Using sheep to control Brachypodium sylvaticum- an invasive weed Ryan Scholz- Senior; Animal Sciences/ Bioresource Research Dr. Howard Meyer- Professor;

Using sheep to control Brachypodium sylvaticum- an

invasive weed

Ryan Scholz-Senior; Animal Sciences/ Bioresource

Research

Dr. Howard Meyer-Professor; OSU Dept. Animal Sciences

Slender False Brome

• Brachypodium sylvaticum– Native to Europe, Asia,

Africa– “Class B” Invasive Species

• First reported as naturalized in 1939 near Eugene, OR

• Widespread in Western Oregon

• Recently discovered in Josephine County and Northern California

Background

• B. sylvaticum (cont.)– Habitat

• Common in shaded forest understories

• Gradually moves into un-shaded regions

• Out-competes many native plants

Background

• Control– Spray

• Accord ® (Glyphosate)

• Velpar® (Hexazinone)

– Super-heated foam• Waipuna machine

– Mechanical Removal– Burning/ mowing

• Appears to be ineffective

Background

• Control (cont.)– Grazing

• Relatively low palatability

• Observations indicate grazing can be effective

• Studies are underway to learn more

Grazed Un-Grazed

Research Timeline

• Pasture Study – 2004/2005– Confinement Trial– Pasture Trial

• Orphan Study – 2005• Seed Viability Study – 2005/2006/2007

– In situ– In vitro– In vivo

Pasture Study - 2004/2005

Experimental Design

• Pre-Trial Training– Treatment- Grazed on B.

sylvaticum– Control- Grazed on

standard pasture– All lambs grazed for 3

week training period• First 2 weeks with

mothers

• Third week after weaning

• Study repeated 2005

Confinement Feeding

Pasture Study – 2004/2005

Experimental Design

• Confinement Feeding Trial- wether lambs– Lambs from pasture

training– To determine their

willingness to eat B. sylvaticum after training

– Offered fresh cut B. sylvaticum after overnight fast

Confinement Feeding Trial

• Procedure– Lambs removed from fields at 4:00pm and housed

in barn overnight– Individually penned lambs offered 250g fresh cut B.

sylvaticum at 10:00am• Lambs allowed to eat for 30 minutes• Uneaten B. sylvaticum collected and weighed

Confinement Feeding Trial

• Procedure (cont)– Lambs held off feed

overnight; test repeated following morning

• Conducted immediately following training and again one month later

Data- 2004

Exposure 1 Exposure 2

Day 1 Day 2 Day 1 Day 1

Treatment 116g 152g 176g 232g

Control 78g 119g 145g 140g

Data- 2005





Results

• Exposure was effective– Treatment lambs

consumed more (P<.05)– Effects still present one

month later (P<.05)– Conditioning effect

observed in control lambs (P<.05)

Treatment

Control

Pasture Grazing

Pasture Study – 2004/2005

Experimental Design

• Pasture Grazing Trial- ewe lambs– To measure:

• Relative preference in a pasture setting

• Continued preference over extended period of time

– Grazed plots located in dense stands of B. sylvaticum

Pasture Grazing Trial

• Procedure– Four 100m2 B. sylvaticum plots enclosed with

temporary electric fence– Four 1m2 clippings taken from each plot before and

after grazing– Sheep grazed on two plots over 2 consecutive days

Data

2004 2005



Control 21g 14g 42g 11

Results

• Observations and Results indicate training to be effective– Treatment lambs

appeared to spend more time grazing

– Treatment lambs consumed more B. sylvaticum (P<.05)

Orphan Lamb Study

Hypothesis

• Artificially reared lambs exposed to B. sylvaticum juice as an additive in milk will have an increased affinity for B. sylvaticum as adults when compared to unexposed sheep.

Experimental Design

• 24 orphan lambs reared on milk replacer– Born via caesarian

2/14/05– 12 treatment lambs

given B. sylvaticum juice in milk for 14 days (d. 21-35)

– Confinement feeding trial during summer

Data





Results

• No significant difference– All lambs showed

aversion to B. sylvaticum on first exposure (compared to Pasture Training)(P<.05)

– No Difference between treatment groups (P>.05)

– Control adjusted to B. sylvaticum faster than treatment (P<.05)

Seed Viability Study

Hypothetical Problem

• Sheep utilized to control B. sylvaticum– Graze plant in later

summer– Ingest viable seed

• Animals moved from B. sylvaticum to “clean” field– B. sylvaticum seed

excreted in feces– Potential for spread of B.

sylvaticum

Hypothesis

• B. sylvaticum and L. multiflorum Lam. (perennial ryegrass) seeds which are digested by sheep will have decreased germination rates when compared to undigested seed.

Experimental Design

• 4 sheep were ruminally cannulated

• B. sylvaticum seed was collected in late summer

• L. multiflorum Lam. seed used as comparison

• In sacco, in vitro, in vivo digestion techniques used

• Seed viability will be determined at OSU Seed Lab

In sacco trial


In sacco Trial

• 3.0g seed in Dacron digestion bags

• Placed in rumen for 3, 6, 12, 24, 48 and 72 hours

• Samples washed and dried following digestion

• Weights obtained to determine amount of digestion

Data- in sacco

Results

• Both species lost ~4% in first 3 hours– B. sylvaticum steadily

increased to 7.5% by 72 hours

– L. multiflorum Lam. steadily increased to 7.5% by 24 hours, jumped to 11% and plateaued by 48 hours

In sacco trial


In vitro Trial

• 1000mL rumen fluid collected from 4 sheep• Samples digested in 35°C rumen fluid for 24 or

48 hours– 90ml rumen fluid mixed with 10ml McDougal’s

Buffer– 0.25g seed + 0.25 substrate

• NDF used to estimate post-ruminal digestion

Data- in vitro

Results

• Significant difference (p<0.05)– Digestion times for B. sylvaticum and L. multiflorum

Lam. with like substrates– Like digestion times for L. multiflorum with like

substrate and B. sylvaticum substrate– Like digestion times for L. multiflorum Lam. with

and without post-ruminal digestion

Results

• No significant difference (p>0.05)– 24h and 48h digestion of L. multiflorum Lam. seeds

with B. sylvaticum substrate– 24h and 48h digestion of L. multiflorum Lam. seeds

with post-ruminal digestion

Discussion

• Current results are promising but have limited application– Show digestion of seed– Effect of digestion on

viability to be determined (work in progress)

Big Picture

• Pre-weaning training with mothers is effective (P<.05)• Incorporation of juice in milk was not effective <P>.05)

– Very expensive and time consuming– Possibly needed longer exposure time– May have created an aversion

• Seed digestion results inconclusive – awaiting germination results– Sheep should be held off of “clean” pasture for a minimum of

72 hours following grazing B. sylvaticum in seed

Questions

Special thanks to:

• Dr. Howard Meyer• Dr. Deborah Clark• Nichole Scholz• Tom Nichols• Mark Keller• Dr. Mike Gamroth• Joel Haas• Dave Bohnert• Wanda Crannell• Dr. Morrie Craig

• OSU Dept. Animal Sciences

• OSU Research Office- URISC Grant

• Howard Hughes Medical Institute- Summer Fellowship Program

• OSU Seed Lab- Dale Brown

• OSU Seed Extension Office- Tom Silverstein

Using sheep to control Brachypodium sylvaticum- an invasive weed Ryan Scholz- Senior; Animal Sciences/ Bioresource Research Dr. Howard Meyer- Professor;

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