Why do your seemingly healthy-looking calves suddenly come down with pneumonia? Why this happens is a question that has plagued many producers over the years. Respiratory diseases in pre-weaned calves are always producers’ concerns, with unpredictable outbreaks.
The frustrating thing is that your calves may not even be considered “high risk” for pneumonia. They are still with their mother and are not having to deal with any stressors, such as changes in environment or diet. Understanding the why and how of this disease is crucial for any cow/calf producer.
What is summer pneumonia?
As mentioned earlier, summer pneumonia is a term used to describe a respiratory disease that affects pre-weaned calves that are still in the pasture. It can be hard to pinpoint any causes because it affects both well-managed and poorly-managed cow herds. Despite its mysterious nature, there are some things about it that we do know.
The viruses that cause summer pneumonia are the same, which typically cause respiratory diseases post-weaning. Agents such as Mannheimia haemolytica, Haemophilus somni, Pasteurella multocida, Infectious Bovine Rhinotracheitis Virus, and Bovine Respiratory Syncytial Virus and some of the more common causes. However, unlike other respiratory diseases, the symptoms of this virus can be tricky to see.
Symptoms
Signs of this disease in pre-weaned calves do not always include things such as cough or rapid breathing. These signs can be more evident if the herd is moved, however. Generally, something like sluggishness, a reluctance to keep up with the herd, or drooping of ears are what is commonly seen with summer pneumonia.
Part of the reason not much is known about this disease is that few calves are available for post-mortem examination. Typically outbreaks of summer pneumonia do not cause high death losses to occur. While this fact is a good thing, it makes learning anything about this disease a little challenging. Generally, a veterinarian will take nasal swabs from the infected to locate the infectious agents. Although, any bacteria or viruses found in the nasal passages may not accurately show the infection deeper in the lungs.
What causes summer pneumonia
Though a specific cause of this disease has yet to be found, some factors have been shown to cause it to happen. I do caution that these factors alone are not to be used as a diagnosis on their own. As always, you should consult a veterinarian before deciding on treatments.
Colostrum
When herds were diagnosed with summer pneumonia, two patterns emerged. According to the University of Nebraska, one of these is calves that are very young (a month of age or less). The other are valves that reach 90- 120 days of age. As you may have guessed, colostrum plays a part in these factors.
With the younger calves, the risk of summer pneumonia is believed to be because of poor colostrum quality or quantity. The dam’s poor nutrition causes the poor state of colostrum before calving due to things like drought. If you need to provide a colostrum replacer, I talk about what to consider in a previous post, “5 astonishing truths about colostrum to start calves right”.
When it comes to older calves, the effectiveness of the colostrum is the factor. As calves age, the protection from colostrum begins to decline. These four-month-olds or older are in the sickness sweet spot. They are too old for the colostrum to be of any use, and they are too young to have developed their own immunity to viruses. Helping their immunity is where having the correct vaccination program in place.
Vaccination age and type
Many calves will get their first respiratory vaccine when they are very young. The age when they get their vaccines will play a role in their effectiveness. Really young calves, like two months of age, will not have as good of a response as one that is seven to eight months of age. Of course, though it may not be as effective e vaccines at any age are better than no vaccines at all.
The type of vaccine you use will also play a part in its effectiveness. Visiting your veterinarian or local feed store will tell you that not all vaccines are identical. You can choose from many different types: viruses or bacteria, modified live or killed. It is essential to visit your veterinarian to determine what vaccines will work for you and your operation.
Outside factors
Some of the other types of factors that are believed to cause summer pneumonia are:
-Calves are exposed to older calves that may be carriers of different viruses, though they do not show symptoms themselves.
-Hot, dry, dusty conditions can wreak havoc on the respiratory tract’s standard defense mechanisms. These dusty conditions usually happen in later summer.
-Wide temperature swings between day and night
-The added stress of crowding and separating them from their mommas, such as during breeding.
Treatment options
Treating calves with summer pneumonia, all in all, is very frequently successful. There have been reasonable recovery rates with certain antibiotics and anti-inflammatory medicines. Despite their successes, there are some issues with them.
The main issue is that they are challenging to apply to individual calves when they are in the pasture. Despite it being difficult even to identify which ones are sick, it can be hard to even get near the calf in the field to administer the medicine. If a high amount of the herd is affected, pre-weaning vaccinations and antibiotics can be given to the calves.
Vaccine considerations
Using vaccines against respiratory viruses at branding and turnout have to be used by producers to try to reduce summer pneumonia from occurring. A word of caution, though, summer pneumonia can still happen even in a well-vaccinated herd.
Vaccines that possess IBRV, BRSV, Parainfluenza-3, and Bovine Viral Diarrhea Virus are used to keep these at bay. They are available in killed and modified-live versions.
When it comes to young calves, intranasal vaccines are a trendy choice. They are believed to offer good local immunity and stimulate excellent overall immunity in the nasal passages. If these are, a good option is something to discuss with your veterinarian.