A Silent Threat to Lamb Health and Profits: Pneumonia Strikes North American Flocks
Across North American pastures, a silent threat lurks, impacting the health and profitability of sheep farms: Chronic Non-Progressive Pneumonia (CNP). This widespread disease can afflict as many as 20-30% of lambs within a flock, leading to financial losses for shepherds across the country. “On average, flocks have 20–30% of lambs affected," research has shown.
CNP, also known asبره上的慢性非进展性肺炎, is caused by a combination of bacteria, mycobacteria, and viruses. It manifests in lambs as difficulty breathing, panting even after light exercise, and coughing. While some lambs may exhibit these symptoms, many might have sub-clinical CNP – lacking obvious signs but suffering reduced growth rates, highlighting the sneaky nature of this threat.
Beyond direct animal health concerns, CNP impacts farmers’ bottom lines in several ways. For example, diseased carcasses are often downgraded at slaughter, leading to reduced earnings.
One study, tracking a flock of 500 lambs with typical pneumonia levels, found that downgraded carcasses led to an estimated $2,920 in losses. That translates to roughly $5.80 per affected lamb – a significant hit for already tight margins.
Furthermore, affected lambs grow at a much slower rate, taking considerably longer to reach market weight. “Significantly affected lambs can grow 50% slower than unaffected lambs," experts explain.
Imagine lambs with CNP only gaining 75 grams per day instead of the healthy 150 grams. Reaching a market weight of 37 kilograms from 30 kilograms might take an extra 47 days and require an additional 66 kilograms of feed – an extra expense for the farmer.
While CNP can afflict any flock, certain factors can increase the risk. These include stress due to mingling with new lambs post-weaning, breeding your own ewe replacements (leading to prolonged yard time for lambs) and high temperatures combined with humidity and dust.
One of the most effective ways to combat CNP is through careful sheep management practices. "It is recommended that farmers try and reduce the extent and duration of open-mouth panting by lambs when moving them," guidelines suggest. This might involve using satellite yards for lamb handling or strategically designed laneways that allow lambs to move at their own, less stressful pace.
Finally, ensuring ewes are in optimal condition before lambing is crucial. Well-fed ewes produce lambs who grow faster and are weaned earlier, reducing their exposure to the bacteria and viruses that cause CNP.
For more information, refer to our fact sheet on pneumonia and pleurisy in sheep:
[Link to Fact Sheet]
By understanding the causes and implementing proactive strategies, farmers can minimize the impact of CNP and protect the health – and ultimately, the earning potential – of their flocks.
