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Special Thanks to Present and Past Stakeholders! Affiliation Name Crow Valley Livestock Cooperative Steve Anderson, Leonard Ball, Dana
Bowman, Jason Kern, Andy Lawrence, Scott Timm
The Nature Conservancy Terri Schulz, William Burnidge Bird Conservancy of the Rockies Seth Gallagher, Angela Dwyer Environmental Defense Fund Ted Toombs Colorado State University Extn Casey Matney USDA - NRCS Rachel Murph USDA - FS Kim Obele CO State Land Board Matt Pollart We thank Nick Dufek, David Smith, Jeff Thomas, Pam Freeman, Matt Mortenson, Jake Thomas, Craig Lawrence, Melissa Johnston, and the many ARS and CSU field technicians that made this experiment possible, and CVLC for providing the cattle.
Example of cattle foraging behavior in the AGM herd (red circles) versus a paired TGM herd (yellow circles). The example shows GPS collar fixes for 1 steer in each treatment collected every 5 minutes over a 13-day period in 2014. AGM cattle grazed in more linear pathways, moved longer distances while grazing, and spent less time per day engaged in grazing behaviors.
Tradeoffs between Vegetation Management and Livestock Production under Adaptive Grazing Management
David J. Augustine1, Justin D. Derner1, Maria E. Fernandez-Gimenez2, David D. Briske3, Hailey Wilmer1, Lauren M. Porensky1, Kenneth W. Tate4, Leslie M. Roche4
1USDA-Agricultural Research Service, Rangeland Resources Research Unit, Fort Collins, CO 80256 / Cheyenne, WY 82009, 2Department of Forestry and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80253, 3Ecosystem Science and Management Department,
Texas A&M University, College Station, TX 77843, 4Department of Plant Sciences, University of California-Davis, Davis, CA 95616 *Correspondence: [email protected]
Grazing Plan Implementation In 2014, cattle were moved among pastures when one of three triggers – residual forage biomass, cattle behavior, or maximum number of grazing days - was achieved in the currently grazed pasture.
In 2015, the maximum days threshold was removed such that moves among pastures were only based on forage biomass and cattle behavior.
Due to 2 consecutive years of above-average spring precipitation and forage production rates, the AGM herd grazed 7 of 10 pastures in 2014 and 4 of 10 pastures in 2015. Thus, a substantial portion of the landscape under adaptive grazing management was rested in 2014 and/or 2015.
Rested
Rested
Sept 9 August 8
Rested
May 16
May 30 July 23
June 20
July 8
2014(214 steers)
Aug 20
July 7
Rested Rested
Rested
Rested
May 30 May 27
Rested
Rested
2015(224 steers)
0
50
100
150
200
250
300
350
400
450
500
2013 2014 2015
Annual Precipitation (mm)
Long-termMean
Vegetation Responses
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
AGM TGM
RATE
OF
INCR
EASE
, 201
3 -2
015
Pastures Rested in 2014
0
0.5
1
1.5
2
2.5
3
3.5
AGM TGM
RATE
OF
INCR
EASE
, 201
3 -2
015
All Pastures
Res
idua
l For
age
Bio
mas
s (k
g/ha
)
400
600
800
1000
1200
1400
1600
AGM TGM0
500
1000
1500
2000
2500
3000
Residual Biomass after Grazing Season
0
100
200
300
400
500
600
2013 2014 2015
ANPP
(kg
ha-1
)
AGM
TGM
Aboveground Production by C3 Perennial Gramminoids
Rate of Increase in Western Wheatgrass
Tiller Density
Conclusions
Managing cattle as a single large herd rotated among many pastures instead of many small herds distributed evenly among pastures resulted in an economically significant loss in livestock weight gains (15-16% over 2 above-average precipitation years).
Large reductions in weight gain occurred in spite of adaptive selection of pasture sequences based on temporal patterns of forage production and availability (i.e. initiating grazing season in C3-dominated pastures, followed by rotation to C4-dominated pastures later in grazing season).
Reduced livestock gains with increased stock density are consistent with measured changes in diet selection and animal foraging behavior. High-stock-density steers foraged in more linear pathways and consumed diets with reduced crude protein content throughout both growing seasons, as compared to low-stock-density steers.
Reduced diet quality occurred during the first week after steers were rotated into a new pasture. These results indicate a strong effect of herd size, regardless of how quickly animals move among pastures.
Benefits of resting pastures for a full growing season were not readily measureable after 2 years of treatments. One C3 perennial grass increased in density 44% more rapidly in rested compared to moderately grazed pastures, but this species increased in both treatments. We have not yet detected an increase in C3 gramminoids production.
A unresolved question is whether future enhancements in forage production and residual biomass due to AGM could enhance livestock production during drought.
Literature Cited
Fuhlendorf, S.D., D.M. Engle, R.D. Elmore, R.F. Limb, and T.G. Bidwell. 2012. Conservation of pattern and process: Developing an alternative paradigm of rangeland management. Rangeland Ecology and Management 65, 579-589. Kachergis, E., J.D. Derrner, B.B. Cutts, L.M. Roche, V.T. Eviner, M.N. Lubell, and K.W. Tate. 2014. Increasing flexibility in rangeland management during drought. Ecosphere 5, 1-14.
The Adaptive Grazing Management Experiment
In 2012, we initiated an adaptive grazing management experiment in the shortgrass steppe of northeastern Colorado, USA, where 11 stakeholders representing ranchers, state and federal land management agencies, and non-governmental conservation organizations met to develop and implement an adaptive grazing management plan for ten 130-ha pastures. Stakeholder Group members determined: 1) Overall management goals, and specific objectives
related to each goal. 2) Grazing management strategies that would be
implemented to achieve the objectives 3) Types of monitoring data to inform adaptive
management 4) Triggers for cattle movement among pastures
• Cattle in the Traditional Grazing Management (TGM) treatment are distributed evenly among 10 pastures, and graze them continuously during May – Oct.
• Cattle in the Adaptive Grazing Management (AGM) treatment are managed as a single herd rotated among pastures, with the objective of grazing 8 of 10 pastures (and resting the remaining 2 pastures) given average precipitation, and adjusting this grazing plan in response to intrannual precipitation variability.
• AGM and TGM pastures have the same overall stocking rate, but stock density is 10-fold greater in the AGM treatment.
Cattle Responses
Date
May 23
May 30
June
6Ju
ne 13
June
20Ju
ne 27
July
3Ju
ly 8
July
15Ju
ly 23
July
29Au
g 5Au
g 12
Aug 1
8Au
g 26
Sept
2Se
pt 8
Sept
23Se
pt 29
Crud
e Pr
otein
in D
iet
4
6
8
10
12
14
16
AGM HerdPaired TGM Herd
May 23
May 30
June
6Ju
ne 13
June
20Ju
ne 27
July
3Ju
ly 8
July
15Ju
ly 23
July
29Au
g 5Au
g 12
Aug 1
8Au
g 26
Sept
2Se
pt 8
Sept
23Se
pt 29
Dige
stibl
e O
rgan
ic M
atte
r in
Diet
54
56
58
60
62
64
66
68
70July 15July 23July 27Aug 5Aug 12Aug 19N.a.N.Aug 27Sept 3Sept 11Sept 18Sept 25
Crud
e Pr
otein
in D
iet
4
5
6
7
8
9
10
11
12
AGM HerdPaired TGM Herd
July
15Ju
ly 23
July
27
Aug 5
Aug 1
2Au
g 19
N.a.N
.Au
g 27
Sept
3Se
pt 11
Sept
18Se
pt 25
Dige
stibl
e O
rgan
ic M
atte
r in
Diet
58
59
60
61
62
63
64
2014: 2-4 week rotations 2015: 5-6 week rotations
AGM TGMPercent time foraging (grazing fixes/total fixes) 35.1 51.7Mean foraging angle (degrees per 5 min) 146.3 134.8Mean foraging distance (meters per 5 min) 43.6 40.9
AGM Website:
Introduction Rangelands are characterized by temporal variability in weather overlaid on spatial topoedaphic variability (Fuhlendorf et al. 2012). In semiarid rangelands in particular, droughts create major financial hardship for livestock producers around the world. Strategies for coping with drought include reducing livestock numbers, leasing forage, temporarily grazing rangeland beyond its capacity, and increasing supplemental feed, but these involve economic or ecological costs. Alternative approaches to increase enterprise flexibility in responding to drought are clearly needed (Kachergis et al. 2014). Managing the spatial distribution of livestock during wet periods in order to enhance future production potential could improve ranch- scale resilience during droughts, but has not been evaluated at scales relevant to livestock producers.
Selected Goals:
Red Circles: AGM steer foraging locations Yellow Circles: TGM steer foraging locations Black crosses = Bedding, standing, travelling
2014
2015
P=0.10
P=0.81
P=0.64