NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 1 of 11
Assessment Schedule – 2011
Subject: Describe manipulations to influence growth and development, and productivity,
in livestock or plants (90454)
Evidence Statement
SECTION A: AGRICULTURAL SCIENCE
Question
ONE
(a)
Achievement
Achievement with Merit
Achievement with Excellence
Controlled Feeding in Intensive Pig Production
Describes how feed
constituents affect growth and
development.
Explains the difference in
protein intake.
Example:
Very young animals are
developing muscle rather than
fat, therefore a high-protein diet
is essential. As the animal
ages, muscle is mainly
developed, so there is less
need for protein. Also, excess
feed protein, which is expensive
to provide, will be converted
into fat.
• Fishmeal is a source of
protein for muscle
development.
• Mineral mix supplies calcium
and phosphorus required for
bone development.
A1
Example:
M1
(b)
Describes a manipulation.
(c)
Example:
Pellets reduce dust problems
and encourage consumption of
all the necessary ingredients.
No selection of unpalatable
ingredients is possible.
A2
Explains how a manipulation
influences growth / development
and productivity.
Justifies the use of formulated
feeds in intensive pig
production.
Example:
Example:
Animals require water, energy,
protein, fats, vitamins and
minerals in order to grow and
develop in a healthy state.
While minerals and vitamins are
consumed in smaller quantities,
they are essential for body
processes. Any deficiency in
one of these requirements will
adversely impact on growth and
development.
Pigs are monogastric animals,
and in a housed environment
can only eat what they are
given. In an outdoor
environment they have the
freedom to select what they
want to eat. Using pelleted feed
means that all the important
ingredients are contained in the
pellet, which encourages
consumption and reduces
wastage. Pellets also minimise
respiratory problems due to
dust / powder. Production takes
advantage of the fact that
young pigs have the capacity
for growth, and if not fed
correctly then stunted growth
results. The desired growth rate
is mainly muscular with some
fat, but it takes amino acids
from protein to form the muscle,
and this involves feeding highprotein diets as well as highenergy diets to maintain body
function, as well as some
excess being deposited as fat.
M2
Formulated feeds match the
changing growth and
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 2 of 11
development requirements of
growing pigs, resulting in fast
growth rates with minimal body
fat. The faster pigs achieve a
desired carcass weight and a
high feed conversion ratio, the
quicker the turnover of pigs in
the production system.
E
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 3 of 11
Question
TWO
(a)
Achievement
Achievement with Merit
Achievement with Excellence
Impact of Tailing Practices on Growth / Development
Describes factors that account
for difference in size.
Explains how factors produce
difference in size.
Examples:
Example:
• age of the lamb
A lamb 4 weeks of age will be
smaller than a lamb seven
weeks of age, because it has
consumed more food nutrients
required for growth.
• condition of the ewe during
pregnancy
• milking ability of the ewe
• single or multiple birth
• sex of the lamb.
M1
A1
(b)
(c)
Describes an action that
causes temporary growth
checks and permanent
change(s) in development.
Explains how a manipulation
influences growth / development
and productivity.
Example:
• Tailing using a hot iron to
sever the tail from the body
may cause a short-lived pain
for some hours following the
action, decreasing appetite
and nutrient intake.
• Tailing using a hot iron to
sever the tail from the body.
OR
• Castration using elastrators
and a rubber ring on the
testicles.
A2
Example:
OR
• Castration removes testicles
and the source of
testosterone. As a result, the
castrated lamb will grow at a
reduced rate and at the same
time produce a carcass with
more fat.
M2
Justifies castrating male lambs.
Example:
Intensive properties are usually
on flat to rolling country where
soil type and climate favour
growth of improved grass
species, and where the
topography allows stock to
graze rather than browse over
vast areas of native pastures
common on high country
properties.
The intensive farmers have
some assurance that they can
finish lambs to desired target
weights, and therefore use
breeds that have the genetic
capacity for high liveweight gain
with little fat. These attributes
are further accentuated if rams
are left as rams, as the
presence of testosterone
produced by the testicles
favours a fast growth rate and
minimal fat cover. Such animals
provide scope for processors to
develop a range of cuts required
by the market, and therefore
higher prices are paid. It is
important that the ram lambs
are killed at an early age, for if
left as a ram for a year then it
will be heavily discounted for
price, due to perceived meat
taint.
High country conditions,
especially the low-quality
pastures and walking on hills,
means that it will be difficult for
lambs to receive the necessary
nutrients to support an adequate
growth rate. Because lamb
growth rates are low, there will
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 4 of 11
be a significant time interval
before medium to heavy-weight
lambs can be produced, and if
left as ram lambs, the farmer
runs the risk that they may
become sexually active,
producing unwanted
pregnancies. In addition, if it
takes too long to get ram lambs
to killing weights, they may be
discounted at processing plants.
Wether lambs do not have the
same risks associated with
them, and although they have a
higher fat content than ram
lambs, this will not be a
significant disadvantage on this
property.
E
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 5 of 11
Question
Achievement
THREE
Internal Worms and Drenching
(a)
Describes mode of infection.
Example:
Eggs develop in bottom layers
of pasture and when grazing,
especially close to ground,
animals consume larva with
herbage material.
A1
Achievement with Merit
Explains how worms cause
loss of productivity.
Example:
Larva develop into worms, and
to do so require a food source.
Worms can suck blood to
absorb nutrients or can cause
irritation of the gut lining,
resulting in poor digestion and
absorption of food nutrients.
Loss of nutrients to worm
activity means less for growth
and other functions such as
wool production.
M1
(b)
Describes the action.
Example: faecal egg counts
Fresh dung is gathered from a
paddock for analysis. Decision
is based on the flock worm
burden, not individual lambs.
OR
Example: Administering the
correct dose
Involves weighing the sheep to
establish the range in
liveweight, then reading label of
drench container to establish
dose for the heaviest sheep. Lift
sheep’s head, insert gun in
corner of mouth and over
tongue to ensure no “spitting
out” of drench.
A2
Explains the ability to destroy
worms.
Example: faecal egg counts
This practice will determine
whether worms are present and
hence the need for drenching,
or whether the existing drench
being used is killing the worms.
By establishing when drenching
is required and what drenches
are effective, the efficiency of
drenching can be increased.
Low worm burdens maximise
growth rates to mature size for
breeding purposes, while
strategic drenching has a lower
cost, both in terms of drench
and labour required.
Example: Administering the
correct dose
Each animal must receive the
correct dose for effective
drenching. If an animal is
missed or is under-dosed due to
faulty technique, then its worm
burden will not all be killed,
resulting in the animal dunging
out worms to reinfest pasture
and other sheep. Low worm
burdens maximise growth rates
to mature size for breeding
purposes, while strategic
drenching has a lower cost, both
in terms of drench and labour
required.
M2
Achievement with Excellence
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 6 of 11
(c)
Justifies a planned drenching
policy.
Example:
Drenching can be an expensive,
unpleasant and time-consuming
practice, and this is made worse
if excessive drenching occurs
because previous drenching
does not appear to have been
effective. It is essential to
ascertain whether the type of
drench being used is effective.
The best method for finding this
out is to drench, then take
faecal samples to determine kill
rate. Overuse of one type of
drench can produce drench
resistance which could restrict
options for worm control in the
future. Faecal egg counts are a
diagnostic tool that gives
information on need for
frequency, drench type and
drench resistance. Waiting for
signs of scouring is too late,
because the animal is spreading
worms to others and the
productive damage has already
been done. While this approach
may minimise cost and labour,
production losses will be
occurring, even though it may
only be obvious in some
animals. Animals that continue
to scour after regular drenching
indicate either poor drenching
technique or drench resistance.
E
Judgement Statement
Achievement
Achievement with Merit
Achievement with Excellence
2 A1
2 M1
2 M1
2 A2
2 M2
2 M2
2E
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 7 of 11
SECTION B: HORTICULTURAL SCIENCE
Question
ONE
(a)
Achievement
Achievement with Merit
Achievement with Excellence
Crop Pests
Describes how a chewing pest
affects plants and plant growth.
Explains how a chewing pest
reduces productivity.
Example:
Example:
The insect would eat the leaves,
stems or roots of the plant. This
would damage the plant,
reducing growth.
The eating of leaves would
reduce the surface area
available for sunlight
absorption, reducing
photosynthesis and therefore
growth. This, in turn, limits
productivity.
A1
Leaf damage reduces the ability
of the plant to photosynthesise
and produce sufficient energy
for growth, thereby slowing
growth. If the early leaves
essential for heart development
are destroyed, then quality
factors such as heart formation
and maturity are adversely
affected.
M1
(b)
(c)
Describes how burning is used
to control insect pests.
Example:
The burning of infected plant
material means that the insect
pests and viruses they are
carrying are removed from the
growing environment. Only
material which is showing signs
of infection are burnt.
Explains how the use of
pesticides can cause resistance
in insect pests.
Justifies the use of burning in
glasshouse production.
Example:
Removal and burning of
infected plant material is
effective in preventing the
spread of pests, as it removes
the source, but the productive
base for the grower will be
reduced and must be replaced.
Burning may be regarded as
environmentally undesirable,
but is necessary to destroy
resistant pests and the viruses
they can carry.
Lettuce aphids live in the heart
of the lettuce. Repeat exposure
to pesticides that do not kill the
aphids and their short life cycle
results in new generations
becoming resistant to
pesticides.
A2
M2
Example:
Spraying with insecticide should
ensure that insects responsible
for damage are eliminated, but
success will be dependent on
timing and location of pests.
These pests live in the heart of
the lettuce, so are difficult to get
to. Insects are generally
becoming more resistant to
chemicals, so more are needed
at a higher cost.
The use of chemicals could be
regarded as being not
environmentally friendly, and
will have a cost component.
Blanket application using
machinery means the operation
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 8 of 11
is straightforward and less likely
to be compromised by human
behaviour.
E
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 9 of 11
Question
TWO
(a)
Achievement
Achievement with Merit
Achievement with Excellence
Harvesting Crops
Describes features of a crop
ready for harvest.
Explains how sunlight and
temperature affect harvest time.
Example: sweet taste
Example:
• ripe colour, eg red apples,
orange mandarins – deeper,
brighter colour
Sunlight increases the
photosynthesis of a plant,
producing more sugars which
are stored in the fruit, causing it
to ripen more quickly with a
sweet taste. Water stress can
cause more sugars to be stored
in the fruit, speeding up
ripening.
• softened skins
• yields to pressure
• increased sugar levels.
A1
Higher air temperatures
increase the production of
ethylene within the plant,
increasing ripening. It also
increases chemical reactions,
which further speed up ripening.
However, cold nights are
needed for apples to change
colour or ripen.
M1
(b)
(c)
Describes how a test is
performed to find the correct
time for harvest.
Explains how the grower knows
when to harvest the crop using
this test.
Justifies the use of a test for
growers to know when to
harvest their crop.
Example:
Example:
Example:
• uses a sample of fruit juice
and views through
a refractometer
• high brix levels indicate high
sugar levels in solution.
The use of a test can be labourintensive, but it tells the growers
when to harvest fruit in order to
obtain the best quality fruit for
sale.
• cuts apples in half and sprays
iodine onto cut surface
• skin of fruit is removed, then a
metal rod is inserted under
pressure.
A2
• low starch levels, as all starch
has turned to sugar
• pressure reading on
penetrometer.
M2
Over-ripe fruit is harder to store
and does not keep well for
getting to market. With fruit,
storage and transport times
must be taken into
consideration, and so testing is
a useful tool to determine
correct harvesting time.
Unripe fruit is lower in quality
and leads to lower returns.
Markets demand sweet fruit,
and a few extra days on the
plant can make the difference
between under- and overripened fruit. Testing helps to
minimise the chance of
harvesting at the wrong time.
E
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 10 of 11
Question
THREE
(a)
Achievement
Achievement with Merit
Achievement with Excellence
Hydroponics
Describes the effects that TWO
major nutrients have on growth /
productivity.
Explains how controlling these
factors leads to a high crop
yield.
Example:
Example:
Increasing nutrients and
changing the proportions of
nutrients for different stages of
growth, eg:
The law of the minimum applies
– production is limited by the
nutrient in least supply.
• Nitrogen – a critical nutrient in
leaf formation, but also
important for flowering and
fruit set.
• Phosphorus – a critical
nutrient in root development.
• Potassium – a critical nutrient
in fruit formation.
Nutrient levels can be altered in
response to data from tissue
tests.
Excesses of other nutrients
cannot be utilised to
compensate, therefore a
balanced application of nutrients
is essential to maximise yield /
productivity. By using
hydroponics, the nutrients can
be supplied in a measured way
that maximises growth.
M1
A1
(b)
(c)
Describes how nutrient levels
are changed.
Example:
Nutrient levels – both amounts
and nutrient composition – are
altered by the use of different
fertiliser mixes in response to
plant requirements, data from
tissue tests, and weather
conditions.
A2
Explains why the hydroponics
system is changed during the
growing cycle.
Example:
Increasing nutrients, and
changing proportions of
nutrients, for different stages of
growth. Nutrient levels are
tested and altered in response
to data from tissue tests to
determine accuracy of nutrient
levels and provide data that can
be acted on. It is essential that
at the fruiting stage potassium
levels are high, whereas during
the development stages plants
receive a higher proportion of
nitrogen to develop leaf for
photosynthesis.
On hot days the water intake for
plant cooling purposes via
transpiration is increased, but
nutrient levels are decreased to
avoid an oversupply.
M2
Justifies the use of hydroponics
by giving reasons why this
method produces a more
reliable supply of quality
produce to markets than soilbased production.
Example:
Hydroponics is commonly
associated with the use of
protected environments such as
glasshouses. The technique
allows for accuracy in the supply
of required plant nutrients, and
this cannot be achieved by any
system that is exposed to the
vagaries of the weather. As a
result of the control the grower
has over growth factors,
seasonality issues associated
with production can be
overcome, even if at some
expense. The growing media is
rejected at the end of the
growing season, and therefore
diseases associated with
monocultures in a soil medium,
even if in a glasshouse, are
overcome. Harvesting can be
carried out in any conditions,
and therefore market
requirements can be met.
While hydroponics is a highcost system, the higher yields of
quality produce that can be
NCEA Level 2 Agricultural and Horticultural Science (90454) 2011 — page 11 of 11
delivered to market when supply
from other sources is limited
means that high prices and
profits are possible.
E
Judgement Statement
Achievement
Achievement with Merit
Achievement with Excellence
2 A1
2 M1
2 M1
2 A2
2 M2
2 M2
2E