Bovine respiratory disease (BRD) is a broad term for bacteria and viral pneumonia. BRD is very common in the first 30-60 days after feedlot induction due to increased stress. At our feedlot, our veterinarian performs post-mortem procedures on all mortalities. This allows us to understand the cause of death and changes/improvements we can make to our treatment protocol to prevent other mortalities.
Before I get into the results of our post-mortems, I would like to share our feedlot induction protocols for this year. We have switched over to Merck products this year. We were only able to get enough of the Nasalgen intranasal BRD vaccine for one feedlot pen (366 head). Therefore, we are comparing the intranasal vaccine against the injectible (Vista Once) vaccine. Our protocol upon induction for the intranasal group was Bovilis Nasalgen, Bovilis Vista BVD, Vision 8 Somnus with Spur, Zuprevo, and a Revalor G implant. The implant we used was based on our predicted ADG and our production goals for this year's feedlot cattle. The other groups received Vista Once, Vision 8 Somnus with Spur, Zuprevo, and Revalor G.
The Nasalgen and Vista Once both claim protection against at least 5 bacterial and viral pathogens that cause BRD in cattle. These include bovine respiratory syncytial virus (BRSV), infectious bovine rhinotracheitis virus (IBR), parainfluenza 3 virus (PI3), Mannheimia haemolytica and Pasteurella multocida. Vista Once allegedly has protection against 6 viral causes and 2 bacterial causes of BRD.
Our post-mortem examinations have revealed the presence of BRSV and coronavirus. There has been some Mannhemia and Mycoplasma present in the calves as well. Today I am going to focus on BRSV.
Bovine respiratory syncytial virus (BRSV) is an RNA virus that forms syncytial cells. These types of cells have multiple nuclei which allows rapid communication. BRSV is highly contagious through respiratory aerosols and cow-to-cow contact. Clinical signs of BRSV include fever, depression, increased respiratory rate, coughing, off-feed, and nasal discharge. Viral interstitial pneumonia has no specific treatment. However, the secondary bacterial pneumonia that occurs concurrently with the BRSV can be treated. Antimicrobials and an NSAID can be used in treatment for this condition. It is important to keep the animal hydrated and in a clean environment with access to feed. However, in severe cases, secondary bacterial pneumonia paired with viral pneumonia will become fatal. When a necropsy is performed, there will be significant lesions, pulmonary edema, and interstitial emphysema found. Samples can be taken to confirm in the laboratory that BRSV is present in the animal.
Talk with your veterinarian to ensure you are using proper vaccines, proper antimicrobials, and perform post-mortems on all calves. The only way you can learn and improve is by going the extra mile, having the discussion, researching, and actually seeing. We will share our observations of the intranasal pen versus the injectable pen at shipping time. Please let me know if you have any questions.