When it comes to breeding for that next generation of Holsteins, an increasing number of Canadian dairy producers are adding bulls that offer two traits – Polled and A2A2 – to their genetic requirements. “That is the definite take away from a recent examination of the top bulls siring registered Holstein progeny today in this country,” observes Dave Eastman of Validity Genetic Testing in Ontario, who did the research.
A Holstein Canada compiled list of the top 30 bulls with most registered progeny born in a three-month period from October 1 to December 31, 2021, reveals the growing popularity that sires possessing the Polled and A2A2 genes have among dairy producers as they make their genetic decisions.
Good “Proven” bulls still remain in demand by Holstein breeders accounting for 60% of the 19,143 total registrations recorded by Holstein Canada born during that three-month period. A total of 14 bulls were “Genomic”, or unproven, bulls at the time their semen was used from January to March of 2021. These Genomic bulls sired 40% of the progeny registered.
43% of all progeny from Genomic bulls were from Polled sires*. *From top 30 list
What is most striking though about those 14 Genomic bulls is that five were “Polled”. Those five Polled bulls sired a whopping 43% of all the Genomic sired progeny in that time frame, reflecting a huge increase in the usage of Polled sires by dairy producers.
In all, six of the top 30 bulls on this list possess the Polled gene (Homozygous or Heterozygous). Collectively, they sired almost 20% (19%) of the registered Holstein progeny born in the last quarter of 2021.
The Beta-Casein variant A2A2 is the other trait Canadian dairy producers are increasingly looking at when selecting bulls. In this latest Holstein Canada summary, 13 of the list’s top 30 sires carry the A2A2 genotype and sired 42% of the registered progeny born from October through December 2021. Four of these 13 were Proven bulls. Breaking this down further, 13 bulls (10 Proven) were coded A1A2 and sired 45% of the registered progeny. Just four bulls (two proven) were A1A1 and sired 13% of the registrations. This confirms the large decrease in usage and selection by A.I. companies of any bulls that do not carry the A2A2 variant.
What is prompting these trends? Cost, time, labour, animal health and personal safety are the key reasons when it comes to Polled. It currently costs $30/head to dehorn a dairy animal in Canada. Rising public awareness and disdain for the practice of dehorning is also driving the shift towards Polled. With more high ranking, top performing Polled animals in the Holstein breed, dairy producers now feel more confident in incorporating Polled genetics into their breeding strategy.
With testing for the A2 gene now easier, more dairy producers are adding this trait to their selection criteria. Lactanet recently began offering A2 (Beta-Casein) Genotype reports that include an A2 Herd Summary and A2 Animal Summary giving Canadian producers an overview of the A2 status in their herd and animals. These reports are freely available to Lactanet’s DHI customers, making it even simpler for producers wanting to increase the frequency of A2A2 cows in their herd.
While traits such as feet and legs, mammary system and components will always remain essential when selecting sires, it’s obvious today’s Holstein breeders are increasingly seeing value in the use of Polled and A2A2 sires in their breeding programs.
Written by Bonnie Cooper, freelance writer. For more information contact David Eastman, Validity Genetic Testing, Rockwood On, Cell 905-866-7800, email Dave@validtytesting.com
