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Frost and Johnsongrass Don't Mix
•
Keys to Success in Stocker Production •
2010 Beef IQ Program Will Be Held in
Booneville
Frost and Johnsongrass Don't Mix
Jeremy Powell, DVM,
PHD
Autumn is upon us. The air is crisp, and freezing
temperatures will soon be here. With temperatures dropping,
remember that frost can lead to problems with cattle grazing
sudangrass, sorghum-sundangrass hybrids and grain/forage
sorghum. Plants that are members of the sorghum family can
produce a toxin called prussic acid (cyanide) which is very
toxic to animals. This toxin occurs at elevated levels when
these plants have been stressed from conditions such as frost.
The toxin can be found in frosted leaves and stems within a few
hours after thawing and wilting occur. Johnsongrass (Figure 1)
is a member of the sorghum family, and is commonly found in many
grazing pastures throughout our state.
Figure 1. Johnsongrass.
Prussic acid poisoning prevents the body's ability to utilize
oxygen in the blood. Therefore, affected cattle may show
anxiety, rapid pulse and progressive weakness. It is common to
find dead animals with no previous signs of illness. Other signs
may include labored breathing, muscular twitching, convulsions
and sudden death due to suffocation. Ruminant animals such as
cattle, goats and sheep appear to be most commonly affected,
while reports of poisoning in horses are rare.
Sodium-thiosulfate is the preferred treatment for prussic acid
poisoning. It must be injected intravenously (IV) and very slowly. Since dosage and method of administration are
critical, it is recommended to consult a veterinarian to
administer the proper treatment.
A toxin called prussic acid occurs at elevated levels when plants of the sorghum family have been stressed from conditions such as frost.
Under normal conditions, sorghum-type plants 18 to 24 inches
tall are less likely to contain high concentrations of the
toxin. Prussic acid concentration decreases as the plants become
taller and more mature, and immature plants contain the highest levels of toxin. Toxin content of leaves is higher than
that of stems, with upper leaves containing more than the lower
ones.
Do not graze sorghum forage on a night when frost is likely.
If frost is in the forecast and the pasture is questionable,
producers should move cattle away from sorghum forages for
several days following a frost. If the forages were safe to
graze prior to a frost, then grazing can be reestablished 10
days following a frost. Sorghum forages require 28°F for a
killing frost; however, even a "light" frost may damage plants enough to increase
toxin levels.
Baling or ensiling sudangrass, sorghum-sundangrass hybrids
and grain sorghum immediately following a frost is safe because
the prussic acid will breakdown and dissipate during the harvesting process. Do not feed the
hay for a few days after harvesting to allow the toxin to
dissipate.
Most perennial forages are not a concern following a frost.
Generally, forage plants do not produce toxins and can be grazed
and fed to livestock safely after a frost. However, remember to
take precaution with sorghum forage when frost is in the
forecast. For more information about grazing management and
livestock production, contact your county Extension office.
Keys to Success in Stocker Production
Paul Beck, Associate Professor
There are several economic advantages to retaining raised calves
or purchasing calves and selling them later in groups at heavier
weights. These stocker (growing calves on pasture) or backgrounding
(growing calves using mixed feeds or stored forages) programs add
value to cattle for feedlots because they desire cattle that are
weaned, are from a minimum of suppliers, are familiar with feed
bunks and water sources and have minimal health issues.
The aforementioned desires expressed by feedlot cattle buyers
explain the considerable discounts that lightweight, unweaned bull
calves sold in one-head lots receive at livestock auctions.
Short-term (35- to 45-day) pre-conditioning programs add value to
calves because these programs provide evidence the calves being
marketed 1) are weaned, 2) have been processed (dehorned, castrated,
dewormed and vaccinated ) and 3) are familiar with feed sources. By
adding additional weight on calves with longer-term ownership, more
value is added to the calves because heavier cattle require fewer
days to finish and typically finish at more acceptable body weight.
Regardless of the type of backgrounding program, marketing decisions
must be well thought out so that the greatest benefit can be gained
from the time and money committed to this enterprise.
By adding additional weight on calves with longer-term ownership,
more value is added to the calves because heavier cattle require
fewer days to finish and typically finish at more acceptable body
weight.
One advantage of growing retained calves to heavier weights to be
sold directly to feed yards is the reputation of your cattle. Bull
purchasing decisions, breed makeup and carcass performance all can
be bid into the price of the cattle; but poor choices in breed
makeup and bull selection, a bad reputation for performance and
carcass quality can also be bid into the price of the cattle.
Purchase of additional calves can increase profitability of the
operation, but care should be taken to purchase the types of cattle
that will gain quickly, have minimal health problems and have breed
makeup and color pattern that bring top dollar at sale. It is also
essential to have adequate facilities to process, sort, catch, load
and doctor retained and purchased stocker calves.
One common wreck that occurs is receiving purchased cattle in the
same facilities as the retained calves. Calves retained from the
home ranch should have virtually no health problems, but to bring in
and co-mingle purchased cattle with ranch calves exposes the ranch
calves to every disease that the purchased calves were exposed to,
practically ensuring health problems in ranch calves as well as
purchased calves.
Health is one of the primary issues defining performance and
profitability. If the initial cost of a set of stocker calves is
$500/calf for every 1% death loss there is a $5/head cost that must
be made up when cattle are sold. An even larger problem may stem
from the number of cattle that are chronic with respiratory disease.
Chronics will not perform as well as healthy cattle, they are not
worth as much as healthy cattle, and they use up the same amount of
resources as healthy cattle, along with the cost of medicines used
to "save" the animal. Because death loss and chronic morbidity is
such an expensive problem, fresh or incoming cattle must be watched
carefully and treated as soon as clinical signs are identified.
The performance of stocker calves is much more sensitive to
forage quality and stocking rate than other classes of livestock.
Wheat forage commonly contains 25 to 30% crude protein and 75 to 85%
digestibility; this level of protein and energy is adequate to meet
the nutritional requirements of a stocker calf gaining over 3 pounds
per day. Summer grasses often lack the digestibility to provide
adequate energy for high levels of gain. In order for a calf to gain
2 pounds per day, diet digestibility should be 67% or greater. Often
calves grazing summer grasses gain only 1.5 pounds per day or less
without supplementation. Fertilization of warm-season grass pastures
increases the crude protein content and increases forage growth by
30 pounds of forage for every pound of actual N applied. The
additional forage growth must be utilized to maintain forage quality
and avoid waste.
2010 Beef IQ Program Will Be Held in
Booneville
The University of Arkansas Division of Agriculture is once again
offering its popular Beef IQ program. This program, which has been
attended by over 140 cattle producers, is now in its fourth year -
and fifth location. For those who are not familiar with the program,
it is an in-depth, informal educational activity for cattle
producers and managers.
The program is completed in six, seven-hour sessions scheduled
over the course of the year (9 a.m. on Mondays, February 22, March
15, April 12, May 17, September 20 and October 25). Each session
highlights a specific management topic: Genetics, Reproduction, Herd
Health, Economics, Forage Management and Nutrition.
This year's program will be held near Booneville, Arkansas, in
cooperation with the USDA, Dale Bumpers Small Farm Research Center.
The deadline for signing up is January 8. The registration fee for
the program is $100 per person or $150 per couple and includes meals
and one set of resource materials for all six sessions.
For more information, contact your local county Extension office
or sign up by calling (501) 671-2177. Registration forms can also be
downloaded at
http://www.aragriculture.org/livestock/beef/beef_iq.htm.
Jeremy Powell, DVM Associate Professor - Veterinarian
Brett Barham, Ph.D. Assistant Professor - Breeding and Genetics
The information given herein is for educational purposes only.
Reference to commercial products or trade names is made with the
understanding that no discrimination is intended and no endorsement
by the Arkansas Cooperative Extension Service is implied.
Printed by the University of Arkansas Cooperative Extension
Service Printing Services.
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