Milk Fever (dairy cows) Flashcards
What are the two main types of minerals needed in dairy cow nutrition?
Macro minerals (e.g., Ca, P, Mg) required in grams per day, and micro minerals (e.g., Fe, Cu, Zn) required in milligrams per day.
Name the four functions of minerals in dairy cows.
- Structural (bones and tissue),
- Physiological (acid-base balance, nerve impulses),
- Catalytic (enzymes, hormones),
- Regulatory (biochemical reactions).
Why is calcium important in dairy cows?
It supports nerve and muscle function, blood clotting, and hormonal balance, and is a primary component of bones.
What percentage of calcium in blood is free ionized, and what is its role?
50%; it is essential for muscle and nerve function.
How does the cow’s body regulate calcium levels?
Through parathyroid hormone (PTH), calcitonin, and vitamin D3, which adjust Ca mobilization, reabsorption, and absorption.
What is milk fever and when does it commonly occur?
Milk fever is a form of hypocalcemia that occurs when the demand for calcium for colostrum and milk exceeds the cow’s calcium supply, usually after calving.
Define subclinical and clinical hypocalcemia in terms of serum calcium levels.
Subclinical: 1.5-2.0 mmol/L;
Clinical: below 1.5 mmol/L post-calving.
How does a high pre-partum calcium diet affect milk fever risk?
It can reduce the cow’s ability to mobilize bone calcium post-calving, increasing the risk of milk fever.
What impact does low magnesium have on calcium metabolism?
Low magnesium impairs PTH release and vitamin D3 activation, reducing calcium mobilization and increasing milk fever risk.
How does potassium affect calcium mobilization and milk fever risk?
High potassium can lead to metabolic alkalosis, which impairs calcium mobilization from bones, raising milk fever risk.
What dietary strategy can help prevent hypocalcemia in dairy cows before calving?
A low-calcium diet before calving (60-80 g/day) to activate calcium mobilization systems.
What is an anionic diet, and how does it help prevent milk fever?
An anionic diet includes salts that acidify blood, enhancing calcium resorption from bones and improving absorption.
What is the ideal urine pH range indicating effective calcium mobilization in dairy cows?
6.2-6.8, which reflects a suitable acid-base balance for preventing hypocalcemia.
How is Dietary Cation-Anion Balance (DCAB) calculated, and why is it important?
DCAB = (Na + K) - (Cl + S); it helps control blood pH and promotes calcium mobilization.
What feeding practice can reduce milk fever risk using oral calcium supplementation?
Administering 50-125 g of calcium at calving and 24 hours later, with calcium propionate preferred for reduced irritation.
