It can arise in one of three ways:

1. Loss of blood through haemorrhage. Typical examples would be gastric ulceration, trauma to the vulva or a ruptured liver.
2. Lack of haemoglobin due to dietary insufficiencies, particularly iron and copper.
3. Reduced numbers of red cells. These are produced in the bone marrow and any disease, infection or toxic state affecting it may result in anaemia.

Clinical signs

The pig is pale and becomes breathless on exertion. The mucous membranes of the eyes are pale. They can be compared to a normal pig if there is doubt about interpretation. Haemorrhage may be obvious to the exterior or it can occur through bleeding into the tissues or the gut. Warfarin poisoning can cause severe bleeding into the tissues.

Diagnosis

Anaemia can be diagnosed on clinical grounds and by examining a sample of blood. This is tested for the red cell volume and the haemoglobin levels. (Normal levels 9-15g/100ml), anaemia <8g/100ml). A stained blood smear will also confirm the shape and size of the red cells and whether there are any bacteria present. Specific cell types are involved in the different anaemias. Iron dextran toxicity associated with vitamin E deficiency may give rise to anaemia in piglets.

Treatment

• The intestine can absorb only small amounts of iron daily which may not be enough to reverse the anaemia quickly. Nevertheless iron and copper levels in the feed should be checked. It is also helpful to give an injection of iron dextran 300-500mg depending on the age of the pig.
• Specific treatment and prevention will depend on the cause. Refer to the specific conditions in the index.
• In severe cases electrolytes can be given either by injection or by mouth.