L12: Mineral Nutrition II Flashcards Preview

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Flashcards in L12: Mineral Nutrition II Deck (14)
1

*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

2

*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

3

*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

4

*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

5

*List good dietary sources of Magnesium

  • legums, esp. lucerne
  • Wheat bran
  • Mg blocks
  • Magnesium oxide
  • Mg sulfate or chloride in troughs

6

*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

7

*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

8

*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

9

*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

10

*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
     

11

*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

12

*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

13

*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

14

*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