Introduction

• The most common clinical disease of calcium regulation in cattle is hypocalcemia (also called milk fever or parturient paresis).
• The average annual incidence of milk fever in the UK is approximately 5%, but individual farms can have an incidence of 60-70% during certain periods of the year.
• The incidence of milk fever can vary widely from farm to farm, between certain periods of the year, between different ages and between different breeds of cow.
• However it should be possible to maintain the incidence of clinical hypocalcemia to below 5 cases per 100 calvings.
• Subclinical hypocalcaemia (defined as serum calcium levels below 2.0 mmol/l in the absence of clinical signs within 48 h of calving) is present in approximately 50% of lactation 3 + cows. Recent studies have linked subclinical hypocalcemia with potential harmful effects on cow health and productivity. 
• The estimated direct costs of a single, simple case of milk fever has been calculated to be £130.89 from lost productivity, treatment and labor costs. However, milk fever may result in uterine inertia, dystocia, uterine prolapse, retained fetal membranes and “downer cow” syndrome, as well as predisposing to the development of environmental mastitis. These indirect costs mean that the overall average costs of a case of milk fever rise to £420.63 when these indirect costs are taken into account.
• Calcium and phosphorous imbalances may also result in defects in bone function and metabolism.

Overview of calcium metabolism

Factors affecting calcium metabolism in the adult cow

Phosphorous metabolism

Signs of calcium and/or phosphorous imbalance or deficiency

Diagnosis of calcium and/or phosphorous deficiencies

Control of acute hypocalcemia via dietary manipulation in late pregnancy

Calcium and phosphorous supplementation of the diet (non-pregnancy)

Calcium and phosphorous toxicity

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• Goff J P (2014) Calcium and magnesium disorders. Vet Clin North Am Food Anim Pract 30 (2), 359-381 PubMed.
• Grünberg W (2014) Treatment of phosphorus balance disorders. Vet Clin North Am Food Anim Pract 30 (2), 383-408 PubMed.
• Reinhardt T A, Lippolis J D, McCluskey B J, Goff J P & Horst R L (2011) Prevalence of subclinical hypocalcemia in dairy herds. Vet J 188 (1), 122-124 PubMed.
• DeGaris P J & Lean I J (2008) Milk fever in dairy cows: A review of pathophysiology and control principles. Vet J 176 (1), 58-69 PubMed.
• Husband  J (2005) Strategies for the control of milk fever. In Pract 27, 88-92 PubMed.
• Davies I H (2000) Skeletal and other disorders associated with inadequate dietary mineral and vitamin supplementation in growing cattle. Cattle Pract 8 (2), 139-143.
• Neves RC, Leno BM, Bach KD, McArt JAA. (2018) Epidemiology of subclinical hypocalcemia in early-lactation Holstein dairy cows: The temporal associations of plasma calcium concentration in the first 4 days in milk with disease and milk production J Dairy Sci. 101(10):9321-9331 PubMed.
• Kerwin AL, Ryan CM, Leno BM, Jakobsen M, Theilgaard P, Barbano DM, Overton TR (2019). Effects of feeding synthetic zeolite A during the prepartum period on serum mineral concentration, oxidant status, and performance of multiparous Holstein cows. J Dairy Sci. 102(6):5191-5207 PubMed
• Domino AR, Korzec HC, McArt JAA (2017) Field trial of 2 calcium supplements on early lactation health and production in multiparous Holstein cows. J Dairy Sci.100(12):9681-9690 PubMed.
• Thilsing-Hansen et al (2002) Milk Fever Control Principles: A Review Acta Vet Scan 43(1) 1-19 PubMed

Other sources of information

• Macrae A I & Esslemont R J (2015) The Prevalence and Cost of Important Endemic Diseases and Fertility in Dairy Herds in the UK. In: Bovine Medicine. 3rd edn. Ed: Cockcroft P D. Wiley-Blackwell, UK. pp 325-337.
• Suttle N (2010) Phosphorous. In: Mineral Nutrition of Livestock. 4th edn. Ed: Suttle N. CABI, UK. pp 122-167.
• Suttle N (2010) Calcium. In: Mineral Nutrition of Livestock. 4th edn. Ed: Suttle N. CABI, UK. pp 54-91.
• SRUC (2022) Rickets in heifers grazing fodder beet Vet Rec Vol 190 (10) p408