What is milk fever?

Milk fever, parturient paresis or hypocalcaemia is a metabolic disease primarily of dairy cows but it can affect suckler cows also. The condition usually occurs one or two days just prior to or just after calving. At this time a large amount of calcium is required for the production of colostrum and milk, with the calcium coming from the cow’s available ‘body pool’. Ten litres of colostrum draws out 20 -25g of calcium in a single milking, this is 10 times the available body pool. Demand outstrips supply and to cope, the cow must both release calcium from bone reserves, and increase absorption of the mineral from the gut. If this fails to happen efficiently blood calcium levels fall and clinical signs of milk fever become apparent.

Correct nutrition in the dry period can play an important part as an aid to the prevention of milk fever.

What symptoms will the cow show?

A loss of appetite may be the first sign. This is often difficult to detect as cows close to calving have a low dry matter intake. As the symptoms progress the cow may become unsteady when she walks with widespread muscular tremors. More often the cow is found in a recumbent position with her head tucked into her flank and her legs stuck out awkwardly. Her temperature is sub-normal; her muzzle dry and rumen activity is reduced.

What is sub-clinical milk fever?

Clinical milk fever still affects about 8% of dairy cows in UK at an estimated cost to the industry of £6000 per 100-cow herd. This figure does not take into account the losses associated with sub-clinical hypocalcaemia. Unnoticeably low blood calcium levels predispose dairy cows to a variety of other pre-parturient problems.

Hypocalcaemia has been implicated in cases of retained placenta, displaced abomasums, mastitis and ketosis. Even if you have never seen a clinical case of milk fever, sub-clinical hypocalcaemia could be losing you 50 – 100 litres of milk from the next lactation.

What goes wrong?

The processes of releasing calcium from the bone and increasing absorption from the gut are linked to the activity of parathyroid hormone (PTH). If blood calcium levels fall, PTH is produced to stimulate the release of calcium from bone stores. PTH also stimulates the cow’s kidneys to produce a second hormone (via Vitamin D) which stimulates calcium absorption from the intestine. It is now well known that the production of PTH is a magnesium dependant process, therefore a deficiency of magnesium may even prevent the production of PTH.

A further complicating factor is that the PTH dependent metabolic processes are depressed if the cow’s blood pH is slightly alkaline. A more efficient response can be achieved if blood pH is slightly acidic.

Blood pH is controlled by the balance between cations (sodium and potassium) and anions (chloride and sulphate). A balance favouring anions will increase the acidity of the blood.
It is therefore crucially important that any proprietary dry cow supplement should not only supply magnesium but also promote the correct dietary cation: anion balance.

How can you protect against milk fever?

Correct nutrition together with monitoring of cow condition over an 8 week dry period is the best aid to the prevention of milk fever. A diet high in calcium and potassium (grass or grass silage) can increase the incidence of milk fever by reducing the mobilisation of calcium from the skeleton. Magnesium supplementation should be available throughout the dry period to meet the needs of the PTH. A suggested dry cow feeding programme could be:

8 weeks to 4 weeks prior to calving

  • Grass/grass silage restricted
  • Straw ad-lib.
  • MPower Dry Cow Syrup
  • TUB DC

4 weeks prior to and up to calving

  • Production forage restricted
  • Straw ad-lib.
  • MPower Dry Cow Syrup
  • TUB DC
  • 2 kg production cake

Why MPower Dry Cow Syrup and TUB DC?

MPower Dry Cow Syrup is a specifically formulated liquid supplement for feeding throughout the dry period. One of the great advantages of a liquid supplement is the fact that magnesium can be supplied in a more available and palatable form. Magnesium, from magnesium chloride, as well as meeting the needs of the PTH also helps to keep the blood slightly acid, thus helping the PTH activation mechanism.

TUD DC not only supplies additional trace elements to meet the cow’s needs at this important time but will supply an additional source of phosphorus. Often, but not always, cases of milk fever occur with the cow showing a low level of both calcium and phosphorus in the blood. Where this occurs it is essential to supply a palatable source of phosphorus in an available form.

What else can I get from MPower?

MPower also contains Acetona, a product unique to the Denis Brinicombe Group. Acetona is a source of sugar that resists degradation in the rumen and passes directly into the blood to boost glucose levels. This means that the liver can produce more usable energy from body reserves for milk production. The effect is not only to improve the energy supply, but also to reduce the level of partly broken down body fats which cause problems such as ketosis around calving. Cows with ketosis never fully reach their potential peak lactation and with disrupted energy metabolism are difficult to get back into calf.