Arkansas Agriculture
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Animal Science E-News
April 2011 - Vol. 5, No. 1
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Growth-Promoting Implants and Our Food Supply •
Frequently Asked Questions on
Fescue Answered by Research •
Improving Grazing Management •
Arkansas 4-H Horse Activities
Benefit From Plum Creek Grant •
Is Beef From Naturally-Managed Cattle
Better Than Beef From Conventionally-Managed Cattle? •
Supplementing Pasture for Dairy Cows
Growth-Promoting Implants and Our Food
Supply
Dr. Paul Beck, Associate Professor
Growth-promoting implants are used to increase the growth rate
and feed efficiency of growing and finishing cattle by about 3% to
5%. Implants function by supplying very small amounts of compounds
that act like naturally occurring hormones, thereby increasing
muscle growth and reducing fat deposition. Because fat requires more
energy to deposit than muscle, gains and feed efficiency are
increased.
Research at the University of Arkansas Livestock & Forestry
Research Station and the Southwest Research & Extension Center
indicates the relationship between growth rate and implant response.
When cattle are on a high plane of nutrition and gaining well, one
expects the implanted calf to have all the necessary nutrients to
get all the benefits from the implants, but with limited nutrients
added performance from implants may be limited. Use of this
technology is an important way to decrease breakevens and increase
profitability of the stocker cattle enterprise.
When calves grazing wheat pasture at the LFRS near Batesville
were implanted with a product that supplies a combination of
testosterone- and estrogen-like compounds (Component TE-G; VetLife),
gains were increased by 0.37 lb/day (from 2.36 to 2.73 lb/day for
non-implanted and implanted steers, respectively) or by nearly 40
pounds over the 100-day grazing period. At the same time, steers and
heifers at the SWREC near Hope were implanted with estrogen-like com
pounds (Synovex-S and Synovex-H, from Fort Dodge Animal Health; for
steers and heifers, respectively). Over two years, gains of cattle
on a high plane of nutrition were increased by 0.35 lb/day (from
2.15 lb/day for non-implanted cattle to 2.5 lb/day for implanted
cattle), while gains of cattle on a low plane of nutrition were
increased by 0.40 lb/day (from 0.89 lb/day for non-implanted cattle
to 1.29 lb/day for implanted cattle). Performance was increased by
15% to over 40% by implanting; this is a benefit to the producer
that will have definite impact on the bottom line. Value of gain
(the value of each additional pound of gain adjusted for price
slide) over the last five years has averaged over $95/cwt. So, if
gains are increased by 40 pounds over a 100-day grazing period,
profits will be increased by about $37 per calf!
In the past couple of years, I have been approached by people
uninvolved with agriculture and even some ranchers who believe use
of implants is affecting the sexual development of our youth,
increasing cancer risks and other assorted and sundry maladies.
There are also many health care professionals and educators
spreading this belief with no scientific data to corroborate.
Here are some facts to consider. Estrogen content of beef from a
non-implanted steer is 6 nanograms/lb; from an implanted steer, 14
nano grams/lb; from an open mature cow (where most of our hamburger
comes from), 31 nano grams/lb. Compare these numbers with the
estrogen content of some common vegetables: potatoes, 225 nano
grams/lb; peas, 340 nano grams/lb; and cabbage, 10,880 nanograms/lb.
The estrogen content of beef is closer to zero than it is to the
values we see from vegetables, and it is very unlikely that there is
any impact of the estrogen content of our diet on our health or
development of young people. Implants provide tremendous benefits to
the profitability of the beef industry with absolutely no risk to
the safety of our food supply and are essential to our duties in
feeding the world's expanding population.
Frequently Asked Questions on Fescue
Answered By Research
Dr. John Jennings, Professor-Forages
During producer meetings and through other events, many questions
have come up regarding the use and management of toxic fescue as
well as some myths or misconceptions about the fescue endophyte.
Arkansas has about two million acres of fescue, and most of it is
infected with the toxic fescue endophyte.
The toxic fescue endophyte is a fungus that grows inside the
fescue plant. It produces toxins that reduce livestock growth, but
provides benefits to the plant, making it more tolerant of drought,
overgrazing and pest attack. Recent research has focused on
replacing the toxic endophyte with a nontoxic novel endophyte to
improve animal growth, while maintaining good plant persistence. In
this article are answers to some frequently asked questions about
fescue and fescue toxicity based on Arkansas research conducted by
Dr. Ken Coffey, Dr. Paul Beck, Dr. Mike Looper and Dr. Chuck West.
Question: Aren't fungus-free fescue and NE
(novel endophyte) fescue the same?
Answer: No. Fungus-free fescue contains
no endophyte. It provides good animal performance but has poor
persistence under grazing and stressful growing conditions. The NE
(novel endophyte-infected) fescue has a nontoxic endophyte that
provides both good animal performance and good plant persistence.
Question: Do fields planted with the NE
fescue revert back to toxic fescue after a few years?
Answer: No. The toxic endophyte cannot
spread from plant to plant, so a NE fescue plant will never become a
toxic fescue plant. However, if toxic fescue seed is spread into a
NE fescue field, it can become established and spread in the field.
Toxic seed can be carried in on equipment, by feeding mature toxic
fescue hay and by cattle that have consumed toxic fescue seed in
pasture or hay within two days of going into the NE fescue pasture.
Question: What effect does toxic fescue
(E+) have on my cows?
Answer: Recent research shows that the
toxic fescue affects reproduction rates of spring-calving herds much
more than fall-calving herds. Spring-calving herds had calving rates
(63-day breeding season) of only 44% when grazing toxic fescue
year-round. Converting 25% of the pasture to NE fescue improved
spring calving rates to 80%. Fall-calving herds maintained calving
rates of over 95% whether on toxic fescue year-round or if 25% of
the pasture was converted to NE fescue.
Question: What effect does toxic fescue
have on my calves?
Answer: Spring-born calves are more
affected than fall-born calves. Springborn calves on toxic fescue
had adjusted weaning weights 73 pounds lower than calves on 100% NE
fescue. Converting 25% of the pasture to NE fescue only improved
weaning weights by 10 pounds. Fall-born calves on toxic fescue had
adjusted weaning weights 49 pounds lower than their spring-born
counterparts on 100% NE fescue. Converting 25% of the pasture to NE
fescue improved fall-born calf weaning weights by 26 pounds or more
simply, converting 25% of the pasture gained 53% more calf weaning
weight.
Question: Does fescue hay become less toxic
during storage?
Answer: Yes. Levels of ergovaline, the
toxic alkaloid produced by the endophyte, has been shown to decline
by 23% in hay at Batesville and 79% at Fayetteville between June or
July harvest and sampling in February.
Question: Can I reduce fescue toxicity by
maintaining mixed pastures with bermudagrass?
Answer: Yes, but not entirely. Calves
weaned from cows grazing bermudagrass pastures mixed with either
endophyte-free fescue or orchardgrass weighed 48 to 52 pounds per
head more than calves weaned from bermudagrass/toxic fescue mixed
pastures. Cows on the bermudagrass pastures mixed with orchardgrass
or endophyte-free fescue also had greater body condition scores and
body weights than cows on the bermuda/toxic fescue forage.
Question: Does rotational grazing reduce
the fescue toxicity?
Answer: No. Studies on cow/calf
production on bermudagrass pastures mixed with endophyte-free
fescue, orchardgrass or toxic fescue showed no difference in cattle
performance for pasture rotation frequencies of twice a month or
twice a week. Rotating pastures twice a week did not improve
persistence of the orchardgrass or endophyte-free fescue compared to
rotating pastures twice a month. This was a well-managed study in
which the pastures were not overgrazed. In overgrazing conditions,
just maintaining nontoxic forages is difficult, so in an indirect
way, rotational grazing may reduce fescue toxicity if it reduces
overgrazing and maintains nontoxic forages.
These are just a few Frequently Asked Questions I have heard
lately. For more information on managing fescue toxicity, novel
endophyte fescues and forage management, contact your local
University of Arkansas Extension office.
Improving Grazing Management
Kenny Simon, Program Associate-Forages
One of the demonstrations associated with "300 Days of Grazing"
is improving grazing management. Improving grazing management allows
increased utilization of the available forage, thus helping extend
the grazing season. Research demonstrated increasing the pasture
rotation frequency from twice a month to twice a week increased the
number of grazing days by 40%.
Many livestock producers have permanent cross fences on the farm,
but all too commonly the gates are open and livestock roam freely.
The first step in improving grazing management is to shut the gates
and confine the livestock to one pasture at a time and begin
rotating among the existing pastures.
The second step is to subdivide the existing pastures with
electric fence. Electric fence offers many benefits over traditional
barbed or woven wire. One big advantage is cost. In improving
grazing management demonstrations, electric fence costs
approximately $0.30 per foot - a $0.73 per foot cost savings over
traditional fence, not including labor. Other benefits of electric
fence include its durability, its ease of construction and
maintenance and its light weight and ease of transport.
Electric fence is a psychological barrier, not a physical barrier
like barbed wire or woven wire. Therefore, the effectiveness of any
electric fence depends on the fence's ability to deliver an
unpleasant shock when touched. The ability of the fence to deliver
that shock depends on two main things: 1) the energizer and 2) the
grounding system.
At the heart of an electric fence system is the energizer, also
called the charger. There are several factors to consider when
selecting which energizer will be best suited for your individual
operation. What will be the power source for the energizer? What
size energizer is needed? What is the impedance of the energizer?
What are the energizer's warranty and service after the sale?
The three main sources of powering an energizer are 1) 110V or
220V plug-in, 2) battery or 3) solar. Plug-in main power units are
the most cost-effective per joule. They are usually the most
practical for permanent systems, require less maintenance and are
available in higher joule ratings than battery- or solar-powered
units. Battery- or solar-powered units work well in remote locations
where a power outlet is not available.
Battery-powered units will cost more per joule than plug-in
units, plus there is an additional battery cost. Deep-cycle
batteries, which can discharge slowly and completely, should be used
for powering these energizers.
Solar power units are the most expensive per joule. Solar panels
can be used with battery-powered energizers to keep the battery
charged. However, solar panels can be expensive, often costing as
much or more than the energizer.
The joule rating determines what size energizer is needed. A
joule is the amount of power that pushes the electrical pulse down
the fence wire. When comparing energizers, check to see if the unit
is rated in stored joules or output joules. Stored energy is the
amount of energy stored in the capacitors of the energizer. The
output joule is the amount of energy delivered to the fence and is
about 30 percent less than stored energy. A general rule of thumb is
1 output joule is needed per 3 miles of wire. This is dependent of
the type of wire being used, quality of the insulators, the
grass/weed load on the fence, etc.
Most of the energizers on the market today are low impedance.
Impedance means leakage. So, a low impedance energizer will have the
ability to resist leakage caused by minor shorts or vegetation on
the fence. For an energizer to be considered low impedance, the
duration of the pulse must be less than 0.003 of a second. The
duration of pulse for better quality energizers will be 0.0003 of a
second. Having a very short duration of pulse eliminates the risk of
fire, because no heat is built up on the wire.
 Before
making the final selection of an energizer, check the manufacturer's
warranty. Warranties will vary in length and items covered. Some
manufacturers offer a two-year warranty, while others have a
one-year warranty. Some units cover lightning damage. Like anything
else, the unit may need to be serviced. Ask the retailer if the unit
can be repaired "in house" or if the unit will have to be shipped
off for repairs. What is the average turnaround time on units that
need to be repaired? In the event the unit needs to be serviced, are
loaner units available?
A proper grounding system is the most important step in having an
effective electric fence. Eighty percent of electric fence problems
can be eliminated with proper grounding. The ground rods serve as an
antenna for collecting soil electrons. The better the grounding
system, the more electrons collected, which enables the energizer to
deliver a powerful shock.
Galvanized ground rods of ˝ inch or larger diameter should be
used. Three feet of ground rods are needed per output joule. For
units that require more than one ground rod, space the rods 10 feet
or more apart and connect ground rods to the energizer with one
continuous wire. The ground rods should be placed in area that holds
moisture, such as a drip line on the north side of a building.
In summary, electric fence is an effective way of controlling
livestock. Take the time to research energizers. Do not let price
alone be the deciding factor: remember, the energizer is the heart
of the system. If the energizer is not of sufficient quality, then
the whole system fails. The energizer must be grounded properly to
work efficiently. Even the best energizer will not function properly
if the grounding is inadequate. Take time to talk with your neighbor
or other producers who are using electric fence and learn some of
the dos and don'ts.
Arkansas 4-H Horse Activities Benefit From
Plum Creek Grant
Mark Russell, Equine Instructor
Arkansas 4-H horse activities will benefit from a $5,000 grant
from the Plum Creek Foundation. Workshops, clinics and competitions
are conducted statewide and are open to any interested child. This
grant will guarantee the equine 4-H program will be able to extend
educational opportunities to all children - even those who do not
own or have access to horses - in pursuit of our goal to spread the
joys of horsemanship.
The funds will also help provide education materials and
supplies, help pay for a computer system to tabulate scores, trail
equipment, show supplies and handheld radios for show personnel and
trail guides to communicate. The grant was provided to the Arkansas
4-H Foundation, a nonprofit organization that supports the
educational mission of the Arkansas 4-H program, which is part of
the University of Arkansas Division of Agriculture.
"Plum Creek recognizes the importance of The Arkansas 4-H
Foundation within the community, and we are proud to play an
important role in ensuring the future success of this valuable
organization," said Richard Stich, senior wildlife biologist for
Plum Creek. Plum Creek is the largest and most geographically
diverse private landowner in the nation with approximately 7 million
acres of timberlands in major timber-producing regions of the United
States, including 747,000 acres in Arkansas. For more information,
visit
www.plumcreek.com.
Is Beef From Naturally-Managed Cattle
Better Than Beef From Conventionally-Managed Cattle?
Shane Gadberry, Associate Professor
The next time you go to the grocery store, take notice of the
amount of meat counter space offering all-natural and possibly
organic products. Public concern over food safety, nutrition and
farm animal well-being is creating supply chains that provide
consumers more choices for how they want livestock managed before
they enter the food supply.
Terms such as "natural" and "organic" have taken on the
personification of being "healthier" or "safer" because livestock
marketed as such have not received growth promotants or antibiotics
(general guidelines for natural) or they meet more strict guidelines
for organic, which includes organic management of pastures (no
herbicides, no synthetic fertilizers). The question remains, "Are
these alternatively managed sources of protein ‘healthier' or
‘safer'?"
 A
study was recently published in Arkansas Animal Science
(the annual research update for the University of Arkansas, Division
of Agriculture's Department of Animal Science) comparing
naturally-branded products to conventionally-fed commodity beef.
This study compared steaks purchased from five different
natural-brand programs to steaks from two commodity beef packers.
These steaks were subjected to tests for tenderness and fatty acid
analysis, and a panel of consumers rated each steak for beef flavor,
tenderness and juiciness.
All of the products compared were similar in moisture content,
marbling and color characteristics. There were greater cooking
losses observed with commodity beef. Consumers rated steaks from
commodity beef juicier than the natural products. Comparison of
tenderness by Warner-Bratzler shear force or the consumer panel
indicated natural or commodity beef products were equally tender.
Texture, flavor and overall impression from eating commodity or
natural beef was similar. Natural beef is generally perceived as
healthier by consumers; however, the steaks compared in this study
did not differ in saturated, monounsaturated or polyunsaturated
fats.
Overall, this study showed that the only way consumers would be
able to distinguish natural beef from commodity beef would be by
reading the label. In addition, the fatty acid analysis indicated
that the natural product was not healthier than conventional beef.
If interested in learning how management affects beef quality and
consumer interest in meat choices, consider attending the upcoming
Beef Quality Conference on April 9 at the UA Community College in
Morrilton, Arkansas. More information about the conference is
available at
http://www.uaex.edu/news/january2011/0114Beef_Conference.htm.
Supplementing Pasture for r Dairy Cows
D. Wayne Kellogg, Professor
Pastures are a great asset on dairy farms in Arkansas. During the
early growth stage, the pasture provides an excellent source of
protein. Indeed, well-fertilized grasses or grass-legume mixtures
should contain well over 20% protein. How should this excellent
resource be utilized to the greatest advantage? Two topics should be
considered to optimally use pasture for dairy cows.
First, the combination of stocking rate and pasture rotation are
important. The herbage available depends on these factors. Depending
on the type of pasture, cows can consume the most dry matter while
grazing ryegrass, bermudagrass or fescue if the plants are 8 inches
tall (summer annuals, such as pearl millet or sudangrass, must be
taller than this before grazing). Then, cows should be removed when
the stubble height is only 3 to 4 inches tall (6 to 8 inches tall
for summer annuals) and offered another pasture that has had
opportunity for regrowth.
Clipping of pasture may be helpful to permit uniform regrowth.
The time for regrowth permits pastures to regain the optimum height
for grazing, but it also permits the plants to establish strong root
reserves.
Obviously, the number of cows per acre will determine how long
grazing can occur before rotation. If continuous grazing is
practiced, the minimum stubble height should be much higher -
perhaps as much as 50% taller - to maintain root reserves.
The second topic is supplementation. Dairy cows need a readily
available energy source along with pasture. In Florida, a "winter"
experiment was conducted with ryegrass/clover pastures. Increasing
the grain mixture from 1 pound for 3.5 pounds of milk produced to 1
pound of grain for 2.5 pounds of milk produced caused a decrease in
forage intake, and milk yield remained at about 44 lb/day.
Overstocking was a greater factor because dry matter intake of
pasture was reduced as much as 8 lb/day per cow when additional
supplement was fed, and milk yield decreased. If pasture were
limited or if grain were inexpensive, this might be profitable.
Thus, it would seem that the old "rule of thumb" still holds:
provide 1 pound of supplement mixture for every 4 pounds of milk for
Holsteins. For Jerseys, or other cows with higher fat and protein in
milk, the supplementation rate should be 1 pound of grain for 3
pounds of milk. By-products that contain readily digested fiber,
such as soybean hulls and whole cottonseed, may fit better with
high-protein pastures than starchy feeds such as corn - which works
well with lower quality pastures.
Pastures are a great resource in Arkansas, but quality of the
forage changes with the season. Flexibility is needed in stocking
rate and in providing supplementation.
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