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What are the costs of clinical and subclinical milk fever on my farm?

The costs associated with lost productivity and impaired animal health as a result of clinical and subclinical cases of milk fever (low blood calcium) are often much higher than expected – in this blog we’ll explain why these losses can be so high and how their effects can be mitigated.

11-02-2021, updated on 11-02-2021
milk fever

The transition from late pregnancy to lactation requires dairy cows to undergo enormous physiological changes: one of the most important changes involves the balance of calcium, with cows that are unable to maintain adequate blood calcium concentrations becoming susceptible to higher rates of early postpartum metabolic disorders and reduced milk production.
Cows that are affected by clinical milk fever (clinical hypocalcemia) are instantly identifiable: they will show clear signs of severe calcium deficiency including an inability to stand and a cold feel to the touch.

Despite a much higher incidence compared to clinical hypocalcemia, the effects of subclinical milk fever (subclinical hypocalcemia) are often severely underestimated: while an effected cow will be able to stand and function largely as normal, she will perform much less efficiently as a result of the underlying calcium deficiency and will be much more susceptible to diseases (see below for more information).

Incidence of clinical and subclinical milk fever

Research carried out in Germany (Venjakob et al. 2017) sampled blood from 1380 recently calved cows on 115 farms. The reported incidence of clinical hypocalcemia was found to be relatively low, at 0% in heifers up to 16.1% for cows with 4 or more lactations. Meanwhile, the incidence of subclinical hypocalcemia (blood calcium concentrations less than 2.1 mmol/L) in the same population of cows was much higher, ranging from 14% in heifers to 71% for cows with 4 or more lactations (Table 1).


Lactation 1

Lactation 2

Lactation 3

Lactation ≥ 4

Threshold 2.1 mmol/L 32/228a

Table 1. Prevalence (no./total; % in parentheses) of subclinical hypocalcemia 0 to 48 h after parturition in dairy cows stratified by parity. Source: Venjakob et al. 2017

a-d Different superscripts within rows differ, P < 0.05


Gate-way disease

Hypocalcemia is not only associated with reduced performance in terms of post-parturition milk production, but also as a gate-way to numerous subsequent dairy cow diseases and health disorders including mastitis, ketosis, dystocia, retained placenta, prolapsed uterus, metritis, udder edema, displaced abomasum and fatty liver (Horst et al., 1997. and Curtis et. al., 1985.)*.

Table 2. The estimated cost of key health disorders in dairy cows:

Metabolic Event

Estimated cost/incidence

Milk Fever¹ €312
Subclinical Hypocalcemia² €113
Displaced Abomasum³ €362-496
Ketosis³ €71-82
Retained Placenta³ €130-190
Metritis³ €157-166


The hidden thief

The lost revenue associated with subclinical hypocalcemia far exceeds that of clinical hypocalcemia. In a publication by Oetzel (2012), using data from a previous study (Oetzel, 2011) and the economic costs associated with clinical milk fever suggested by Guard (1996), estimated that the economic losses caused by subclinical hypocalcemia on a typical farm can be nearly four times greater than the losses associated with clinical milk fever.
This is primarily because the incidence rate of subclinical hypocalcemia is 10 times higher than the incidence rate of clinical hypocalcemia.

Table 3. The estimated economic impact of clinical and subclinical milk fever on a farm with 250 cows:


Estimated cost/ incidence

Average incidence

Cows affected per year

Total loss per year

Clinical milk fever

€312 6% 15 €4680

Subclinical milk fever

€113 60% 150 €16.950


Prevention is better than cure

The most effective way of mitigating the losses associated with milk fever is to prevent the onset of the condition in the first place: the addition of Animate (a concentrated and highly palatable anionic mineral product which helps to optimise calcium metabolism) to the dry cow ration can help to reduce the incidence of clinical hypocalcemia (milk fever) and subclinical hypocalcemia (low blood calcium). Its inclusion within the diet can also help to reduce the incidence of metabolic and non-metabolic disorders associated with hypocalcemia, thereby resulting in improved cow performance during the critical transition phase and greater subsequent milk yield.


Find out more

If you would like to find out more about Animate and how it can improve the health and performance of your freshly calved cows please contact us to request a free transition assessment with a Phibro expert who will work with you to discuss the following:

  1. Current situation analysis: we’ll assess your herd’s current status and identify areas for improvement.
  2. Design a milk fever prevention protocol: we’ll recommend where improvements can be made and how Animate can unlock your herd’s full potential.
  3. Evaluation: we’ll carry out a detailed review to make sure the changes we’ve put in place are working effectively and, where necessary, provide additional support and advice to enable your herd to continue to improve.


* Horst et al., 1997. JDS.80:1269-1280
* Curtis et. al., 1985. JDS.68:2347-360
¹Cost per case from veterinary fees, drugs, labor, lost or discarded milk and culling (C. Guard, et al., 1996)
²Non-infectious diseases: Milk fever in Encyclopedia of Dairy Sciences. Vol. 2. F.J. W. Fuquay, P.F., McSweeney, P.L.H., ed. Academic Press, San Diego Oetzel 2011. Lost milk yield and direct costs associated with ketosis and displaced abomasum’s
³Liang, Di, “Estimating the Economic Losses from Diseases and Extended Days Open with a Farm-Level Stochastic Model” (2013). Theses and
Dissertations--Animal and Food Sciences. Paper 22. http://uknowledge.uky. edu/animalsci_etds/22. First value is for first parity animals and second value is for mature cows.


Arnout Dekker
Arnout Dekker
Arnout Dekker is the Marketing Manager Europe of Phibro and has 7 years experience as a veterinarian. He is passionate about cows, dairy farm advisory and farm management. Helping farmers with advice and proven products to keep their cows healthy, produce better, be more profitable and sustainable is what drives and motivates him.

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