Bovine Flashcards
Bovine Leukosis Virus
Transmission
Clinical findings
Dx
Retrovirus
2nd most common cattle neoplasia after SCC
Transmitted by blood transfer between animals (insect vectors)
4 syndromes: calf, thymic, skin and adult
Calf form: widespread tumor mets
Thymic form: seen in 6 - 8m calves
Skin form: only nonfatal form, seen in young adults - superficial cutaneous tumors that regress after a few weeks
Adult form: 4 - 8y; wide distribution of mets
Dx: need histologic dx; serologic test for adult form, severe lymphocytosis
Control: test and cull
Bovine Respiratory disease (BRD)
Agent
Disease name
CS
Manheimia (pasterurella) haemolytica
enzootic pneumonia
CS: bronchopneumonia and fibrinous bronchopneumonia and pleuritis
Bovine corona virus
Neonatal calf diarrhea or winter dysentery
Fecal-oral respiratory transmission
Zoonotic - causes diarrhea in humans
Milk fever Cause Risk factors
CS
Stages
Treatment
Cause: onset of heavy milk production which depletes serum Ca so rapidly that hormonal control cant keep up
Risk factors: seen in dairy cattle and island breeds (Jerseys & Guernesy), occurs within 1 - 2 days of calving
CS: recumbency, S shaped neck, severe bloat, death
Stage 1: tachycardia and weakness
Stage 2: flaccid paralysis and muscle fasciculations; S-shaped neck
Stage 3: Lateral recumbency, severe bloat, coma
Treatment: add anionic salts to diet 2 - 3 weeks before calving (aka DCAD diet) you want to acidify the blood to increase Ca mobilization
What are the 3 primary controllers of Ca in the cow?
- Calictonin = decreases iCa
- PTH = increase Ca; decrease P
- Vit D = increase Ca; increase P
Explain the pathophys of Mg in the cow
So what are effects of low vs high Mg
Mg is used to make AChE which is used to inhibit ACh(excitatory)
High Mg –> too much AChE –> flaccid paralysis
Low Mg –> not enough AChE –> muscle fasciculations
What are the 3 disease processes of Phosphorus and how they lead to decreased P?
- Severe acute hopophosphatemia: increased PTH = increases P in urine in order to retain Ca
- Postparturient hemoglobinuria = reduced 2,3DPG in RBCs prevents Na/ATP pump from working, fluid runs into cells and they burst, leading to anemia
- Rickets = distorted long bone growth leading to elongated epiphyses
How do you treat severe acute hypophosphatemia (caused by increased PTH) and postparturient hemoglobinuria?
Sodium monophosphate
How do you treat/prevent rickets?
Maintain a Ca:P of about 2:1
Where is Mg absorbed in adults?
Rumen
Where is Mg absorbed in calves?
SI
What type of diet can cause hypoMg?
Give 3 examples
A diet high in N and K –> they inhibit Mg absorption
3 examples:
- Rapidly growing grass pasture especially in the spring or fall
- Heavily fertilized pastures (too much N)
- Cereal grains
Why is it so important to maintain Mg in the diet?
Bc there is no hormonal system to regulate Mg in the body; Mg must be continually ingestested in order to maintain normal Mg.q
Grass tetany What is it How is it caused CS Dx Treatment Prevention
HypoMg - caused by eating a diet too high in N and K that it inhibits Mg absorption
CS: early: muscle fasciculations and aggressive behavior. Late signs: recumbent, repetitive muscle contractions, convulsions, seizures
Dx: measure Mg in blood or urine (not very reliable), CSF post mortem
Tx: emergency! IV CMPK and oral Mg oxide
Prevention: feed legumes (avoid rapid growing grasses), Mg blocks
Most common cause of hypoK in the cow?
Decreased feed intake
Clin path associated with hypoK?
K <2.5 mEq/L
Increased muscle enzymes (CK & AST)
How do you treat hypoK?
K supplementation Iv and oral
IV max rate = 0.5 mEqkg/hr
KCl is most common oral salt
Why are ketotic cows at risk for hypoK?
Bc you treat ketosis with dextrose
These drugs divert K into the cell
Alkalosis causes a decrease in K
In a negative energy balance what 3 things mobilized to make glucose?
- Glycerol (fat mobilization
- Aminio acids (msucle catabolism)
- Glycogen (from liver)
What are the 3 types of ketone boies commonly seen?
- Acteone
- Acetoacetate
- Beta-hydroxybutyrate
Difference between primary and secondary ketosis
In secondary ketosis, the diet is fine (unlike primary ketosis), the ketosis occurs secondarily form a separate disease-induced inappetance.
This is far more common
What puts a cow at risk for ketosis
- A cow 6 weeks from parturition
- A high performance (milk production) cow
- Overcrowding
How is ketosis most commonly diagnosed?
Urine dipstick - it measures acetoacetate - not betahydroxybutyrate
What are the most commont treatments (3) for ketosis?
- Dextrose - short-term solution (rapidly increases blood glucose)
- Ethylene glycol