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More Than Gain
Cattle producers are
getting closer to knowing and utilizing the genetic potential of
feed efficiency.
By Wes Ishmael |
Whoever first uttered that
immortal maxim about being unable to manage something without
measuring it was likely someone in the cow business—casting a
wishful and frustrated glance at his cows, then at his hay pile.
You know that feed costs comprise the lion’s share of annual cow
carrying costs. Peruse the research literature and you
understand why: 70-75% of dietary energy consumed by beef cows
goes toward maintenance alone.
Consequently, you understand if you could alter average feed
efficiency—how much a cow consumes, relative to her
production—just a little, you could make a giant difference in
the bottom line.
Specifically, Mark Allan, explained in an article last year,
“With 70-80% of the total variable costs in beef production
being feed costs, the slightest improvement in feed efficiency
will have a significant impact in profitability in multiple
areas of beef production (see RFI Value).” Allan is a molecular
geneticist who until recently worked in the Nutrition Research
Unit at the U.S. Meat Animal Research Center (MARC). In December
he went to work for Pfizer Animal Health as Associate Global
Director of Technical Services.
Unfortunately, you also realize how impossible the dream can
seem.
Identifying feed efficiency in cattle has always been an
after-the-fact process and fairly convoluted besides. At least
on a group basis, it’s easy to determine how much feedlot cattle
consume, relative to how much weight they gain, which yields a
feed-to-gain ratio. Heretofore, that’s about all anyone had to
go on when it came to feed efficiency.
The chief challenge with this kind of information is that
feed-to-gain only tells you a part of the efficiency story. It
tells you something about feed intake and gain, but says nothing
about animal weight or body composition at the time, nothing
about how efficiently an animal utilizes each pound consumed for
maintenance.
Consequently, using feed-to-gain as a selection tool on the
front side of the equation would mean choosing animals that
consume more, gain more or both. On both counts, you typically
are selecting for cattle that gain more, which also usually have
larger mature size. So, you end up selecting for cattle with
higher dietary maintenance requirements, though you still have
no idea how efficient the cattle are for maintenance.
The New Measuring Stick
That’s why Residual Feed Intake (RFI) has captured the
industry’s imagination in recent years. In basic terms RFI (also
known as Net Feed Efficiency) is defined as the difference
between an animal’s actual feed intake and the feed intake
expected for maintenance and weight gain. In other words,
RFI measures the efficiency of cattle to utilize each pound of
feed consumed. Icing on the cake comes with the fact that it is
independent of gain.
At least it does when it comes to growing and finishing cattle.
Though RFI is a useful tool, Allan is quick to point out, “All
the data generated to date is in growing and finishing bulls and
steers. There is presently no evidence that RFI in growing and
finishing animals equates to efficiency in the cow.”
With RFI, a lower number is more beneficial. Compared to those
with a higher RFI, a lower number means the animal consumed less
feed than expected for the performance it achieved.
“This information can be utilized in the selection of bulls
expected to sire calves with lower finishing feed costs and
daughters with lower feed maintenance requirements,” explains
John Dhuyvetter, an area livestock specialist at North Dakota
State University’s North Central Research Extension Center in
Minot.
The notion of RFI isn’t new, nor is the knowledge about what is
required to calculate it, but technology in recent years has
made it more practical to exploit the potential.
As the RFI definition suggests, calculating it requires
collecting individual animal intake data. Researchers have
accomplished this over the years by various means, everything
from housing and feeding cattle individually—weighing feed in
and out of the bunk—to more automated systems whereby test
animals are limited to a specific feeding gate. Each method was
time consuming and too expensive to be utilized beyond isolated
research projects. Plus, such systems couldn’t account for how
the systems changed cattle behavior and the subsequent impact on
feed consumption and conversion.
“The lack of progress in understanding the genetics of feed
efficiency stems from the difficulty in trying to accurately
measure individual intakes, coupled with extreme costs and beef
cattle’s long generation interval,” says Allan. “Feed efficiency
is difficult to define and needs to be evaluated in the
producing female, as well the growing/finishing animal.”
Enter a handful of companies that have developed automated daily
intake and behavior monitoring systems that make collecting the
data accurate and economically feasible.
Arguably the most popular commercial systems in the United
States today come from Grow-Safe, LLC, a Canadian company.
According to the company, GrowSafe technology is behind more
than 120 scientific publications. More than 40 agricultural
universities utilize their systems.
The company’s efforts in this area trace back to the early
1990’s, developing monitoring systems capable of reading
multiple low frequency Radio Frequency Identification (RFID)
transponders in close proximity to one another. By 1996 that
meant they could develop a system by which individual cattle
could be monitored in a feedlot situation for how often they
went to the feed bunk and how long they stayed each time. A few
years later, the folks at GrowSafe incorporated, among other
things, the accurate measure of animal weight, feed intake and
animal behavior. In 2002, the addition of other measures,
including thermal imaging and ultrasound started bringing more
customers into the fold. All told, a system today can integrate
data from up to 256 external devices, environmental and biologic
sensors. So, the system is about lots more than individual feed
intake, though that aspect is central to ferreting out RFI.
Incidentally, the feed efficiency research facility MARC
installed several years back has a one-time capacity of 300
head. It comes from a European company and allows them to also
track individual feed and water intake, as well as about
anything else your mind can conjure.
Not only are universities using the systems, but also some
feedlots, bull test stations and even individual producers.
“We can begin adding positive selection pressure for a trait
that hasn’t been selected for to this point,” says Kent Abele,
owner and manager of the Green Springs Bull Test (GSPT) at
Nevada, MO. GPST was the first publicly accessible bull test
station in the U.S. to install a GrowSafe Feed Intake Monitoring
System, making it the first public facility in the nation
offering individual feed efficiency and residual feed intake
data on a volume of bulls.
It’s an eye-opener, too. According to Abele, there are huge RFI
variations between animals, as well as noticeable differences
between breeds. All add up to significant differences in cost.
Dhuyvetter explains, “In yearling bulls on feed tests, the
variation is more than 5 pounds less feed per day for similar
performance. Selection for low RFI could reduce cow herd
maintenance requirements by up to 10 percent through time.
Research also indicates selection for low RFI would lower
methane emissions and reduce nutrients in manure.”
“The really exciting thing is that we’re starting to see a high
correlation between feedlot efficiency and forage efficiency,”
says Abele.
Taking the Genetic Step
Ultimately, as with other individual animal measures, the
keystone value of individual animal RFI data will come with its
incorporation into Expected Progeny Differences (EPDs) and other
genetic prediction tools.
“Heritability of feed efficiency has been estimated to be
moderate, with values ranging from .28 to .44. These values
indicate that genetic variation among and within beef cattle
populations does exist for feed efficiency, making genetic
selection possible,” says Allan.
Some breed associations already offer EPDs based upon RFI. An as
example, the Red Angus Association of America provides members
with an EPD for Maintenance Energy, and the American Angus
Association calculates an economic EPD for Cow Energy Value. As
well, some genomics companies offer individual DNA tests for RFI
or as part of overall genetic profiles.
According to Dhuyvetter, current markers identify a portion of
the variation in RFI, with the most favorably rated genotypes
saving about 2.5 pounds of feed per day at similar gains,
compared with the least favorable genotypes. He explains that
for many breed populations, the practical range of variation
that current markers identify is more likely to be .5 to 1
pound.
What’s more, Whole Genome Selection could accelerate the breadth
and depth of RFI data and subsequent genetic predictions. In
simple terms, according to the Agricultural Research Service,
Whole Genome-enabled animal selection is a technique that scans
the animal’s genome, the makeup of its DNA and predicts its
genetic merit as a potential future parent. For more information
about Whole Genome Selection, see So Cool, in July August ’08
Western Cowman.
As with any other trait of economic importance, Abele cautions
folks to keep it within the perspective of balanced trait
selection. More specifically, he suggests producers use other
traits to identify bulls they’re interested in, then make sure
those bulls have an RFI that keeps them among the top two-thirds
of the population for the trait.
Moreover, Allan explains, “It is critical with RFI that it is
used in an index. Many of the RFI animals with the best RFI are
in the bottom 50% for gain (low appetite, low gain)…We need to
be careful not to select for animals with decreased appetite on
the cow side. In some environments, limiting cow appetite could
have terrible consequences.”
“The economic potential from widespread improvement in feed
efficiency is huge for the cattle industry,” Dhuyvetter says.
“At today’s high grain and feed prices, the measurement,
evaluation and application of improving feed efficiency are
rightly receiving a lot of industry and academic attention.”
Side Bar
- RFI Value
According to Alberta Agriculture and Rural Development (AARD),
research in Alberta and Australia indicates that efficient
growing animals (as measured by RFI) are efficient as adult
cattle. As well, progeny of efficient beef cattle are also more
efficient than those of less efficient cattle. Further, the
folks at AARD say this same research shows that selection for
low RFI can:
lower maintenance requirements of the cow herd by 9-10%
reduce feed intake by 10-12%
have no effect on average daily gain or mature size
improve feed conversion ratio by 9-15%
slow gain in empty body fat by 4%
lower weights of liver, stomach and intestines
have no effect on distribution of 9 wholesale cuts
improve calf-weight-per-cow feed intake by 15%
lower methane emissions by 25-30%
reduce manure nitrogen, phosphorus and potassium
Source: Alberta Agriculture and Rural Development, Agri-Facts,
July 2006
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