well recorded animals that have been genotyped allows us to predict the impact of various SNP effects. Females and proven males contribute to this reference population.
Genotyping provides us with information on the alleles/genes an animal has actually received from its parents. From this, the known SNP effects can be used in its evaluation. LIC’s reference population is over 100,000 animals.
Genomics provides geneticists with an estimate of what ‘good’ or ‘poor’ genes the animal inherited well before the animals’ own performance, or that of her progeny, can be measured. And if there are not large numbers of progeny (which is generally the case for cows), genomics helps us better understand what proportion of an animal’s performance superiority will be inherited by its offspring.