Training Lambs to be Weed-eaters Experiments on the efficiency of Ovis airies for use in the biological control of Brachypodium sylvaticum- a non-native bunchgrass Ryan Scholz- Junior; Animal Sciences/ Bioresource Research Dr. Howard Meyers- Professor; OSU Dept. Animal Sciences Dr. Deborah Clark- Sr. Instructor; OSU Biology Program
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Training Lambs to be Weed-eaters Experiments on the efficiency of Ovis airies for use in the biological control of Brachypodium sylvaticum- a non-native.
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Training Lambs to be Weed-eaters
Experiments on the efficiency of Ovis airies for use in the biological control of Brachypodium sylvaticum- a
non-native bunchgrass
Ryan Scholz-Junior; Animal Sciences/ Bioresource Research
Dr. Howard Meyers-Professor; OSU Dept. Animal Sciences
Dr. Deborah Clark-Sr. Instructor; OSU Biology Program
Control
– Grazing• Observations at OSU
indicate grazing is effective
• Studies are underway to investigate this
– H. H. Meyer
• Relatively low palatability?
– Nutrition Tests
– Endophyte Tests
Grazed Un-Grazed
Planned Studies
• Pasture Training– Lambs to be grazed with mothers on B. sylvaticum
• Bummer Lamb Training– Bummer lambs to be fed B. sylvaticum
• Seed Viability• Nutritional Analysis
Pasture Training Study
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
– 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
• Yearling trial– Ewe lambs will be kept– Pasture trial will be repeated with same lambs next
summer• Determine the continued preference over extended time
• Study replication
Bummer Lamb Study
Hypothesis
Orphan lambs which are fed milk replacer containing B. sylvaticum will have an increased affinity for B. sylvaticum as adults when compared to unexposed sheep.
Experimental Design
• Breeding/ lambing– 25 ewes given luteinizing hormone for estrus
synchronization, and bred– Labor induced using hormone treatment
• Lamb Care– Lambs divided into control and experimental groups– Experimental lambs receive milk replacer with B.
sylvaticum juice
• Confinement feeding trial– Lambs will undergo same confinement feeding trial
as pasture raised lambs.
Seed Viability Study
Hypothesis
• B. sylvaticum seeds digested and later deposited by Ovis airies will have a significantly diminished ability to germinate.
Experimental Design
• To determine the risk of further spread of B. sylvaticum through seeds deposited by sheep used for control.
• Two Trials– Forage Diet
• Sheep on forage diet to achieve similar ruminal micro biotic content as grazing sheep
– Concentrate Diet• To facilitate easy and accurate recovery of seeds from
feces
Experimental Design
• Ripe seeds collected and dried to ~10% moisture– B. sylcaticum– Loliium multiflorum (control)
• ~5 gram samples weighed to 1/10000g accuracy and sealed in Dacron digestion bags
• Samples inserted into rumen cannulas and allowed to digest for 72h, 48h, 24h, 12h– Control sample placed in water for 30m
Experimental Design
• After removal from rumen:– Samples washed thoroughly – Dried to ~10% moisture– Weighed to 1/10000g accuracy– Germinated in 25°C/15°C chamber
Data
• Average sample weight loss
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.2000
0h 12h 24h 48h 72h
Time
Weig
ht
(g)
B. sylvaticum L. multiflorum
Further Research
• Concentrate Diet Trial– Replication of Dacron bag procedure– 15g seed introduced directly into rumen
• Recovered from feces
• Further investigation into mode of digestion• Neutral/Acid Detergent Fiber tests