production dx Flashcards by Rachel Sim

what is ionized Ca involved in?

muscle contraction
blood coagulation
enzyme activity 
neural excitability
hormone secretion

How well did you know this?

Not at all

Perfectly

what is the normal range for total blood Ca in an adult cow?

2.1 to 2.5mmol/L

How well did you know this?

Not at all

Perfectly

what total blood Ca range would be considered subclin hypoCa?

1.38-2.0mmol/L

How well did you know this?

Not at all

Perfectly

when does subclin hypoCa tend to occur?

periparturient period (50% of older cows)

How well did you know this?

Not at all

Perfectly

what are the followed risks of having subclin hypoCa?

ketosis 
DA
mastitis
metritis
fatty liver

How well did you know this?

Not at all

Perfectly

what are the impacts of subclin hypoCa?

decreased fertility, milk yield, immunity

How well did you know this?

Not at all

Perfectly

what results in a degree of hypoCa?

onset of lactation

How well did you know this?

Not at all

Perfectly

what is the total blood Ca for milk fever?

<1.4mmol/L (failure of Ca homeostasis)

How well did you know this?

Not at all

Perfectly

when does milk fever usually occur?

24h pre-partum or 72h pp

sometimes several wks pp

How well did you know this?

Not at all

Perfectly

what are the impacts of milk fever during calving?

dystocia
stillbirths
RFM
uterine prolapse

How well did you know this?

Not at all

Perfectly

what is milk fever?

clin hypoCa
availability of Ca rather than true def 
life threatening!
increases risk of other dx (met & infectious)
age
breed

How well did you know this?

Not at all

Perfectly

what is stage I milk fever CS?

excitability
nervous
weak
shift weight & shuffle HF

How well did you know this?

Not at all

Perfectly

what is stage II milk fever CS?

sternal recumbency
mod to severe depression
partial paralysis
lying down w head turned into flank

How well did you know this?

Not at all

Perfectly

what is stage III milk fever CS?

lateral recumbency
completely paralyzed
bloated
severe depression to coma

How well did you know this?

Not at all

Perfectly

what CS is present in all stages?

protrusion of tongue
thermoreg ability loss
cutaneous circulation depressed: cold extremities e.g. ears & dry muzzle
rumen stasis
increased HR
absent PLR

How well did you know this?

Not at all

Perfectly

tx for stage I milk fever?

oral Ca: CaCl 50g; Ca proprionate 75-125g; CaCl + CaSO4 fat coated bolus

SC 23% Ca soln: divided for at least 4-5 sites 75ml each; may be ineffective in dehydrated cows

How well did you know this?

Not at all

Perfectly

tx for stage II and III milk fever?

IV Ca (jugular vein) 
500ml of 23% Ca borogluconate (10g Ca)
400ml of 40% Ca borogluconate (12g Ca) 
slow admin - sudden increase in HR > arrhythmia > STOP! 
\+ 
oral Ca: once cow is alert & able to swallow +12h later
or
Sc Ca 
\+ 
palliative care

what are the early signs of tx responsiveness for stage II and III?

tremors
PLR
wet muzzle
eructation 
urination 
defaecation

prevention for hypoCa?

nutrition pre-calving:
low Ca diet at prepartum (<100g)
nutritional antagonists/binders of Ca (zeolite)
Vit D supplementation
assurance dietary magnesium supply (0.4%)
slight acidification of blood reducing ratio of strong cations (Na+/K+) to strong anions (Cl- + S^2-) to increase PTH activity (DCAD diet): monitor urine pH > can result in met acidosis
Ca supplementation @ calving
monitor Ca in blood (24-48h pp)

what management approach should be used to prevent hypoCa?

good management:
avoid stress
no overcrowding
no group movement
social factors
feed management (low K silage) 
etc.

what is hypoMg?

more common in beef, but also occur in dairy: risk factor for milk fever 
life threatening to cow (acute cases) 
sudden death (e.g. 4-8wks pp beef cattle - peracute cases)

what are the risk factors for hypoMg?

older cows (decreased ability to absorb dietary Mg)
rapid changes of diet: lush grass (moving fields), low fibre (straw can slow rumen transit), weather (rain leaching), diet restriction (inadequate supply/ration access)
high lvls of K/ammonia
low lvls of Na

how does hypoMg result in milk fever?

decreased secretion PTH (<1.4mg/dL)

decreased tissue sensitivity to PTH (<1.6mg/dL)

what is the normal lvl of mg in an adult cow?

plasma: 0.80-1.0mmol/L
CSF: approx. 1mmol/L

dietary Mg absorption
young calves - small intestine
adult - rumen: [Mg] in rumen fluid, Mg transport mechanism (Na vs K)

when should blood sampling be done for hypoMg?

10 cows w/i 12h pp - periparturient cow status 1st weeks of lactation: lactating cow's diet

what is hypoMg tetany?

<0.5mmol/L (plasma) | ataxia + tetanic muscle spasms + hyperexcitability + hyperesthesia

what lvl of Mg would result in seizures & convulsions?

<0.4mmol/L (CSF)

tx for seizures & convulsions from hypoMg?

IV Mg IV sedation (xylazine: 0.05mg/kg) IV MgSO4 20% (200-300ml) - slow admin: cardiotoxicity if have resp distress, excessive slowing/increase HR: STOP admin! or Mg & other macroelements IV + Mg SC IV sedation (pentobarbitone: 3mg/kg; xylazine: 0.05mg/kg) IV MgSO4 (30ml 25% soln) combine w Ca borogluconate (400ml 40% soln) - remaining 370ml SC (over at least 4 sites)

other tx for hypomg?

Mg SC: SC inj MgSO4 50% soln (200ml - at least 4 sites) | Mg enema: rectal infusion of Mg salts (MgCl up to 5 tbsp in 250ml warm water)

what should you check for if hypoMg relapses 12-24h after tx?

check dietary intake (40g) | offer concentrates, see risk factors

prevention for hypoMg?

``` K&Na content in diet molasses-based licks/buckets (Mg & Na) concentrates w Mg & Na water medicated w Mg salts intraruminal boluses containing Mg pastures dusted w calcined magnesite ensure adequate ration intakes! ```

causes of hypophos

``` inadequate dietary P supply (diet/soil) excessive P losses compartmental P shifts (dextrose/insulin) combi of several mechanisms: - increased milk ptdn - decline of DMI - increase glu & cortisol @ parturitiion - renal losses ```

what are normal levels of phosphate in an adult cow?

1.4-2.6mmol/L (serum)

what are norm lvls of phosphate in growing cattle?

1.9-2.6mmol/L (serum)

what lvl of phosphate = severe hypophos

<0.5mmol/L (serum)

when does acute hypophos occur in dairy cows?

ard parturition | early lactation

which animals tend to get chronic hypophos?

grazing animals in arid regions - low P soil content | fast growing calves: low P ration/milk

CS for acute hypophos?

muscle weakness recumbency IV haemolysis downer cow syndrome periparturient haemoglobinuria

CS for chronic hypophos

``` bone demineralisation impaired fertility anorexia pica (abnormal eating) poor growth/weight loss impaired milk pdtn ```

tx for hypophos (anorexic cattle)

oral supplementation: NaPO4 salts 150-270g, monoK phos, monoCa phos 200-400g

tx for hypophos (recumbent cattle)

``` slow IV inj: NaPO4 salts -Na glycerophosphate -can result in life-threatening hyperK + oral supp, ```

prevention for hypophos?

grazing animals: - fertilising soil w phosphorus - free access to high-phosphorous minerals - water supp