The number of dairy animals DNA tested – or genotyped – in Australia has escalated in the four years since commercial services became available, particularly in recent years with improvements in reliability, lower costs and greater understanding of the various ways results can be used to improve genetic gain.
Michelle Axford from the Australian Dairy Herd Improvement Scheme (ADHIS) said the number of females tested in 2015/16 was double the number tested the previous year, and the number of bulls was up 50%.
The reliability of a genotype for a calf is now equivalent to a bull with 35 daughters or a cow with eight lactations of data.
This improved level of confidence is having a profound effect on genetic improvement in the Australian dairy herd.
"Genotyping is now a standard practice by bull companies and female genotypes are having an increasing role for herd management,” Mrs Axford said.
Improvements in the reliabilities of bull genotypes has seen dairy farmers increasingly confident in using young genomic bulls over their herds and it has given them a wider choice of bulls. Young genomic bulls make up almost two thirds of bulls in the latest list of top 100 bulls for Balanced Performance Index (BPI).
“Thanks to genomics, we now have a wider range of bulls from different countries and companies, that are profitable and have strengths in different traits,” she said.
The drop in the cost of standard genomic testing from $90 four years ago to $50 today has made it more affordable for dairy farmers to genotype some or all of their herds.
Female genotypes can be used for a variety of purposes. Having heifer calves genotyped gives farmers the option to save on rearing costs by selecting those with the highest genetic merit to keep and selling the surplus at a younger age. Alternatively, some people keep all heifer calves but used sexed semen over those of highest genetic merit and a beef breed over the others. Both approaches speed up genetic gain by breeding replacements from the herd’s top genetics.
Genotyping includes a parentage verification process which is helpful to ensure the accuracy of records and sort out mis-matched calves. Stud breeders use this for pedigree records and registering embryo transfer (ET) calves. They are also increasingly using genomic results in the marketing of elite animals.
To get started, dairy farmers commonly begin by genotyping each group of heifer calves which means the bulk of the herd is done within five years.
For more information contact Michelle Axford, ADHIS Extension and Education Manager, ph 0427 573 330 email firstname.lastname@example.org.