Three Day Sickness
BEF is transmitted through mosquitoes and biting midges.
Infected cattle can show a wide spectrum of clinical signs. Clinical signs include a sudden onset of fever (temperature as high as 41-42?C) with loss of appetite and increased breathing and heart rate. Affected cattle often shiver and become very stiff and lame on all four legs. There may be severe constipation in some cases and diarrhoea in others, which is caused by reduced rumen function. Watery discharges from the eyes and the nose often occurs.
The first sign in dairy cattle is often a sudden and sharp drop in the milk production. In some cases, lactation may stop completely. The highest producing animals are usually most severely affected. In most of the cases, milk production returns to normal progressively with recovery but the level is always lower than pre-illness. Cows in late stage of pregnancy may abort.
The disease is more severe in adult cattle than in young animal; in fat animals than in lean animals, in heavy bulls than in light steers, in high lactating cattle than in dry cows. Bulls and fat cows loose condition rapidly and regain their body weight slowly after recovery. Calves are least affected, those less than 12 months of age usually show mild clinical signs and calves less than 3-6 months of age are not affected by the disease.
BEF has a short course of 3 days, a complete recovery occurs in 95-97% of the cases regardless of the severity of the clinical signs.
Treatments are usually effective if given in the early stage of the disease. The affected cattle should be rested during the acute phase of the disease. Symptomatic treatment with anti-inflammatory drugs has been found to be beneficial. Various antibiotics can be used if there is a suspicion of secondary bacterial infection.
Animals that have gone down should be provided with adequate shelter, water and food, as cattle exposed to hot weather are much more likely to die. They can be rolled over several times a day to maintain the blood circulation and avoid permanent muscle damage on the down side. It is important to get them back on their feet as soon as possible. Calcium injection can be given as it often helps to get recumbent cattle back on their feet.
BEF affects the swallowing reflex, therefore during the acute phase of illness; no medication should be given orally to avoid inhalation pneumonia.