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 unshaded 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
Data- Trial 1
13%
Treatment
Control
4%
21%
54%
33%
57%
22%
96%
Total Eaten
Not Eaten
100.0g B. sylvaticum
Waste
Data- Trial 2
13%
Treatment
Control
21%
27%
54%
33%
57%
11%
62%
Total Eaten
22%
Not Eaten
250.0g B. sylvaticum
Waste
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
250.0
Weight (g)
200.0
150.0
Beginning
Final
100.0
50.0
0.0
Treatment
Control
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