Which species does hypocalcaemia typically manifest in?
Cattle
When does hypocalcaemia manifest?
from a couple of days before calving to a week after calving
What causes hypocalcaemia?
a lack of availability of Ca rather than a deficiency
In cattle when is it considered to occur?
- total [Ca] plasma < 2.0mmol/L
- [Ca2+] plasma < 1.1mmol/L
On average how much circulating Ca do cows have?
about 3g
What is the requirement for Ca in 1kg/1L colostrum?
2.5g
What are the functions of Ca in the body?
- muscle contraction - skeletal & smooth (rumen, uterus, limbs)
- signal transmission between neurones & neuromusculular junction
What is the Ca requirement for milk per day in lactation?
about 70g/d of Ca
describe the aetiopathogenesis of hypocalcaemia
- decreased SM contractility
- decreased cardiac muscle contractility
- decreased skeletal muscle contractility
- decreased neurotransmission
- decreased apocrine gland function
what are the clinical signs of hypocalcaemia?
- muscular weakness
- decreased gut motility
- decreased thermoregulation (hypothermia)
- cardiovascular collapse
- death
- bloat
- dry faeces/constipation
what are associated conditions with hypocalcaemia at calving and after calving?
At calving:
- dystocia
- still births
- retained foetal membranes
- uterine prolapse
After calving:
- ketosis
- fatty cow syndrome
- hepatic lipidosis
- abomasal displacement
What are the implications on E balance?
- decreased ruminal and abomasal contractions, so less E intake
- interferes with insulin release, causing associated hyperglycaemia
how can hypocalcaemia cause osteodystrophy?
- if calcium intake is inadequate then it causes osteodystrophy
- mostly occurs in cattle on cereal or grass hays/straw with a low Ca content
- can be accompanied by vit D deficiency
what are the clinical signs of osteodystrophy?
- poor growth rates and inappetance
- thickening of metaphyseal regions of long bones
- dental pitting & gum deformity
- lameness
- recumbency
