Genomic selection cuts three years off bull assessment
It has been made possible by genomic selection, a topic which will be on the minds of many during next week’s World Holstein Friesian Conference in Killarney.
On Thursday, Richard Spellman of New Zealand’s Livestock Improvement Co-operative will speak on genomic selection, which LIC believes is the most significant development in farm productivity improvement since artificial breeding began in New Zealand more than 50 years ago.
By selecting bulls for widespread use based on their DNA profile, rather than waiting to assess the performance of their daughters, the “generation interval” can be shortened by three years.
LIC has put huge resources into researching this area and developing a product called DNA Proven.
In Ireland, the Irish Cattle Breeding Federation and Teagasc have begun a major project to develop genomic selection for Irish dairy cattle breeding.
According to ICBF, the technology is evolving very rapidly and, based on results from other countries, it is capable of providing, at birth, an estimate of economic breeding index (EBI) with a reliability of 50% to 60%. This means that as much can be detected about the genetics of a newborn heifer or bull as is normally known about three years later from having 10 to 15 progeny, with their production traits fully recorded.
The cost of DNA testing for genomic selection has in recent years been cut to €200.
The technology is expected to have a dramatic impact on cattle breeding. It means some of the high costs associated with progeny testing can be saved.
ICBF expects that genomic selection will result in much more use being made of young bulls through AI.
Later this month, the preliminary results are expected from research to determine the role of genomic selection in breeding for the Irish dairy and beef industries.
Farmers around the country learned about the technology when ICBF went hunting for samples of semen from as many as possible of the AI bulls used in Ireland over the past 30 to 40 years.
DNA analysis of these samples was the first step in establishing the associations between the known DNA sequences of animals used in Ireland and their EBI.
Working with the AI companies, ICBF obtained semen from about 800 of these AI sires. However, it turned to farmers for samples from a further 1,930 bulls that it knows were used on Irish dairy farms. Farmers were offered €30 per straw from each of these named bulls.
ICBF also made contact with several countries seeking access to semen or genotypes from bulls of mutual interest. One country agreed to provide genotypes from about 90 bulls.
By incorporating genomic data into EBI evaluations, the evaluations can be made more accurate, and genetic progress could be speeded up 50% over the next 10 to 15 years.
In contrast, some cattle breeding companies have opted to keep DNA genotypes and their interpretation secret, relying on farmers’ willingness to purchase “genomically selected” bulls without the benefit of EBIs (or their equivalent in other countries).
To achieve their targets, ICBF will set up a facility for DNA storage, extraction and genotyping.
In New Zealand, DNA Proven semen will be available from LIC for limited use when bulls are yearlings, and for widespread use as two year olds.
Normally, widespread use does not happen until bulls are five years old.
DNA will be used to select bulls from a much wider genetic pool, and the much shorter generation interval will accelerate genetic gain.
Traditionally, hundreds of bulls in New Zealand could be considered for possible selection by daughter proving, but DNA enables consideration of thousands of young bulls. LIC have calculated that DNA Proven semen will be worth between €1 billion and €1.8bn billion in extra profit to the dairy farmers of New Zealand over the next 20 years.
