Week 6 Flashcards
Describe the trade-off in yield versus quality for hay making
Cutting time v’s quality decline
Decided by favourable weather conditions
Dried to a level of preventing heating and burning in the shed
75-80% DM
What is low quality pasture
Less than 60 % DMD or ME lower than 8.5 MD
Outline the factors that affect the rate of drying
Length of stubble
Type of mower
Turning of swath
Conditions
Faster part of swath to dry
Leaf Lamina
Legumes vs grasses for drying
Grasses dry faster
Describe the effect that conditioning has on hay and outline any positives
Increases the speed of stem drying
Increases water loss from grass
Requires less turning, raking
negatives of conditioning
Overdrying is biggest problem
Rain events decrease quality of condidtioned hay more than unconditioned
This is amplified more with rain after mowing
Outline some of the losses that occur in haymaking
DM can decline by 14% for grass, 20% for legumes
Losses higher in poor weather
Machinery Losses - each time incurs penalty
Respiration- 19% can be lost (9-14 days in paddoc)
Other lossed of hay
Feeding out losses 40%
Factors effecting feed out losses of hay
Environ - wind, rain
Animals trampling
Microbial degratation
Handling
Effects of croimpling on hay
Inc. oss of quality but less drying time
Storage of hay losses
10%
Describe the fermentation process for silage and outline key factors that affect the success of making silage.
Respiration of CHO’s = O2, water, Energy
If O2 is excluded, temp rise of 2-3 degrees
Respiration can decline withing mins if o2 excluded efficiently
Ensiling preserves herbage by encouraging fermentation of carbs
How to carbs ferment to Lactic acid in SIlage
Lactobacillus bacteria
Silage pH reduction to
4.2
What does low pH inhibit
Growth of clostridia. grows in arerobic conditiond and reduces the N value in feed.
Increases the pH lavel and produces putrefying compounds (acetic acid, amine)
Silage v Hay
Silage has high ME and palatibility
Cant transport pr market silage
Stock eat hay first
Silage making more expensive
Describe the effect of phyto-oestrogens in clover
Sub and red clover Low lambing % Dystocuia - difficult lambing Post natal mortality Ewe Infertility Prolapse Lactating in virgin ewes Teat development in weathers
Management of phyto-oestrogen
Modern cultivars have much lower levels
Cows less affected as they have higher oestrogen levels
Signs of bloat
Rapid fermentation producing large amounts of gas (co2 and ch4)
Bloat occurs when bubbles form, preventing belching
Increases rumen pressure against the lungs
Pasture factors of bloat
High soluble protein content
Rapid digestion of feed
High conc. of small feed particles
Species for bloat
Lush green growth of legumes
Lucerne, white, red, sub clover
YOung and vegetative
Legumes with tannins preventing bloat
Lotus, serradella
Pasture management to manage bloat
Maining grass /legume balance graze in pm Feed hay before grazing strip grazing prevents selectivity Protein declines with stage of development Spray with bloat oils/tannins
Describe the causes of hypocalcemia (milk fever) and methods to reduce the risk of hypocalcemia
Plasma Ca concentrations too low to support normal nerve and muscle function
Low K forages are useful to reduce cation-anion diff
Feed dry cows low K sources to prevent
Describe the causes of hypomagnesia (grass tetany)
Low Mg in cerebro - spinal fluid
Grazing of fresh material in late autumn/early spring
Bos Taurus more susceptible than Bos Indicus
Factors leading to Low Mg
Mg level in herbage absorbed or retained affected by high K in soil, low levels of available Ca and P
Low feed availability - below 1000kg D/Ha
Treatments of Hympomagnesia
Feed 4kg hay per day
Causmag
High legume content in paddock
Describe the causes of nitrate poisoning
NO3- reduced to NO2- in rumen
High levels convert haemaglobin to methoglobin
How does NO3- accumulate in plant tissue
High N in soil
Growth rapidly decelerates due to low light, droughtm temp
methods to reduce the risk of nitrate poisoning
Prevent hungry stock by feeding hay of mature grass before allowing access to paddock
Prevent Gorging recently sprayed weeds
Prevent grazing of highly fertilised crops, especially 7 days after rainfall, low temp, cloudy weather
Endophytes
Fungus that infects grasses
Produce toxic compounds
In Perennial rye and tall fescue
Endophyte safe approach
Sow safe perennial ryegrass or so phalaris instead
