Locoweed: A Natural Disaster and BIOSECURITY RISK

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Locoweed A Natural DisasterandBIOSECURITY
RISK

• David Graham
• Agricultural Extension Agent
• New Mexico State University Cooperative Extension
  Service
• Union County New Mexico

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Locoweeds and MilkvetchesA Bio-Security
Issue???

• Biosecurity is the policies and measures taken to
  protect from biological harm. It encompasses the
  prevention and mitigation from diseases, pests,
  and bioterrorism, of the following area
• economy
• environment
• public health
• which includes food and water supply,
  agricultural resources and production, pollution
  management, blood and blood product supplies
  Biosecurity warrantly attempts to ensure that
  ecologies sustaining either people or animals are
  maintained. This may include natural habitats as
  well as shelter, productive enterprises and
  services, and deals with threats such as
  biological warfare or epidemics. This is related
  to the more passive concept of biosafety.

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Locoweeds and MilkvetchesA Bio-Security
Issue???

• Bio-security issue is an integral part of any
  agricultural emergency response plan.
• An accepted definition of an agricultural
  emergency is any incident having a negative
  impact on agriculture, including any outbreak of
  disease, or natural or man-made emergency that
  could result in economic or human losses.

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Locoweeds and MilkvetchesA Bio-Security
Issue???

• THE ANSWER IS YES.
• SO --- WHO CARES?
• WE SHOULD IF WE DEVELOP AN AGRICULTURAL ANNEX
  TO OUR COUNTY EMERGENCY PLANS, WE CAN INCLUDE
  MITIGATION AND PLANS FOR LOCOWEED INVASIONS EQUAL
  TO OTHER EMERGENCIES.

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Common Locoweeds and Milkvetches of New Mexico

• OXYTROPIS CRAZYWEEDS
• ASTRAGALUS LOCO or MILKVETCHES
• Oxytropis
• lambertii, sericea

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Common Locoweeds and Milkvetches of New Mexico

• Astragalus
• agrestis, allochrous, amphioxys,
  bisulcatus.ceramicus, crassicarpus, drummondii,
  emoryanus, humistratus, lentiginosus,
  lonchocarpus, missouriensis, mollissimus,
  nuttallianus, praelongus,pubentissimus,pracemosus,
  tephrodes,tompsonii, wootoni

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Oxytropis lambertii
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CERTAIN SPECIES ARE SIGNIFICANTLY RESPONSIBLE FOR
ECONOMIC LOSSES

• Oxytropis sericea
• WHITE LOCOWEED
• Astragalus Mollissimus
• PURPLE LOCOWEED

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CERTAIN SPECIES ARE SIGNIFICANTLY RESPONSIBLE FOR
ECONOMIC LOSSES

• Astragalus emoryanus
• Red Stem Peavine
• Astragalus Wootoni
• Garbancilloor Rattleweed

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Research Challenges

• Localisms and pre conceived ideas.
• Mineral and feed salesmen.
• Old and outdated information.
• INTERNET JUNK SCIENCE

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SWAINSONINE

• Although the toxin content of locoweeds is not
  very highgenerally less than 0.2 of the plants
  dry weightit appears to be highest in the
  flowers and seeds. However, because of its
  exceptional potency, it has been calculated that
  levels as low as 0.001 can cause poisoning.

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THE ENDOPHYTE

• Swainsonine is known to be produced by some
  fungi, including a plant pathogen and an insect
  pathogen.
• Also, some forage plants are poisonous due to
  toxins produced by fungi living between the
  plants cells (endophytes). Festucosis, for
  instance, is a result of toxins in this case
  swainsonine

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SWAINSONINE cont

• The chemical structure of swainsonine is not
  complex and is quite similar to simple sugars,
  such as mannose and glucose, which it appears to
  mimic. As a result of this imitation, it stops
  the action of the enzyme a-mannosidase, which is
  essential for the proper functioning of all
  animal cells.

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SWAINSONINE cont

• We know that the water soluble swainsonine is
  dispersed very rapidly into the animal body.
• We know that its influences are seen in
• 1. The Reproductive System
• 2. The Circulatory System and organs
• 3. The Nervous System.

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SWAINSONINE cont

• We know that the swainsonine makes its rounds
  and is eliminated within 48 hours through the
  urine and the milk in lactating animals.
• We know that when animals are removed from access
  to swainsonine, the cells recover in the same
  order they became damaged.
• 1. The Reproductive System
• 2. The Circulatory System and Organs (immune
  system)
• 3. The Nervous System (This system does not
  heal)

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ECOLOGY ANDPHYSIOLOGY

• When the rain falls may affect locoweed density
  (Dec. Jan. Feb. some influence, Mar. Apr. May
  consistent influence, June, July, Aug. NO
  influence, Sept. Oct. Nov. NO influence)
• Drought-stressed locoweed contains more
  swainsonine
• Swainsonine content is a direct result of fungi
  infecting locoweed
• Swainsonine content varies from plant to plant,
  leaf to leaf on same plant.

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MANAGEMENT

• BIOLOGICAL
• CONTROL
• BY
• INSECT

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FOUR-LINED LOCOWEED WEEVIL

• Four-lined locoweed weevil (Cleonidius
  trivittatus) is the most important insect to
  attack woolly locoweed. The adults (fig. 1a) are
  grayish to brownish and about 1/2 to 1 inch long
  with 4 dark stripes down their backs. They feed
  on the leaves and stems of locoweed however, the
  immature larvae cause most of the damage. Larvae
  (fig. 1b) are 1/8 to ¾ inch long, legless, cream
  colored, C shaped with a brown head and jaws.
  They can be found feeding on the outside or
  inside of the root of woolly locoweed.

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FOUR-LINED LOCOWEED WEEVIL

• Weevil larvae construct a chamber inside the root
  or in the soil adjacent to the root in which they
  pupate (fig 1c). Adults lay individual, bright
  yellow eggs (fig. 1d) in the late fall through
  early spring, that are commonly covered with
  chewed locoweed leaves.
• Feeding by two weevil larvae killed most sizes of
  woolly locoweed in our research plots.

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NEW RESEARCH NOW SHOWSDr. David Thompson and
Kevin Gardner 2008

• PLANT STRESS CAUSED BY INSECT ACTIVITY DOES NOT
  AFFECT THE SWAINSONINE CONCENTRATION

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MANAGEMENT

• RANGE AND LIVESTOCK
• MANAGEMENT

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ANIMALS AFFECTED BY LOCO TOXICITYALL ANIMALS ARE
AFFECTED, BUT METABOLISM DETERMINES THE EXTENT
AND SEVERITY

• HORSES
• ELK
• CATTLE, SHEEP
• DEER
• PRONGHORN ANTELOPE

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ANIMALS AFFECTED BY LOCO TOXICITYWHY DO THEY EAT
LOCOWEED?

• WE DONT KNOW
• SMALL ARE PRONE TO EAT LOCOWEED
• SOCIAL FACILITATION!!!!!!

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ANIMALS AFFECTED BY LOCO TOXICITY

• BREED DIFFERENCES?
• INDIVIDUAL ANIMALS
• SOCIAL FACILITATION

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Reducing Locoism with MANAGEMENT

• Old recommendations that we think are not valid.
• 1. Graze animals that are familiar with the
  range. This is probably counterproductive,
  because cattle learn to eat plants, especially
  locoweed, from older, more experienced animals.
  This behavior often is called social
  facilitation, or peer pressure. Naive cattle
  that have never grazed locoweed are a safer bet.
• 2. Dont graze wheat pasture cattle on locoweed
  rangeland. This old recommendation assumes that
  cattle coming off wheat are more likely to graze
  green plants such as locoweed. Research conducted
  during this project found no difference in
  locoism incidence between wheat pasture cattle
  and native range cattle. All cattle prefer green
  locoweed to brown grass. Wheat pasture cattle are
  no more likely to graze locoweed than other
  cattle.
• 3. Supplement animals with protein, plenty of
  salt and minerals. The idea that cattle are more
  likely to graze locoweed if deprived of salt and
  minerals, or short on protein, is not conclusive.
  We highly recommend range livestock receive good
  mineral, protein, and energy supplements when
  vegetation warrants supplementation. However, the
  only way a supplement will reduce locoism is if
  it prevents cattle from grazing locoweed. Thus
  far, no such supplement exists.

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Reducing Locoismwith Management

• Options that have been proven to reduce locoism.
• 1. Create locoweed-free areas. It would be nice
  to be able to spray the entire ranch. However,
  this is not economically feasible for everyone
  and may not be necessary. Creating pastures that
  are free of locoweed provides greater management
  flexibility when a safe area is needed.
• 2. Observation. Removing cattle that are observed
  eating locoweed provides relief to the animals
  and also prevents them from teaching other cattle
  to eat locoweed.
• 3. Range readiness. Dont graze locoweed-infested
  pastures until warm season grass has started
  growing. This date varies from year to year, but
  by June 1, warm-season grasses should provide
  enough green feed to keep cattle from searching
  for locoweed. The other danger period is in the
  fall, when grasses start curing and locoweed once
  again becomes a preferred plant.
• 4. Cyclic grazing. Grazing locoweed-infested
  pastures for less than 4 weeks followed by
  grazing a locoweed-free pasture for 4 to 6 weeks
  may avoid the need to totally abandon locoweed
  pastures.(May work for yearlings)
• 5. Rotational grazing. Graze the
  locoweed-infested pastures during the safe
  period (June to September) and the locoweed-free
  pastures prior to June and after September.
  Remember, these dates are only guidelines and you
  will need to spend some time observing cattle
  grazing locoweed-infested pastures to determine
  when they quit locoweed and when they start
  grazing it again.

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Reducing Locoismwith Management

• 6. Flash grazing. Naive cattle normally will not
  graze locoweed until grazing pressure forces them
  to eat the plant. A series of trials were
  conducted near Des Moines, N.M. In the first
  trial, naive yearling cattle did not graze
  locoweed until grass use was heavy. In the second
  trial, the same cattle started eating locoweed
  when grass use was light to moderate. By the
  third trial, the same yearlings ate locoweed
  first and preferred it to other plants.
  Therefore, we recommend that grass use never be
  heavy or severe in order to prevent cattle from
  learning to eat locoweed.
• 7. Culling. Locoweed affects reproductive
  performance. Cows that are open in the fall need
  to be culled, because they MAYBE have eaten
  locoweed and need to be sold. Culling open cows
  makes economic sense and also has proven to
  reduce the number of locoweed eaters on the
  ranch.
• 8. Aversion. Although this option is still
  experimental, we believe it offers a lot of
  promise for reducing locoism. Cattle have been
  trained to avoid eating locoweed through a
  process of conditioned food aversion. Cattle are
  fed locoweed, then dosed with an emetic, lithium
  chloride (LiCl), to induce gastrointestinal
  distress. The cattle associate locoweeds taste
  with a belly ache and avoid grazing it. Aversion
  training works best on naive cattle not familiar
  with locoweed. Steers familiar with locoweed
  require several doses. Dosage rate is critical,
  with 200 mg LiC1 per kg body weight being the
  most effective. Averted cattle must then be kept
  away from non averted locoweed eaters to prevent
  peer pressure or social facilitation from
  negating the aversion. This suggests the idea of
  averting replacement heifers so that their
  offspring will never be taught to eat locoweed.

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Effects on Pregnancy

• LOCO WEED EFFECT ON PREGNANT COWS
• Dr. K.E. Panter USDA/ARS Poison Plant Lab
• Cattle graze loco 10 to 14 days during Pregnancy
• Pregnancy 0-25 days Cows return to
  estrus
• Pregnancy 25-60 days Cows reabsorbing of
  fetus (usually no sign), with light grazing may
  have full term births with weak calves or sick
  calves.
• Pregnancy 60-120 days Abortion (may find
  fetus in pasture), some may reabsorb fetus. May
  have cows with hydropsy. With light grazing may
  have full term births with weak or sick calves.
• Pregnancy 120-280 days Weak calves, poor
  nursing ability, deformed calves, may be fully
  developed fetal abortion or still birth, and if
  calves live, they will be chronics and poor
  doers.
• There is no quantification to amount of
  swainsonine ingested or any correlation of
  swainsonine ingestion and fetal condition.
• May see pneumonia in cattle linked to damage
  to the immune system. May see un-related illness
  in new born because of immune system damage.

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Reducing Locoismwith Management

• REDUCE OR ELIMINATE STRESS
• Physical Stress
• Nutritional Stress
• 1. Supplement correctly (range monitoring)
• 2. Dont turn out hungry animals
• OBSERVE, OBSERVE, OBSERVE

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MANAGEMENT

• USING HERBICIDES
• TO CONTROL LOCOWEED

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CONTROLLING LOCO WITH HERBICIDES

• Locoweed can be controlled at all growth stages
  by several different herbicides. It pays to spray
  under ideal weather conditions and shop for the
  best herbicide price.

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Comparison of herbicides Astragalus control

• Growth
  Stage
• Herbicide Dosage(Per./ac)
  Spring Bloom Fall
• Picloram 0.25 lb.
  E E
  E
• Picloram 0.375 lb
  E E
  E
• Picloram 2-4-D(14) 0.94 lb.
  E E E
• Metsulfuron 0.1875 oz/ac
  F E E
• Metsulfuron 0.375 oz/ac
  F E E
• 2-4-D 4.0
  lb. F F
  F
• E Excellent G Good F Fair P Poor

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Controlling Locoweed with Herbicides

• Additives increase herbicide uptake by locoweed
  regardless of leaf hair architecture.
• Locoweed Herbicide Uptake after 24 Hr.
• Species Picloram
  Ally
• Purple Locoweed 8.9 alone
  15.3 alone
• 83.4 With
  Diesel 47.3 With Diesel
• White Locoweed 11.8 alone
  14.5 alone
• 81.4 With
  Diesel 79.9 With Diesel
• Diesel added at Approximately 15 by volume

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This publication is Out of print but can Be
viewed copied at http//cahe.nmsu.edu

PUBLISHED IN 1999 NMSU
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WHERE ARE WE ON LOCO RESEARCH? WE THINK

• ANIMALS START EATING LOCOWEED BECAUSE OF A
  NUTRITIONAL NEED.
• OR
• SOME AS A CURIOSITY
• AND
• HORSES??? BOREDOM
• THEN SOCIAL FACILITATION KICKS IN.

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SOME THINGS WE BELIEVE BASED
ONOBSERVATIONS AND EXPERIENCE

• RANGE READY
• LOWER STRESS PHYSICAL NUTRITIONAL
• SUPPLEMENTS ONLY WHAT IS NEEDED
• FEED GROUNDS
• MONITORING
• AVERSION
• TURN OUT FULL NEW ANIMALS

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THE ONLY THING WE KNOWN FOR CERTAIN

IN LOCOWEED THERE IS NO EASY BUTTON