improving intake of medusahead: is it possible? by tyler hamilton, juan villalba and beth burritt,...
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Improving Intake of Medusahead: Is it Possible?
Tyler Hamilton, Juan Villalba and Beth Burritt
What ‘s Wrong with Medusahead?
1. It produces little biomass2. It’s mostly stem with little leaf3. It has nasty awns 4. It’s high in silica and low in nutrients5. It produces a thatch that smothers other
plants, doesn’t readily breakdown, and is highly flammable.
“A team of genetic engineers couldn’t have devised a more ecologically lethal and effective invasive weed than the aptly named medusahead rye.”
"It's like a piece of land that's stolen from you or from your ranch that no longer produces feed.”
Questions1. How does supplementation intake of
and preference for medusahead?
2. Is medusahead aversive?
3. How does the addition of silica dioxide to the diet affect intake?
How much medusahead will a sheep eat?Do supplements enhance intake and preference?
Group 1:High-Energy
Group 2:High-Protein
Group 3:Choice
Group 4:No Supplement
After 20 min., all animals had ad libitum access to fresh medusahead for 5 hours/day.
Measured intake and preferenceTrial 1 Trial 2 Trial 3
Ingredient, % High Energy High Protein
AlfalfaSoybean MealBeet PulpBarley
DE, Mcal/kgNDF, %Protein, %
Protein/Energy
7030
3.5431.711.3
3.2
6040
3.0031.928.8
9.6
Supplement Ingredients and Nutritional Composition
1 2 3 4 5 6 7 8 9 100
2
4
6
8
No Supplement High Energy High Protein Choice
Inta
ke, g
/Kg0
.75
SEM
Intake of Medusahead (Seedhead Emergence) by Lambs Fed Three Different Supplements or
No Supplement
Medusahead: 4 to 8 g/kg 0.75/5 hr
Requirement: 55 g/kg 0.75/d
Translation:
1 2 3 4 5 6 7 8 9 100
2
4
6
8
No SupplementHigh energyIn
take
( g/
kg 0
.75)
Intake of Medusahead Intake (Seedhead Emergence) by Lambs Fed a High Energy
Supplement or No Supplement
bbb
a aa
Figure 2
1 2 3 4 5 6 7 8 90
2
4
6
8
No Sup-plementHigh EnergyHigh ProteinChoice
Inta
ke, g
/Kg0
.75
Intake of Medusahead (Mature) by Lambs Fed Three Different Supplements or No Supplement
Figure 2
1 2 3 4 5 6 7 8 9 100
5
10
15
20
No sup-plementHigh energyHigh ProteinChioce
Inta
ke, g
/Kg0
.75
SEM
Intake of Medusahead (Thatch) by Lambs Fed Three Different Supplements or No Supplement
1 2 3 4 5 6 7 8 9 100
5
10
15
200
5
10
15
20
ControlHiEHi ProChoice
Figure 2
Trial 3 – Thatch
Trial 1 – Seedhead Emergence
Inta
ke (g
/kg
0.75
)Comparison of Medusahead
Seedhead Emergence vs. Thatch
None HE HP CH0
20
40
60 HayMedusaheadSupplement
Figure 1
None HE HP CH0
20
40
60Trial 2 – Total Intake – Mature
Trial 1 – Total Intake – Seedhead Emergence
None HE HP CH0
20
40
60Trial 3 – Total Intake – Thatch
Intake of Tall Fescue Hay, Medusahead and Supplements at Three Stages of Medusahead Maturity
C HE HP CH0
20
40
60
C HE HP CH0
20
40
60
Merdusahead Hay
Choice between TF hay and medusahead at three stages of maturity
C HE HP CH0
20
40
60Trial 2- Mature and Hay Trial 3 – Thatch and Hay
Trial 1 - Seedhead Emergence and Hay
Crude Protein Silica0
2
4
6
8
10
12
Green MatureThatch
%Crude Protein and Silica Content of Medusahead
at Three Stages of Maturity
Is Silica Involved in the Intake Response to Medusahead?
Familiarized with alfalfa from 8 am to noon. Then, fed tall fescue hay from noon to 2pm.
After familiarization, lambs were fed their respective treatment diets (8 am to noon) and tall fescue hay from noon to 2pm.
Alfalfa - Control Alfalfa + 2.5% SiO2 Alfalfa + 4.5% SiO2
1 2 3 4 50
5
10
15
20
25
30
70
80
90
100
110
120 Silica added to Alfalfa
70
80
90
100
110
120
Alfalfa
2.5% Si
4.5% Si
1 2 3 4 50
5
10
15
20
25
30
Before adding Silica to Alfalfa
Tall Fescue Intake Before Adding Silica to Alfalfa
Tall Fescue Intake After Adding Silica to Alfalfa
Inta
ke (g
/kg
0.75
)
Is Medusahead Aversive?
Fed coconut-flavored beet pulp
1-LiCl (1.5 mg/Kg BW – Aversive)
2-Tall Fescue Hay (4g/Kg BW – Not Aversive)
3-Medusahead (4g/Kg BW – Unknown)(Average amount eaten in Trial 1)
Then they received intraruminal infusions of:
1-Jul 2-Jul 3-Jul0
5
10
15
20
25
HayLiClMedusaheadIn
take
, g/K
g0.7
5Is Medusahead Aversive?
Results• Intake of and preference for medusahead is
enhanced (sort of) by supplements high in energy.• Intake of medusahead is low and decreases even
further as the plant matures.• Intake of medusahead by unsupplemented animals
was low, even though they ate least DM and nutrients.
• Medusahead does not to induce a food aversion in sheep.
• Silica likely reduces intake of medusahead.
Questions?