Livestock Health and Soil
Nutrition
Tiffany Bennett
Livestock Consultant
Brian Hughes
Senior Soil and Land Management
Consultant
NRM Pathways to Productivity Expo – October 11th 2012
Bordertown Civic Centre
Mineral disorders in livestock
15 + essential mineral
Major Ca, Cl, P, Mg, K, Na, S
Trace Co, Cu, Fe, I, Mn, Se, Zn, Mo
Ultra traces 15? As, B, Cr, Ni, Si, V,
Key Issues SE
Mg, Co, Cu, Se
Soil pH and nutrient availability

3
Increasing
acidity
4
5
TOO MUCH:
•aluminium
•manganese
•Iron
NOT ENOUGH:
•magnesium
•calcium
•potassium
•phosphorous
•molybdenum
Optimum pH
6
7
Increasing
alkalinity
8
9

10
TOO MUCH:
•sodium
•Boron
NOT ENOUGH:
•iron
•zinc
•manganese
•copper
•phosphorous
Introduction
 Complex interactions in the soil have important influences on the
availability of an element in pasture. E.g excess of any element in
the soil will reduce the uptake of others
 Address some common soil/animal interactions relevant to the
South East of SA
-
Copper
Cobalt/B12
Selenium
Grass Tetany
Phlaris Staggers
Page  4
Grass Tetany (Hypomagnesia)
 Caused by low levels of blood magnesium.
 Generally affects stock in late autumn, winter and spring
 Can cause significant production losses even with no signs of illness
 Often occurs during lactation or late pregnancy due to increased
body demands
 May occur in soils with adequate magnesium due to poor root
development.
Page  5
Grass Tetany (Hypomagnesia)
 Signs include
- in coordination, restlessness, over alert appearance, excitable,
aggressive, convulsions.
- May be induced when animal are disturbed with a high mortality in
affected animals.
 Grasses or cereal crops tend to have low magnesium and a high
content of organic acids that tie up magnesium in the rumen.
 Thin animals or fat animals that are losing condition can be at high
risk
Page  6
Grass Tetany (Hypomagnesia)
 High nitrogen and/or potash fertilisation reduce the availability of
magnesium from the pasture. Avoid grazing soon after fertilisation
application.
 Cold, wet, windy weather intensify the problem due to short periods
of fasting particularly in paddocks lacking shelter.
 Provision of hay during periods of lush, rapid pasture growth can
help reduce the incidence.
 If magnesium is fed over a long period of time it is important to add
dicalcium phosphate as magnesium can reduce phosphorus
absorption.
Page  7
Magnesium deficency Interactions
 High dietary levels of potassium and nitrogen will inhibit magnesium
absorption from the rumen
 Diets low in sodium increase magnesium requirements by indirectly
raising potassium concentrations in the rumen
 Increased dietary levels of calcium increase dietary magnesium
requirements
Page  8
Predicting Grass Tetany Risk
from Soil Tests
K/ (Ca+Mg) > 0.07-0.08
 ie. Exchangeable Potassium divided by Exchangeable Calcium
plus Exchangeable Magnesium –use cmol(+)/kg figures
 Risk factor only on these soils as actual incidence based on many
other factors
 Soil types at risk identified in the MLR/SE- either soils with very high K
or fairly acid and low Ca/Mg
Predicting Grass Tetany Risk
from Plant Tests
K/ (Ca+Mg) > 2.2
 use % figures
 Risk factor only as actual incidence based on many other factors –
high N
 Will find legumes in the same paddock have a ratio approx ½ of
perennial grasses
 Annual grasses variable but similar in July samplings
SE Study by Lewis and Sparrow in 1991
 Looked at 3 soil types across 22 sites
 Solodised Solonetz- sandy loam over clay
 Rendzina- black clay over limestone
 Siliceous Sand- deep light sand
 Surveyed tetany deaths over previous 5 years
SE Study by Lewis and Sparrow in 1991
Mean Results
Soil Type
Siliceous Sand
SL over Clay
Rendzina
At risk levels
July Soil Indicator
0.025
0.10
0.058
> 0.07-0.08
July Legume
Indicator
0.62
1.24
0.73
> 2.2
July Perennial
Grass Indicator
1.78
2.26
1.72
>2.2
Death over last 5
years
nil
9 of 12 sites
nil
Grass Tetany – Can we improve the soil and plant
levels and reduce risk?
 Study at Wistow – Acid SCL over clay
 History of grass tetany
 Soil level 0.23 (very high aim <0.08)
 Pasture level (2.7, aim for <2.2)
 Phalaris dominant pasture
 Trialled a range of limes/ dolomites and CaO and MgO
Effect on Soil Ratio Levels- immediate, persisted at
least 3 years
Effect on Soil Magnesium Levels- at 3 years
Effect on Ratio Plant Levels- immediate, did not
persist at 3 years
SUMMARY- soil and plant side
 Soil and plant tests are good risk indicators as are soil types in SE
 Anedotally, some farms have decreased incidence of grass tetany
by liming and dolomite and improve legume content of pastures
but still an issue in some years
 Trials indicated can easily change soil cations in the surface 0-10cm
but much less affect on plant cations
Grass Tetany (Hypomagnesia)
 Treatment
- Inject a combined calcium and magnesium solution under the skin.
Sometimes need to repeat treatment (consult a veterinarian)
- Success in treating animals depends on treating animals quickly
- Reduce any stress from weather
- Often animals do not eat and pregnant animals often succumb to
pregnancy toxaemia
Page  18
Grass Tetany (Hypomagnesia)
 Can be prevented by the following methods
- Dust pasture with magnesium oxide at the rate of 60g per cow per day or 10 g per
sheep per day if strip grazing.
- Grass tetany blocks. Not all animals may consume enough magnesium.
- Epsom salts (magnesium sulphate) or magnesium chloride may be added to the
trough preferably via a dispenser. Risky if animals consume too much magnesium
they will scour and epsom salts can be unpalatable if animals are not used to the
taste. Water consumption can vary depending on weather and diet.
- Magnesium oxide may be sprayed on the hay or pored on the cutting edge of the
bale. 500gms of magnesium oxide mixed with molasses and two litres of water
which is suffice for 10 cows or 100 sheep. Magnesium oxide can also be applied
to hay as a dry powder during baling and kept separate for high risk periods.
Page  19
Cobalt by Soil Type
 Severe deficiency – coastal regions on shelly soils
 Less severe on terra rossa, calcareous and siliceous sands, podzolic
soils, podzols, and groundwater rendzinas or much of the SE. Red
gum country OK
 Phalaris staggers linked to Cobalt. Can spray out in Autumn but
generally not used as fertiliser
 Worse on salt areas
Cobalt/Vitamin B12
 Vitamin B12 is synthesised by the rumen microbes from dietary
cobalt
 Cobalt deficiency signs in sheep and cattle are a result of vitamin
B12
 Soil cobalt concentrations and cobalt availability in plants is poorly
correlated
Page  21
Cobalt/Vitamin B12
 High manganese soils bind strongly with cobalt making it
unavailable to plants
 Liming (high pH)has been associated with reduced cobalt uptake
in pastures
 Cobalt levels in pasture are at their lowest in spring
 Lush pasture growth favours the development of cobalt defincy
due to reduced ingestion of soil
Page  22
Cobalt/Vitamin B12
 Cobalt deficiency is generally seen as un-thriftiness and poor
growth of stock
 Extreme cases of cobalt deficiency result in emaciation, poor
appetite, weeping eyes, scaly ears, nervous signs including
blindness and convulsions and death.
 Sheep are more susceptible to a deficiency than cattle, because
of the role of B12 in the microbial synthesis of methionine which is
required for wool growth.
 Young animals are more susceptible due to a higher requirement
Page  23
Cobalt/Vitamin B12
 Supplementation with varying results can be given in drenches, licks and foliar sprays
 Cobalt can be applied to pasture with varying results, except on high pH soils which fix
cobalt and soils high in manganese.
 Cobalt can be applied to hay
 Slow release intra-ruminal bullet/bolus that can provide a steady supply of cobalt. Give to
animals older than 2 months who have fully functional rumens.
 May need a grinder if grazing calcareous soils as pellet may get coated with calcium
phosphate.
 Subcutaneous injection. Two types aqueous and microencapsulated. An injection of
microencapsulated B12 in an oil carrier can be effective in lambs for up to 8 months and 4
months in calves. Aqueous solutions may last for three months.
Page  24
Cobalt/Vitamin B12
 Cobalt supplementation of females after giving birth is not an
effective means of supplementing lambs/calves.
 Milk provides only a fraction of the lambs/calves daily requirements
 Females at risk of cobalt deficiency should receive cobalt bullets at
least 8 weeks prior to giving birth to ensure adequate levels of B12
in the foetal liver and colostrum
 An injection of B12 to the lamb/calf at 6-8 weeks of age should
provide adequate B12 until weaning
Page  25
Phalaris Staggers
 Prolonged access to phalaris dominant pastures in areas that are
marginal or deficient in cobalt.
 Caused by a toxic alkaloid contained in the phalaris plant.
 Can develop months after grazing phalaris
Page  26
Phalaris Staggers Symptoms
 Cattle:
- Excitable, develop mild hind limb weakness, mild in-coordination, weight
loss due to damage to the nerves on the face and jaw making it difficult
to chew and swallow, tongue may protrude and drool saliva
 Sheep:
- excitability, tremors, twitches, head shakes, head nodding, leg weakness,
leg stiffness, bounding, hopping, jumping, saw horse rocking, kneeling,
buckling over, frequent falling followed by vigorous struggling to get up
Page  27
Phalaris Staggers
 If animals are driven and yarded convulsions may be induced.
 Animals can be slow to recover and often never recover fully from
Phalaris Staggers.
 Sheep are more susceptible than cattle
Page  28
Phalaris Staggers
 New varieties of phalaris contain lower levels of toxic alkaloids
(Holdfast, Sirosa, Sirolan)
 Phalaris staggers can still occur on new low alkaloid varieties of
phalaris but it may take longer for staggers to develop
 Older varieties tend to have outbreaks after only weeks whilst
newer varieties can take months before staggers develop
 Staggers can even develop several weeks or months later after
being removed from phalaris pasture
Page  29
Phalaris Staggers Prevention
 Cobalt modifies the rumen bacteria which detoxify the alkaloids.
 Cobalt levels are highest in pasture between November and March
and lowest between June and September
 Can be prevented but not treated with cobalt bullets as cobalt
stimulates bacteria in the rumen that destroys the phalaris toxin.
Injections of cobalt/B12 are not effective.
 Provision of cobalt through a stock lick or block can have varying
results
Page  30
Phalaris Toxicity/posioning is Different to Phalaris
Staggers
 Phalaris staggers is not to be confused with phalaris toxicity in which a toxin
in phalaris results in an ammonia overload and sudden death or
Polioencephalomalacia (PE) like nervous form.
 Occurs in a the beginning and end of the growth season especially in drier
years
Page  31
Phalaris Toxicity/posioning is Different to Phalaris
Staggers
 Associated with:
- phalaris dominant pastures
- moisture stress or repeated frosting
- Insufficient time to adapt to phalaris, rapid ingestion following feed
deprivation,
- new season growth/very short reshooting phalaris plants
- Light patchy rainfall during a dry period
- Grazing pressured management systems (cell grazing/ strip grazing)
Page  32
Phalaris Toxicity/Posioning is Different to Phalaris
Staggers
 Phalaris toxicity/poisoning if a PE like form can result in animals
dying within a few hours or a few days
 Symptoms can include depression, cease feeding, unco-ordinated
gait, collapsing, wandering, sometimes convulsions, coma and
death
 Animals found still alive can recover within 48-72 hours but long
term effects on production are not yet known.
 New low alkaloid varieties are potentially just as posionious as older
varieties
Page  33
Copper
 Two main types SE
1.Soils low in Copper- can apply to soils and pasture. Can have a
long residual value!
2.Soils where interactions occur which reduce Copper availability to
the plant eg high Mo &/or S- needs to be applied to animals
 Copper – animal requirements higher than plants
Livestock Mineral Requirements vs plant
growth (from Judson and McFarlane)
Mineral
Min
Concentration
Sheep diet
Min
Concentration
Cattle
Minimum
Adequate young
Phalaris
Minimum
Adequate
Subclover
Magnesium g/kg
1.2
1.9
1.5-2.0
1.0-1.5
Phosphorus g/kg
1.3-2.5
1.8-3.2
1.8-2.0
2.8-3.2
Copper mg/kg
7
7-10
2-4
4-5
Selenium mg/kg
0.05
0.05
0
0
Copper and Molybdneum
 Do not apply molybdenum unnecessarily
 Liming soils increases the availability of molybdenum but can induce a copper
deficiency if levels are marginal
 Do not allow sheep to graze pasture once molybdenum is applied until after a
heavy rain
 If diagnostic tests of liver and plasma indicate low copper status as do pasture
mineral tests and the deficiency is simple then application of copper to the soil may
be the most cheap and effective way of correcting the deficiency as copper is not
readily leached from the soil and may persist for more than 20 years.
Page  36
Copper
 Genetic difference in copper metabolism between breeds of and within breeds.
 Needed for maintenance, growth, production and reproduction.
 To maintain adequate levels of copper in tissues the animal needs a constant
supply to keep replacing what is lost in urine, faeces and skin.
 Animals that are growing muscle or bone or are producing wool, milk or offspring
require higher amounts of copper.
Page  37
Copper
 Calcium, Phosphorus and Magnesium concentrations in bone are increased with
adequate copper supplementation.
 The availability of copper in pasture varies with the season and copper is less
available in lush green feed in winter and spring than dry feed. This is due to lush
green feed also being high in sulphur and molybdenum.
Page  38
Copper Signs
 Copper in cattle is associated with a fading coat colour and development of thin
sparse dry hair (yellow herefords and bronze tinged black cattle). Facial hair around
the ears and eyes is the first affected.
 Signs of copper deficiency is loss of pigment in black wool, followed by loss of crimp
(steely wool) in sheep.
 Swayback occurs in lambs from ewes with a low copper status (irreversible once
symptoms have occurred).
 Decreased growth rates, illthrift and fragility of the long bones.
 Diarrhoea and anaemia
 Infertility
Page  39
Copper Supplementation
 Drenching with copper sulphate is not recommended as it is ineffectively dispensed
in the rumen and the risk of toxicity is high. Lasts a couple of months.
• Injections – last about 6 months
• Bullets – last about 6 to 12 months
• Copper sulphate in licks and drinking water – can’t control dose rates and
consumption
Page  40
Copper Toxicity
 Sheep are very susceptible to copper toxicity and should only be given copper if
there is a know deficiency issue.
 Long term ingestion of heliotrope or salvation jane contain alkaloids that have been
associated with chronic copper toxicity. Damage to the liver from the alkaloids
increases the tendency for copper to accumulate in the liver.
 Animals grazing subterranean clover dominate pastures long term may also be
susceptible to copper toxicity due to the high level of available copper in sub
clover.
 In both of the scenarios above the accumulation copper concentration in the liver
and kidney results in jaundice and death.
Page  41
Selenium
 Widespread on Acid Soils - higher rainfall >500mm including
podzols, sand over clay, deep sands and lighter red gum soils.
 Some interaction with high S, high Fe or waterlogging
 Overlap with Vit E
 Mostly sheep issue
 Sodium selenite can also be applied to pasture in superphosphate
at a rate of 10g/hectare which can be effective for up to 2 years.
Selenium
 Selenium is essential for animals but not plants
 Lowest levels of selenium are found during spring and summer and there is variation
between years
 Generally seen as ill thrift
 Selenium deficiency will depress live weight and wool growth and in extreme cases
death.
 Selenium deficiency will cause infertility in females due to embryo loss at the time of
implantation
 Retained membranes in cows
Page  43
Selenium
 Deficiency of selenium results in white muscle disease.
 Other factors include stress, unaccustomed exercise, unsaturated fatty acids in
clover pastures and vitamin E deficiency due to young animals grazing oat stubbles
or dry pasture.
 White muscle disease affects lambs up until the age of weaning and calves up to
three to four months of age.
 Lesions may develop on the skeletal and/or heart muscle resulting in respiratory
issues or death
 Affected animals walk with a stiff legged gait and are unable to stand.
Page  44
Selenium
 Selenium has a role in resistance to disease and antibody production
 Selenium is transferred to the foetus across the placenta and females require
selenium to be supplied adequately in their diet to transfer it to milk.
 An animal has its highest requirement for selenium during conception and
pregnancy.
 The requirements for selenium are influenced by breed, stocking rate, climatic
conditions and the amount of Vitamin E and Sulfur in the diet.
Page  45
Selenium Supplementation
 Testing for selenium is based on the selenium containing enzyme glutathione
peroxidase (GSHPx) in blood and liver.
 Determine a deficiency before supplementation as selenium is toxic in excess
 Supplementation can be oral via with sodium selenate/selenite or through drenches
and vaccines.
 Injection or drenching with selenium needs to be repeated every 6-10 weeks.
 Intraruminal pellets cannot be given prior to weaning but are effective if given to
females and the selenium is transferred in milk. If pellets are given it is essential to
administer a grinder or second pellet to ensure the pellet is releasing selenium.
Problems can still occur with the development of encrustations
Page  46
Diagnostic Aids – Soil Testing
 Soil testing has limited diagnostic value for livestock nutritional issues apart from
grass tetany.
 However, pH and major nutrients value are important to know
 Plant and soil tests will often differ as a leaf analysis reflects the nutrients in the plant
when sampled while soil test shows the amount of nutrient stored in the more
available forms in the soil.
 Soil tests should be used to determine a cost effective fertiliser program in
conjunction with a leaf test
 Trends in soil test values over time are the best indication of farm nutrient status
Page  47
EDTA Cu Soil test variation
Diagnostic Aids – Plant Tests
 Useful too for indicating plant health and the availability of nutrients to the plant and
animal
 Be careful not to contaminate pasture samples with soil as they can lead to
unusually high levels of some trace elements
 Leaf tissue test gives a snapshot of the plant nutrient status at the time of testing
 Leaf analysis only reflects the nutrients available to the leaves and those which the
soil balance allows the plant to extract
 Leaf tissues tests should be used to correct plant deficiencies through foliar sprays
(bypass soil imbalances)
Page  49
Diagnostic Aids – Plant Tests
 Selective grazing by animals can influence the accuracy to which this test can
determine if animal dietary needs are being met
 Intensive grazing regimes may be more reflective
 Plant tests give an indication for grass tetany, Copper, limited value for Se and
Cobalt
Page  50
Diagnostic Aids – Animal Tests
 Animal tissues are a better guide to diagnosing mineral deficiencies compared to
blood plasma (Liver biopsy or bone samples)
 Must consider results with case history and clinical signs
 History should take in time of year and seasonal conditions
 Test animals to analyse the effectiveness of your supplementation
program/management strategies before you have an issue
 Deficiencies can be more prevalent during different times of the year e.g.
copper/cobalt during winter/spring
 Most effective method of determining marginal deficiencies
Page  51
Other Animal Tests
 Urine testing is unreliable due to changes in the amount of water excreted
 Hair and wool samples are useful in determining a copper deficiency but as a
general rule factors such as colour, breed, body location, season and surface
contamination affect the accuracy as an indicator of body mineral stores
 Faecal testing for phosphorus deficiency has been used but varies with location and
season
 Milk can be used for accurate assessment of Iodine, selenium and vitamin B12
reserves.
Page  52
Water and Feed Tests
 Underground water is variable in quality and significant quantities of sodium,
calcium and magnesium salts can be consumed
 Water troughs can contain significantly higher concentrations of salt sue to
evaporation
 During cooler weather and when moisture levels are high in pasture water has less
impact on overall mineral consumption
 In intensive situations it is important to test hay and grain for mineral levels. Trace
element content can be significantly affected by the location the crop was grown.
Page  53
Do You Have
Any Questions?
Page  54