Argentine stem weevil: farmer awareness and the effectiveness of
different ryegrass/endophyte associations
A.J. POPAY, K. RIJSWIJK and S.L. GOLDSON
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Abstract
Argentine stem weevil (ASW) is a highly destructive
pest of ryegrass that has recently been associated
with increased incidences of field damage. A survey
of farmer awareness and management practices in
relation to this pest was carried out. Many (47%)
farmers sowed favoured plant hosts such as short-term
and tetraploid ryegrasses. A field trial, undertaken near
Hamilton, compared the effects on ASW larval damage
of 10 different ryegrass/endophyte associations in
comparison with an endophyte-free control with and
without seed treatment. U2 endophyte in a diploid
perennial festulolium and AR37 endophyte in a hybrid
tetraploid, an Italian diploid and a tetraploid perennial
ryegrass had significantly less damage (<26%) than all
other treatments (>42%). NEA2 endophyte in a diploid
perennial ryegrass and AR1 endophyte in short-term
ryegrasses failed to protect plants from severe damage
by this pest. Farmers need to be aware of the risks of
ASW damage to short-term and tetraploid ryegrasses.
Keywords: ploidy, short-term ryegrasses, larval
damage, endophyte strains, pasture management
Differences in nitrogen uptake and marginal yield response
between low and high yielding perennial ryegrass (Lolium
perenne) genotypes
M. HARMER, C. FARLOW, A.V. STEWART and D.R. WOODFIELD
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Abstract
Current nitrogen (N) use recommendations for
perennial ryegrass (Lolium perenne) were derived from
the response of historic genotypes certified or bred
between 1930 and 1970. Despite significant increase
in the yield of modern cultivars in seasons of lower
forage growth (late spring through winter), no existing
research considers the impact of this on N response
functions or N uptake characteristics. In light of this
a multi-year genotype by N rate trial was established.
Data analysed confirms significant differences exist
in the slope and intercept of genotype N response
functions. Higher yielding modern cultivars had more
than twice the marginal response to N of old genotypes
in summer and autumn in addition they also yielded
more when no N fertiliser was applied. Nitrogen uptake
characteristics of higher yielding cultivars in the first
winter were significantly greater than low yielding
genotypes, thus they may present a different N leaching
risk than older genotypes. Farm-scale implications of
these preliminary findings warrants consideration once
a larger dataset is available for analysis.
Keywords: pasture, nitrogen fertiliser, genetic gain, N
leaching, nitrogen economics
Different combinations of perennial ryegrass and white clover
phenotypes do not affect mixture yield under cutting management
during establishment
L. ROSSI, D.F. CHAPMAN and G.R. EDWARDS
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Abstract
A field experiment was conducted for 12 months
under irrigation and cutting management to
determine if interactions between perennial ryegrass
and white clover cultivars of different phenotypes
could affect pasture yield and botanical composition
during establishment. Four ryegrass and four clover
cultivars, differing in leaf and tiller/stolon traits,
were grown in all combinations (n=16), along with
monocultures of each (n=8), as sub-plots under
two nitrogen fertiliser levels (100 or 325 kg N/ha/
year). Dry matter yield and botanical composition
were measured on nine occasions and ryegrass
and clover population densities were determined
four times. Total annual yield was similar for all
mixture combinations due to substitution between
the sward components. While there were significant
yield differences among ryegrass or clover cultivar
monocultures, these seldom explained differences
in mixture yields. Mixtures yielded more DM than
ryegrass monocultures under both N treatments (+1.3
to +3.9 t DM/ha/year).
Keywords: perennial ryegrass, white clover, dairy, dry
matter yield, nitrogen fertiliser, phenotype, competition
Diurnal changes in the nutritive composition of four forage species
at high and low N fertiliser
L.A. BOX, G.R. EDWARDS and R.H. BRYANT
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Chicory and plantain have been suggested as alternative
grazed forages to perennial ryegrass for New Zealand
dairy systems. While diurnal changes in plant chemical
composition have been described for ryegrass there is
currently little information for herbs. This experiment
aimed to compare the effect of nitrogen inputs (low
and high) and harvesting time (am versus pm) on
the chemical composition of four forages (ryegrass,
plantain, chicory and white clover). The effect of
harvest time was greater than N fertiliser inputs on
chemical composition for all forages. Ryegrass showed
the greatest increase in water soluble carbohydrate
diurnally, at the expense of neutral detergent fibre and
to a lesser extent crude protein. This suggests afternoon
allocation of ryegrass may be beneficial to improve the
nutritive value of pasture on offer; allocation timing is
less important for white clover, chicory and plantain.
Keywords: chicory, clover, crude protein, plantain,
ryegrass, water soluble carbohydrate
Dry matter yield and the prevalence of barley yellow dwarf and
ryegrass mosaic viruses in old and young perennial ryegrass
M.B. FARQUHAR1, C.S. WINEFIELD1 and C.C. EADY2
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Abstract
Modern pasture management of perennial ryegrass
results in reduced reseeding and increased reliance on
asexual tiller multiplication. This may exacerbate viral
impact by providing longer-living hosts to exploit,
thus the effect of ryegrass age on sward performance
and viral load was investigated. Genetically similar 10
year old field plants and 10 year old seed were used
to produce ‘mini-swards’ of ‘old’ (tiller derived) and
‘young’ (seed derived) ryegrass lines. Dry matter yield
and viral load (ryegrass mosaic, and barley yellow
dwarf) were assessed over 10 months. For all lines
the old mini-swards produced less biomass (4-29%)
and viral load was significantly greater at most time
points. Cause and effect between viral load and yield
were not proven as other factors such as genetic drift,
epigenetics, or other latent pests or diseases could not
be ruled out.
Keywords: Lolium perenne, barley yellow dwarf virus,
ryegrass mosaic virus
Economics of a variable rate fertiliser strategy on a Whanganui hill
country station
M.D. WHITE, A.K. METHERELL, A.H.C. ROBERTS, R.E. MEYER and T.A. CUSHNAHAN
view more
Abstract
Automated flow control coupled to differential GPS
guidance systems in aerial topdressing aircraft will
allow variable rate (VR) fertiliser strategies to be
applied on hill country farms. The effectiveness of these
strategies will be enhanced with the use of remotely
sensed hyperspectral data to categorise and quantify the
farm landscape in greater detail. The economic benefit
of a variable rate fertiliser strategy in comparison to a
single rate (blanket) strategy was evaluated for a case
study Whanganui hill country station. The analysis
illustrates the robustness of a VR strategy in the face
of volatile returns in that it produced a higher 10 year
cumulative net present value (NPV) and remained at a
positive advantage at three different stock gross margins,
in comparison to a blanket approach. The effectiveness
of hyperspectral imagery for defining effective pasture
areas to assist development of more precise variable rate
fertiliser applications, compared to the current visual
classification from farm photography is discussed.
Keywords: economic benefit, variable rate fertiliser,
hyperspectral data
Effect of autumn regrowth interval and nitrogen fertiliser on dry
matter yield and plant characteristics of six forage species
K.E. MARTIN, R.H. BRYANT, S. HODGE and G.R. EDWARDS
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Abstract
Cold temperatures and drainage increase nitrogen (N)
losses from livestock production systems, so autumn
management and forage type were investigated as
strategies to mitigate N loss whilst meeting animal
requirements. The effect of regrowth interval and
fertiliser rate on plant dry matter (DM) yield, plant N
and digestible organic matter in the DM (DOMD) was
measured in six forage species over 4 weeks regrowth,
in Canterbury in autumn 2015. As regrowth interval
increased, herbage DM yield increased (from 180 kg
DM/ha to 922 kg DM/ha, P<0.05) and N response
rates were highest in perennial ryegrass and plantain
(P<0.05). Herbage N% in autumn was high at >3.2% of
DM and, in grasses and herbs, was positively associated
with N application rate but negatively associated with
regrowth interval (P<0.001). Delayed grazing by up
to 4 weeks, under a moderate N regime, improved
herbage quality and reduced herbage N% in autumn.
These results suggest plantain is a suitable alternative to
perennial ryegrass to reduce N losses without impeding
farm production in autumn.
Keywords: chicory, plantain, perennial ryegrass,
cocksfoot, white clover, red clover, nitrate leaching,
nitrogen response rate
Establishment year productivity, botanical composition and
nutritive value of grass/lucerne/plantain dairy pasture mixtures
M.B. DODD, D.E. DALLEY, D. ELLIOTT and C.M. WIMS
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In the context of dairy grazing systems, pasture
mixtures including tall fescue, lucerne and plantain
have been identified by animal modelling as having
potential to both improve milk production and reduce
urinary nitrogen excretion. A grazed paddock-scale trial
was established in the Waikato in September 2015 to
test this in two short-term grazing trials including these
species. This paper presents the pasture production,
botanical composition and nutritive value data
generated from four pasture mixtures sown in spring
2015 and sampled until autumn 2017 (18 months). The
pasture mixtures represented a comparison between
perennial ryegrass and tall fescue, with and without the
herb narrow-leaved plantain. The inclusion of plantain
in grass-lucerne mixtures had a positive effect on firstyear
herbage dry matter (DM) production, by ~2.6 t
DM/ha/year in ryegrass-based pastures and ~1.6 t DM/
ha/year in tall fescue-based pastures. Where plantain
was included, the proportion of grass was reduced by
more than half from autumn 2016 through to summer
2016-2017, while the proportion of lucerne was
reduced to a lesser degree. The proportion of plantain
was 35-70% through most of the first year, declining
to <20% in the second autumn. Plantain pastures
had slightly less crude protein (CP %) in winter, but
the inclusion of plantain did not significantly affect
digestibility or metabolisable energy in any season.
Given the evidence from other studies that plantain can
reduce urinary nitrogen concentration in dairy cows,
this study indicates that it can be a useful component in
mixed pastures from a forage production and nutritive
value perspective.
Keywords: nitrogen, pasture production, narrowleaved
plantain, perennial ryegrass, tall fescue
Estimation of ergovaline intake of cows from grazed perennial
ryegrass containing NEA2 or standard endophyte
C.C. EADY, J.R. CORKRAN, K.M. BAILEY, G.A. KERR and A.M. NICOL
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Abstract
Ergovaline concentration was measured monthly
from December 2015 to April 2016 in herbage of
perennial ryegrass pastures containing NEA2 or
standard endophyte (SE) in the Waikato, Manawatu
and Canterbury. Ergovaline concentrations were
then combined with estimated pasture intake, pasture
botanical composition and cow liveweight data from
experimental dairy farm systems in the Waikato and
Canterbury to estimate dairy cow ergovaline intake
(mg/kg LW0.75/day). For the diploid ryegrass ‘Trojan’
with NEA2 estimated ergovaline intake ranged from
0.01 to 0.029 mg/kg LW0.75/day, levels at which
no significant animal production effects have been
reported. Ergovaline intake of tetraploid ryegrass
‘Bealey NEA2’ was at least an order of magnitude
lower than this. For the diploid ryegrass, ‘Bronsyn’
with SE, ergovaline intake was 0.016 to 0.056 mg/kg
LW0.75/day, which at the highest level carried a ~20%
risk of causing animal production effects for 15% of
the samples. AR1 and AR37 pastures, used as controls,
contained nil or trace amounts of ergovaline.
Keywords: alkaloid, Epichloë festucae var. lolii,
Lolium
Farmer adoption of pasture renewal practices: the influence of
credible information sources
W.YANG and K. RIJSWIJK
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Abstract
Effective pasture management in the dairy sector is
supported by the pasture renewal practices (PRPs)
undertaken by farmers. However, the rate and extent
of adoption of PRPs by farmers is influenced by their
attitudes toward pasture renewal. The aim of this paper
was to help the understanding of drivers and barriers
that could be derived from the investigation of farmer
attitudes to pasture renewal, and to relate credibility
of information sources to their perceptions of pasture
renewal. A two-step process was applied to existing
survey data of dairy farmers in the Waikato and Bay
of Plenty regions of New Zealand. First, a factor
analysis clustered the dairy farmers into different
groups based on their attitudes to pasture renewal. The
results show that satisfaction with previous pasture
renewal experiences was an important factor affecting
farmer adoption. Second, the results from a correlation
analysis between the different clusters, indicates that
information from local experts and farmers was valued
the most by all groups as they were perceived to be the
most credible. Motivated farmers also tended to seek
guidance from credible publications and websites.
Keywords: pasture renewal, dairy farmers, information
credibility, factor analysis
Further field evaluation of the controlled release nitrogen fertiliser
Smartfert®
D.C. EDMEADES and R.M. McBRIDE
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Five field trials were conducted over 2 years in which
the effects of single applications of different rates of
a controlled release nitrogen (N) fertiliser, Smartfert,
on pasture production and pasture N concentration
were measured, relative to the same rates of SustaiN.
The 2016 trials also compared multiple applications of
SustaiN with a single application of Smartfert. Pasture
responses to SustaiN relative to the control generally
occurred within the first one to three harvests following
application and then declined and became negative in
the later harvests. The pasture responses to Smartfert
developed more slowly and were greatest after the
third harvest. In terms of total production significant
(P<0.05) responses to Smartfert relative to the same rate
of N applied as SustaiN occurred in three trials. SustaiN
significantly increase pasture production at one site
relative to Smartfert. In three trials pasture production
from single applications of Smartfert applied at 100
kgN/ha were the same and in one case better (P<0.05)
than three consecutive applications of 33 kg N/ha of
SustaiN. The soluble N fertilisers, urea and SustaiN,
elevated the mixed-pasture N concentration relative to
control and to Smartfert in the first harvest following
application. The nitrogen use efficiency (NUE, kg DM/
kg fertiliser N applied) of Smartfert was significantly
greater (P<0.05) than for SustaiN in two trials.
Keywords: fertiliser, nitrogen, nitrogen use efficiency,
pasture, Smartfert, urea, SustaiN
Helicropping – early adopters’ experiences
P.M.S. LANE and B.E. WILLOUGHBY
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Abstract
Aerial establishment of pasture and crops in hill
country in New Zealand has received mixed publicity.
Popularly referred to as ‘spray and pray’ this detracts
from the success some practitioners have achieved
with ‘helicropping’, a highly structured process that
has the potential to markedly change hill country
farming. Four farmers with an average of 4.5 years
(range 2 to 7 years) of helicropping in New Zealand
hill country were interviewed using a semi-structured
snowball technique. Cross-case analysis was used to
analyse themes of learning experience of helicropping,
crop establishment, utilisation and economics, and
the management of potential risk of soil loss from hill
country cropping and harvest. Generally, all aspects
ranked highly in terms of success. However, there was
a strong message that this was attributable to strictly
following a prescribed process that reduced risks both
to a profitable return and to soil conservation.
Keywords: hill country, soil conservation, pasture
renovation, no tillage
Identification of operational performance attributes for pasture
measuring devices
C.R. EASTWOOD and B.T. DELA RUE
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Abstract
Farmers have expressed difficulty determining the
performance of precision farming devices both
before and after purchase. The aim of this study was
to develop guidelines for operational performance
of pasture measuring devices using a Delphi survey
method with 25 dairy pasture management specialists.
The eight important attributes of devices for use on
dairy farms, as identified by survey respondents were:
the device is easy to use; weekly data are available
during high pasture growth periods; data are available
within 24 hours of measurement; data are accurate;
data are collected quickly; data are easily uploaded into
third party software; the device is easy to maintain;
and the device has been/can be calibrated for ryegrass/
clover swards. The attributes identified through this
process provide measurement device developers with
a design guide. The results also provide farmers with a
list of attributes to consider when investing in pasture
measuring devices or services.
Keywords: pasture measurement, technology
development, precision grazing, Delphi survey
Identification of pasture mixtures that maximise dry matter yield
A.D. BLACK, S. ANDERSON and S.K. DALGETY
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Abstract
A mixture experiment was conducted to identify an
optimal pasture seed mixture that maximised dry matter
(DM) yield under irrigated, sheep-grazed conditions in
mid-Canterbury, New Zealand. Nineteen seed mixtures
were created using a simplex design from a pool of
four species: perennial ryegrass, plantain, white clover
and red clover. Seed mixtures were drilled into plots in
March 2015 and the yield from sowing to May 2017 was
modelled. The model analysis defined the optimal seed
mixture proportions as 0.25 ryegrass, 0.28 plantain and
0.47 red clover of total number of seeds per unit area, or
7.5, 6.3 and 8.2 kg/ha, respectively (22.0 kg total seed).
This mixture was predicted to yield 39.81 t DM/ha after
2 years. Ryegrass and plantain interacted more strongly
with red clover than white clover, leading to increased
yields over monocultures (diversity effects). Additional
yield benefits arose from the three-species mixture of
ryegrass, plantain and red clover.
Keywords: diversity effect, pasture establishment,
perennial ryegrass, plantain, red clover, seed mixtures,
simplex design, white clover
Implementing change: barriers and opportunities
T.A. NELSON, M.A. BROWN, S.J. FIELKE, A.D. MACKAY, P.R. PAYNE,
A.P. RHODES and W. SMITH
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Abstract
Severe flooding and slips in the Manawatu-Whanganui
region in 2004 resulted in the implementation of the
voluntary Sustainable Land Use Initiative (SLUI), to
support recovery and increase resilience. This paper
identifies the barriers, opportunities and lessons for
the implementation of Whole Farm Plans (WFPs).
The research, conducted in 2016, involved interviews
with 40 farm households. The findings demonstrate
that the values and priorities of both SLUI and non-
SLUI households were similar, highlighting the need to
increase profitability, productivity and environmental
protection. Both adopters and non-adopters express
similar concerns about SLUI, including perceptions
about its bureaucratic nature, cost and complexity.
They differed to an extent when believing the SLUI
aligns with their own values and goals. Non-signatories
highlight their resistance to government intervention.
They also feared the SLUI would thwart productivity
and profits. There remains a need to more explicitly
integrate social values and goals in any strategy to
implement Whole Farm Plans.
Keywords: Sustainable Land Use Initiative, barriers,
opportunity, values, environment, resilience
Implications for winter grazing managements and dead material
on the performance of young cattle in spring
D.R. STEVENS, B.R. THOMPSON and G.R. WOOD
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Abstract
Data from an experiment investigating the impacts
of winter dead material content and winter grazing
intensity on spring pasture productivity and botanical
composition, were used to estimate the impacts of
agronomic outcomes on the potential production
of young cattle during spring. The experiment was
replicated at two sites (heavy and light soil types of
moderate to high fertility in a cool temperate climate).
Q-Graze software was used to determine liveweight
gain (LWG) and grazing days of Angus steers (300 kg
starting liveweight) grazing the pastures during spring
at a stocking density of 20 steers/ha (an overall stocking
rate of approximately 4 steers/ha). The reduction in
dead material by intensive winter grazing strategies
increased the estimated quality of pasture available
by 0.5 MJ ME/kg DM (P=0.002). Spring pasture
production was higher when winter dead material
content was low or medium compared with a high
winter dead material content, leading to a reduction
in LWG of 0.38 kg LW/day (P<0.05). The imposition
of intensive winter grazing on pastures with medium
proportions of dead material increased steer LWG
in spring from 0.39 to 0.64 kg/day, and from 0.22 to
0.33 kg/day when high dead material content was
present in winter (P<0.05). Total LWG/ha for spring
was increased by using intensive grazing management
to remove winter dead material, and with medium or
high dead material content compared with using a lax
grazing approach (P<0.05) in winter.
Keywords: cattle, dead material, grazing intensity,
liveweight gain, spring, winter
Implications of increased use of brought-in feeds on potential
environmental effects of dairy farms in Waikato
S.F. LEDGARD, N.L. BARTLETT, P.J. VAN BOHEEMEN, B.R. WILTON,
S.B. ALLEN and D.P. MUGGERIDGE
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Abstract
The effects of increased use of brought-in feeds were
evaluated across 25 dairy farms in central Waikato.
Farms were classified into low, medium and high feedinput
categories based on <500, 500-1200 and >1200
kg DM/cow, covering a range typical of that in the main
dairying regions of New Zealand. Average milksolids
(MS)/ha was 1087 and 1900 kg in the low and high
feed-input categories, but total land-use/tonne MS
was the same when all off-farm land was accounted
for. Average estimated on-farm nitrogen (N) leaching
increased from 26 to 30 kg N/ha/year between the low
and high feed-input categories, but off-farm leaching
sources were equivalent to an increase of 20 and
84%, respectively. Greenhouse gas emissions/on-farm
hectare were 61% higher on high feed-input farms, but
the carbon footprint and N leaching per tonne MS were
similar across feed-input categories. High feed-input
farms used feed-pads and increased effluent area (66
versus 21% of farm) to increase nutrient efficiency.
Mitigation analyses indicated that N leaching could
be decreased by optimising effluent area, reducing N
fertiliser rate and utilising low-N feeds.
Keywords: nitrogen leaching, whole farm system,
greenhouse gases, land use
Information required from research programmes when introducing
legume forage systems into challenging environments
T.A. NELSON1, S.M. ZYDENBOS2 and D.R. STEVENS3
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Abstract
The use of legumes to increase animal performance is
well known, but why are sheep and beef farmers not
using a legume forage system in New Zealand hill
country, and what information do they need before
introducing a legume forage system? A co-innovation
process was started to explore the challenges sheep and
beef farmers face introducing a legume forage system
into hill country and their information needs. The first
step in this process, reported here, was to run eight
workshops throughout New Zealand which 105 farmers
and agribusiness representatives attended. Results
showed that getting the right information from trusted
sources was the highest priority for farmers looking to
introduce a legume forage system. Information provided
by the science community and industry needs to be
region specific as the range of knowledge around legume
species differs across regions. Some of the information
required by farmers is already well documented, but
may not be in the hands of the right people.
Keywords: challenges, forage, farm system,
information requirements, knowledge, legumes, sheep
and beef farmers
Levy oration – 2016
Lessons learnt and future opportunities
Richard Green
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It is indeed a great honour and a privilege to be
recognised by my peers with the prestigious Levy
Oration award. There are so many people that have
supported me throughout my career, many of whom are
in this room today. I have always tried to just get on
with things and do my bit for the industry, often through
connecting people and ideas. Receiving an award like
this is very humbling, particularly when considering
how many people make a difference in their own way
to our great pastoral industry.
Given that I am only half way through my career,
I thought I would use about half my time to reflect
on and share the things I have learnt to date, and then
to look ahead and share my thoughts on what I think
needs to happen to realise the potential of our Agri-food
industry.
Lime application can help protect pastures against black beetle
PJ Gerard and DJ Wilson
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Abstract
Black beetle attacks pasture grasses in the northern and
coastal North Island and with a warming climate, the
beetle has extended its range and damage has become
more prevalent. On-farm investigations into prevention
of damaging populations suggested that black beetle
density was inversely related to soil pH. Two replicated
block experiments, the first in 2013-2015 on two
farms, and the second on four farms in 2015-2017
investigated the effects of late spring agricultural lime
applications at the rate of 5 tonne/ha on summer black
beetle populations. The results showed that lime can
help suppress black beetle populations. Importantly, the
effect of lime persisted into the second year in Trial 2,
preventing larval populations reaching damaging levels
of over 40/m2. This adds to the already well-known
benefits of lime in improving soil health and pasture
quality, vigour and persistence.
Keywords: agricultural lime, soil pH
Lucerne with a high coumestrol content is not a suitable feed for
ewes just before and during the early breeding period
L.M. CRANSTON, P.R. KENYON, R.L. FIELDS, D.J. MOOT,
R.A. CORNER-THOMAS, P.D. KEMP and S.T. MORRIS
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Abstract
The objective was to determine whether grazing
lucerne for 7 days before breeding and for the first 7
days of breeding affected the reproductive performance
of ewes with different body condition scores (average
of 3.2 versus 3.7). This was compared with grazing
a grass-based sward with a high proportion of dead
herbage that was available at the time of breeding in
a summer dry region (Wairarapa) in autumn 2016. The
lucerne contained large amounts of fungal infected
stem and dead herbage, which induced high levels of
coumestrol (107 ± 15 mg/kg DM). By the end of the
feeding period the grass and lucerne on offer were
both of low quality (7.8 MJ ME/kg DM). Ewes that
grazed lucerne for 7 days before breeding and for the
first 7 days of the breeding period produced 18 fewer
(P<0.05) foetuses per 100 ewes joined, compared
with ewes grazing grass. These findings indicate there
was no benefit of grazing ewes on lucerne with a high
level of coumestrol under summer drought conditions
compared with grazing poor quality grass.
Keywords: alfalfa, coumestrol, drought, flushing,
nutrition, oestrogen, reproduction
Milk fatty acid and protein profiles of late-lactation dairy cows as
affected by time of allocation of a fresh strip of ryegrass-based
pasture
R.E. VIBART, M. TAVENDALE, D. OTTER and D. PACHECO
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Abstract
Eighty late-lactation dairy cows were used to examine
the effects of allocating a new strip of a perennial
ryegrass-based sward in the morning (AM) or in the
afternoon (PM) on milk fatty acid (FA) and protein
profiles. Milk total polyunsaturated FA (PUFA) were
greater from cows on AM herbage, whereas total
saturated and monounsaturated FA (MUFA) were
similar. Time of allocation only affected the milk
protein α-casein, which was greater in milk from cows
on PM herbage, in turn affecting the casein:whey ratio.
Under the current conditions, timing of allocation
altered the herbage nutrient supply to cows; a greater
concentration of precursor FA in AM herbage resulted
in a greater concentration of beneficial FA in milk
compared with cows on PM herbage. Quantifying the
composition of FA in herbage could potentially aid in
the design of grazing strategies to increase precursors
of beneficial FA in dairy products.
Keywords: fatty acids, milk proteins, herbage
composition, time of allocation
Modelling options to increase milk production while reducing N
leaching for an irrigated dairy farm in Canterbury
P.C. BEUKES, P. EDWARDS and T. COLTMAN
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Abstract
The Forages for Reduced Nitrate Leaching programme
(FRNL) aims to address the challenge of presenting
farmers with alternatives for forage production that
will sustain milk production and farm profit, but
simultaneously reduce nitrogen leaching by 20% from
current levels. This paper describes the improvements
made to a dairy model comprising three software
packages, and how this model was used to evaluate
proposed farm system changes on a Canterbury dairy
farm (Canlac Holdings) associated with the FRNL
programme. After a baseline scenario was sensechecked
against actual farm physical and financial
data for the 2014-2015 season, alternative options
were modelled in an additive way by expanding the
effluent area, growing fodder beet on the platform,
replacing some pasture with maize silage, growing
diverse pastures on 7% of the milking platform, and
including a feed pad. The cumulative effect of these
changes was an increase of 3 and 13% in production
and profit respectively, but only a 5% decrease in
nitrogen leaching as estimated for the combined
platform and support block areas over 3 climate years.
A hypothetical scenario, of a third of the platform in
diverse pastures, less nitrogen fertiliser, all fodder beet
grown on the milking platform, lifted and fed on the
feed pad, and with an oats catch crop following fodder
beet, increased production and profit by 2 and 10%,
respectively, with a reduction in N leaching of 19%.
This result indicates that high-performing farmers have
scope to reduce N leaching by ~20% and still increase
profit by implementing some of the options emanating
from the FRNL programme.
Keywords: diverse pastures, dairy farm system, fodder
beet, effluent block, feed pad, catch crop
NZGA PRESIDENT’S ADDRESS 2016
Systems research: the need for a change of thinking
DR Stevens
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Farm systems research has a long history of success
in New Zealand. Recent reviews have highlighted the
progress made through the traditional and pragmatic
approaches that have been used (Clark 2013; Stevens
et al. 2016). However, as the world and technologies
change ever more rapidly around us, is it time to change
from the pragmatic problem solving approach to one of
deeper understanding?
NZGA PRESIDENT’S ANNUAL REPORT FOR 2015/2016
DAVID STEVENS
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The year has been an eventful one with a successful
conference in Masterton hosted by John Dalziel and his
team. Being able to capture Professor Colin Holmes on
video, now available to all, was an absolute highlight.
Optical sensors for variable rate nitrogen application in dairy
pastures
K. WIGLEY, J.L. OWENS, J.A.K. TRETHEWEY, D.C. EKANAYAKE, R.L. ROTEN and A. WERNER
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Reducing the amount of nitrogen (N) fertiliser applied
to dairy pastures down to agronomically optimised
levels would have positive economic and environmental
results. The ability of commercially available optical
sensors to estimate biomass yield and foliar-N uptake in
pastures was investigated. Vegetative indices (Simple
Ratio, SR; Water Index, WI; and Normalised Difference
Vegetation Index, NDVI) from two active optical
reflectance sensors (N-Sensor, Yara; and Greenseeker,
Trimble) were compared with manually measured
biomass and N-uptake in above-ground foliage. There
were three measurements over time, from pastures that
had received different N fertiliser applications rates (0,
10, 20, 40 and 80 kg N/ha). It was found that the sensors
were able to detect differences in biomass and foliar
N-uptake following defoliation of grazed pastures. The
tested optical sensors have the potential to inform a
real-time variable rate fertiliser application system.
Keywords: pasture, nitrogen, optical sensors
Pastoral farming and the science interface – a farmers view
DV Pearce
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Introduction
Farmers are deluged with information on commercially
valuable or politically topical issues. Information that
is not politically or commercially driven may still be
vitally important to a pastoral farming business and
farmers need to consciously try and fill the gaps.
This quote from Johnathon Swift seems appropriate:
“That whoever could make two ears of corn, or two
blades of grass, to grow upon a spot of ground where
only one grew before, would deserve better of mankind,
and do more essential service to his country, than the
whole race of politicians put together.”
Post-sampling procedure affects the measured nutritive value of
perennial ryegrass (Lolium perenne)
T.M. DALE, R.M. GREENFIELD, K.N. TOZER and C.A. CAMERON
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Abstract
Estimates of pasture nutritive value are affected by
how samples are stored and dried before laboratory
analyses. To determine which post-sampling procedures
best preserved nutritive value, a range of procedures
were compared for one diploid and one tetraploid
perennial ryegrass cultivar in June 2016 and April
2017. Treatments included different combinations of
transportation from the field to the laboratory either in
liquid nitrogen or in a chilly-bin with ice-packs, storage
at room temperature (19°C), a chiller (3°C), standard
freezer (-18°C) or a -80°C freezer, and drying either in
a freeze-drier or an oven at 65°C for 48 hours. Samples
were sent to a commercial laboratory for near-infrared
reflectance spectroscopy analysis.
Values were higher for one or more of metabolisable
energy, soluble sugars, non-structural carbohydrate,
and organic matter digestibility, and lower for neutral
detergent fibre and ash, when comparing transportation
in liquid nitrogen with a chilly-bin, freezer storage
(-80°C and standard freezer) with chiller and room
temperature storage, and freeze-drying with ovendrying
(P<0.01). Freeze-drying was the most critical
factor in preserving the nutritive value.
Keywords: freeze-drying, oven-drying, liquid nitrogen,
pasture sample storage, nutritive value preservation
Post-truth, alternative facts and the role of the Environmental
Protection Authority
J.S. ROWARTH
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Abstract
The Environmental Protection Authority (EPA)
administers six Acts and is charged with making net
benefit decisions for New Zealand. Regulatory Science,
which is supported by the research results from
traditional science, enables evaluation of evidence,
risks and uncertainties. To take appropriate account
of the Treaty of Waitangi, an external Māori advisory
group works with a focussed staff unit to ensure that
Māori values are included in the decision-making
process. Society is also included through consultation
and hearings, and it is in the context of increasing
global suspicion of government, media and science in
general that the role of the EPA is increasingly about
education and engagement, while continuing to make
decisions that protect the environment whilst enhancing
lifestyle and the economy.
Keywords: communication, HSNO, net benefit, policy,
regulatory science, risk analysis, RMA, trust, values
Post-weaning performance of East Friesian cross ewe lambs
grazing ryegrass or plantain-based pastures after rearing on two
contrasting diets
D.R. STEVENS, F.W. KNOL, B.A. NEIPER,3 and S.A. McCOARD
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Abstract
Artificial rearing is used routinely on dairy sheep farms.
Different strategies are used to optimise the growth and
development of the young lamb with an economic ration
of milk and other feed components. Early weaning,
and early introduction to pasture can both reduce these
costs, but may also reduce the liveweight gains of the
growing lamb. Can differences in pre-weaning feeding
strategies be mitigated using specialist pastures such as
plantain/red/white clover? Lambs from an experiment
investigating the impacts of rearing with and without
meal access (n=30/group) and weaned at 12 weeks of
age were grazed on either perennial ryegrass-based
or plantain/red clover-based pastures in 3 replicates.
Liveweight gain, animal health, feed supply and feed
quality parameters were recorded over the following 5
weeks. Liveweights of the lambs reared on the different
feeding regimens were similar at 12 weeks of age when
the grazing study began (25.9 kg). Using plantain/red
clover-based pastures provided no advantage to the
liveweight gain of lambs reared under different milk
and concentrate feeding regimens. Both feed types
provided adequate nutrition to ensure growth rates of
approximately 180 g/day over the 5 week measurement
period in late spring. However, lambs reared under
a high concentrate system has consistently lower
liveweight gains (160 g/day) over the 5 weeks than
those lambs reared with access to pasture (200 g/day;
P<0.05). Feed quality was high on both pasture types.
Symptoms of photosensitivity were recorded on both
pasture types, but predominantly in lambs reared with
ad libitum access to meal until week 10 of life, posing
a question over functional liver development. This may
have also affected liveweight gain.
Keywords: artificial rearing, lamb liveweight gain,
ryegrass, plantain, post-weaning
Reducing nitrogen fertiliser alters dairy shed effluent quality
S.J. DENNIS
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Abstract
Dairy farmers using low rates of nitrogen fertiliser
observed reduced odour in milking sheds, and a smaller
growth response of pasture to effluent application.
Effluent samples from four conventional (>100 kg
N/ha/year, “high-fert”) and three low-nitrogen (N)
fertiliser (<50 kg N/ha/year, “low-fert”) properties
were collected in January 2017 and analysed for total N
concentration, N form, mineral nutrient concentration
and pH. Total effluent N concentration was comparable
between both classes of farm. However, low-fert
properties had a higher proportion of N in organic
forms as opposed to ammoniacal-N than high-fert
properties (mean 75% and 59% organic on low- and
high-fert properties, repectively, P<0.01). Low-fert
effluent also had a lower pH, higher P concentration,
and nearer optimal N:P ratio than effluent from highfert
properties. It was hypothesised that reducing N
fertiliser may result in more nutritionally-balanced
effluent (N:P ratio), causing microbes to multiply more
rapidly (lowering pH), storing N in microbial biomass,
reducing ammonia emissions and odour, and reducing
the risk of N leaching from effluent applied to pasture.
Keywords: dairy shed effluent, nitrogen fertiliser,
ammonia, organic N, environmental loss
Response of pastures to fertiliser nitrogen on two peat soils in the Waikato region
W.T. CARLSON, G.L. LUCCI and M.S. SPROSEN
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Abstract
Fertiliser nitrogen (N) response trials were conducted
on Waikato dairy pastures on two contrasting peat
soils: a well-developed Kaipaki peat loam and a lessdeveloped
Rukuhia peat. On the well-developed site the
most efficient N fertiliser rate in spring was 25 kg N/
ha with a response of 22 DM/kg N applied. However,
in autumn the most efficient rates of N fertiliser were
75 and 100 kg N/ha, with an average response rate of
11 kg DM/kg N. At the less-developed site, the most
efficient rates in the spring were 25 to 75 kg N/ha
with an average response of 18 DM/kg N applied. In
autumn, the maximum response rate of 21 kg DM/kg N
was reached through application of 50 and 75 kg N/ha.
Results indicate that greater yields are expected from
larger applications of N fertiliser on less-developed
peat. However, the environmental consequences of
increased N fertiliser applications have not yet been
assessed.
Keywords: nitrogen fertiliser, pasture production, peat
Sediment and nutrient losses under winter cropping on two
Manawatu hill country soils
L.L. BURKITT, J.L. WINTERS and D.J. HORNE
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Abstract
Aerial spraying and surface seeding of winter crops in
uncultivable hill country areas is rapidly being adopted
as a method of increasing winter feed supply and as a
precursor to regrassing. However, there is little research
on the sediment and nutrient losses that may result
from this practice. In the current study, winter swede
crops were established on an imperfectly and on a welldrained
soil and these crops were grazed by beef cattle.
Soil damage caused by the winter grazing of the swedes
generated sediment losses that were 5.5 times greater
on the imperfectly drained soil than the well-drained
soil. Surface runoff over 3 months (which included crop
grazing and the non-grazed crop stubble period) resulted
in losses of 1.1 t/ha of sediment, 0.85 kg of phosphorus
(P)/ha and 5.4 kg of nitrogen (N)/ha from the poorly
drained soil. This key risk period contributed between
88 and 99% of the total annual sediment and total N and
P losses, compared to the pre-crop (pasture) and crop
establishment phase. A simple comparison with two
other sediment and nutrient loss studies located on the
same farm as the current study, suggested that the losses
associated with winter cropping in this landscape may
be extreme. The current study highlights the need for
targeted mitigation strategies and/or strategic grazing
management to reduce soil and nutrient losses and to
minimise the impacts on waterways of winter grazing
of hill country crops.
Keywords: winter cropping, hill country, surface
runoff, sediment losses, nutrient losses
Soil inorganic nitrogen in spatially distinct areas within a
commercial dairy farm in Canterbury, New Zealand
D.C. EKANAYAKE, J.L. OWENS, S. HODGE, J.A.K. TRETHEWEY, R.L. ROTEN,
M. WESTERSCHULTE, S.BELIN, A. WERNER and K. CAMERON
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For precision nitrogen (N) fertilisation of grazed dairy
paddocks, soil N distribution needs to be quantified. It is
expected that farm infrastructure will affect inorganic-N
distribution due to its influence on cow grazing
behaviour. Surface soil from four spatially distinct
areas (main gate, water troughs, non-irrigated and the
remaining pasture) was analysed for soil ammonium-N
(NH4
+-N) and nitrate-N (NO3
--N) from three paddocks
(180 soil samples) on an irrigated commercial dairy
farm in Canterbury, New Zealand. Variation between
paddocks was higher for NO3
- (P<0.001) than for
NH4
+ (P=0.52). Differences between spatially distinct
areas were detected for NH4
+ (P<0.001) but not for
NO3
- (P=0.37), though there was variation in NO3
-
with distance from the gates and troughs. This study
demonstrates methods for classifying spatially distinct
areas of grazed pasture to quantify their influence on
inorganic-N distribution. Further research is required to
better understand variability.
Keywords: nitrogen, spatial nitrogen distribution,
distinct areas
The effect of deferred grazing in spring and early summer pastures
on pasture growth rate and feed quality
B.P. DEVANTIER, D.R. STEVENS, G.M. RENNIE and K.N. TOZER
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Abstract
Maintaining pasture quality in late spring and early
summer is a challenge in many hill country farming
systems where pasture growth often exceeds animal
demand. One possible management tool is to defer
grazing on a portion of the farm to enable the desired
grazing management and animal performance on the
remainder. This study aimed to evaluate the effect of
timing and duration of deferred grazing in mid-spring
to early-summer on subsequent pasture accumulation
rates, composition and quality, from mid-spring
through to the following winter. A factorial design
(3 durations x 3 closing times) in eight replicates
compared withholding grazing (nil, 1 or 3 grazings), in
three closing periods, mid spring, late spring, and early
summer. Grazing pasture when covers reached 2500 -
3000 kg DM/ha to a residual of 1500 kg DM/ha was
the standard grazing regimen used. Grazing after the
exclusion period aimed to achieve the same residual as
in the control treatment based on a feed budget. Short
early closures resulted in little, or no change in pasture
quality and quantity for the remainder of the season.
Longer closure periods reduced pasture quality due to
increases in the proportions of dead and reproductive
stem. This effect was reduced with later closings. The
control (nil deferred grazings) and mid-spring closings
had a net loss of dead matter (-1000 and -420 kg DM/
ha, respectively), while the late –spring and earlysummer
closings accumulated 60 and 180 kg DM/ha,
respectively. These differences in dead matter were
the major driver of the differences of net herbage
accumulations (P=0.018), with net accumulations from
7990 kg DM/ha for the control (Nil) closings to 9660
kg DM/ha for the December (late) closings. Deferred
grazing can be used to alter feed availability and
utilisation while maintaining net pasture production
over spring, summer and autumn.
Keywords: grazing management, pasture quality,
deferred grazing, net pasture accumulation, dead
matter, reproductive tillers, metabolisable energy
The implications of winter milk premiums for sustainable
profitability of dairy systems
T.L. CHIKAZHE, K.A. MASHLAN, P.C. BEUKES, C.B. GLASSEY, J. HAULTAIN and M.B. NEAL
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Abstract
Matching seasonal pasture growth to cow demand has
been the key to New Zealand’s ability to produce milk
competitively. However, driven by the need to process
milk all year for value-add products like UHT milk,
Fonterra has increased the incentive for producing
milk in the winter. This has some farmers questioning
their spring calving approach and considering calving
outside spring to increase profitability of their system
using the winter milk premium. In an attempt to
answer farmer’s questions, modelling was done using
OVERSEER® for the environmental footprint and
Farmax Dairy for the economic impact of changing the
calving season. The objective of the modelling was to
highlight key factors that need careful assessment for
individual farm situations before deciding to change
calving season. Whole farm system modelling was
done for Ruakura and Pukekohe pasture growth profiles
in the Waikato, and Te Hana and Maungatoroto growth
profiles in Northland to consider the implications from
both a profitability and environmental perspective.
In the four districts modelled results suggest the key
drivers for autumn calving profitability are: seasonal
pasture growth profile, soil type, winter milk premium
and cost of infrastructure/equipment upgrade. Regions
with pasture growth profiles that remain profitable after
changing from spring to autumn without the winter milk
premium are the most ideal, as there is no guarantee the
premium will stay at the current level.
Keywords: modelling, winter milk premium, pasture
growth profile, profitability, nitrogen leaching
The relative strengths of phosphate fertiliser application and white
clover cultivar introduction for hill pasture improvement
D.F. CHAPMAN, A.D. MACKAY, B.P. DEVANTIER, D.A. COSTALL and P.J. BUDDING
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Abstract
Combinations of four phosphorus (P) fertiliser rates
(0, 8.5, 22.5 or 26.5 kg/ha/year of citrate-soluble P)
and three pasture types with different white clover
germplasm, ‘resident’ cv. Huia and cv. Tahora were
compared in self-contained, replicated farmlets grazed
by sheep over 4 years. Fertiliser increased white clover
herbage accumulation (HA) 3- to 4-fold compared with
the control treatment, and increased total sward HA by
50%. Introduction of Tahora white clover significantly
increased white clover and total sward HA and nitrogen
fixation compared with the resident and Huia-sown
swards. Sheep liveweight gain was significantly greater
in all systems fertilised with P (438 versus 243 kg/ha
for the unfertilised control) and in systems sown with
Tahora (425 versus 372 kg/ha for resident and Huia).
Keywords: phosphorus fertiliser, white clover,
cultivars, herbage accumulation, animal production
The value of legumes to a Whanganui hill country farm
J.M. RENDEL, A.D. MACKAY and P.N. SMALE
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There is interest in the sheep and beef sector in lifting
the legume content of hill pastures. This interest is
tempered by the uncertainty of the benefits and how
much farmers can afford to spend to achieve them. The
objective of this study was to quantify the value to a
hill country farm of differing proportions of legumes in
a mixed species pasture using AgInform® (Integrated
Farm Optimisation and Resource Allocation Model).
AgInform® is a multi-year farm systems model, adapted
so that the legume proportion of pasture as it influences
pasture growth and animal performance through its
influence on diet could be included as variables in the
model. Three levels of legume (Low, Base and High)
in a mixed pasture were modelled. The model predicts
that increasing the legume proportion increases farm
profitability although not in a linear manner with
increasing legume proportion. This analysis provides
an indication of the investment that hill country farmers
can afford to increase the legume proportion in mixed
pastures.
Keywords: farm systems, legume, variability,
AgInform®, multi-year
Tolerance of newly sown cocksfoot-clover pastures to the herbicide
imazethapyr
T.R. LEWIS, R.J. LUCAS, R.W. HOFMANN and D.J. MOOT
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In New Zealand, subterranean clover is recommended
as a companion legume in mixed swards, particularly
in dryland cocksfoot-based pastures. However,
establishment of cocksfoot is slower than perennial
ryegrass and therefore weed ingress is more common.
An experiment at Lincoln University, Canterbury
showed imazethapyr applied when clover was at
the 3-4 trifoliate leaf stage, and cocksfoot at the 2+
leaf stage, increased the subterranean clover content
of the pastures by at least 1000 kg DM/ha, despite
initial visual phytotoxicity responses. Balansa and
white clover pasture yields were not different to their
unsprayed unweeded controls. Imazethapyr application
controlled broadleaf weeds from early in the season.
The herbicide application reduced cocksfoot yields by
70% in early spring, but yields recovered and were not
different to the unsprayed unweeded controls at 1350 ±
260 kg DM/ha after grazing. Imazethapyr application
improved subterranean clover pastures through an
increase in clover content by suppressing weeds and
temporarily reducing the rate of cocksfoot growth.
Keywords: subterranean clover, Spinnaker herbicide, seedling, white clover, balansa clover
Trajectory and causes of decline in the botanical composition of
dairy-grazed pasture in the Waikato
J.M. LEE, E.R. THOM, C.D. WAUGH, N.L. BELL, M.R. McNEILL, D.J. WILSON and D.F. CHAPMAN
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Abstract
Herbage accumulation, botanical composition, tiller
density and insect pest populations were monitored
over 6 years for four perennial ryegrass functional
types grazed by dairy cows in the Waikato. The aim
was to identify genotypic and environmental factors
contributing to ryegrass persistence failure in the upper
North Island. Perennial ryegrass content of pastures
declined as low as 60% of total herbage mass (HM)
in summer of the first 3 years but recovered in autumn
to at least 75%. However, following two successive
severe summer/autumn droughts in Years 2 and 3, and
subsequent grass grub larvae populations exceeding the
damage threshold of 200/m2, by 4 years after sowing
(autumn 2015), ryegrass had fallen to 20% of HM. This
pattern was repeated in the following 2 years, and was
not prevented by any combination of ryegrass functional
type, endophyte, seeding rate, or best-practice dairy
cattle grazing and soil nutrient management. The
abiotic and biotic environmental stresses dominated all
other factors.
Keywords: pasture persistence, perennial ryegrass,
drought, insects, black beetle, dairy systems
Validation of perennial ryegrass cultivar Forage Value Index rankings using independent trial data
C.I. LUDEMANN, C.M.WIMS and D.F. CHAPMAN
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Abstract
The current DairyNZ Forage Value Index (FVI)
categorises ryegrass cultivar-endophyte combinations
into five, ‘star rating’ groups for dry matter (DM)
yield using data from the National Forage Variety Trial
(NFVT) system. However, variability in performance
of cultivars between trials raises the question of how
cultivars with different star ratings perform against
each other under different conditions. The validity of
the FVI star rating categories for perennial ryegrass
was assessed using cultivar DM yield data from two
independent trials outside the NFVT system and under
dairy cow grazing with white clover. Results from the
trials were used in Monte Carlo simulations to provide
a probabilistic determination of the likelihood of high
FVI rated cultivars outperforming the low FVI rated
cultivars. Results indicate selecting high FVI (5 star)
perennial ryegrass cultivars over lower FVI (3 star)
cultivars deliver greater contributions to dairy operating
profit in over 94% of the simulated iterations for the
Waikato and Canterbury.
Keywords: Forage Value Index, Lolium perenne, plant
breeding, selection, cultivars
Variable and differential application of nutrients to a hill country
farm
JD Morton and A Gillingham
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Abstract
Traditionally fertiliser has been aerially applied at
a uniform rate to hill country, but the technology
now exists to apply nutrients at a variable rate (VR)
and each nutrient differentially, depending on the
production potential and pasture composition of each
part of the hill. A hypothetical case study of a sheep
farm was modelled to show the economic benefits of
VR application of phosphorus (P) and sulphur (S) and
differential application of nitrogen (N), compared with
application of a uniform rate of P and S. The financial
analysis demonstrates that the VR strategy of less P and
S to steeper slopes where there is low legume and more
on easier slopes where there is more legume, costs less
than the application of P and S at a uniform rate over
all slopes. The cost saving could be used to apply N to
steep land on both sunny and shady aspects and easy
land on sunny aspects. This differential N application in
late winter/early spring ensures better pasture cover for
lactating ewes to improve ewe condition at weaning.
When this gain in condition was maintained through to
mating, lambing percentage increased in the following
spring. The benefit from this increased lamb production
was an increase in financial returns of $63/ha/year. A
qualitative sensitivity analysis indicated that this value
remains stable in response to changes in the proportion
of each slope class, soil Olsen P level, the relative cost
of fertiliser P and N and sheep to cattle ratio.
Keywords: differential application, hill country, lamb
production, nitrogen, phosphorus, aerial topdressing,
variable rate
Winter rotation length effect on pasture production and animal
performance
C. MATTHEW, M.A. OSBORNE, Y. LIU, X. DUAN and F. HOU
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Abstract
Data comparing pasture production in winter pastures
subject to 16, 48 or 72-day rotation lengths were
recovered from experiments at Massey University to
support teaching of grazing management. ‘Farmlets’
with 16 breeding ewes on 0.8 ha were run from 2011-
2016, and herbage production estimated from metabolic
energy budgeting (MEB). The data illustrate: the roles
of pasture cover and animal body weight as buffers to
neutralise the impact of weather variability, the use
of controlled cover release via the grazing rotation to
partially meet winter feed deficit, and the potential
value of MEB in systems research. Grass grown from
May to September (early pregnancy to mid-lactation)
was 3850, 4220 and 4840 kg DM/ha for 16, 48 and 72-
day rotations, respectively. As a result of a reduction
in herbage accumulation and the premature release of
autumn-saved pasture to animals, the 16-day rotation
failed to overwinter the animals in five of the 6 years,
the exception being a winter with high pasture growth.
Keywords: winter rotation length, pasture growth rate,
teaching pedagogy
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