Hypocalcemia

Hypocalcemia is the most important mineral disorder affecting transition dairy cows.¹ At the end of the dry period cows have to adapt their metabolism because with the onset of lactation they require a high amount of calcium to be released into the milk. In order to satisfy this sudden need for calcium cows may draw on two different sources: They can absorb calcium via the feed or mobilize their own calcium reserves (mainly from bones). But if they do not manage to balance their metabolism in time, the blood calcium level sinks below normal and they fall ill with hypocalcemia.

5-10% of the cows suffer from clinical signs each year.² Typical signs are muscle weakness, unsteadiness on feet, staggering, reluctance to move, lying down and inability to stand up, clouding of consciousness, coma and death.

But this is only the tip of the iceberg. Subclinical hypocalcemia is much more frequent. Most cows have some degree of hypocalcemia at calving.³ Up to 50% of second and greater lactation dairy cattle have low blood calcium concentrations (˂2.1mmol/l) around parturition without apparent clinical signs.^2,4 The prevalence of hypocalcemia increases with age and number of lactations.⁵

As calcium is essential for skeletal and smooth muscles to work properly, as well as for nerves and the immune system to function, low calcium levels have far reaching consequences. Hypocalcemia has a negative impact both on the health and the productivity of the cow. Cows with hypocalcemia are 8 times more likely to suffer from mastitis or ketosis, they have a much higher risk of LDA, retained placenta, dystocia, metritis and culling.² Hypocalcemia around calving is associated with reduced milk yield.^4,6 Subclinical hypocalcemia is approximately 4 times more costly than milk fever because it affects a much higher percentage of cows in the herd.⁴

For further information see www.bovikalc.com

References

1 Mulligan et al.: Production diseases of the transition cow: Milk fever and subclinical hypocalcaemia. Irish Vet. J. 2006 (59):697-702.
2 Houe et al.: Milk fever and subclinical hypocalcaemia. An evaluation of parameters on incidence risk, diagnosis, risk factors and biological effects as input for a decision support system for disease control. Acta vet scand. 2001 (42): 1-29.
3 DeGaris et al.: Milk fever in dairy cows: A review of pathophysiology and control principles. The Vet. J. 2009 (176):58-69.
4 Oetzel: Oral calcium supplementation in peripartum dairy cows. Vet Clin Food Anim 2013 (29):447-455.
5 Reinhardt et al.: Prevalence of subclinical hypocalcemia in dairy herds. The Vet. J. 2011 (188):122-124.
6 Chapinal et al.: The association of serum metabolites in the transition period with milk production and early-lactation reproductive performance. J. Dairy Sci. 2012 (95):1301-1309.