Downers cow syndrome
The Downer's cow, otherwise known as creepers, is commonly a fatal condition of dairy animal associated with the unsuccessful treatment of cases of milk fever and is clinically characterized by alertness, unable to get up and stand and recumbency ever after treatment with calcium and magnesium solution.
Etiology: The disease occurs as a complication of parturient paresis, if the treatment is delayed or due to under dosing with calcium solution. Due to prolonged recumbency, radial and peroneal nerves may be injured resulting in inability to get up. Difficult parturition associated with large foetus, and injury to sciatic and obturator nerves during parturition may result in this syndrome. Hypocalcaemia with hypophosphatemia result in prolonged recumbency which may block the blood supply and ischemic neuromuscular necrosis occurs. It is seen commonly in high-yielding animals and usually occurs 7-10 days after calving. Chronic hypomagnesaemia accompanied with hypocalcaemia may also cause the disease. Hypocalcaemia with hypophosphatemia is also attributed to cause this disease.
Pathogenesis: When animals remain in recumbency for longer period, the muscles of hindquarter reveal ischemic necrosis resulting in tissue anoxia, cell damage and inflammatory changes including edema. Due to edema, there is further pressure on the muscle cells and nerves are also affected. These recumbent animals may suffer from acute mastitis and traumatic injury of the limbs.
Clinical signs: T he disease is usually noticed after parturient paresis but occasionally, it can occur without hypocalcaemia. Such animals do not get up 24 h after calcium therapy. However, they remain bright and alert, and feed and water intake is slightly reduced. Body temperature and heart and pulse rates remain almost normal. In some cases after calcium therapy tachycardia is noticed. Passage of faeces and urine is also normal but urine has excess amount of protein. These animals remain in recumbent position and if lifted with support, they are unable to bear the weight on hind limbs and usually fall when support is withdrawn. When the animals are managed properly, they may get up in 4-5 days but if they are recumbent for 7-8 days, the prognosis of such cases is poor. When peroneal nerve is damaged, fetlock joints are flexed. The recumbent animals suffer from coliform mastitis or bed ulcers. Death of the animals usually occurs within 3-4 days of onset of symptoms as a result of intensive parenteral calcium therapy and developing myocarditis.
On postmortem examination, haemorrhages around the hip joint, ischemic necrosis of muscles, haemorrhages and edema of nerves of limbs, muscular damage and dilatation of heart are noticed.
Diagnosis: The animals which are not able to rise within 24 h after 2 injection of calcium are referred as downers. On urine analysis, presence of ketone bodies and protein is recorded while serum examination reveals higher activity of CPK and AST enzymes due to muscular damage.
Treatment: The cows which are dehydrated and have low water intake, can be given normal or dextrose saline @ 3-5 litre by intravenous route. The solutions containing potassium, calcium, magnesium and phosphorus may also be given intravenously for better response. Use of nervine tonics in the form of B1, B6 and B12 can be given @ 10 ml intramuscularly on alternate days for 6 days. The animals should be provided with soft comfortable bedding and should be turned frequently to avoid muscle damage and ischemic necrosis. Sand bedding under the animal is highly recommended as it keeps the floor dry and will be soft and comfortable. Calcium should not be given in excess amount in such cases. Use of corticosteroids, tonics, vitamin E and selenium were found beneficial, in some cases. Better managemental practices including provision of soft bedding and muscle massage are of great importance.