Minerals Flashcards by Oscar Gale

Concentration of major elements in animal tissues

(all in g/kg)
Calcium 15
Phosphorous 10
Potassium 2
Sodium 1.6
Chlorine 1.1
Sulphur 1.5
Magnesium 0.4

How well did you know this?

Not at all

Perfectly

Concentration of trace elements in animal tissues

(all in mg/kg)
Iron 20-60
Zinc 10-50
Copper 1-5
Molybdenum 1-4
Selenium 1-2
Iodine 0.3-0.6
Manganese 0.2-0.5
Cobalt <0.1

How well did you know this?

Not at all

Perfectly

Functions of calcium (Ca)

Structural component of skeleton (dynamic)
Controls cell excitability (nerve & muscle)
Regulates muscle contraction
Regulates blood coagulation
Many enzyme actions

Rigid homeostatic control of plasma calcium ion concentrations
- (Vitamin D & hormones)

How well did you know this?

Not at all

Perfectly

Sources of calcium (Ca)

Must take relative availability Ca:P into account
Ideally should be within the range 1:1 to 2:1

Foods which supply an Ca:P in an ideal ratio:
Leafy greens
Hay / silage
Animal products (milk, meat, eggs)

Some foods contain more P than Ca & require artificial ration balancing:
Bran
Cereals
Roots
Legume & oil seeds

Corrective sources of calcium :
Limestone flour
Poultry: soluble grit (e.g. limestone/oyster shell)

How well did you know this?

Not at all

Perfectly

Factors affecting absorption of calcium (Ca)

Much plant Ca is bound as phytates (prevents absorption in monogastrics but rumen microflora can release (phytases)

Oxalates: Bind Ca to form insoluble salts  bound in this form, calcium cannot be absorbed by animals
(Significant quantities in spinach, sugar beet tops etc)

Total absorption of dietary Ca & P decreases as dietary concentration becomes excessive

High fat diets  Excess dietary free fatty acids bind Ca (& Mg) to form insoluble soaps

Enteritis: Inflamed mucosa will not absorb Calcium

How well did you know this?

Not at all

Perfectly

Causes of acute deficiency of calcium (Ca)

HYPOCALCAEMIA
Occurs if sudden decrease in blood calcium (sometimes also Mg & P) concentrations  homeostatic control sluggish to correct

Female mammals at the onset or peak of lactation
-High demands of mammary gland for calcium to synthesise milk

Laying hens
- High calcium demands of eggshell production

How well did you know this?

Not at all

Perfectly

Details of deficiency of calcium (Ca) in dairy cattle

MILK FEVER
Commonly from 1 day before calving to 3 days post-partum
High demand for Ca for lactation
High-yielding cows in their third & subsequent lactations most susceptible
Slow homeostatic adaptation to increased Ca demand; mechanisms unable to prevent a sudden decrease in blood Ca levels

How well did you know this?

Not at all

Perfectly

Signs of deficiency of calcium (Ca) in dairy cattle

MILK FEVER
Flaccid paralysis (progressive)  general uneasiness, dullness, paddling/shifting of hind legs, dry muzzle, constipation, inability to stand, coma & death

Recumbency (‘Downer Cow’)

Rumen stasis

Pupil dilatation

How well did you know this?

Not at all

Perfectly

Signs of deficiency of calcium (Ca) in bitches, sows, and beef cattle

ECLAMPSIA (lactation tetany)

How well did you know this?

Not at all

Perfectly

General signs of chronic deficiency of calcium (Ca) in growing animals

HYPOCALCAEMIA
High rate of skeletal growth (↑Ca & P demand)
- beware of breeds / species with high growth rates

Osteodystrophy = abnormal bone growth
- Deficiencies of Ca, P, Vitamin D
- Nearly always accompanied by osteoporosis -> loss of Ca & P from bones making them thinner & weaker, increased incidence of fractures

Rickets = failure of bone to ossify
- Vitamin D deficiency (classically)
- In ruminants a deficiency of either Vitamin D or P can cause rickets

Treatment involves correcting Ca:P balance in diet

How well did you know this?

Not at all

Perfectly

Signs of chronic deficiency of calcium (Ca) in puppies and kittens

Excessive P (secondary Ca deficiency)

How well did you know this?

Not at all

Perfectly

Signs of chronic deficiency of calcium (Ca) in foals

Poor artificial rearing; gut parasites; low hay & high cereal diets (secondary deficiency)

How well did you know this?

Not at all

Perfectly

Signs of chronic deficiency of calcium (Ca) in calves and lambs

Unsupplemented high cereal / straw diet

How well did you know this?

Not at all

Perfectly

Signs of chronic deficiency of calcium (Ca) in piglets

Failure to supplement dietary Ca, P, vitamin D

How well did you know this?

Not at all

Perfectly

General signs of chronic deficiency of calcium (Ca) in growing animals

Except in late pregnancy & early lactation, skeletal Ca & P reserves are high and can be withdrawn upon if temporary imbalance

Mobilisation of skeletal Ca & P long term = osteomalacia
- Weakened, thin bones; easily fractured
- Increased incidence of osteoarthritis

Decreased milk yields

Urethral calculi in entire and castrated male lambs fed high concentrate diet

Horses, goats & pigs - demineralisation of bones of skull & compensatory collagen deposition causing thickening of the bones (‘bran disease’ - excessive P)

How well did you know this?

Not at all

Perfectly

Sources of phosphorous (P)

Must take relative availability Ca:P into account
Ideally should be within the range 1:1 to 2:1

Foods which supply an Ca:P in an ideal ratio:
Leafy greens
Hay / silage
Animal products (milk, meat, eggs)

Some foods contain more P than Ca & require artificial ration balancing:
Bran
Cereals
Roots
Legume & oil seeds

Function of phosphorous (P)

Same as Ca me thinks (might wannna check that)

Factors affecting absorption of phosphorous (P)

Oxalates & phytates  much plant P is organically bound as salts of phytic acid - in simple-stomached animals little of the phytate is available
Excess dietary Ca or P inhibit the absorption of P or Ca

General signs of deficiency of phosphorous (P)

HYPOPHOSPHATAEMIA
Abnormal bone growth & osteomalacia
Reduced growth rates
‘Pica’ (abnormal appetites) eg. bone/wood chewing
Infertility??

Functions of magnesium (Mg)

Closely associated with calcium & phosphorous

~70% total body magnesium is present in bone;
Most common enzyme activator
Muscle contraction
Propagation of nerve impulses

NB: There are no body reserves and no homeostatic regulation; it is dependant on dietary intake to maintain function

Sources of magnesium (Mg)

All green plants (chlorophyll)
Meat & bone
Colostrum
Magnesite & calcined magnesite

Absorption of magnesium (Mg)

20–30% of dietary Mg
Decreased by high copper & high phytate P intakes

Signs of deficiency of magnesium (Mg) in calves

HYPOMAGNESAEMIA
Calves fed (unsupplemented) all-milk diets (2 – 3 months)
- Milk is a poor source of Mg
- Mg absorption decreases with age

Signs of deficiency of magnesium (Mg) in beef cattle and sheep

HYPOMAGNESAEMIA
Beef cattle & sheep fed on low quality roughage (straw) or fodder crops (kale, beet)
- Symptoms may occur over several days
- Dullness, hyperaesthesia, convulsions, death

Signs of deficiency of magnesium (Mg) in lactating cattle and sheep

HYPOMAGNESAEMIA GRASS STAGGERS = EMERGENCY! Signs: Hyperaesthesia Recumbency Incoordination Convulsions Muscle tremor Death Frequent cause of SUDDEN DEATHS

Sub-clinical hypomagnesaemia

Possibly a cause of reduced fertility & milk production in dairy cattle

Predisposing factors for grass staggers:

Spring Rapid grass growth = Mg uptake by plant Grass diarrhoea = faster passage of digesta through the gut decreases Mg uptake Bad weather = grass intake reduced as cows shelter Fertilisers: Nitrogen fertilisers - ↑rumen NH3 which depresses Mg uptake Potassium fertilisers - ↑Mg excretion Liming – ↓ grass Mg concentration Autumn Gradual ↓ in grass Mg Year round Stresses which decrease food intake (eg. Bad weather/ dog worry)

Control or prevention of deficiency of magnesium (Mg)

Provide shelter Introduce to spring grass slowly Use fertilisers with care & avoid K fertiliser in spring Provide mineral (Mg) licks Top dress pastures (calcined magnesite) Increase clover in swards Supplement diet or water with Mg Mg rumen boluses AVOID STRESS!

Deficiency of ... is uncommon or rare

Sodium Potassium Chloride Sulphur

Functions of copper (Cu)

Important in formation of some plasma proteins (eg. ceruloplasmin) Component of other blood proteins & plays a role in oxygen metabolism Vital role in many enzyme systems, eg. component of cytochrome oxidase in oxidative phosphorylation Essential for normal hair, wool & feather pigmentation & crimp in wool Essential for immune function

Absorption of copper (Cu)

CuSO4 is the most readily absorbed copper salt Metallic copper is poorly absorbed

Transport & tissue use of copper (Cu)

Loosely bound to albumen in the plasma Stored & released from the LIVER to meet body requirements

General signs of deficiency of copper (Cu)

Anaemia (impaired RBC formation) Abnormal bone growth Abnormal hair, feather & wool growth Loss of hair pigmentation Cardiovascular disease Most common in sheep and cattle

Signs of deficiency of copper (Cu) in sheep

SWAYBACK Affects lambs born to Cu2+ deficient ewes Failure or degeneration of normal neural development in the lamb a) Congenital (from birth) Signs: Stillborn, weak  ataxia, paresis, unable to stand, death Irreversible b) Delayed onset (few weeks old) Signs: Normal at birth  depressed growth rate, rapid onset hind limb weakness, ataxia then paresis & death Can be prevented/reduced in Cu deficient lambs by parenteral injection of small doses of Cu complexes

Signs of deficiency of copper (Cu) in cattle

Common 3–9 months of age Especially in suckler calves, where the dam may not be Cu deficient Signs: - Failure to thrive - Poor growth - Stiff gait / lameness - Loss of hair pigment

Problems with copper and molybdenum

Certain pastures in England & Wales (‘teart’ pastures – high Mo) are known to cause scouring & unthriftiness in grazing cattle The molybdenum concentration in ‘teart’ pastures can be 10 to 50 fold greater than ‘normal’ Rumen microbes form sulphides which combine with Mo to form THIOMOLYBDATE Thiomolybdate binds copper to form COPPER THIOMOLYBDATE - decreases Cu absorption & causes signs of Cu deficiency, despite adequate dietary Cu provision

Signs of copper toxicity

Jaundice Appetite loss Hepatic coma & death

Cause of copper toxicity

Copper accumulates in liver, causing cell necrosis Tolerance: pigs > horses > cattle > sheep

Problems with copper toxicity in sheep

Marked differences in copper tolerance between breeds While sharing a common pasture, North Ronaldsay sheep may demonstrate copper toxicity while the Scottish blackface breed are copper deficient Liver [Cu] varies considerably between breeds Take care with copper treatments, especially in sheep