Livestock Health & Soil Nutrition Seminar

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 • TOO MUCH: • aluminium • manganese • Iron • NOT ENOUGH: • magnesium • calcium • potassium • phosphorous • molybdenum • TOO MUCH: • sodium • Boron • NOT ENOUGH: • iron • zinc • manganese • copper • phosphorous

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 Introduction Page 4

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. Grass Tetany (Hypomagnesia) Page 5

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 Grass Tetany (Hypomagnesia) Page 6

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. Grass Tetany (Hypomagnesia) Page 7

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 Magnesium deficency Interactions Page 8

Predicting Grass Tetany Riskfrom 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 Riskfrom 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 1991Mean Results

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

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 Grass Tetany (Hypomagnesia) Page 18

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. Grass Tetany (Hypomagnesia) 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

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 Cobalt/Vitamin B12 Page 21

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 Cobalt/Vitamin B12 Page 22

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 Cobalt/Vitamin B12 Page 23

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. Cobalt/Vitamin B12 Page 24

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 Cobalt/Vitamin B12 Page 25

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 Phalaris Staggers Page 26

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 Phalaris Staggers Symptoms Page 27

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 Phalaris Staggers Page 28

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 Phalaris Staggers Page 29

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 Phalaris Staggers Prevention Page 30

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 Phalaris Toxicity/posioning is Different to Phalaris Staggers Page 31

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) Phalaris Toxicity/posioning is Different to Phalaris Staggers Page 32

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 Phalaris Toxicity/Posioning is Different to Phalaris Staggers 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)

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. Copper and Molybdneum Page 36

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. Copper Page 37

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. Copper Page 38

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 Copper Signs Page 39

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 Copper Supplementation Page 40

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. Copper Toxicity 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 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 Selenium Page 43

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. Selenium Page 44

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. Selenium Page 45

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 Selenium Supplementation Page 46

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 Diagnostic Aids – Soil Testing Page 47

EDTA Cu Soil test variation

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) Diagnostic Aids – Plant Tests Page 49

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 Diagnostic Aids – Plant Tests Page 50

Livestock Health & Soil Nutrition Seminar