Iron injections as iron dextran are given by intramuscular or subcutaneous injections to piglets between one and seven days of age. This is to correct the development of iron deficiency that leads to anaemia. A dose level of 100-200mg per piglet is required. If sows or gilts become deficient in vitamin E and / or selenium during pregnancy, piglets are also born deficient. Under such circumstances the enzymes which metabolise the iron cannot function and the iron then becomes toxic.

Clinical signs

The piglet becomes acutely lame, a dark swelling occurs at the site of the injection (usually the thigh) and about 50% of the litter or more die within hours.

Diagnosis

The association between injections and symptoms is usually clear and the clinical signs are typical. The cut muscle surface where the iron has been injected loses all its structure and appears almost like wet fish muscle. This is due to necrosis (death) of the tissues.

Treatment

• The initial reaction often is to blame the iron. It is true that inferior quality iron dextrans (usually the cheap ones) are more likely to be associated with severe disease than better quality ones but the primary problem is selenium/vitamin E deficiency.
• As soon as the condition is recognised all the piglets that have had iron within the last two days should be injected with vitamin E/selenium according to the manufacturers recommendations.
• All females due to farrow within seven days should be injected with vitamin E/selenium.
• Sows within the last month of pregnancy should be injected with vitamin E, two weeks before farrowing.

Management control and prevention

• Excessive oxidation of fats in the sow feed is the most common cause of low vitamin E status. Oxidation results from poor storage of cereals or corn and particularly in situations where the bottoms of feeds bins are not cleaned out and moisture has gained access.
• As a precaution add an extra 150im/tonne of vitamin E to the sow feed for the next two months.
• Check the sources and storage facilities of all feed grains.