Summer pneumonia, sometimes referred to as pasture pneumonia, is a disease that is usually observed in calves on pasture late in summer. It can affect calves from one month old to even five months old who have yet to be weaned. The issue with this disease is that little is known about it, and it can pop up from nowhere.
Why do your seemingly healthy-looking calves suddenly come down with pneumonia? This question has plagued many producers over the years. Respiratory diseases in pre-weaned calves are always producers’ concerns, with unpredictable outbreaks.
Grasping the intricacies of summer pneumonia, even if your seemingly healthy calves may not be considered “high risk,” Is a crucial step. This knowledge empowers you as a cow/calf producer, enabling you to take proactive measures and make informed decisions for your herd’s health.
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 involves 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 ones that typically cause respiratory diseases post-weaning. These include Mannheimia haemolytica, Haemophilus somni, Pasteurella multocida, Infectious Bovine Rhinotracheitis Virus, and Bovine Respiratory Syncytial Virus. However, unlike other respiratory diseases, the symptoms of this virus can be tricky to see, underscoring the need for early detection and a comprehensive health management plan.
Symptoms
Signs of this disease in pre-weaned calves do not always include cough or rapid breathing. However, these signs can be more evident if the herd is moved. Summer pneumonia is generally seen as ‘sluggishness,’ where the calf appears less active than usual, and a ‘reluctance to keep up with the herd,’ where the calf lags behind or separates from the group. Other signs can include drooping ears and, in some cases, a mild fever.
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 good, it makes learning about this disease challenging. Generally, a veterinarian will take nasal swabs from the infected to locate the infectious agents. However, any bacteria or viruses found in the nasal passages may not accurately show the infection more profound in the lungs.
What causes summer pneumonia?
While a specific cause of summer pneumonia has yet to be found, several factors have been shown to contribute to its occurrence. These include poor colostrum quality or quantity, exposure to older calves that may be carriers of different viruses, hot, dry, dusty conditions that can compromise the respiratory tract’s defense mechanisms, and wide temperature swings between day and night that can stress the calves’ immune system. It’s important to note that these factors alone should not be used as a diagnosis, and consulting a veterinarian is always recommended.
Colostrum
When herds were diagnosed with summer pneumonia, two patterns emerged. According to the University of Nebraska, one of these is very young calves (a month of age or less). The other are calves 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. Suppose you need to provide a colostrum replacer. In that case, 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 a crucial factor. As calves age, the protection from colostrum begins to decline. 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. This underscores the importance of ensuring that calves receive high-quality colostrum within the first few hours of life. Helping their immunity is having the correct vaccination program in place.
Vaccination age and type
Many calves get their first respiratory vaccine when they are very young. The age at which they get their vaccines will play a role in their effectiveness. Really young calves, like two months of age, will not have as good a response as one that is seven to eight months of age. Of course, though it may not be as effective, 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
When it comes to treating calves with summer pneumonia, there are several options available. Certain antibiotics, such as oxytetracycline or florfenicol, have shown reasonable recovery rates. Additionally, anti-inflammatory medicines like flunixin meglumine can help reduce fever and inflammation. It’s important to note that these treatments are often successful, providing a sense of confidence in their effectiveness.
The main issue with treating calves with summer pneumonia is that it can be challenging to apply treatments to individual calves when they are in the pasture. It can be difficult even to identify which ones are sick, and it can be hard to even get near the calf in the field to administer the medicine. If a large portion of the herd is affected, pre-weaning vaccinations and antibiotics can be given to the calves. This result underscores the importance of early detection and a proactive approach to herd health management.
Vaccine considerations
Producers must use vaccines against respiratory viruses at branding and turn out to try to reduce the risk of summer pneumonia. A word of caution, though: Summer pneumonia can still happen even in a well-vaccinated herd.
Fortunately, vaccines that possess IBRV, BRSV, Parainfluenza-3, and Bovine Viral Diarrhea Virus are readily available. They come in both killed and modified-live versions, offering a variety of options to suit your herd’s needs and giving you a sense of security in disease prevention.
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, they are something to discuss with your veterinarian.
