The first sex-selected calf conceived from frozen sexed semen
was born in the early 1990’s, and in 2004 this technology became
commercially available. Sexed semen has been used the most by
dairymen, since it’s more desirable to produce heifer calves
than bulls in that industry. The earliest research on semen
sorting was done in the 1980’s at Colorado State University
(with a USDA grant) and this technology has been continually
improving. Today you can figure that at least 9 out of 10
calves produced by use of sexed semen will be of the desired
Currently, a growing number of beef producers are beginning to
utilize this option. Depending on their needs they can tweak
their calf ratio to have a higher number of bull calves from
their best cows (if they are seedstock producers selling bulls)
or more steers from a terminal cross, or more replacement
heifers. This is an excellent way to raise good replacements
from selected cows.
Seedstock producers may use bloodlines with maternal qualities
for brood cows and other bloodlines they’d use for marketing
bulls. In female sales, bred cows and heifers are often worth
more if bred with sexed semen. Some buyers want heifers
guaranteed to have heifer calves while others want females that
will produce only male calves. There may be a good market for
offering good female bloodlines in a 3-way package—a cow with
heifer calf at side and bred back to have another heifer calf.
Sex determination can be an advantage for reducing calving
difficult in first calvers, since heifer calves are typically
smaller at birth than bull calves. You may also want your best
cows to have heifers, giving you a chance to make faster genetic
progress in improving your herd, enabling you to keep more good
females and cull more deeply. Some producers may opt to get
heifers from the top 10 to 15 percent of their cows and steers
from the rest of the herd.
The University of Idaho Nancy Cummings Research Ranch at Salmon,
Idaho has done a 2-year study on the use of sexed semen to
generate replacement heifers. Even though this was a research
trial, the heifers produced are being utilized as replacements
for the University ranch herd.
Dr. John Hall, Superintendent at the research ranch, explained
that the original herd of donated cows represented many breeds
and now the Center is trying to build more uniformity into the
herd. “We want to eventually have a black baldy cow base. One
of the stipulations for our herd is that it be functional and
efficient, paying its way just like any other rancher’s
commercial herd,” says Hall. The cattle must make a profit,
just like they would in the real world. They have to pay their
own way, and generate the money to pay all cattle and ranch
expenses as well as some salaries of the Center’s employees.
The sexed semen project was a way to produce a uniform group of
heifers from the best cows on the ranch.
In 2008 they bred 37 cows with X-sorted semen from the Angus
bull Bon View New Design 878, with semen supplied by ABS
Global. They only bred the cows that were observed in natural
heat, and had a 67 percent pregnancy rate, which is very high
for sexed semen. “This high success rate may have been partly
due to the fact that we pre-selected the cows, and we only
inseminated the individuals that we observed in heat,” said
The rest of the cows in that group were bred to a cleanup bull
introduced later into the herd. When the calves were born in
the spring of 2009, there were 22 AI calves from the sexed-semen
“Of the 22 AI calves, 21 were female and one was male, which is
pretty typical for the ratio you’d see when using sex-sorted
semen. In that small group of cows—some of which settled to the
sexed semen and the remainder to the cleanup bull--we shifted
the sex ratio to 77 percent female and 23 percent males,” said
Hall. This kind of program would enable a producer to pick out
his best cows and breed them with sexed semen from a bull with
outstanding maternal qualities to sire replacement heifers—and
have a greater probability of having heifer calves. Conversely,
a rancher wanting mostly steers to sell could breed all his cows
with sexed semen from a bull that sires offspring with
outstanding growth and carcass traits.
“We are very excited about the possibilities for this, and have
been working with ABS Global, the company that provides the
sexed semen for us,” says Hall. In 2009, the research ranch
bred 100 cows with X-sorted semen, using fixed time AI and heat
synchronization (breeding the cows all at one time, on one day),
as a test to see how well this might work in a more typical
producer situation. In this research trial, the conception rate
was only 48 percent, with the remainder of the cows settling a
cycle later to the clean-up bulls.
The Center and various semen companies were interested in
finding out how well this method might work. Even though sexed
semen costs about double the price of regular semen, this may
still be a tool some producers might choose if it means more
guarantee of getting replacement heifers from their best cows,
or more steers to market if this is their goal.
Adam Simmons, the ABS Global representative (from Idaho Falls,
Idaho) who worked with the research ranch on this project says
that any rancher can order sexed semen through his company.
“There is some information that we give to the producer and
require that they review before they purchase sexed
semen—because you don’t get as high a pregnancy rate using it,
and we want our customers to be fully aware of this fact,” says
For instance, customers need to realize that during the sorting
process some sperm cells are lost and all cells of the undesired
gender are discarded, leaving less total sperm cells. This
lower sperm concentration may adversely affect fertility,
resulting in lower conception rates.
“Currently we only recommend its use on heifers, in a natural
standing heat. The university trials are being done to see how
well it can do on cows that are synchronized, but due to the
extra cost of sexed semen and the lower conception rate (not as
high as with regular AI) we still just recommend it only for
heifers—because the AI conception rates for them is typically
better than for cows anyway, and conception on natural heat is
better than with synchronized heats,” he explains. This would
give a producer the most success for the dollars spent, since
sexed semen is more expensive than regular semen and you don’t
want to waste this expense with a poor conception rate.
One of the questions asked by producers is whether semen from
any bull can be made available for use as sexed semen or if only
certain bulls’ semen is available in this form. “In general,
only certain bulls are being offered, by various semen
companies. ABS has the broadest selection, of all the AI
companies. But we also offer this service on any bull the
rancher might want to try,” says Simmons.
“Most of our competitors outsource their sexing. ABS actually
owns the technology and thus they brought the sexing facility
right to our home lab in Wisconsin. We therefore have the
capability to sort semen on any bull desired. There are always
some exceptions, but basically if a customer wanted this service
on a certain bull, and agrees to buy everything that is
collected on that bull in one collection, we will do any bull
you want—as long as that particular bull’s semen will freeze and
go through the sexing process. Thus a producer could purchase
sexed semen (choosing male or female calves) from just about any
bull that we offer,” says Simmons.
In general, however, ABS offers a fairly broad range of bulls to
choose from, in which sexed semen is already readily available.
“We have a regularly updated list of these bulls,” he says.
The costs for sexed semen will depend somewhat on the base cost
for the semen from each individual bull, with an additional
charge for the sexing. “Sexed semen is more expensive than
regular semen, just because about 2/3 of the semen is wasted
when it is sorted,” he explains.
“As a rule, conception rates are about 10 percent lower with
sexed semen than with conventional semen. Producers always have
to realize that conception rates in general will vary from ranch
to ranch, depending on who is doing the AI work, the condition
of the cattle, etc. Some ranchers will get only 40 percent
conception while others get 70 percent conception rates with
conventional AI. You can usually figure that sexed semen rates
will be about 10 percent lower than that ranch’s typical AI
conception rate,” he says.
For best results, ABS recommends that producers carefully follow
their published guidelines for semen thawing and handling, and
use highly experienced and trained ABS professionals for the
inseminations. Highest conception rates will be obtained on
well grown, well managed virgin heifers, with the inseminations
taking place 12 hours after the heifers are first observed in
Some commercial producers are opting to use sexed semen because
they can raise replacements from their best cows, knowing that
almost all of the conceptions will result in heifer calves.
These will be often be better than any heifers they could
purchase—since they know the history on their own cows and can
select the genetics and traits they want. They can also
maintain a closed herd, eliminating the risk of introducing
disease by bringing in purchased animals.