Over the past decade, genotyping has steadily gained momentum in Irish dairy herds, transforming the landscape of cattle breeding. In 2023, the launch of the groundbreaking National Genotyping Programme (NGP) marked a major milestone, dramatically expanding the volume of genotypes within Ireland’s national database. This world-first initiative is at the forefront of revolutionising the country’s cattle breeding industry.
Prior to 2023, only 6.5% of the national dairy herd had been genotyped. Thanks to the NGP, this figure has surged to an impressive 35%, with continuous growth expected. As of September 2024, a total of 4,300 dairy herds are actively participating in the programme and over 520k dairy calves have been genotyped.
The continued success of the national dairy herd is largely dependent on the breeding decisions made each year. Herds involved in the programme have experienced significant benefits, with herd EBI (Economic Breeding Index) reliability increasing by up to 20%. This enhanced reliability empowers farmers to make data-driven, informed decisions about their breeding strategies, optimising herd performance and productivity. Coupled with the use of Sire Advice, this newfound precision is expected to accelerate genetic gains across Ireland’s dairy sector.
One of the standout achievements of the NGP is the number of parentage errors that have been subsequently resolved. The 2024 data shows that 17.47% of the dairy calves genotyped to date in 2024 had a sire error, with 8.67% having a dam error.
The table below outlines the levels of parentage corrections made on dairy animals in 2024 as a result of the NGP.
Having the correct parentage information through genotyping ensures that calves sold privately or through the marts have accurate Commercial Beef Values (CBVs). This provides both the buyer and seller more confidnece and assurance around their sales and purchasing decisions. This development positions the NGP as a key player in advancing dairy-beef integration, setting the stage for a more sustainable and profitable future for both sectors.
By genotyping calves at birth, the DNA of twin births can be analysed in more detail. Cases of heteropaternal and identical twins can be identified which are often difficult to confirm without a DNA profile from both animals. Heteropaternal twins occur when two or more eggs are fertilised by two or more males during the same reproductive cycle resulting in twins with different sires. Identical twins originate from a single fertilised egg that divided into two distinct embryos. Both animals in this scenario will have identical DNA. In 2024 to date in NGP herds, 1.6% of calvings from a dairy sire and dairy dam resulted in twin births. Of these twins born, 5.8% of these were heteropaternal and the incidence of identical twins was 4.7%.
What is Genomics?
Genomics is the study of an animal’s DNA, or “genotype,” typically gathered from a tissue or hair sample. DNA is inherited in sections, and genomic testing identifies which specific chunks have been passed down from the parents to their offspring.
The first key use of genomics is to confirm an animal’s parentage, ensuring the recorded dam and sire are correct. Secondly, genomics assesses traits such as milk production and carcass weight by comparing an animal’s genotype to those of proven animals. This allows superior traits to be identified even before any performance data has been recorded. By combining genomics with traditional phenotypic data, a more reliable index is generated. Genomic testing adds DNA analysis to existing performance data to enhance the accuracy of evaluations like EBI (Economic Breeding Index) or Eurostar ratings.
What is a Reference Population and Why Does it Matter?
A reference population is a large group of genotyped animals with highly accurate performance records, such as milk yield and fertility. The relationships between DNA and performance traits are derived from this population. Expanding the reference population is crucial for improving the accuracy of genomic predictions.
How Has the NGP Expanded the Reference Population?
The National Genotyping Programme has significantly boosted the reference population. For Milk Production, an additional 227,000 animals have been added, increasing the total to 350,000. For Calving Interval, the population has grown by 72,000, bringing the total to 117,000. Similarly, Survival data now includes an extra 114,000 animals, increasing the total to 186,000.
What Does This Mean?
The expansion of the reference population offers several advantages, including:
- Enhanced predictability of production traits
- Greater accuracy in fertility trait assessments
Essentially, this large increase in data is resulting more accurate figures across the board. This gives farmers more confidence when it comes to decision making for their herd.
How Will This Affect My Animals’ EBI?
While the overall impact on the national dairy herd’s EBI will be minimal, individual animals may see slight adjustments to their figures.
When will these update be made?
The reference population was updated in conjunction with the September evaluation. The latest figures are now available to view.
If you have any queries, please don’t hesitate to contact the HerdPlus team on 023-8820452 or email [email protected].