It is also known as puerperal haemoglobinuria or nutritional haemoglobinurea and results in intravascular haemolysis, haemoglobinuria and anaemia.
Etiology: The disease is caused owing to low phosphorus level in the diet and excessive ingestion of cruciferous plants. Mortality rates may be up to 40%. This disease is found more in crossbred cows than buffaloes. It occurs usually 2-4 weeks after calving. The high producing dairy animals in their third to sixth lactation are commonly affected.
Pathogenesis: Low phosphorus in diet causes hypophosphatemia. Lactation further reduces its level in blood. There is reduction in glycolysis and ATP synthesis in erythrocytes which increases fragility of RBCs and haemoglobinuria occurs. Copper and selenium also play role in the pathogenesis of this disease. Due to copper deficiency, there is deficiency of superoxide dismutase that helps in converting free radical oxygen into hydrogen peroxide and oxygen and thereby, cells are protected against the harmful effects of free radicals. However, in deficiency of this dismutase enzyme, radical oxygen is available which damage the cells and helps in production of the disease.
Clinical signs: Affected animals show signs of inappetance, weakness, reduction in milk yield and haemoglobinuria. The mucous membranes become pale and body temperature is normal initially followed by subnormal in later stage. They also suffer from dehydration and their faeces becoming dry and firm. Later on jaundice and depraved appetite develop along with dyspnoea and tachycardia. Such animals usually die within few days due to anaemic anoxia.
Diagnosis: The disease is diagnosed by symptoms and confirmed by urine examination which reveals presence of the haemoglobin. Blood analysis reveals low level of phosphorus and RBCs have heinz-bodies. The disease should be differentiated from leptospirosis which has acute fever, red coloured milk, and abortions; bacillary haemoglobinuria has acute fever, hemoglobinuria, dysentry and abdominal pain; babesiosis has history of ticks infestation, acute fever, abortions and blood smear positive for Babesia spp.; chronic copper poisoning has severe jaundice but no fever and anaplasmosis which does not reveal haemoglobinuria, high fever, has history of ticks and blood smear reveals positive result for parasite.
Treatment: In severe cases, transfusion of large amounts of whole blood @ 4-6 liters is recommended. For the replacement of phosphorus, 120 g sodium acid phosphate can be dissolved in 600 ml water and half of it is given by intravenous route, and half by subcutaneous route. Use of 125 g bone meal or dicalcium phosphate given twice daily by oral route is also highly effective. Besides, they should be given haematinic mixture containing copper, iron and cobalt salts by oral route. The animals kept in the areas suspected for having copper deficiency, should be given inorganic copper salts orally or organic copper preparations by parenteral route. The use of ascorbic acid has also been found beneficial for its treatment.