Page 19 - Dairy Dimension - July Aug 25

| Volume 1 | Issue 5 | July-Agu 2025 ARTICLE | Volume 1 | Issue 5 | July-Agu 2025

enhances intestinal absorption of dietary calcium.

· Calcitonin: Secreted from the thyroid gland, calcitonin
counteracts PTH by inhibiting bone resorption during
calcium excess.
In the immediate postpartum period, the outflow of
calcium into milk can exceed 30–40 g/day, placing
immense stress on these homeostatic systems. The
speed and efficiency with which cows adapt determines
whether they remain normocalcemic or develop clinical
or subclinical hypocalcemia.
Factors influencing hypocalcemia risk include:

· Parity: Multiparous cows are at greater risk due to
Dr. Shipra Tiwari reduced bone resorption efficiency.

maintaining the productivity and welfare of high-yielding · Breed: Jersey cows are more susceptible compared
dairy herds. to Holsteins.
Introduction · Diet: High dietary cation-anion difference (DCAD)
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Calcium (Ca) is a vital macromineral involved in diets predispose cows to hypocalcemia, while
numerous physiological processes, including bone controlled prepartum calcium intake enhances
Calcium Homeostasis in formation, nerve conduction, muscle contraction, and · adaptation.
blood clotting. In dairy cows, calcium becomes especially
Genetics: Genetic predisposition to milk fever has
Post-Parturient Dairy Cows: critical during the periparturient period due to the been documented, with heritability estimates being
sudden onset of lactation. The abrupt increase in
low but significant.
calcium demand for colostrum and milk synthesis often Environmental Stressors: Heat stress, overcrowding,
Implications for Health, Productivity, exceeds the body's immediate capacity for mobilization · and poor transition cow management exacerbate the

and absorption, leading to hypocalcemia. risk.
and Metabolic Resilience Post-parturient hypocalcemia, commonly referred to as Globally, the prevalence of clinical hypocalcemia ranges

“milk fever,” has long been recognized as a disorder
by Dr. Pawar Rutik Namdev & Dr. Shipra Tiwari, MVSc. Scholar, Department of affecting high-yielding cows. However, recent research from 3% to 10%, while subclinical hypocalcemia may
Livestock Products Technology, College of Veterinary Science and Animal Husbandry, DUVASU Mathura affect up to 50% of multiparous cows in early lactation.
suggests that subclinical hypocalcemia—though not
visibly apparent—may be far more prevalent and equally Clinical and Subclinical Hypocalcemia:
Abstract detrimental. Its hidden impacts on feed intake, immune Differentiating Impacts
Calcium metabolism during the periparturient period function, and reproductive performance underscore the · Clinical Hypocalcemia (Milk Fever): Characterized
plays a crucial role in the health and productivity of dairy need for a deeper understanding of calcium dynamics to by recumbency, muscle weakness, cold extremities,
cows. The sudden surge in calcium demand for design effective preventive strategies. and potentially coma if left untreated. Immediate
colostrum and milk synthesis immediately after calving Physiology of Calcium Homeostasis intravenous calcium therapy is required.
often exceeds the body's homeostatic capacity, Calcium homeostasis in dairy cows is tightly regulated · Subclinical Hypocalcemia (SCH): Defined as blood
predisposing cows to both clinical and subclinical through a complex interplay of hormones and tissues. calcium <2.0 mmol/L without obvious clinical signs.
hypocalcemia. These disorders not only compromise The key regulatory mechanisms include: SCH leads to immunosuppression, reduced dry
animal health but also negatively impact fertility, milk matter intake, and increased risk of secondary
· Parathyroid Hormone (PTH): Secreted in response to
production, and overall farm profitability. This review
declining blood calcium, PTH stimulates bone disorders such as ketosis, displaced abomasum,
examines the physiological basis of calcium dynamics in resorption, enhances renal calcium reabsorption, and mastitis, and impaired fertility.
post-parturient dairy cows, assesses the consequences
increases synthesis of active vitamin D. While clinical cases are more visible, SCH imposes a far
Dr. Pawar Rutik Namdev of impaired regulation, and discusses practical strategies · 1,25-Dihydroxyvitamin D (Calcitriol): Produced in the greater hidden economic burden by reducing herd
for its prevention and management. A thorough kidneys under the influence of PTH, calcitriol productivity and longevity.
understanding of these mechanisms is essential for

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