Weaning, drafting, drenching and shearing create the perfect environment for pneumonia and pleurisy in lambs.
However, some simple management ideas can reduce the risk of these production limiting diseases.
Pneumonia is a disease that causes lesions in the lungs. The most common form is Chronic Non-Progressive Pneumonia which can be caused by bacteria, mycobacteria or viruses.
Symptoms are usually not obvious, although lambs will be slower growing and often pant and cough following exercise.
Lambs with pneumonia are more likely to develop pleurisy, which is where lungs stick to the chest wall. At processing, affected carcasses are downgraded or condemned.
A 2000/2001 study carried out on a database of 1719 farms in Canterbury, Manawatu and Gisborne found the prevalence of pneumonia ranged from 0–100% per flock. But on average, flocks had 24% of lambs affected.
The number of flocks with some pneumonia present ranged from 40–70% – in other words it is very common and costly. Slower growing lambs cost more to feed and then their carcasses are downgraded.
Risk factors include high temperatures and humidity, crowding, stress, dust, excessive exercise, poor ventilation, low immunity and high parasite burdens.
Preventing Pneumonia
- A healthy animal with good nutrition, up-to-date animal health and minimal stressors are at reduced risk of developing pneumonia.
- Keep the time of yarding lambs to a minimum.
- Water the yards before use to reduce dust.
- Keep mob sizes small to reduce animal stress and dust inhalation.
- Avoid shearing lambs at weaning.
- Minimise the stock movement in the middle of the day when dust levels are highest and avoid long distance movements where possible.
- Reduce the extent and duration of open-mouth panting when mustering or droving lambs.
- Satellite yards can reduce long-distance movements. Try and reduce pressure on lambs when droving, laneways are ideal as allow lamb to drift at their own pace.
