Most of us think of pneumonia as a fall problem, something that shows up at weaning when calves come off the cow, get sorted, hauled, and mixed with strangers. But there’s a version that runs through nursing calves in the middle of summer, out on grass, with the cow standing right there. It’s easy to miss and easier to underestimate, and it kills good calves in the two-to-four-month range when everything looks green and fat.
The trouble with summer pneumonia is that it hits when your cattle are spread out across the biggest, roughest country you’ve got. In May you can eyeball every calf twice a day. By mid-June the pairs are strung out over a section or more, calves are bedded down in the brush while the cows graze off, and a sick one lays up by himself where you’d have to ride right over him to find him. On the far allotments you might go days between good looks at the calf crop.
Why it comes on now
A few things line up against the calf this time of year. The antibodies he got from his mother’s first milk are fading right about the age he’s hitting now, and his own immune system isn’t fully up to speed. At the same time, the summer weather in this country runs him through a wringer — ninety in the afternoon, down into the forties on a clear high-country night, and a dust cloud every time the herd moves or you trail them to fresh grass. Those daily temperature swings and the dust irritate the airway and give the bugs an opening.
The pathogens themselves are the usual respiratory crowd. Viruses like BRSV, IBR, and PI3 knock the lining of the airway down first, and then the bacteria that live in a calf’s nose all along — the pasteurella-type organisms — move into the lungs and do the real damage. Stress is the trigger that tips it over: a hard trailing day in the heat, working and branding late, a storm that pushes everything into a coulee, or just a bunch of calves close together at the water in dusty conditions.
Branding timing plays into it too. A calf that’s roped, worked, and vaccinated on a hot, dusty afternoon is under a load right when he’s most vulnerable. That’s one more reason to get the crew out early and be done before the day heats up.
What a sick calf looks like
Catch it early and you save the calf; catch it late and you’re often too far behind. Learn what an off calf looks like from horseback, because that’s usually how you’ll find him.
- Ears down and a dull, gaunt look — he’s quit sucking and he’s not following the cow.
- Standing off by himself, hunched, sometimes with his head lowered and neck stretched out.
- Breathing fast, or working hard at it, with the flanks pumping. You may hear a soft cough when he moves.
- Clear or snotty discharge at the nose, and eyes that look sunken as he goes off feed and water.
- A cow bawling and hunting, bag full, calf nowhere in sight — go find that calf.
By the time a calf is breathing with his mouth open and won’t get up, the lung damage is heavy and the odds turn against you fast. The early, subtle ones are the ones worth chasing down.
Stay ahead of it
You can’t dust-proof Montana in July, but you can stack the deck. A respiratory vaccination program built with your veterinarian — often a round on the calves before or at turnout, timed so their own immunity is coming up as the maternal protection fades — gives the calf a fighting chance against the viral side of it. Some outfits time a summer booster or a nose-spray product; that’s a conversation to have with your vet based on your calving dates and your country.
Beyond the needle, it’s about taking pressure off. Move cattle in the cool of the morning instead of the heat of the day. Keep water clean and spread out so calves aren’t jammed into one dusty hole. Don’t stack a long haul or a hard gather on top of a branding day. And ride through the pairs often enough that you’re actually looking at calves, not just counting cows.
When you do find a sick one, get him treated early with an antibiotic your vet has you set up for this — and treat the full course, not just until he perks up. A calf that relapses because you quit too soon is a calf you’ll be doctoring twice, and the second round rarely goes as well as the first. Pull records on the ones you treat, because a calf that had pneumonia on grass is one to watch clear through to weaning.
