Parturient Paresis

Question 1

what is a “transition” cow?

Answer 1

when a cow is in late gestation and is preparing to calve and transitions from being a dry cow to a fresh cow

Question 2

when talking about hypocalcemia, what are the two main things that are responsible for the clinical signs we see?

Answer 2

• failure to mobilize calcium and to maintain normal calcium homeostasis
• failure to mobilize sufficient calcium to maintain serum calcium levels resulting in paresis

Question 3

when a cow becomes hypocalcemic, were is all the calcium going?

Answer 3

just before calving, calcium leaves the blood and is sequestered in the mammary gland for colostrum/milk formation

Question 4

list some things that hypocalcemia causes (physiologically) and WHY they happen

Answer 4

• paresis: need calcium for muscle contractions
• increase risk of mastitis: teat sphincter muscle contractility reduction, infection can get in
• predisposition to DA: rumen and abomasum motility is reduced
• increased risk for metritis: without calcium, immune cell function is impaired
• mobilization of body fat resulting in higher blood NEFAs
• increased risk for fatty liver: more NEFAs
• ## reduction in fertility

Question 5

briefly explain the hormone response to low calcium levels in the blood

Answer 5

PT gland detects low Ca, so it releases PTH, which tells the bones to resorb more calcium AND tells the kidneys to reabsorb Ca

vitamin D also increases GI absorption of Ca, and it also tells the bone to resorb more from bone

Question 6

name 3 risk factors for hypocalcemia

Answer 6

• being a fresh cow >3 lactation (usually a 5 year old cow or older, like old ladies with bad bones)
• Jerseys and Guernseys
• hypomagnesia–>interferes with PTH

Question 7

how prevalent is clinical vs subclinical hypocalcemia?

Answer 7

clinical: 2-8% in dairy cows within 48hrs of birthing
subclinical: 50% multiparous cows, and 25% primiparous cows

Question 8

who more commonly has subclinical hypocalcemia, heifers or cows?

Answer 8

heifers

Question 9

what are the stages and associated clinical signs of hypocalcemia?

Answer 9

STAGE 1: still standing and ambulatory, hypersensitivity and hyper excitability, mildly ataxic/wobbly

STAGE 2: can’t stand, sternal recumbency, S shape neck, cold temp/extremities, decreased PLR, tachycardia, weak pulses, anorectic, bloat

STAGE 3: loss of consciousness, in lateral recumbency, muscle flaccidity, severe bloat, aka SUPER BAD!!!

Question 10

how much calcium is bound to albumin?

Answer 10

about 50%

Question 11

how do you diagnose hypocalcemia? (list diagnostics)

Answer 11

total calcium test: less expensive, not as affected by sampling conditions

ionized/free calcium test: more accurate measurement of available calcium, more finicky, and the test can be affected by hydration status and albumin status, more expensive

cowside: ISTAT iCa–>great but tempermental machine OR Horbia Ca test–>pain to callibrate but is 100% sensitive!!!

Question 12

how should you treat stage 1 hypocalcemia?

Answer 12

oral calcium bolus, immediately after calving and then a 2nd bolus 12-14 hours later. This comes in pill form. ONLY for cows that are ABLE TO STAND

Question 13

why is an oral calcium bolus offered in pill form instead of liquid form?

Answer 13

liquid form is a risk of aspiration and pharyngeal irritation

Question 14

to prevent hypocalcemia in my herd, shouldn’t I just give every cow a calcium oral bolus?

Answer 14

NO! You shouldn’t give it to heifers and you shouldn’t give it to cows that don’t need it–>this can interfere with their ability to regulate calcium next time

Question 15

how should you treat stage 2 and 3 hypocalcemia?

Answer 15

500mls of calcium gluconate IV –>do NOT give to subclinical cows/cows with no clinical signs, we don’t want to mess with their PTH response

Oral calcium bolus–>do not give to cows that cannot stand or cannot swallow, do not give if cows do not respond to IV calcium

Question 16

why (in stage 1) do we give an additional dose of oral calcium 12-24 hours after the first dose?

Answer 16

because after the first dose there will be a relapse: the problem gets fixed and then PTH calms down, so calcium does back down again.

Question 17

how should I administer IV calcium?

Answer 17

SLOOOOOOWLY, over 10-12 minutes, otherwise you can stop the heart

DO NOT USE THE MILK VEIN

Question 18

can you give calcium borogluconate subcutaneously?

Answer 18

yes! it required adequate perfusion, just don’t give more than 75mls per site

**do not give a Ca product with glucose formulation, it will burn the skin

Question 19

what is the DCAD Diet and why is it used/how does it work?

Answer 19

it is a prevention method for hypocalcemia. The goal is to make the diet more acidic (essentially creating a metabolic acidosis) so that more calcium is available (diets high in alkalinity leads to clinical hypocalcemia). the cow will buffer the lower acidic state by mobilizing stored calcium from their bones

Question 20

what sorts of things are added to a diet to make it more acidic? (DCAD diet)

Answer 20

anions like S, Cl, S, P, AND anionic salts like Bio-Chlor and SoyChlor

OR you can decrease K+

Question 21

what is the recommended DCAD “levels” idk how to put this???

Answer 21

should be -100 to -200 mEq/kg

Question 22

what is the best way to monitor if your DCAD diet is working?

Answer 22

test the “close up cows” urine pH, it should be in the 6-6.5 range for holsteins and 5.5 to 6 for jerseys

Question 23

explain why you would feed a diet LOW in calcium to prevent hypocalcemia in your herd? How is this accomplished?

Answer 23

the idea is to stimulate PTH secretion–>prolonged exposure to PTH stimulates bone resorption and renal production. However, this is hard to accomplish! Best way is to use calcium binders so the cows do not absorb calcium (feed this diet only until they calve)

Question 24

explain why you would supplement vit D to prevent hypocalcemia in your herd? It this method often used?

Answer 24

it promotes absorption of Ca from the GI tract. This is very expensive, but some farms do it!! vit D supplement combined with DCAD decreases subclinical hypocalcemia!

Question 25

describe why hypophosphatemia can be common in transition cows

Answer 25

phosphate is required for fetal skeletal development in the last trimester of pregnancy. Phospahte also gets dumped into the milk/colostrum

Question 26

list some risk factors for hypophosphatemia in cows

Answer 26

• hypocalcemia–> PTH (in response to low calcium) interferes with the kidney and saliva and tells them to excrete it

Question 27

You have a fresh cow that is down, unable to get up, and has some flaccid muscles. You decide to initiate treatment and give calcium supplementation IV. After a few hours, there is no change. What are you thinking, and what do you want to do next?

Answer 27

I’m thinking she could have hypophosphatemia since she did not respond to the calcium treatment but clinical signs appeared to be hypocalcemia

I want to treat this cow with phosphate supplement!

Question 28

what are some ways in which you can treat hypophosphatemia?

Answer 28

• 6-23g monosodium phosphate dissolved into 1L of saline IV
• oral supplementation 50-500 g monosodium phosphate
• cal Mag Phos plus combination

Question 29

what are pros and cons of using “Cal Mag Phos” combo treatment?

Answer 29

if the cow is low in more than one deficiency it can treat them all at once, and it doesn’t “hurt” the cow to give any extras, BUT it might make the cow more prone to having issues in the future

Question 30

What are some clinical signs of hypokalemia in cows?

Answer 30

• flaccid paralysis
• recumbency
• S shaped neck
• cardiac arrhythmias/ventricular tachycardia

Question 31

list 3 causes of hypokalemia

Answer 31

• hypocalcemia
• chronic anorexia or GI stasis (not eating anything!)
• repeated administration of a drug called isoflupredone acetate, or “Predef” (not on market anymore)

Question 32

How do you treat hypokalemia?

Answer 32

Oral KCl 50g/100kg BW

Question 33

causes of hypomagnesemia?

Answer 33

an increase in ruminal pH OR high dietary K reduced rumen abroption of Mg

Question 34

risk factors of grass tetany/hypomagnesia?

Answer 34

lush pastures high in K and N, low in Mg and Na

inadequate Mg in forages

Bad weather

Question 35

how does grass tetany present? How can it be differentiated from hypocalcemia?

Answer 35

a MID lactation diary cow usually with hypocalcemia signs (downer cow, spasms, staggering, paddling, high HR, high RR, looks more like tetanus)

hypocalcemia would be right after calving

Question 36

best way to diagnose grass tetany?

Answer 36

vitreous humor samples after death, CSF, don’t use blood sample after death–>muscles rupture and release Mg to give false elevation

Question 37

grass tetany treatment?

Answer 37

magnesium IV, takes longer to bounce back and see resolution of signs

can also give oral epsom salts