Bovine Respiratory Disease Complex Flashcards
What two things are necessary for treatment success when using antibiotics?
Proper antibiotic use as well as the calves defenses
-drugs alone wont do the job
Prior to 1992, what was used to treat infections in stocker cattle?
Not a lot was available besides oxytet and sulfas
-no single dose treatments were available
-there was a ton of extralabel drug use
What was the golden era of antibiotic use in stocker operations?
Started with the introduction of Micotil in 1992 (first highly effective therapy against BRDC)
What is the current era of antimicrobial use for BRDC
Due to a rise in vitro resistance clinically used antibiotics appear to be less effective than they were previously causing mortality in feedyards to increase
What are the 3 causes of apparent treatment failure?
Problem with the timely recognition of disease, antibiotic resistance, or the presence of superbugs
What are some of the reasons that timely disease recognition may be difficult for BRDC?
-It often is difficult to diagnose until its too late and farmers aren’t as observant as they think
-often cases arent caught until the calves are open mouth breathing
What is the pathogenesis of mannheimia hemolytica infections?
- immune cells in the lung move to attack mannheimia
- White blood cell engulfs the bacteria
- White blood cell implodes killing it and the bacteria
- Mannheimia produces leukotoxin that attacks the WBC before it attacks the bacteria
- When WBC die they release the substances they used to kill the bacteria resulting in severe lung damage
Define metaphylaxis
Mass medication of cattle with antibiotics in populations at very high risks of outbreaks
If you have treated a herd metaphylactically, how should you change your protocol when treating a sick animal?
Use an antibiotic in a different class
When should you treat cattle metaphylactically?
If on arrival there is a greater than 35% chance of the calves getting sick, they are very high value calves. Can use as a substitute for time/labor of treating the sick calves
In the middle of an outbreak can use if the treatment failure is not related to antibiotic resistance, 25% of the calves were treated in one day, or 10% of the calves were treated for 3 days in a row
What does mycoplasma cause?
Pneumonia which is just as deadly as manheimia, joint problems resulting in severe lameness, and ear infections
Describe the signs of BRDC caused by mycoplasma?
Poor responsiveness to therapy, relapses from 1 week to 1 month later, hacking cough, mild signs follows shortly by severe labored breathing, clear nasal discharge, low temps compared to other causes of BRDC
Describe the lameness caused by mycoplasma
Severe swelling/lameness in one or more joints
-lameness is severe enough to cause calf to starve to death if not put in small lot with easy access to feed and water
-most calves will recover if given enough time (weeks to months)
How do you treat mycoplasma joint problems?
Antibiotics of little use, NSAIDs have little clinical effect, but opening abscesses may help (be careful not to enter joint capsule)
What is the best treatment for H Somni infections
Prevention with 1 gm CTC per 100 lbs of bodyweight
-not approved
What is recommended for when you should give up on treatment in BRDC cases?
After 3 treatments the chance of recovery is poor
How long should you wait before switching the antibiotic used?
Wait at least 48 hours to see if first line of treatment is effective before changing the regimen
What are two other lay term names for BRDC?
Pneumonia and shipping fever
T/F: Feedlot producers over time are shifting to be more okay with paying a premium to buy pre-vaccinated and processed animals
True
T/F: overtime feedlot mortality has trended downward
False, it has trended upward
