A coughing calf most likely has a respiratory infection, and the right treatment depends on what’s causing it. The two most common culprits are bovine respiratory disease (BRD), which accounts for the majority of calf illness and death, and lungworm. Both are treatable, but they require different approaches. Before reaching for any medication, the first step is figuring out how sick the calf actually is.
Assess the Calf Before You Treat
Not every cough means a calf needs medication. An occasional dry cough in dusty conditions is different from a persistent, wet cough paired with a snotty nose and droopy ears. A widely used scoring system developed at the University of Wisconsin evaluates four things: rectal temperature, nasal discharge, eye or ear appearance, and the cough itself. Each category gets a score from 0 (normal) to 3 (severe). A total score of 5 or higher, or scores of 2 or 3 in two or more categories, indicates respiratory disease that needs treatment.
Take a rectal temperature first. A reading of 39.5°C (103.1°F) or higher signals fever, which points toward an active infection rather than just irritation from dust or poor ventilation. A fever combined with thick nasal discharge, labored breathing, or a calf that’s off feed is a clear signal to act quickly.
What Causes Coughing in Calves
Bovine respiratory disease is by far the most common reason calves cough. It typically starts with a viral infection that damages the lining of the airways, making them vulnerable to secondary bacterial invasion. The result is pneumonia. Common viruses involved include bovine respiratory syncytial virus, parainfluenza-3, and bovine herpes virus-1. Once bacteria move in, the usual suspects are Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis. BRD is often caused by multiple pathogens at once, which is part of what makes it so aggressive in young calves.
Lungworm is the other major cause of coughing, especially in calves on pasture during their first grazing season. The parasite Dictyocaulus viviparus lives in the airways and triggers a harsh, persistent cough. Calves with lungworm may cough in fits, breathe rapidly, and lose condition even though they’re still eating. If your calf has been on pasture and hasn’t been dewormed, lungworm should be high on your list.
Less commonly, coughing can result from poor ventilation in calf barns, irritation from ammonia buildup in bedding, or aspiration from improper bottle or tube feeding.
Antibiotics for Bacterial Pneumonia
When a calf has a fever and signs consistent with BRD, antibiotics are the primary treatment. Several classes are approved for use in cattle with respiratory disease, and your veterinarian can help you choose based on what’s circulating in your herd, local resistance patterns, and withdrawal times if the calf is destined for beef production.
Some commonly used options combine an antibiotic with an anti-inflammatory in a single injection. One FDA-approved combination pairs florfenicol (an antibiotic) with flunixin meglumine (an anti-inflammatory) to treat both the infection and the fever in one dose, given under the skin in the neck. Other antibiotics your vet may recommend include long-acting formulations that provide several days of coverage from a single shot, which reduces handling stress on a sick calf.
Timing matters enormously. Calves treated within the first 24 hours of showing symptoms respond far better than those treated days later. Once lung tissue is severely damaged, even the right antibiotic can’t undo the scarring. This is why daily observation of your calves, checking for early signs like a slight nasal discharge or a calf standing apart from the group, pays off more than any single drug choice.
Anti-Inflammatory Medication for Fever and Pain
Pneumonia causes significant inflammation in the lungs, and calves with BRD are often in real discomfort. Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used alongside antibiotics in cattle, which is notably different from the approach in human medicine where NSAIDs aren’t recommended for pneumonia. In calves, these drugs bring the fever down and can make the animal feel well enough to keep eating and drinking, which supports recovery.
Meloxicam is one of the most frequently used options for calves. In some European operations where antibiotic use is being reduced, NSAIDs are increasingly used alone in the early stages of respiratory disease. They reliably lower rectal temperature, though research suggests they have limited effect on the actual inflammation deep in the lungs. For that reason, if a calf has a genuine bacterial infection with fever, pairing an NSAID with an appropriate antibiotic gives the best outcome.
Dewormer for Lungworm
If lungworm is the cause, the treatment is an anthelmintic (dewormer) rather than an antibiotic. Ivermectin and doramectin are both effective against Dictyocaulus viviparus. Doramectin is typically given as an injection at 200 micrograms per kilogram of body weight. Ivermectin is available as an injectable, a pour-on, or an intraruminal bolus that provides extended protection.
Levamisole is another option that works against lungworm and can be useful in cases of heavy infestation where repeated treatment is needed. In trials where calves developed active parasitic bronchitis on pasture, levamisole was used as a rescue treatment. Keep in mind that calves with heavy lungworm burdens can temporarily worsen after deworming as the dead parasites break down in the airways, so watch them closely for a few days after treatment.
Supportive Care While the Calf Recovers
Medication alone isn’t enough. What you do around the calf in the days following treatment makes a real difference in recovery speed.
Isolate the sick calf in its own space with fresh, dry bedding to keep it warm and reduce the chance of spreading infection. Cold, wet conditions force a calf to burn energy on maintaining body temperature instead of fighting infection. If the calf is chilled, administer warm fluids to help bring its core temperature up.
Keep offering milk or milk replacer at the usual dilution and temperature, but reduce the volume per feeding and feed more frequently. A good rule of thumb is roughly one quart up to four times per day rather than larger, less frequent meals. A sick calf’s gut doesn’t handle large volumes well, and smaller meals are more likely to stay down.
If the calf is dehydrated (sunken eyes, skin that tents when pinched, weakness), offer oral electrolytes between milk feedings. Space electrolyte feedings at least two hours apart from milk to avoid interfering with digestion. Only give oral electrolytes if the calf can still stand on its own and doesn’t have a bloated abdomen. Provide access to fresh, clean water at least twice a day.
Preventing the Next Case
Vaccination is the most effective way to reduce the frequency and severity of respiratory disease in your herd. A standard protocol starts with a priming dose at branding, around 2 to 4 months of age, using either a modified-live injectable vaccine or a cold-adapted intranasal vaccine covering the major respiratory viruses: IBR, PI3, BRSV, and BVD. The intranasal route has the advantage of stimulating local immunity right in the airways.
A booster follows 2 to 4 weeks before weaning or at weaning itself, using an injectable modified-live vaccine. Weaning is one of the highest-risk periods for BRD because the stress of separation, diet change, and often transport all hit at once and suppress the calf’s immune defenses.
Beyond vaccines, the environment matters. Good ventilation in calf barns prevents ammonia and pathogen buildup. Keeping bedding clean and dry, minimizing overcrowding, and reducing mixing of calves from different sources all lower disease pressure. For lungworm, strategic deworming at turnout and again mid-season protects first-season grazers while still allowing enough low-level exposure to build natural immunity over time.