AHPS weeks 9 and 10 Flashcards
What are the three factors that mean FCE in fish can be close to 1?
- don’t thermoregulate (poikilotherms)
- ammonia secretion via the gills is more effective
- don’t support their bodies against gravity
At what stage of development are salmon transferred to salt water? What is an indicator that they are ready for this to happen?
Smolt
- they turn silver
Would test a group in saline water first anyway to be sure
How old are salmon when they are usually harvested for meat? How heavy?
2 - 2.5 years, 4 - 4.5 kg
What is the optimum temperature range for Atlantic salmon?
15.9 degrees - 17.5 degrees
Problems arise above 18
What is the optimum temperature range for
ocean trout?
10 - 22 degrees C
What is the optimum temperature range for yellowtail kingfish?
22 degrees C
What is the optimum temperature range for Southern bluefin tuna?
19 - 21 degrees C
What is the optimum temperature range for Barramundi?
26 - 28 degrees C
Do barramundi require salt or fresh water?
Both - young in salt, mature in fresh
What effect can non-optimal water temperatures have?
Reduce fertility
Increase susceptibility to disease
What determines water ‘quality’? Does this vary with temperature?
Amount of dissolved O2 - warmer water holds less oxygen
What is desirable level of O2 dissolved in water? What happens if this is too low?
75 - 80%
Fish can vomit
How much protein does a growing salmonid require? Is there a limiting amino acid?
400g/kg
Yes - lysine
Why include CHO in salmonid feed?
Acts as an alternative energy source which spares dietary protein for muscle growth
What management strategy is used to ensure salmon availability year round?
Manipulate the photoperiod in smolts
What are two advantages of total destocking?
Low supp feed cost
Good preservation of pasture and soil
What are three disadvantages of total destocking?
Lose genetic progress
High cost to buy more stock after drought
Risk introduction of disease with new stock
What are two disadvantages of partial destocking?
High cost supp feed
Damage to pasture (unless use SCA)
What stock would you sell if partial destock?
Less productive stock
- wethers in merino system
- old cows in dairy or beef system
What roughage percent should be provided when feeding grain ration?
20%
What health concerns do you need to address when feeding a grain-based ration to your SCA stock?
Ca:P ratio - grain is high in P, so add 1.5% CaCO3 to feed to balance
Vitamin E deficiency - comes from green feed - supplement stock every 6 weeks
How many MJ ME per DSE per day is recommended for maintenance during a drought?
5 MJ ME / DSE
How much bare ground needs to be exposed before risk of soil erosion is high?
20 - 30%
What is the stocking rate of a SCA?
1000 sheep/0.5Ha
How much water needs to be provided to stock in SCA?
5L/sheep/day
50L/cow/day
What is the starting rate for grain introduction in sheep?
50g/head/day
What is the starting rate for grain introduction in cows?
500g/head/day
Why are animals at increased risk of pulpy kidney during a drought? How can you mitigate this risk?
C. perfringens E overgrowth in intestines due to increased CHO in diet
Can give booster vacc pre-SCA and introduce grain feed slowly
What disease can occur if animals become vitamin E deficient?
White muscle disease
How might animals be at risk of plant poisonings?
Being released from the SCA onto pastures post-drought too quickly
Weeds and toxic species may have grown above their previous proportion. Should release stock with full stomachs and phase out the supp feed over 1 week
How can you protect water sources from contamination?
Monitor them, put up fences, plant vegetation
What is the most common honey bee species in AU?
Apis mellifera
What is honeybee nemesis
Varroa destructor
What is colony collapse disorder?
Stressors such as insufficient food, disease or mites cause young bees to leave the hive too early and subsequently die
What is NBPSP?
National Bee Pest Surveillance Program
What are six potential roles of the vet in honeybee disease surveillance?
Technical advice for pest disease management programs
Advice on biosecurity programs
help with NBPSP
Prescribe required drugs e.g acaracides
Strategic disease management advice
Sample and test hive for residues
