Reproduction
commercial crossbred populations.
Unfortunately, there are not yet any
independent, peer-reviewed papers in
the scientific literature documenting
the field performance of genomic
tests for commercial heifer selection.
Value of genomic testing
To estimate the value of genomic testing
for replacement heifers, Van Eenennaam
modeled the breakeven cost of testing
all 45 potential replacement heifers
born per 100 cows (weaning rate = 90%;
50% female) per year in a commercial
herd with a replacement rate of 20
percent (i.e. 20 replacement heifers were
selected each year). For this estimate
it was assumed that the commercial
producer was not basing heifer
replacement decisions on performance
records. To select replacement heifers
a multiple-trait maternal selection
index was developed that included
maternal, pre-weaning performance,
post-weaning performance,
and carcass traits. For economic
weightings, it was assumed that the
producer was retaining ownership
34 | OCTOBER 2017
through feeding and marketing
the cattle on a value based grid.
The maternal trait with the highest
relative economic value in that index
was weaning rate (i.e. number of
calves weaned per cow exposed).
A hypothetical DNA test with an
intermediate accuracy (0.3) with regard
to the selection objective was then
modeled. The breakeven cost of testing
replacement heifers was approximately
$24 per test. In other words, to test all
of your potential replacement heifers
the cost of the test would need to be
under $24 for it to provide a positive
return on investment assuming the
accuracy of the test is 0.3. As the
accuracy of the test increases, the
breakeven cost will decrease. Of this
value, less than $10 was associated
with traits of economic value to the
cow-calf sector (i.e. cow-calf producer
that does not retain ownership),
with the majority of the value being
realized by post-weaning genetic
improvement (i.e. feedlot/carcass traits).
If we consider that producers are likely
to have at least a visual estimate of
weight, and possibly some information
on the age of the heifer, utilizing this
information would further decrease
the breakeven value of the information
provided by genomics testing. The value
of obtaining a commercial replacement
heifer genetic evaluation is significantly
less than that for bulls because bulls
produce more descendants from
which to derive returns for accelerated
genetic improvement. The breakeven
estimate of $24 per test does not take
into consideration the possibility of
reallocating those funds for improved
bull selection. For the herd with 45
replacement heifers the potential
investment would be $1080. The
question becomes, which is better,
investing more in the sires that will
produce the future replacement
heifers or spending the money on a
tool to improve the selection of the
current crop of replacement heifers?
It should be noted these calculations
are based on the value of genomic
information to make heifer replacement
decisions in a commercial beef herd.
The dairy industry is successfully
using genomic testing on commercial
replacement females. However, there are
some important differences between
the dairy and beef industry that
make genomic testing of commercial