Week 6 Flashcards by Matt Champness

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

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What is low quality pasture

Less than 60 % DMD or ME lower than 8.5 MD

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Outline the factors that affect the rate of drying

Length of stubble
Type of mower
Turning of swath
Conditions

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Faster part of swath to dry

Leaf Lamina

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Legumes vs grasses for drying

Grasses dry faster

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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

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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

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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)

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Other lossed of hay

Feeding out losses 40%

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Factors effecting feed out losses of hay

Environ - wind, rain
Animals trampling
Microbial degratation
Handling

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Effects of croimpling on hay

Inc. oss of quality but less drying time

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Storage of hay losses

10%

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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

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How to carbs ferment to Lactic acid in SIlage

Lactobacillus bacteria

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Silage pH reduction to

4.2

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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