What virus primarily targets GI but can lead to pneumonia when cow is immunosuppressed and has synergism with other pathogens?
Bovine Viral Diarrhea
What happens to fetus if cow is infected with BVD while pregnant?
- Cerebellar hypoplasia
- Persistently infected/shedding
Which bacteria cause Fibrinous pneumonia?
- Mannheimia hemolytica
what are some of the virulence factors associated with mannheimia? 3
- (protease, capsular-polysaccharide, outer membrane components)
Is pasteurella more or less virulent than mannheimia? Is it considered a primary or secondary pathogen?
- less severe signs - vague/no clinical signs ("lungers" but not dead)
- secondary (commensal in nasopharynx)
What enables pasteurella to resist phagocytosis?
What type of pneumonia will it cause?
- Capsule and LPS
- Purulent pneumonia
- - leukotoxins kill WBCs =inflammation = more WBCs; bacteria grow on inflammatory fluids
What respiratory complex is pasteurella associated with?
What conditions lead to this problem?
- Enzootic Calf Pneumonia
- Poor ventilation or Housed with adults
Which type of pneumonia causes long term problems, ie poor doers & chronic lung pathology
Pasteurella - won't respond to well to treatments
Is it a good idea to use a rebreathing bag to evaluate a subclinical pasteurella pneumonia? is there a vaccine?
- yes, use rebreathing bag and stethescope far under olecranon
- yes, vaccine
what are 5 systems histophilus somni can affect?
- CNS - high fever, seizures, ataxia
- Muskuloskeletal - joint swellings/lameness
- Cardiovascular - sudden death
- (commensal in upper resp. and urogenital)
what is pathophysiology associated with histophilus somni?
- attach to endothelium in vessels -
- expose collagen -
- plt adhesion -
- thrombus -
- localized anoxia/tissue destruction,
- can gain access to blood stream and spread
what are necropsy findings in feedlot with histophilus somni respiratory infection? 3
- necrotic layngitis and tracheitis
- fibrinous bronchopneumonia
- fibrinous pleuritis
how is histophilus diagnosed in the respiratory system?
Is there a vaccine?
- necropsy or TTL
- vx may be helpful
what are 5 common infections caused by mycoplasma bovis?
- otitis media
- (vs Histophilus)
How does mycoplasma create pathology in the lungs?
- attaches to resp. endothelium
- migrates between cilia
- incr. vascular permeability
- systemic spread possible
Coughing and nasal discharge are NOT consistent with mycoplasma infection, so what other signs can you look for?
- drooping ears (facial n. paralysis, vestibular signs) + fever/anorexia
- not responding to treatment as expected
what will lungs look like on necropsy with mycoplasma infection? 3
- dark red, firm, consolidated cranioventral lobes
- yellow/white firm nodules - coagulation necrosis
- enlarged septa from edema and fibrin
Since mycoplasma does not respond well to traditionally used Abs, what should you use?
- Tulathromycin (Draxxin)
- do not use fluorquinolones in dairy = illegal!
what is the fancy name for Fog Fever?
Who is affected?
- Acute Bovine Pulmonary Emphysema and Edema
- adult beef cattle
what causes fog fever?
- eating growing grasses high in soluble CHO and proteins (alfalfa lush pastures in the fall; 4-10 d after new pasture)
- *no fever* and non-infectious
how do lush pastures lead to fog fever?
What type of pneumonia results?
- high L-tryptophan
- lactobacillus converts it to 3methylindole affects clara cells and type 2pneumocytes
- Interstitial pneumonia
what are clinical signs associated w/Fog Fever, interstitial pneumonia? 5
How severe is disease?
Young or adults?
- acute death +/-signs
- *afebrile* - non infectious;
- loud respiratory grunt
- aggressive when anoxic
- SQ emphysema
- Adults (functioning rumen required)
which lobes are most affected by interstitial pneumonia?
What other signs are seen at necropsy? 3
- Caudal lobes
- emphysema in mediastinum
- rubbery lungs
- pneumothorax if ruptured bullae
what meds can be given to prevent formation of 3methylindole?
- (ionophores to shift microbe population)
What is the cause of a reportable, zoonotic pneumonia in cattle that is carried in the deer population?
- tuberculosis (Mycobacterium bovis)
- -miliary nodules throughout the body
what are clinical signs of tuberculosis infection?
unthrifty, *wt loss* more common than typical pneumonia signs
how is tuberculosis initially diagnosed?
single intradermal (caudal fold) test = 0.1 tuberculin injected then reck in 72 hours (delayed type 4 hypersensitivity)
If there caudal fold test is positive, what test is done next?
What is treatment if this is also positive?
- Comparative cervical test (state vet)
- no Tx, eradication
Upon arrival to feedlot, should you start non-protein nitrogen feed?
Antibiotics in the water as prevention?
Give MLV for common diseases?
- avoid NPN feed at first
- no Abs in water - decr. water intake
- no MLV or surgery at first
what are common vaccines for cattle? 5/8
- brucellosis in dairy calves
what antibiotic is labeled for treatment of pneumonia and has NO milk WDT?
Is it bacteriocidal or static?
- ceftiofur (Naxcel) - 4 day meat WDT
- bacterioCIDAL (inhibits cell wall synthesis)
which drug has same properties as ceftiofur but is administered at base or middle 1/3 of ear and has a 2 week meat WDT, still no milk WDT?
Ceftiofur Crystalline Free Acid (Excede = one time injectable version of naxcel)
what kind of drug is tilmicosin?
What does it treat?
Not labeled for ____
- M. hemolytica
- *not labelled for dairy >20mo*
- toxic to humans
Can sulfadimethoxine (Albon) be used in lactating dairy?
Is there milk WDT?
- yes but NOT in preruminating or veal calves
- 60 hour WDT in milk; 5days in meat
what are milk and meat WDT for oxytetracycline, LA200?
- 28d for meat
- 96hr for milk
In addition to tilmicosin, what are other Abs not labelled for use in lactating dairy? 4
- Oxytetracycline - Tetradure 300
- Florfenicol (Nuflor)
- Enrofloxacin (Baytril) - extralabel prohibited for all cattle
- Tulathromycin (Draxxin)