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 /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 Exposure 1Exposure 2 Day 1Day 2Day 1 Treatment 116g152g176g232g Control 78g119g145g140g

Data Exposure 1Exposure 2 Day 1Day 2Day 1Day 2 Treatment 72g64g87g Control 64g75g56g58g

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 100m 2 B. sylvaticum plots enclosed with temporary electric fence –Four 1m 2 clippings taken from each plot before and after grazing –Sheep grazed on two plots over 2 consecutive days

Data Day 1Day 2Day 1Day 2 Treatment 62g83g106g70g Control 21g14g42g11

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 ) –Confinement feeding trial during summer

Data Exposure 1Exposure 2 Day 1Day 2Day 1Day 2 Treatment 28g50g78g59g Control 16g35g53g69g

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 Seed Viability Study

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 Seed Viability Study

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 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.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