Mineral disorders-adult animals postpartum Flashcards

1
Q

When approaching a downer cow, what are the 5 M differentials?

A
  1. mastitis
  2. metritis
  3. metabolic
  4. musculoskeletal
  5. miscellaneous
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2
Q

What is the cause of hypocalcemisa in cattle?

A

decreased blood ionized calcium concentration (biologically active fraction is ionized calcium)

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3
Q

What are the clinical signs of severe hypocalcemia (periparturient hypocalcemia/paresis)

A

milk fever

5% dairy cows/year

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4
Q

What are the clinical signs of subclinical hypocalcemia?

A
  1. decreased feed intake (poor rumen/intestinal motility), poor productivity
  2. increased susceptibility to other diseases like DA
  3. up to 50% in older cows
  4. channel island breeds more susceptible
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5
Q

Why do we worry about hypocalcemia?

A

Clinical case=334$ (2%, 150 cow, 1 002/yr)

subclinical case=$220 (30% incidence, 150 cow, 10 000/yr)

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6
Q

What are is the pathophysiology of hypocalcemia?

A
  1. 99% Ca stored as hydroxyapatite
  2. blood calcium 2.-2.5mmol/L (ionized calcium bbound to albumin)
  3. lowest levels 12-24hr post partum
  4. parathyroid hormone increases bone mobilization,!!!! (and renal tubular reabsorption)
  5. 1, 25-dihydroxyvitamin D: generated in response to PTH, increases Ca dietary absorption
  6. Hypocalcemia occurs when Ca loss to milk > bone mobilization
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7
Q

What are the factors involved in predisposing to hypocalcemia?

A
  1. metabolic alkalosis
  2. hypomagnesmia
    3
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8
Q

How does metabolic alkalosis predispose to hypocalcemia?

A

1 more cations than anions

  1. decreaseed PTH receptor senstiivity to PTH (receptor changes conformation at higher pH)
  2. decreased ionized calcium
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9
Q

How does hypomagnesemia predispose to hypocalcemia?

A
  1. decreased PTH secretion

2. decreased tissue PTH sensitivity (Mg is a cofactor of the receptor)

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10
Q

What factors in small ruminants predisposes to hypocalcemia?

A
  1. forced exercise
  2. long distance transport
  3. food deprivation
  4. oxalate toxicosis
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11
Q

What are the stages of hypocalcemia?

A

stage 1
stage 2
stage 3

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12
Q

What are the features of stage 1 of hypocalcemia?

A
  1. animal standing
  2. brief episodes of excitement and tetany
  3. hypersentivity and muscle tremor
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13
Q

What are the features of stage 2 of hypocalcemia?

A
  1. sternal recumbence
  2. depression
  3. cool extremities
  4. uterine prolapse
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14
Q

What are the features of stage 3 hypocalcemia?

A
  1. lateral recumbency
  2. comatose
  3. complete flaccidity (flaccid paresis)
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15
Q

What are lab findings of hypocalcemia?

A

low seum total Ca

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16
Q

What is the treatment for hypocalcemi?

A
  1. intravenous calcium gluconate
    -only to recumbent cows
    1g/45kg body weight as a rule of tumb
    500ml bottle contains 8-11g Ca
    Ca is cardiotoxic–administer slowly
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17
Q

Why should you be careful with Ca administration

A

cardiotoxic, dysrythmia–monitor heart rate if dysrhythmias occur, admin rate should be decreased and atropine considered

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18
Q

Why do animals become hypocalcemic after Ca therapy IV?

A

because calcitonin increases and then animal becomes hypocalcemic again

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19
Q

What should be done to prevent animals becoming hypocalcemic after initial Ca therapy?

A
  1. oral calcium supplementation for cows that are still standing or that have just been treated IV
    calcium proprionate more acidic, works better than calcium chloride?
  2. subQ can be good (but not put in multiple sites! slower absorption if put in one site
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20
Q

How is hypocalcemia prevented?

A
  1. dietary cation-anion difference (DCAD)

2. oral calcium at calving

21
Q

What are the features of diatry anion-cation difference?

A

The general principle is decrease absorbable cations and/or increase absorbable anions in ration
compensated metabolic acidosis–increase affinity of PTH for receptor
cations: Na, K, Ca, Mg
Anions: Cl, SO4, PO4
Organic acids rapidly metablizee
DCAD=(Na + K + Ca + Mg) - (Cl + SO4 + PO4)
Aim for negative DCAD

22
Q

How do you practically applicate DCAD?

A
  1. treat K and CL as the variables
  2. keep K close to NRC requirement if possible 8.5g/kg
  3. add Cl to 5g/kg less than K levels
  4. evaluate urine pH after 3-4 days (holsteins 6.2-6.8), (channel islands 5.8-6.3)
  5. add chloride as needed to reduce urine pH (ensure palatability HCl most palatable)–
23
Q

What are issues with changing Na, P or S in diet?

A

Na: udder edema
P-blocks renal 1,25-OH vit D
S-neurologic signs

24
Q

Why doesn’t everyone use a DCAD diet?

A

get 11.5% drop in dry matter intake
works if excellent management, intakes monitored, urine pH of transition cows monitored
usually top 25% of herds will do?

25
Q

What can you do at calving to prevent hypocalcemia?

A
  1. calcium chloride: acidogenic so mobilizes Ca, 25-50g Ca needed, formulations in gel are less effective
  2. calcium propionate: non-acidogenic 75-125g Ca?????
  3. calcium carbonate: limestone, alkalinogenic, drives Ca down
  4. calcium boluses (not currently in canada)–steady Ca
26
Q

Is oral Ca economic if cows on low DCAD program?

A

no

27
Q

What doses of Ca (oral) can be cardiotoxic?

A

250g

28
Q

Why should you not give calcium to cows that have dystocia (potentially)

A

they do better without

29
Q

What are the features of feeding a Ca deficient diet?

A
  1. negative Ca balance increases PTH seccretion
  2. bone resoprtion and 1,25-OH vit D production
  3. works during metabolic aklaosis
  4. need high caclium diet post-partum
  5. can be difficult to reduce calcium levels enough (50%
30
Q

When do you see hypocalcium in ruminants?

A

just prepartum???

31
Q

What can cause cattle to become recumbent and convulsing?

A
  1. hypomagnesemia
  2. acute lead poisoning
  3. polioencehalomalacia
  4. rabies
  5. nervous ketosis
  6. BSE
32
Q

What does hypomagnesemia cause?

A

TETANIC PARALYSIS

motor end plates more sensitive than normal

33
Q

What is the role of Mg?

A
  1. neuromuscular junction
  2. Ach release
  3. motor end plate sensitivity
  4. cholinesterase system
34
Q

Which is more important for Mg concentrations, serum or CSF?

A

CSF

35
Q

Why can cows get hypomagnesmia?

A

Lots of Mg lost in saliva and not a lot reabsorbed, need to eat enough

36
Q

Where do you see impaired Mg absorption?

A
  1. Na: K ratio
37
Q

What is absoprtion of magnesium promoted by?

A

digestible carbohydrates

38
Q

What are risk factors for hypomagnesemia?

A
  1. lush spring pastures
  2. wheat pastures
  3. cattle outwintered on poor feed
  4. low DMI
  5. animal movement
  6. in small ruinants multiple birthds and prior preg toxemia
39
Q

What are the clinical findings of hypomagnesemia?

A
acute:
hyperesthesia
staggering convulsions
rapid death
subacute:
exaggerated movements
spasmotic urination
muscle tremor
chronic:
vague
40
Q

What are lab findings of hypomagnesemia?

A

hypomagnesemia in serum, urine, CSF
hypocalcemia
variable phosphate

41
Q

What is treatment for hypomagnesemia

A

DO NOT GIVE MgSO4 IV!!
can give epsom salts SQ
can give Cal plus IV
combined calcium and magnesium treatment

42
Q

How is hypomagnesemia prevented?

A
  1. nutritional supplementation
  2. magnesium bullets
  3. pasture treatment
  4. pasture management (restrict potash fertilizers in high risk periods)
43
Q

What are the features of hypophosphatemia/

A
  1. often in hypocalcemic cattle

2. some cows continue to have low P after Ca fixed

44
Q

Are phosphite and hypophosphite solutions effective for hypophosphatemia?

A

NO

they are inorganic phosphorus so don’t work (need phosphate)

45
Q

How do you treat hypophosphatemia?

A

oral monosodium phosphate preferred when rumen motility present
2. intrvenous sodium monophosphate, slow IV, NOT within 2hr of Ca (fleet enema in water????)

46
Q

What are the causes of chronic hypophosphatemia?

A

primary: dietary
secondary: high Ca, low vit D

47
Q

What are the clinical signs of hypophosphatemia?

A
decreased feed consumption
pica
weight loss
poor growth
poor milk production
reduced fertility
soft spongy bones
hemolysis with or without hemoglobinuria
48
Q

What is the treatment for hypophosphatemia?

A

correct diet, supportive care