“Rotatinuous” grazing:
Management targets, efficiency of pasture utilization, and enteric
methane emissions by dairy cattle
Alejandra
Marín,
Zoot.
MSc.
PhD
(e)
Climate
Food
and
Farming
Network
(CLIFF)
Workshop
2017
7-­‐11
November,
2017
!

Content
Introduction
Background
Methods
Results and conclusions
Conceptual model
Application of this research
Acknowledgement

My PhD thesis focuses on the sustainable intensification of forage-based
systems, improved animal production and feed efficiency, and on
strategies to mitigate enteric methane emissions by dairy cattle.
The goal of the research is to define grazing management targets to
optimize nutrient consumption per unit of time and increase pasture
utilization efficiency.
Improving grazing management is an effective approach for increasing
animal productivity and reducing GHG emissions intensity (particularly
CH4) per unit of animal product or per area.
Introduction
Research focus

Management targets are plant oriented and focus on harvesting efficiency
Rotational stocking
Herbage quality and quantity would be the main constraint to animal
production on pasture systems
From this perspective...
Background
Pre-­‐Grazing
Post-­‐Grazing
Best
harvest
@me
.
.
.
Herbage
mass
+
+
+
Best
@me
to
leave.
.
.
Herbage
mass
-­‐
-­‐
-­‐
Savian,
2014
Savian,
2014

“Rotatinuous
grazing”
is based on the principle…:
…“take the best
and leave the
rest”… from the
pasture.
(Carvalho, 2013)
Rotatinuous concept is an innovation in grazing
management based on the ingestive behaviour.
The “Rotatinuous" grazing concept
We
are
including
the
“animal
perspec@ve”
Hypothesis: the main constraint is SWARD STRUCTURE . . .
the consequence is time restriction.
Sward structure è maximizes bite mass.

SWARD STRUCTURE
(Pre and post- grazing
sward heights)
Bite mass
Estructures that optimize bite mass
Maximize bite mass and forage intake
per unit grazing time
FORAGE USE EFFICIENCY
MORPHOLOGICAL COMPONENTS
Leaf mass, leaf/stem ratio.
Herbage bulk density.
QUALITY OF FORAGE
NDF, NDA, CP,
IVDMI, Energy
Herbage accumulation rate
Herbage mass
Total herbage production
NO TIME
ANIMAL PRODUCTIVITY
Bite rate
SHORT-TERM INTAKE RATE
(STIR)
DAILY HERBAGE INTAKE
Average daily gain
VFA (C2, C3, C4)
ENTERIC METHANE EMISSIONS
ENTERIC CH4 EMISSION INTENSITY
(CH4/unit animal product or area)
Intake of nutrients
GRAZING TIME*
Conceptual model
Phase I
Phase II
PredicFon
of
the
nutriFonal
composiFon
of
the
Kikuyu
by
near-­‐infrared
reflectance
spectroscopy
(NIR).
Effect
of
sward
surface
height
(SSH)
on
in
vitro
methane
producFon
and
ruminal
fermentaFon
parameters
of
caOle
grazing
kikuyu
swards
-­‐
(IVGPT)

Advances . . . Phase I
Effect of sward surface height on STIR of
heifers grazing in kikuyu swards

Hypothesis:
There is an optimal pre-grazing sward height,
which maximize the short-term herbage intake
rate (STIR) by the animals.
Objective:
Evaluate the effect of the kikuyu sward height
on STIR and determine the sward structure
(pre-grazing) that maximizes bite mass and
herbage intake.
Phase I
The central hypothesis of phase I is…

Phase I: Effect of sward surface height on STIR of heifers grazing in kikuyu swards
STIR= [(W2-W1)/(t2-t1)] + [(W3-W4)/(t4-t3)] x (t2-t1)/ET
Where:
STIR: short-term herbage intake rate (g/min)
W1 and w2: animal’s weight pre- and post-grazing (kg)
t1 and t2: pre- and post-grazing time (min)
W3 and W4: animal’s weight pre- and post- metabolic weight losses(kg)
t3 and t4: pre- and post-metabolic weight losses time (min)
ET: Effective eating time
Intake of forage Metabolic weight losses
Pennings
and
Hooper,
1985
Methods
The STIR could be measured by accurately weighing animals before and after a
grazing bout and making adjustment for metabolic weight loss and precise
recording of eating time.

Experimental unit: Plot
Sampling units : Animal
Metabolic weight losses
IGER Feces and urine collecting bags
ü Treatments:
Kikuyu sward heights: 10, 15, 20, 25, and 30 cm.
ü Size of the plots (500 m2):
Scaled so that average sward height declined
less than 5% over the grazing sessions.
ü Statistical design:
A complete randomized block
4 replicates x treatment. ( two per area and two
per time of the day (am or pm as blocking criterion).
ü Each experimental plot (20) was grazed by three
animals during a single grazing session of 45 ± 5 min.
ü The experiment was carried out in Lages, Santa
Catarina-Brazil between January and May, 2017.
Treatments and design
Methods

Preliminary results
RelaFonships
between
short-­‐term
intake
rate
(STIR,
a)
of
heifers
as
a
funcFon
of
sward
height
(SH)
in
monoculture
of
Kikuyu
(Cenchrus
clandes-nus
(Hochst.
ex
Chiov.)
Results and conclusion
The results showed that
maximization of STIR of kikuyu
grass is reached at sward height
20 cm.
These findings indicate that the
animals maintain a high and
continuous intake rate in that
sward structure. Later this
begins to fall progressively.
STIR
(gDM/min)
20
30
40
50
60
10
15
20
25
30
Sward
height
(cm)
EquaFons
for:
STIR=min((44.14
+
1.31
x
(SH
–
19.71);
44.14
–
0.45
x
(SH
–
19,71))
Marín
et
al,
2017-­‐
h^ps://www.researchgate.net/publica@on/319598924_The_intake_rate_a_strategy_for_the_sustainable_grazing_management

Conclusions
Results and conclusion
Based on this expectancy, we propose a new management
target for Colombian dairy cattle systems based on kikuyu
grass (pre-grazing height: 20 cm) to comply with its
sustainable livestock farming policy commitments.

Next step . . . Phase II
The phase II will be carried out in Medellín, Colombia / 2018
Effect of “rotatinuous” grazing on efficiency
of pasture utilization, and enteric methane
emissions by dairy cattle

Colombia
Medellín
Methods
Phase II: Efficiency of pasture utilization, and enteric methane emissions by dairy cattle
South America
Specialized cattle production
systems is located in the
Andean region.
It is characterized by pasture-
based dairying with high
grade Holstein cattle.
It is generally based on strip
grazed or rotationally grazed
Kikuyu grass and supplement
(30%).

Hypothesis:
By maximizing the intake of herbage per unit
eating time, “rotatinuous” grazing improves the
efficiency of pasture utilization and reduces
enteric methane emissions.
Objective:
Evaluate the effect of a new pasture
management concept “rotatinuous” grazing on
kikuyu grass pasture use efficiency and
enteric methane emissions intensity from
dairy cattle in rotational stocking.
Phase II
SF6
tracer
technique

CLIFF 2017
Scientific training at CIAT. . . Colombia

Training in
near-infrared reflectance spectroscopy (NIR).
1Sample collection
2 Analysis by the reference method
3 NIR spectral analysis
4 Data interpretation (calibration and validation)
Objective: Prediction of the nutritional composition of kikuyu by near-infrared
reflectance spectroscopy (NIR).

Development of the in vitro gas production technique (IVGPT)
Objective: Determine the effect of different kikuyu grass sward surface heights on in vitro
methane production, and also on the main ruminal fermentation parameters (gas
production, pH, in vitro dry matter digestibility (IVDMD), CH4, and volatile fatty acid (VFA)
concentration.
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
40,0
45,0
50,0
0
5
10
15
20
25
30
35
40
45
50
Volume
of
gas
(ml)
OMI
(g)
Accumulated
gas
produc@on
ml/g
OMI
Sward
height
10
cm
Sward
height
15
cm
Sward
height
20
cm
Sward
height
25
cm
Swardheight
30
cm
We hypothesize the optimal pre-grazing
sward height (20 cm) may result in high
dry matter digestibility (IVDMI) and less
in vitro methane production.

Application of this research
This information introduce a new grazing management target in Colombia, based
on the influence of sward structure on herbage intake, which will allow to have
sustainable farm system and greater productivity and consequently less impact of
the enteric methane emissions generated by livestock.
Our goal is to take this knowledge to Colombia to generate solutions in
agricultural production systems and improving smallholder dairy.
!

Rotatinuous grazing is a grazing management concept based on animal behavior
that contributes to food security by enhancing production and quality of food
products, while mitigating impacts of grazing ruminants by decreasing GHG
emissions and external inputs needs.
Rotatinuous grazing represents a technological innovation based on concepts,
not on inputs.
Smallholder appreciate this grazing management because it results in lower
dependence on external inputs and lower labor requirements.
Key messages
!

Acknowledgements
This work was undertaken as part of the Climate, Food and Farming (CLIFF) Network, an
initiative of the CGIAR Research Program on Climate Change, Agriculture and Food
Security (CCAFS). CCAFS is carried out with support from CGIAR Fund Donors and
through bilateral funding agreements.
We thank COLCIENCIAS for their support through COLCIENCIAS Scholarship Program No.
647, as well as the National University of Colombia and the Federal University of Rio
Grande do Sul for facilitating their respective research facilities.
We gratefully acknowledge the generous support we have received from EPAGRI by the
CNPq, MDA/CNPq Edital 38/2014 (Proceso CNPq 472977/2014-8).
!

Thanks
Alejandra Marín
amaring@unal.edu.co