Milk Fever (PDF) - Minster Vets

XLVets Fact Sheet 

Calving and 

Metabolic Disease 

CM 

Milk Fever 

The average milk yield for the UK national herd has increased 

by 30% over the last 25 years, and so the demands of lactation 

now make it extremely difficult for the dairy cow to maintain 

blood calcium concentrations around calving. Consequently, 

milk fever has become an important production disease, with 

an average annual incidence of 4-9% in the UK, and incidences 

of 60-70% not unknown. 

Incidences of milk fever tend to vary 

with age and breed. Jersey cows, 

for example, are more susceptible 

to milk fever. The reasons for the 

perceived increased risk Jerseys 

have to milk fever are unknown, but 

could be related to the fact that they 

usually become older than other 

breeds (Houe 2001). When other 

factors are controlled the difference 

between breeds is likely to be small 

(kusumanti et al.1993). 

The management and nutrition of the 

cow during the dry period can have a 

strong influence on the susceptibility 

of individual animals to the condition. 

The word ‘fever’ is a misnomer, as 

body temperature during the disease 

is usually below normal. 

CLINICAL SIGNS OF MILK FEVER 

The clinical signs of milk fever 

include: 

● Cows that are dull and lethargic 

● Ears are cold to the touch 

● Stiffness in the legs 

In severe cases: 

● The cow becomes recumbent 

● Has a kink in her neck 

● The rumen becomes static 

● Faeces tend to bulge in the rectum 

These well-recognised signs are due 

to the rapid decrease in calcium 

concentrations in the blood which 

occurs close to parturition. 

The basic reason for this hypocalcaemia 

is the inability of some cows 

to match their rapidly increasing 

requirements for calcium for milk 

secretion by absorbing sufficient 

calcium from their gut, or by mobilising 

calcium from their own skeleton. 

Milk fever depresses rumen 

contractility, and other disorders 

such as retained placenta, metritis, 

dystocia, displaced abomasums and 

ketosis are associated with it. 

Due to these periparturient disorders 

and the effect on the rumen, feed 

intake can drop and worsen the 

energy status of the already affected 

cow. This negative energy balance in 

the postpartum cow will have a strong 

influence on subsequent fertility. 

XLVets Committed to UK farming

XLVets Milk Fever 

Calving and 

Metabolic Disease 

CM 

PREVENTION OF MILK FEVER 

Conventional methods for the prevention of milk fever include: 

Method 1: 

Restriction of calcium in the 

prepartum period. 

This activates the calcium homeostatic 

mechanisms. This method is effective 

only if sufficiently low dietary calcium 

levels are fed (20g/day). However due 

to the fixed calcium concentrations of 

forages fed in the prepartum diet, 

manipulation of the diet to low enough 

calcium levels is not possible. 

Both zeolite and vegetable oils have 

been shown to reduce the absorption 

of Ca sufficiently (Wilson, 2003). 

However they may not be suitable 

for other reasons (amount required, 

effects on rumen microbes 

(Goff 2008)). 

Method 2: 

Magnesium supplementation at 

15 to 20g/day. 

This needs to be given with a 

source of easily digestible 

carbohydrates 

to encourage 

uptake. 

Method 3: 

Peripartum supplementation 

of susceptible animals with 

injectable or oral calcium. 

This is labour-intensive, time 

consuming and may even have 

negative effects as a large depot of 

calcium can switch off homeostatic 

pathways. This should not be used 

as a first line prevention. 

THE DIETARY CATION-ANION BALANCE 

It has been shown that prepartum 

dietary cation-anion balance (DCAB) 

is strongly correlated to the clinical 

incidence of milk fever. 

Reducing DCAB rather than the 

calcium content of the prepartum 

ration is now considered the method 

of choice for preventing milk fever. 

What is DCAB? 

DCAB is defined as: 

DCAB (mEq/Kg DM) = (sodium + 

potassium) + (chlorine + sulphur). 

The DCAB ration can be easily 

calculated if the percentage 

concentrations (in Dry Matter terms) 

of sodium, potassium, chlorine and 

sulphur ions are known. 

A negative DCAB ration causes mild 

metabolic acidosis, which increases 

the production of Vitamin D3. This has 

an effect through a series of hormones 

and pathways to cause an increased 

mobilisation of calcium from the bone 

and uptake from the intestines. 

Due to the induced metabolic 

acidosis, and a conservation 

of bicarbonate ions, the 

urine becomes more acidic, 

making urine pH monitoring a 

useful tool for assessing the effect of 

reducing DCAB. 

DCAB Rationing 

For a DCAB ration to be successful, close 

work with your vet and nutritionist is essential. 

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Grass silage analysis must be carried out. 

Urine pH monitoring has to be done on a 

regular basis and a sufficient period of time 

on the diet must occur, at least 3 weeks 

before calving. 

If cows are at grass during the dry period, 

then housing them 3 weeks prior to calving is 

preferable. 

If it is not possible to house 3 weeks prior to 

calving, then move them to a field which has 

not received potash and has sparse growth 

so as to encourage the buffer feed to be 

eaten. 

For further information contact your local XLVets practice: 

XLVets Committed to UK farming. Go to XLVets www.xlvets.co.uk 

Committed to UK farming. Go to www.xlvets.co.uk

Milk Fever (PDF) - Minster Vets

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