Impact of Genomics on Cattle Breeding; DNA Profiling Has Revolutionised Dairy Cattle Breeding and the Next 12 Months Are Crucial to the Direction of the Industry. the First Genomic AI Progeny Test Results Are Coming Online and Will Beg the Question as to Whether Farmers Will Consider Using More Genomic Young Sires Rather Than Older Proven Bulls. BRUCE JOBSON Investigates

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THE US first introduced DNA genomic information into sire evaluations in January 2009 and Canada followed in August of the same year. The technology has helped the AI industry better identify the genetic potential of animals for progeny testing.

Prior to the introduction of genomics, the accuracy of a young bull's evaluation was based on his genetic parent average and the reliability was estimated at about 35% accuracy. The introduction of genomic evaluations has increased the level of accuracy to between 65 and 70%. The increase in reliability is the equivalent of having 20 milking daughters in a bull proof.

Doubling the level of accuracy has given the AI industry increasing confidence to select the next generation of young sires. Importantly, the genomic identification of a group of ET sibling bulls allows sire analysts to better identify the best individual in the group on various type and production traits.

AI companies have been able to cut costs; some having reduced the number of sires coming forward for testing programmes on the basis that better quality young bulls have now been identified.

For example, in North America, a PS133 genomic DNA profile is a cheaper identification method compared to a lengthy five-year PS13,276 progeny test. Selecting one young bull from three full-brothers with identical parent-averages is therefore costeffective.

As the genetic threshold has increased over the past four years, some young bulls have not completed progeny testing owing to lower identified profiles. In the long-term, the benefits will filter through to dairy farmers with better proven bulls entering AI being the end result.

However, let's consider several controversial options. If all goes well, and genomic sires deliver greater accuracy as proven bulls; will breeders again consider using a five year old plus proven bull as part of their breeding programme? Caution has been urged by several parties within the cattle-breeding industry; but as the dynamics have changed, some fast-thinking farmers have realised an opportunity beckons. Marketing elite genomic animals is a new concept and pedigree breeders are keen to maximise on the inherent potential.

Using high genomic young sires will increase the opportunity to breed a young bull for AI purposes as well as, breed a potential high genetic merit bullmother. For the first time, breeders will have more control over their destiny.

By using DNA genomic profiles, UK farmers can now evaluate male and female bovine progeny on an equivalent-basis with North American bloodlines. The mating game has changed forever. Taking the use of young bulls forward, a resulting high ranked 15 month old genomic heifer should be subsequently bred to an even higher genomic young sire in order to maximise the genetics of the next generation. And so on.

A percentage of pedigree breeders will prefer to breed the exclusive show-winning, high type animal for a particular niche market. There will also be a percentage of farmers not prepared or even wishing to breed high genetic animals. Many pedigree and commercial farmers may prefer instead to breed the next generation on the basis of quantifiable daughter improvements on the basis of proven type and production, good mammary traits and quality feet and legs.

However some pedigree breeders, keeping an open eye on the future, will opt to increase the genomic values as well as increasing the potential earning power of their animals. Meantime, commercial breeders have an immense opportunity to propel their herd's genetic potential forward perhaps without constraints. Furthermore the cost of producing genomic young bull semen is undoubtedly cheaper for the AI industry and provides a healthy return. …


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