Summer pneumonia, sometimes referred to as pasture pneumonia, tends to develop late in the season for producers. It usually hits calves that are still on pasture and haven’t been weaned yet—typically between one and five months old. The frustrating part? It often affects calves that look perfectly healthy one day and are sick the next.
So, why does this happen? That’s the question that’s had ranchers scratching their heads for years. Respiratory disease in young calves is always a concern, but summer pneumonia feels especially unpredictable. Some years, you never see it. In other years, it appears without warning—and it’s tough to catch early.
Part of the challenge is that summer pneumonia isn’t fully understood. It doesn’t always follow the rules. It can show up in well-managed herds just as easily as in herds dealing with stress, drought, or nutritional issues. And because symptoms can be subtle, it’s easy to miss until calves are really struggling.
Even if your calves aren’t what you’d consider “high risk,” learning to spot summer pneumonia—and understanding what might trigger it—is a big step in the right direction. Knowing what to watch for helps you take action early, which can result in a faster recovery, fewer losses, and less stress on both you and your calves.
Bottom line: Summer pneumonia may be unpredictable, but that doesn’t mean you’re powerless. A little awareness goes a long way in protecting your herd.
