DIETARY STRATEGIES TO PREVENT MILK FEVER IN DAIRY CATTLE - PowerPoint PPT Presentation

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DIETARY STRATEGIES TO PREVENT MILK FEVER IN DAIRY CATTLE

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DIETARY STRATEGIES TO PREVENT MILK FEVER IN DAIRY CATTLE. MILK FEVER. Parturient paresis syndrome in dairy cattle. as caused by hypocalcemia. CALCIUM METABOLISM ... – PowerPoint PPT presentation

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Title: DIETARY STRATEGIES TO PREVENT MILK FEVER IN DAIRY CATTLE


1
DIETARY STRATEGIES TO PREVENT MILK FEVER IN DAIRY
CATTLE
2
MILK FEVER Parturient paresis syndrome in
dairy cattle as caused by hypocalcemia
3
CALCIUM METABOLISM
4
CLASSICAL DIETARY STRATEGY TO PREVENT MILK FEVER
  • Low calcium intake (20-25 g/day) during dry
    period
  • Normal calcium intake (80-100 g/day) around
    parturition and after that

5
Calcium absorption in dry cows when fed either
low or high Ca rations
Low Ca High Ca Ca intake 47.5
83.7 Ca absorption g/day 2.2
2.3 of intake 4.6 2.7
6
MODERN DIETARY STRATEGY TO PREVENT MILK FEVER
  • Feeding of ration with negative DCAD (- 50 mEq/kg
    DM) during dry period
  • Change to ration with normal DCAD (gt 200 mEq/kg
    DM) around parturition

7
ADVANTAGE OF MODERN VERSUS CLASSICAL STRATEGY
Ration with negative DCAD raises absolute
calcium absorption
8
DCAD Dietary Cation-Anion Difference DCAD
m Eq (Na K ) - (Cl - S 2-) / kg DM
9
Effect of a negative DCAD on the incidence of
milk fever
10
Influence of NH4Cl on urinary pH
NH4 Cl- NH3 H Cl-
H Cl-
ileum

H Cl-
Rumen
Urine
Liver urea
11
Influence of CaCl2 on urinary pH
Feces
Ca2 2 OH- Ca(OH)2
2 H20 2 OH- 2 H
Ca2 2 Cl-
GI-tract

H Cl- (Urine)
12
Urinary pH and Ca excretion in cows fed rations
with either a positive or negative DCAD
DCAD (mEq/kg DM)
276
-170
8.7
7.9
pH
6.1
Ca (g/day)
0.4
13
Hypothesis Ration with a negative DCAD
increases Ca-absorption
(Schonewille et al, 1994)
14
COMPOSITION OF EXPERIMENTAL RATIONS
15
CALCIUM BALANCE AND ABSORPTION
16
HYPOTHESIS The extra flow of Ca through the
body after feeding a ration with a negative DCAD,
can be used to maintain the plasma Ca
concentration at the onset of milk production
17
CALCIUM METABOLISM
18
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19
  • Experiment
  • Induction of hypocalcemia by Na2EDTA (0.9 mmol/h)
    infusion.
  • Infusions were finished when plasma Ca not bound
    to EDTA was about 1.0 mmol/l.
  • Measurement of urinary Ca excretion during EDTA
    infusions (catheter in bladder).
  • Concentrations of Ca in plasma and urine were
    measured colorimetrically in order to obtain the
    concentration of Ca not bound to EDTA
  • (Schonewille et al, 1999)

20
Urinary pH and Ca concentration before the
infusion of EDTA
DCAD (mEq / kg DM)
330
-230
pH
8.73
5.73
Ca (mM)
1.8
11.5
Plt0.05
21
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22
Urinary Ca excretion during EDTA infusion after
feeding a ration with a negative DCAD
23
Rations with a negative versus positive DCAD
- Increase Ca absorption and urinary Ca
excretion. - Increase of the Ca flow through the
body the extra urinary Ca excretion can be
reduced when plasma Ca is stressed.
24
Practical relevance - Assume production of
colostrum is 10 L. (2 g Ca/L.) - Extra urinary
Ca excretion after feeding ration with negative
DCAD is about 6 g Ca /day - The amount of extra
available Ca around parturition is sufficient to
support the production of about 3 L. of
colostrum.
25
  • CONCLUSIONS
  • The reduction of milk fever as induced by a
    negative DCAD, is explained by an increased
    absolute absorption of Ca and by immediate
    availability of the extra Ca flow through the
    body.
  • A negative DCAD can be achieved by the use of
    NH4Cl, CaCl2, MgCl2 an/or MgSO4.
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