SCHOOL EDITION 22 MARCH 2023 - Flipbook - Page 16
16
NEWS
FARMWEEK
JANUARY 28 2021
AFBI’s new catchment
science to support
sustainable aquaculture
BY DR MATTHEW SERVICE &
DR HEATHER MOORE
AFBI FISHERIES & AQUATIC ECOSYSTEMS
BRANCH
D
URING 2020 the Fisheries &
Aquatic Ecosystems team in
the Agri-Food and Biosciences
Institute (AFBI) has been working
with DAERA, NI Environment
Agency and NI Water to investigate
the water quality of inner Dundrum
Bay and the implications for
shellsh quality. This has been
supported by a collaboration with
European partners as part of the EU
Horizion 2020 ‘GAIN’ project.
The main aim of the work is to
develop sophisticated catchment
models which will assist in making
‘sustainable ecosystem’ plans for
the bay. Knowledge gained from this
work could then be used to develop
similar models for other coastal
areas.
During the course of the project
instruments have been situated
in the bay and its catchment to
deliver water quality data in realtime and in-turn inform better water
management processes.
As part of the work, during early
August 2020 a new in situ water
quality monitoring buoy was
deployed at the entrance to the
bay adjoining the Irish Sea. This
instrument logs water quality
every 20 minutes and can be
monitored in real time through a
telemetry system. This is already
demonstrating how water quality in
the bay responds to rainfall events
in the catchment through changes
in salinity and turbidity.
Furthermore, Dundrum Bay has a
healthy aquaculture industry and
the management of the bay must be
designed to support this.
Individual mussels can lter
around 1.5 litres of water across
their gills every hour as they sieve
food and other particles from
the water and in doing so play an
important role in a sustainable
BUOY: FAEB
scientists
deploy new
instrumented
buoy in inner
Dundrum Bay.
ecosystem. Therefore, in order
to develop effective management
plans for the bay, it is crucial to
understand how the feeding rate
of shellsh changes in response to
changing water quality.
In order to establish this, AFBI’s
scientists, in collaboration with
the University of Essex, School of
Life Sciences, deployed a novel
technique to monitor mussel feeding
in late 2020. Magnetic sensors sense
the opening and closing of the shells
as the molluscs lter the water.
Early data shows the sensors have
proved successful and valuable
data being gathered from the bay is
currently under analysis.
Seven factors when selecting
and feeding fat supplements
A
PPLYING new research ndings on
fat supplementation of dairy diets
lets milk producers max on cow
performance.
New research on the impact
individual fatty acids have on cow performance
shows there is a lot to be gained by no longer
viewing fat simply as a concentrated source
of energy, says Dr Richard Kirkland, Global
Technical Manager for Volac Wilmar Feed
Ingredients, pictured below.
“By understanding the fatty acids that
make up fat supplements and how they affect
responses and partitioning of nutrients, dairy
producers can improve specic areas of
herd performance such as milk yield, milk fat
content, body condition score and fertility,”
explains Dr Kirkland.
Below, he outlines seven considerations
dairy producers should have when selecting
fat supplements:
n Think about fatty acids – not fat
There are ve major fatty acids found in
ruminant diets, and each is utilised differently
within the animal. Recent research has centred
on C16:0 (palmitic) and C18:1 (oleic) fatty acids
and their impacts on cow performance during
specic stages of the lactation cycle.
C18:1 improves digestibility of total diet fat,
which increases energy supply. It also increases
the hormone insulin which aids partitioning of
nutrients to improve body condition – making
it particularly benecial when offered in early
lactation. This fatty acid has also been proven
to boost fertility by promoting egg and embryo
development.
In contrast, C16:0 increases the partitioning
of nutrients to milk, particularly milk fat
production. This may be more benecial in mid
to late lactation when a cow is no longer losing
body condition but indicates care should be
taken with supplementation during the fresh
period.
n Fat supplementation is benecial in early
lactation
Through early lactation, when body fat is being
used to supply energy, fat supplementation
needs to be considered in the context of
the impact specic fatty acids have on cow
performance.
Researchers at Michigan State University,
USA, reported that fresh cows offered MegaMax, a rumen-protected fat supplement
containing a 60:30 ratio of C16:0 to C18:1
for the rst 24 days of lactation, produced
notable increases in milk fat (+0.33%) and
yield, resulting in 2.8kg/day more energycorrected milk than the control group of
cows. Importantly, these improvements were
achieved at similar body condition scores.
“This study demonstrated that where the
most appropriate supplement based on the
ratio of fatty acids is offered, milk production
can be improved without detriment to body
condition,” says Dr Kirkland.
n Early fat supplementation benets later in
lactation
In the Michigan State study, cows
supplemented with fat from calving through
to day 67 of lactation produced an additional
5.1 litres additional milk per day, with +0.2%
higher milk fat. However, in the group where
fat supplementation stopped at day 24,
cows continued to produce more milk,
an additional 2.2 litres/day, until the
end of the study at day 67, indicating
a strong carry-over effect from
supplementation in the very early
stages of lactation.
“While more research is needed in
this area, these ndings tell us that
what we do in early lactation can have
a carryover effect with a pronounced
impact on lactation performance.
So, when we think about the cost of
supplementation, we need to consider
that a considered investment
made in fresh cow nutrition
may continue to pay
off later in lactation,”
explains Dr Kirkland.
n Fatty acids must be
rumen-protected
To see the benet
PERFORMANCE: Replacing carbohydrate sources of energy with fat
reduces production of methane, a potent greenhouse gas and helps
enhance your cows’ performance, notes Dr Richard Kirkland.
of individual fatty acids, rumen-protected
fats that have been manufactured to avoid
interference with bre digestion in the rumen
must be used. If unprotected (eg, vegetable
oils or high-oil ingredients such as brewer’s
grains), fat will kill many of the bre-digesting
rumen bacterial species and reduce bre
digestion.
“Rumen-protection is critical to avoid
reductions in rumen bre digestibility and
to ensure delivery of unsaturated fatty acids,
such as C18:1, through the rumen to the small
intestine for absorption,” says Dr Kirkland.
n When it comes to the granule size of fat
supplements, size matters
Research by Volac Wilmar Feed Ingredients
at the National University of Singapore has
reported signicantly higher breakdown
of calcium salts of ‘ne’ granules (