HSC Agriculture Syllabus Notes
10.1- Investigate the complex interaction between the problem organism, the host and the
environment for one animal disease
10.2a- Research using secondary sources an IPM program for an animal production system
10.2b- Evaluate an IPM program, naming the target organism and the animal host. - correct
answer-Disease triangle - Leptospirosis
Top - Host = cows
Right - Environment = wet/damp/moist areas
Left - disease causing organism - Leptospira
Lepto
- Lots of varieties of bacteria (more and more are becoming problematic.)
- Spread in animal urine.
- Wet environment keeps bacteria alive
- Some animals can have no obvious signs of the disease.
Symptoms -
- Abortion or still births
- Lower fertility
- Decline in quality and quantity of milk
- Bloody port-wine coloured urine.
- Severe fever and death in younger animals
Control of Lepto
Prevent contact with urine -
O AMS prevents animals being grouped in milking parlour
O Reducing the number of animals in milking parlour at one time
O Rotation of paddocks
O Reducing access to stagnant water
O Control rodents
Reducing contact with other contaminated fluids
O AI and treat sperm with antibiotic
O Quarantine new animals until vaccination is active
Vaccination -
O Two shots must given 4-6 weeks apart
O Then annually (4-8 weeks before giving birth to give calf temporary protection too.)
Treatment -
O Antibiotics and separation from herd.
IPM control strategies prevention and treatment
,Decrease concentration of animals in milking parlour (AMS or less animals)
Advantages -
- This is a preventative strategy that prevents crowding in the milking shed and thus reduces
the likelihood of cows urinating on each other and thus spreading the disease.
- AMS has positive externalities associated with it other than reducing transmission.
- Welfare benefits
Disadvantages -
- Does not prevent the contraction of the disease and does not act as a form of treatment.
- If AMS is implemented may negatively impact environmental sustainability.
Paddock rotation
Advantage -
- Reduces the risk of the transmission
Disadvantage -
- Need paddocks
- Time
- Money
Reduce access t
5.1a effects of environmental factors on growth, development and production factors. -
correct answer-Light - Plants reflect green light and absorb other parts of the spectrum,
therefore, need full spectrum of light. Light is an input for photosynthesis. Amount of light
also affects flowering, some flowers require less and others more. Intensity of light also
affects photosynthesis (can't grow without light).
Management - Choosing plants that suit a particular region in terms of length of light.
Artificial lighting can be used in glasshouses etc to increase day length and increase
photosynthesis.
Temperature - Each species has its own min max and optimum temperature. It can influence
photosynthesis -> soil temp -> decreases nutrients.
Management - Temp can be modified by use of a glasshouse, choose correct varieties for
differing climates at different times of year. Place covers.
Temperature - Each species has its own min max and optimum temperature. It can influence
photosynthesis leading to increased soil temperature and less nutrients.
Management - Temperature can be modified by use of a glasshouse. Choose correct
varieties for differing climates at different times of year.
Soil moisture - Input for photosynthesis therefore limited amount can limit production. Most
crops rely on rainfall alone. Water logging can reduce flowering.
,Management - Irrigation is the easiest way to improve although it can be expensive.
Irrigation is useful mostly for high value horticultural crops. Increasing organic matter also
prevents water loss.
Co2 O2 ratio - Co2 is an photosynthesis. It can be low in a glasshouse which airflow is low.
In a dense young crop which requires large amounts of co2.
Management - Increasing airflow or using co2 generator in glass house. Planting at lower
densities.
Wind - Wind can cause crops/plants to be uprooted and die or to increase water loss through
transpiration and reduce photosynth
7.3a - Construct a diagram to illustrate the energy losses associated with digestion and
metabolism in animals - correct answer-Flow chart looking thing.
Gross energy in feed, Digestable energy 70% loss in faeces 30%, Metabolisable energy
60% losses in urine and gas 10%, Net energy 40% losses as heat (fermentation and nutrient
metabolism) 20%.
In agriculture we want the nutrients we give the animals to be used for growth and
reproduction.
HOWEVER, before animals can grow and breed, they must first survive!
The body is also not completely efficient and so some nutrients and energy are missed.
To memorise
All the gains
Good - Gross energy
Dogs - Digestible energy 70
Make - Metabolisable energy 60
Noise - net energy 40
F - faces 30
U - urine 5
Grass - gas 5
Hoppers - heat 20
9.2 Identify factors that limit fertility of farm animals including genetics, environment, pests
and diseases, management and nutrition. (doesn't count for trials) - correct
answer-GENETICS:
Genetic differences can occur between species of animals as well as within species. An
animal born as one of twins is more likely to produce twins. Some animals are infertile
because they suffer from peculiarities of genetic origin. Frequently this type of of infertility is
associated with the inheritance of abnormalities in the anatomy or the reproductive
tract/endocrine glands.
, ENVIRONMENT:
There are two main aspects of environment that affect reproduction: 1. Temperature
2. Daylength
High body temperature of males is a cause of poor quality semen. They can also decrease
male's libido which affects mating. Higher temperature increases embryonic mortality and
reduce birth weights of piglets and lambs. A combination of low temperatures and wet/windy
weather will lead to heavy loses of newborn lambs.
PESTS AND DISEASES:
Any disease that affects the health and vitality of an animal may reduce its reproductive
capacity. Diseases can:
- affect fertility indirectly: weakening animals or reducing physical ability to mate eg. footrot,
flystrike
- affect the reproductive organs: stop production of sperm or ova or preventing the passage
of sperm to ova
MANAGEMENT:
A farm manager's role is to ensure that their animals are performing to their maximum
reproductive ability. Some management practices that can increase reproductive efficiency
include:
- select animals for their fertility
- plan joining times considering breeding seasons
- ensure adequate nutrition for stocking rates
- accurately detect oestrus
- control disease by practising IPM
NUTRITION:
The level of nutrition affects the rate of weight gain and hence the growth rate of animals.
The rate of development of the reproductive organs and the onset
of puberty are determined more by bodyweight than age. Mature females on a low plane of
nutrition and below no
9.3a: Evaluate management techniques available to farmers to manipulate reproduction in
farm animals including artificial insemination, multiple ovulation, flushing, embryo transfer
and oestrous synchronisation. (NOT IN TRIALS) - correct answer-Artificial insemination (AI)
A medical procedure whereby semen is collected from a male and later inserted into the
vagina or uterus through a catheter with the intention of making the female animal pregnant.
Generally done before Embryo Transfer.
Sperm from a specific male can be chosen and inserted into the female at a time at which
she is ovulating without the 2 animals ever meeting → resulting in pregnancy → resulting in
birth of offspring
Limitations:
More time/effort required in identifying females in heat (oestrus/ovulating)
Require expertise in performing the process (or need to pay someone to do it)
Conception rates may be lower than in natural matings (depending on the operator
competency)
Advantages:
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