Pasture 4 Flashcards
(19 cards)
Describe how pastures and animals interact
Animal impacts on pasture Pasture impacts on animals Why is pasture quantity important? - Components of daily feed intake - FOO declines
Describe how pastures and animals interact
Animal impacts on pasture
Defoliation - Leaf area and growth - Selective (patch) grazing Nutrients in dung and urine Treading/trampling - Direct effect on plants (leaves and growing points) - Soil compaction - Pugging
Describe how pastures and animals interact
Pasture impacts on animals
- Feed on offer
- Height and density
- Nutritive value
- Metabolic disorders
Describe how pastures and animals interact
(Why is pasture quantity important?)
- Components of daily feed intake
- Intake (g) per bite
- Number of bites per minute
- Grazing time (min) per day
What does FOO stand for?
Feed On Offer
Describe how pastures and animals interact
(Why is pasture quantity important?)
-As FOO declines
- Each bite contains less pasture
- More bites per minute
- Increase grazing per day (may not be enough hours in the day to obtain enough feed for maintenance)
Understand the basics of feed budgeting
- Dry Sheep Equivalent (DSE)
- Rainfall, growing season and potential stocking rate
- Pasture quantity
- Pasture intake will increase as FOO increases until saturation point (where the animals cannot eat anymore)
- The taller the pasture is the higher the intake even if FOO is the same – more accessible
- If pasture is more digestible, it can be processed more quickly, and thus more can be eaten
- Principles of feed budgeting
Understand the basics of feed budgeting
Dry Sheep Equivalent (DSE)
- The currency of grazing animals – the standard measure of stocking rate
- The stocking rate determines profitability
- The metabolisable energy need of a 50kg wether (or non-pregnant, non-lactating ewe) at liveweight maintenance
- Stocking rate = DSE per hectare
Understand the basics of feed budgeting
(Rainfall, growing season and potential stocking rate)
- French equation
DSE/ha = (every 25mm rainfall above 250mm) x 1.3
Understand the basics of feed budgeting
(Rainfall, growing season and potential stocking rate)
- Saul Kearney equation
- DSE/ha = a + (3.4 x growing season) + (0.18 x Olsen P)
- When< 20ha, a= -8.3
- When > 20ha, a = -11.0
- Smaller paddocks allow more stock per hectare as stock are more likely to explore and access all available pasture
- This equation considers when the rain is falling, and thus the growing season and productivity of the pasture
- Rule ofthumb
- DSE/ha = 2 x growing season
- Rule ofthumb
Understand the basics of feed budgeting
Pasture quality
- Feed on Offer (FOO) (the total amount of feed there) or Herbage Mass (the total amount of feed minus the inaccessible section close to the ground)
- Measured in kg of dry matter per hectare (kg DM/ha)
Understand the basics of feed budgeting
Principles of feed budgeting
- Feed budgeting based on FOO levels (set-stocked) or ‘pasture allowance’ (rotational grazing)
- Steps to feed budgeting based on FOO
- What is the target live weight or condition score and what condition are the sheep/cattle in now?
- What energy do they need?
- What can they eat?
- Feeding to match the deficit or surplus
List common livestock health risks associated with grazing pastures
- Factors affecting nutritive value
- Digestibility drops significantly in October/November/December
- Both cattle and sheep are selective grazers
- Protein benchmarks
- Wide range of toxins and metabolic disorders can reduce production and increase mortality
- Alkaloids
- Metabolic disorders
List common livestock health risks associated with grazing pastures
(Factors affecting nutritive value)
- Temperature and light
- Plant maturity
- Plant species
- Botanical composition
- Grazing management
- Digestibility
- Metaboliseabe energy
- Protein content
- Clover percentage
- Ratio of dead:green
List common livestock health risks associated with grazing pastures
(Both cattle and sheep are selective grazers)
- Both cattle and sheep are selective grazers
- Strong preference for clover over grass (70:30); high quality over low quality, leaf over stem…
List common livestock health risks associated with grazing pastures
(Protein benchmarks)
- The rumen micro-organisms need protein (minimum 7% to digest cellulose
- Green pasture is higher protein (grasses 15% and legume 25%), but dry feed in summer can drop to 5%
- Sheep and cows may only need 7-8% protein when dry, 8-10% in late pregnancy and 12-14% in lactation
- Growing lambs or steers require 12-16% depending on live weight
List common livestock health risks associated with grazing pastures
(Wide range of toxins and metabolic disorders can)
- Reduce production and increase mortality
- Fungal and bacterial alkaloids – temperate grass
- Oestrogenic compounds – clovers
- Photosensitising agents
- Bloat and red-gut
- Nitrate poisoning
- Mineral deficiencies
List common livestock health risks associated with grazing pastures
(Alkaloids)
- Neurological disorders associated with
- Phalaris stagger
- Perennial ryegrass staggers (fungal$endophytes)
- Tall-fescue toxicoses (fungal endophytes)
- Paspalm staggers
- Annual ryegrass toxicity (bacterial toxin)
- Lupinonsis (fungal toxin)
List common livestock health risks associated with grazing pastures
(Metabolic disorders)
- Grass tetany – low magnesium in the blood due to low levels of magnesium in green pastures/cereal crops
- Hypocalcaemia – low calcium in winter cereals
- White muscle disease – low selenium/vitamin E in dry pastures during summer and autumn
