Trace Minerals Flashcards
What are the trace minerals?
- Iron
- Copper
- Zinc
- Selenium
- Cobalt
- Molybdenum
- Iodine
- Manganese
What is the major function of iron in the body?
Haemoglobin production
How is iron stored in the body?
- Ferritin - spleen, liver, kidney and bone marrow
2. Haemosiderin
Where do animals get iron from?
Diet - green leafy material, especially leguminous plants.
Is milk a good or bad source of iron?
BAD
What causes iron deficiency?
- Insufficient iron intake
- Poor dietary intake - rare
- Decreased absorption, e.g. chronic blood loss - parasites
- Decreased iron transport - e.g. decreased Cu or protein levels
How does iron deficiency present?
Microcytic hypochromic anaemia
Is iron deficiency common in lambs and calves? Why?
No, as management practices rarely allows them to be raised on an unsupplemented milk diet
How is iron deficiency diagnosed?
- Microcytic hypochromic anaemia
2. Decreased serum iron concentration - <110-150ug/dl
How do we treat iron deficiency?
Give oral ferrous sulphate or parenteral iron dextran
What causes iron toxicity?
Prolonged oral administration of iron
Is iron toxicity common in farm animals?
No
How does iron toxicity affect the body?
By generating excess oxygen-based free radicals, contributing to oxidative stress in cells -> lipid peroxidation
What are the clinical signs of iron toxicity?
- Trembling and convulsions
- Vocalisation
- Bruxism
- GIT disturbances and colic
- Reduced growth
- Concurrent potassium deficiency
What is the function of copper?
- Haemoglobin function
- Oxygen metabolism
- Protein formation
- Metalloenzymes
- Growth and metabolism
Where is copper stored?
In the liver
Are copper levels high in milk?
No!
What causes copper deficiency?
- Copper deficient soils
2. Molybdenum toxicity
How does copper deficiency affect the body?
Microcytic, hypochromic anaemia
What are the clinical signs of copper deficiency?
- Anaemia
- Poor growth
- Bone disorders
- Scouring and GIT disorders
- Depigmentation of hair and wool
- Brain stem and spinal cord disorders
What is enzootic ataxia or swayback?
A disorder seen in lambs due to copper deficiency causing lesions on the brain stem and spinal cod, causing muscular incoordination
How is copper deficiency diagnosed?
Low serum copper - <0.7ug/ml
What causes copper toxicity?
- Over ingestion of copper containing products
2. Ingestion of plants causing copper retention, e.g. sub-terraneal clover
What animals are most likely to be affected by copper toxicity?
Sheep - used in anthelmintic drenches
How does copper toxicity affect the body?
Accumulates over a chronic period, causing necrosis of the liver cells and acute intravascular haemolysis
How much copper needs to be ingested daily for chronic toxicity?
3.5mg/kg
What are the clinical signs of copper toxicity?
- Severe gastroenteritis
- Abdominal pain
- Inappetence and anorexia
- Diarrhoea and dehydration
- Shock
- Anaemia
- Dark brown urine
What congenital lesions are seen in copper toxic ewes?
- Absence of limbs
- Brachygnathia
How do we diagnose copper toxicity?
- Elevated copper levels in the liver
- Elevated liver enzymes - AST, LDH, ALT
- Anaemia
How do we treat copper toxicity?
- Ammonium molydenate - 50-500mg (reduces absorption and increased excretion)
- Sodium sulphate - 0.3-1g
- 20% lysine
- Symptomatic
- Zinc - increases excretion
- Vitamin C - reduced oxidative chages
What is the function of zinc?
- Enzyme systems
- Cell replication and differentiation
- Production, secretion and storage of many hormones
- Immunity
- Electrolyte balance
What is the dietary recommendation of zinc?
23-63mg/kg DM
Where is zinc found?
Cereals and grains (concentrates)
What are the clinical signs of zinc deficiency?
- Inflammation of the nose and mouth
- Stiffness of joints
- Swollen feet
- Parakeratosis
- Reduced reproductive capacity
How do we diagnose zinc deficiency?
Serum zinc levels - <0.4ug/ml
How do we treat zinc deficiency?
2-5g of zinc sulphate to cattle
40mg of zinc sulphate to sheep
Is zinc toxicity common?
No - massive tolerance
What does zinc toxicity do?
Vascular and hepatic necrosis
What disease is caused by selenium deficiency?
White Muscle Disease
What is the function of selenium?
- Component of glutathione peroxidase
- Antioxidase
- Production of thyroid hormones
What causes selenium toxicity?
- Selenium-filled plants
2. Selenium injections (for white muscle disease)
How does selenium toxicity affect the body?
Acts in the opposite manner to the desired effect by inhibiting cellular function - replaces methionine & cystein
What cells are most susceptible to selenium toxicity?
Keratinocytes - destruction of forelimbs and claws
What is the preventative dose of selenium?
0.1-0.2mg/kg
What is the therapeutic dose of selenium?
0.3-0.4mg/kg
What is the lethal dose of selenium?
0.9mg/kg
What are the clinical signs of acute selenium toxicity?
Sudden death
- Severe GIT upset
- Ataxia
- Heart weakness
- Dyspnoea
- Frothing from nose and mouth
- MOF
What is blind staggers?
Sub-acute selenium toxicity
What are the clinical signs of blind staggers?
- Blindness
- Separation from herd
- Bumping into objects
- Forelimb weakness
- Laryngeal and tongue paralysis
- Respiratory failure
- Death
What is alkali disease?
Chronic selenium toxicity
What are the clinical signs of alkali disease?
- Destruction of the claws and hairs
- Lameness
- Laminitis
- Congenital malformations
How do we treat selenium toxicity?
No specific treatment
- Eliminate source
- High dietary protein, copper and arsenic salts
What are the functions of cobalt?
- Formation of haemoglobin
- Works with vitamin B12
- Enzyme production (thyroid)
- Wool growth
Which animals are more commonly affected by cobalt deficiency?
Sheep - due to use in wool
What clinical signs are seen in cobalt deficiency?
- Anorexia
- Poor growth and poor coat
- Conjunctivitis
- Muscle weakness
- Macrocytic normochronic anaemia
- Hepatic encephalopathy
Why does cobalt deficiency cause hepatic encephalopathy?
Causes the accumulation of methymalonic acid in the liver, which is converted to branched fatty acids, resulting in fatty liver degeneration
How is cobalt deficiency treated?
IM vitamin B12 for several weeks
What causes cobalt toxicity?
Cobalt overdose
What are the clinical signs of cobalt toxicity?
- Anorexia
- Diarrhoea
- Poor growth
- Dull dry skin and hair
- PU/PD
- Recumbency, ataxia, seizures
- Sudden death
How to treat cobalt toxicity?
Methionine PO
What is the function of molybdenum?
- Enzymatic processes
- Sulphate and copper metabolism
- DNA production
What happens during molybdenum deficiency?
- Breakdown of amino acid, toxins and drug metabolism
- Sulphate and copper toxicity
- DNA mutation
What are the clinical signs of molybdenum deficiency?
Severe liver dysfunction - icterus and hepatic encephalopathy
How do we treat molybdenum deficiency?
Molybdenum supplementation
What can cause molybdenum toxicity?
- Over-supplementation
- High legume diet
- Low sulphate or copper diet
What are the clinical signs of molybdenum toxicity in cattle?
- Poor growth
- Poor hair coat
- Hypopigmentation around eyes
- Unthriftiness
- Anaemia
- Emaciation
- Lameness
- Poor fertility
- Severe foamy diarrhoea
What are the clinical signs of molybdenum toxicity in sheep?
Enzootic ataxia
How do we treat molybdenum toxicity?
1% copper sulphate
What are the functions of iodine?
- Thyroid hormones - produces thyroxine
- Foetal development
- Immune response
What is the major sign of iodine deficiency?
Goitre - enlarged thyroid gland
What can cause iodine deficiency?
- Low soil content
2. Cabbage, legumes or thiouracil consumption - giotrogenic
What are the clinical signs of iodine deficiency in calves?
- Stillborn
- Die soon after birth
- Goitre
- Weakness
- Blindness
- Poor coat
- Retarded growth
- Apathy
- Alopecia
What are the clinical signs of iodine deficiency in adults?
- Retained placenta
- Stillbirth, miscarriage, abortion
- Infertility
- Irregular oestrous
- Decreased milk yield
How do we diagnose iodine deficiency?
T4 levels <20nmol/l in serum
How do we treat iodine deficiency?
Potassium iodine PO (intaruminal bolus - slow release)
How does iodine toxicity affect the body?
Suppresses thyroid activity
What are the functions of manganese?
- Reproduction
- Bone formation
- Choline metabolism
What causes manganese deficiency?
High calcium or phosphorous levels - suppress the ability to absorb manganese
What are the clinical signs of manganese deficiency?
- Impaired reproduction
- Skeletal deformations - rickets and contracted tendons
- Fat cow syndrome
How does manganese toxicity affect the body?
Interferes with the synthesis of ascorbic acid and absorption of dietary iron - iron deficiency anaemia
What are the clinical signs of manganese toxicity?
- Neurological
2. GIT
How do we treat manganese toxicity?
Dimercaprol chelation
