Pneumonia in lambs and hoggets

Pneumonia in young sheep is a multi-factorial disease involving both pathogens and external factors such as stress, environmental changes and concurrent disease. The main bacteria involved in hogget pneumonia are Pasteurella species and Mycoplasma ovipneumoniae, as well as different viruses and non-infectious causes of lung damage, such as dust from mustering.

Factors such as stress, whether it be from mustering, yarding, drenching or changes in feed, contribute greatly to the development of pneumonia, and the ability of the lamb or hogget to fight the disease without developing chronic damage to the lungs. A few specific husbandry procedures have been linked to the development of pneumonia, notably:

  • Shearing lambs on the day of weaning.
  • Increased average slaughter age of lambs, due to increased stocking rate and density as feed becomes limited in the late summer.
  •  Cold shock following shearing or handling.
  • Following dipping, both shower and plunge, with signs of pneumonia developing four to seven days after.
  • Concurrent development of facial eczema.
  • Transport of sheep.
  • Mustering in dry, dusty conditions.

In acute cases sheep may be found dead, or found lagging behind the mob displaying signs of respiratory distress. In groups of young sheep where pneumonia has developed, many sheep may be seen or heard coughing, and some may develop chronic ill thrift.

The economic losses due to pneumonia can be significant, whether it be from the direct loss of stock on farm, or downgrading of carcasses at slaughter. Studies also show the weight gain of lambs affected by pneumonia to be 50% less than that of a healthy lamb, meaning the time to finish a lamb to slaughter weight may double. Preventing hogget pneumonia is crucial in reducing losses on your farm.

Minimising the predisposing factors for pneumonia is key, and avoiding any unnecessary stress on the lambs or hoggets. Avoid mustering in the dust and heat, and yarding stock for longer than necessary in close confinement. Maintaining stock health over risk periods is also crucial by ensuring adequate feed and appropriate drenching.

If you have concerns about pneumonia in your sheep, please contact us to discuss ways to mitigate the risk and prevent widespread losses.