L12: Mineral Nutrition II Flashcards
*Describe the physiological functions of phosphorous
- more known functions than any other mineral
- [] n bone
- essential for:
- bone development
- nucleic acids, phospholipids, phosphoproteins
- energy metabolsim (ATP, ADP, AMP)
- buffers
*List good dietary sources of of phosphorous
- Milk
- cereal grains
- depends on state, determines if absorbable
- often present as phytates which req. phytases
- animal products containing bone
- hays and straws LOW
*Describe the symptoms arising from a dietary deficiency of phosphorous
- Similar bone disorders to Ca def
- lameness, bone or wood chewing
- low fertility
- poor growth
_*Describe the physiological functions of Magnesium_
- Enzyme activator
- Control nerve impulses
- absorbed from reticulorumen by active transport
- absorbed by lower 1/2 of SI by MNG
- Only 2% of total body Mg available
*List good dietary sources of Magnesium
- legums, esp. lucerne
- Wheat bran
- Mg blocks
- Magnesium oxide
- Mg sulfate or chloride in troughs
*Describe the symptoms arising from a dietary deficiency in Magnesium
(rapid onset symptoms)
- Hypomagnesia (grass tetany)
- Common in ruminants
- Results in:
- nervousness
- muscle tremors
- excessive sweating
- rapid breathing
- convulsions
- loss of appetite
*Describe how grass tetany (hypomagnesia) can develop in ruminants and discuss risk factors
Describe the 3 diff. kinds of grass tetany
- Rapid onset
- slow development
- low Mg levels, staggers
- subclinical
- reduced milk yields, irritability
_*Describe how grass tetany (hypomagnesia) can develop in ruminants and discuss risk factors_
What is the Mg [] for diagnosis of grass tetany in…
cattle?
sheep?
horses?
- cattle below 0.5mmol/L
- sheep 0.2mmol/L
- horses ~4mmol/L
_*Describe how grass tetany (hypomagnesia) can develop in ruminants and discuss risk factors_
How is grass tetany treated?
- IV or SC Mg
- Diet rectification
- horses and cattle maintenance ~2g/kg diet
- sheep <1g/day
_*Describe how grass tetany (hypomagnesia) can develop in ruminants and discuss risk factors_
discuss risk factors (Mg availability)
- Low content in feed
- spring pastures
- grasses lower than legumes
- Av. lower in pastures than conserved feeds
- dry processing increases bioav. of Mg
- Potassium content of pastures
- low k reduces plant uptake of Mg
- reduces Mg absorption in rumen
- Na req. for Mg absorption (3g/kgDM)
- Genetics
- High Rumen Digestible Nitrogen in plants
- precipitate Mg out
_*Describe how grass tetany (hypomagnesia) can develop in ruminants and discuss risk factors_
How can you prevent grass tetanty from occuring?
- Include Mg supplements
- Mg bullets
- Daily oral dose in milkers
- Mg licks
- MgCl in water
- pasture top dressing
- Mg rich plants (chicory, plantain)
- Reduce K fertiliser
- Na licks
*What is Sodium (Na) needed for?
*What is Chlorine (Cl) needed for?
NaCl (salt)
- Sodium
- body fluid reg
- acid-base balance
- muscle/nerve activity (conducting of impulses)
- Most feeds are low in Na and Cl
- Chlorine
- acid-base rel.
- osmotic reg
- gastric secretion
- def. can cause alkalosis
*What is Potassium needed for?
Good dietary sources?
Symptoms of deficiency?
- Needed for:
- osmotic reg and acid-base bal.
- muscle/nerve function
- CHO metabolism
- Dietary sources:
- grains low
- forages high
- Deficiency symptoms:
- reduced appetite
- reduced growth
- lethargy
*What is Sulfur needed for?
- amino acids
- Biotin and thiamin (VB complexes)
- Insulin (glucose reg)
- CoA
- Chondroitin sulfate (bones, cartilage, tendons, vessels)
- RUMEN MICROBES
- Unlikely to be deficient unless feeding high urea
