Performance Line
Genomic Testing Females is an Investment in
your Genetic Future
By Tonya Amen, National Center for Beef Excellence
If you’ve been breeding cattle long,
you are aware of the costs associated
with either raising or buying your
replacement females. Yet, through
the years, we’ve often placed more
emphasis on bull selection. This is not
without reason, of course, as bulls do
contribute heavily to the genetic value
of the herd each year. But, over her
lifetime, a female can also leave a big
mark on the genetic value of a herd.
Genomic traits tests like the HD, LD, and
uLD tests offered through GeneSeek
and Zoetis are used in seedstock for
two primary reasons: 1) to improve the
accuracy selection through increased
accuracy of EPDs or 2) for marketing
purposes. Due to the impact of sires
on genetic improvement and because,
in seedstock operations, selling bulls
is often the main income source, most
breeders who decide to invest in
genomic technology understandably
start with the bulls. However, I’d like
to present the case that females are
also important candidates for testing.
Table 1 shows the progeny equivalents
for traits currently evaluated in the
North American Limousin Foundation’s
National Cattle Evaluation powered by
BOLT. Progeny equivalents illustrate
the average number of progeny
that would have to be measured
for a particular trait to achieve the
level of accuracy delivered on by a
genomic test on young, genotyped,
non-parents. For example, for a non-
parent bull to achieve the level of
accuracy delivered by a genomic test
for CED, a breeder would have to
submit calving scores on 15 heifers
whose calves were sired by him. For
yearling weight, a breeder would
need to submit 24 yearling weight
on his progeny to achieve the level of
accuracy expected by genomic testing.
Now, think about genomic testing
heifers instead of the non-parent bull; a
genomic test will deliver more accuracy
on her EPDs than if you submitted
performance data for all the natural-
service calves she has in her lifetime.
What a tremendous investment in the
genetic future of your herd! Not only
will testing your females improve the
accuracy of selection when it comes
time to make your replacement heifer
choices, but it will also help insure that
you make the best mating choices
when breeding time rolls around. By
adding accuracy to her EPDs before
the heifer is bred, you’ll get a truer
picture of her genetic strengths and
weaknesses, which will give you better
information when