One of the six farmer requirements in the Beef Data and Genomics Programme (BDGP) is genotyping. But what exactly is genotyping, why has such an importance been placed on it, how is it done and does it have use outside of BDGP?
What is it?
Put simply, genotyping looks under the hood. An animal is built from DNA, half of which comes from each parent – but which half? Before genomics, an animal’s breeding index value was assumed to be a parent average: a cow with an index of €50 mated to a €100 bull would a produce €75 calf.
While a good estimate, this is not entirely accurate. What genomics does is identify precisely what parts of their genetics each parent contributed to the calf, painting a more accurate picture of its genetic potential.
Though very rare, it is possible for two full siblings to be completely genetically unrelated, if both inherit exact opposite combinations of their parent’s genes.
Not just BDGP
Those in BDGP must genotype (tissue tag) the equivalent of 60% of their reference number each year during the programme – an animal can be genotyped only once – and have 20% of their eligible breeding females genotyped as four- or five-star on Halloween 2018 and 50% on the same date in 2020.
While not compulsory for non-BDGP farmers, we are at the dawn of an age where genotyping will become the norm. As Table 1 shows, genotyping allows a farmer to accurately identify his or her best animals, improving reliability and speeding up genetic gain.
For buyers in the BDGP, a genomically tested animal will be more attractive than a non-tested equivalent, potentially delivering a premium to the seller. Genomics also detects any parentage errors, offering peace of mind to buyers that what they’re getting is indeed what it says on the tin.
The future
DNA is constant and unique (except for identical twins). In essence, a genotyped animal has a biological passport that it can never lose – following them from pasture to plate. This can and will be used to reassure future meat-eaters that they are eating a product produced in a known setting to a standard they have been promised. It will also make life more difficult for cattle rustlers – ear tags can be swapped, but DNA cannot.
Genomics also has the capacity to identify genetic weaknesses that increase an individual animal’s susceptibility to various diseases. Tuberculosis, BVD and Johne’s disease are 18%, 10% and 9% heritable in cattle. A heritable trait is one that can be selected for and, to put these in perspective, fertility and docility are 5% and 15% heritable respectively.
How do I genotype?
Genotyping cattle involves taking a tissue tag sample from the animal’s ear and sending it to ICBF for analysis. The cost of genotyping has halved in a matter of years, and will undoubtedly continue on this downward trend. In order to genotype his or her cattle, a non-BDGP commercial farmer, or dairy farmer, must be a HerdPlus subscriber. Commercial dairy and beef cattle can be genotyped at a cost of €22/head and ICBF cites research showing a one-to-four return on this investment. Non-BDGP and non-Herdplus pedigree beef animals can be genotyped at a cost of €30/head.
Those wishing to genotype their cattle should select ‘Genomic Services’ in the ‘Services’ tab of their ICBF Herdplus homepage, or call 1850 600 900.
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