Training Lambs to be weed-eaters

Conditioning Ovis Airies for use in the biological control of Brachypodium sylvaticum- a non-native bunchgrass

Ryan Scholz

Dr. Howard Meyers

Dr. Deborah Clark

Slender False Brome

• Brachypodium sylvaticum– “Class B” Invasive Species

• First reported as naturalized in 1939 near Eugene, OR

• Centralized in Willamette Valley

• Recently discovered in Josephine County and Northern California

Background

• Slender False Brome (cont.)– Native to Europe, Asia, Africa

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

• Observations indicate grazing is effective

• Studies are underway to investigate this

• Appears to be relatively low on sheep palatability hierarchy

Hypothesis

• Lambs grazed on B. sylvaticum with their mothers prior to weaning will have an increased affinity for B. sylvaticum as adults when compared to unexposed sheep.

Experimental Design

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

sylvaticum– Control- Grazed on

standard pasture– All lambs grazing for 3

week training period• First 2 weeks with ewes

• Last week weaned

Experimental Design

• Confinement Feeding Trial- wethers– Offered fresh cut B. sylvaticum after overnight fast– To determine the relative preference for B.

sylvaticum after training

• Pasture Grazing Trial- ewes– Grazed on a series of plots containing B. sylvaticum– To measure:

• Relative preference in a pasture setting• Continued preference over extended period of time

Confinement Feeding Trial

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

individually penned– ~250g B. sylvaticum placed in each feeder at

10:00am• Allowed to eat for 30 minutes• Removed from pens• Leftover and wasted B. sylvaticum collected and weighed

– Repeated following morning

• Conducted immediately following training and again one month later

96%

4%

Data- Trial 1

Treatment Control

57%

22%

21%

Total Eaten Not Eaten Waste

100.0g B. sylvaticum

62%11%

27%

Data- Trial 2

Treatment Control

57%

22%

21%

Total Eaten Not Eaten Waste

250.0g B. sylvaticum

Analysis

• Shows training to be effective– Treatment lambs ate

more– Observations indicated

treatment lambs to be less timid when eating

• Some conditioning occurred with control– Likely situational

conditioning

Treatment

Control

Pasture Grazing Trial

• Procedure– Lambs grazed on series of 100m2 plots containing

B. sylvaticum– Four 1m2 clippings taken before and after grazing

• Determine biomass composition• Determine amount biomass removed

– Grazing patterns will be recorded using time-lapse video surveillance system

– Forage consumption and grazing patterns analyzed using forage maps

Data

Pasture Trial- Day 1

0.0

50.0

100.0

150.0

200.0

250.0

Treatment Control

Wei

gh

t (g

)

Beginning

Final

Analysis

• Final Analysis not complete– Observations indicate

training to be effective• Treatment lambs

consumed more B. sylvaticum

• Treatment lambs spent more time grazing

• Trial cut short due to uncontrollable circumstances

Further Planned Research

• Pasture training study– Yearling trial– Study replication

• Bummer lamb study– Bummer lambs fed milk with B. sylvaticum

extract• Seed viability

– Digested seed tested for viability

Questions