Identifying & Preventing Staggers in Cattle & Sheep

April 11, 2022

Staggers is caused by low blood concentration of magnesium and affects both sheep and cattle.  It is most commonly seen in adult lactating animals grazing lush, fast-growing grass pasture but we do see a number of cases in housed animals every year.  Magnesium isn’t stored in the body and therefore the main source is from food.  Absorption will vary with how quickly food passes through the digestive tract and there will be a higher demand during lactation. If feed intakes are reduced due to stress, illness or poor weather then this will also affect magnesium absorption.

Magnesium is important in normal neurological function. Clinical signs therefore include:

  • Sudden death
  • Initial excitability with high head carriage, twitching of muscles and incoordination.
  • Separation from the group. Animals may have startled expressions, exaggerated blink reflex and frequent tooth grinding.
  • Rapid progression to periods of seizure activity

Animals found with clinical signs require immediate treatment with subcutaneous Magniject whilst waiting for veterinary attention to administer a combination of calcium and magnesium slowly into the vein. Stress should be minimised during this time and unfortunately there is always a risk during treatment that the extra stress could kill the animal. If treatment is successful, animals should be offered concentrates and good forage to prevent relapse.

In cases of sudden death, we can confirm the diagnosis by measuring magnesium concentration in the fluid around the eye soon after death. Blood sampling a few other animals in the group can also be useful as the majority of the group may be affected without showing obvious clinical signs.

Factors influencing the availability of dietary magnesium include magnesium levels in the soil and grass which vary considerably.  High levels of potassium or ammonia on pasture inhibit magnesium absorption.  Lush pastures are low in fibre and increase the rate of passage of food material through the rumen reducing time for magnesium absorption.

In terms of prevention, options include:

  • Medicating the sole water supply with soluble magnesium salts such as chloride, sulphate or acetate. These salts aren’t very palatable so follow directions for use carefully.
  • Intra-ruminal boluses which give a reliable slow release of magnesium into the rumen over periods of high risk.
  • Magnesium buckets though these may not be used by all animals in a group and problems can still occur.
  • Supplementation is particularly important during stormy weather when roughage, such as straw, can be beneficial by slowing rumen throughput and allowing time for magnesium absorption.
  • Feeding concentrates containing magnesium will also help to provide sufficient amounts.

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