g) 28-Oct-13 Flashcards
Two examples of atypical bacterial species
Rickettsia, mycoplasma, clamydia, borrelia, bartonella, mycobacterium.
Do not gram stain!
What are the 4 spectrums of the antimicroibial spectrum?
- Gram +ve aerobes
- Gram -ve aerobes
- Obligate anaerobes
- Penicillinase producing Staph
What are clues that might indicate bacterial infection?
Heat, pyrexia, neutrophillia.
BUT these can be produced by other things e.g. neoplasm, stres etc
Three examples that are commonly mistaken as having bacterial aetiology
- Vomiting without diarrhoea
- Haematouria in cat <10 years (too concentrated)
- Blood in faeces (no protective antimicrobials)
Two examples of antimicrobial classes that inhibit cell wall synthesis
Penicillin, Cephalosporin. (Both bacteriocidal)
What are the bacteriocidal drugs?
Penicillin, Cephalosporin, Aminoglycoside, Metronidazole, Fluroquinoles, Potentiated sulphonamides
What are the bacteriostatic drugs?
Tetracycline, Chloramphenicol, non-potentiated sulphonamides, macrolides, lincosamides
Example of an antimicrobial that inhibits cell membrane function
Polymyin, amphotericin B, imidazoles, nystalin
Examples of antimicrobials that inhibit protein synthesis
Chloramphinicol, macrolides, lincosamides, tetracycline (are bacteriostatic) and aminoglycosides (which is bacterocidal)
Why is it important to distinguish between time dependent and concentration dependent bacteriocidal drug?
Time dependent are SLOWLY bacteriocidal. o.e. the plasma levels should remain above the MIC for 80% of the time.
Concentration dependent drugs the peak concentration achieved predicts antimicrobial success
Examples of time dependent bacteriocidal drugs?
Penicillin, Cephalosporin, Potentiated sulphonamides
Examples of concentration dependent bacteriocidal drugs?
Metronidazole, Fluroquinolones, Aminoglycosides
Why can you not given bacteriocidal and bacteriostatic drugs together?
For bacteriocidal drugs to work the bacteria need to be multiplying.
What is the most common type of bacteria to infect the
a) UTI
b) Skin
c) Pyothorax
a) UTI = E-coli
b) Skin = Staphylococcus sp
c) Pyothroax = Obligate/ Faxulative anaerobes
Examples of sites that are difficult to penetrate
CNS (inc brain), eye, prostate, bronchus, mammary gland. The lipid membrane provides a barrier.
Also difficult to achieve in poorly perfused tissues i.e. extremities during shock
When might prophyalactin antibacterials be used in surgery?
-Patients with leucopemia, contaiminated surgury, where surgery lasts over 90minutes, where consequences would be disastrous (orthopaedic),
NEED TO BE ADMINISTERED BEFORE SURGURY SO ADEQUATE LEVELS AT TIME OF CONTAIMINA
What three antimicrobials have extensive activity against OBLIGATE ANAEROBIC (i.e. git flora)
Penicillins, Chloramphinicol ()
Lincosamides (bacteriostatic)
Which antimicrobials undergo extensive entero-heaptic recycling. When would this be advantageous?
Tetracyclines, Chloramphincol, Lincosamides.
Useful if you have to suppress endogenous GIT glora
Which penicillins are effective against gram +ve aerobes
Penicillin G (natural) is a narrow spectrum antimicrobial that is effective against gram + aerobes. It is SENSITIVE to beta lactamases. Aminopenicillins are BROAD spectrum but susceptible to beta-lactamases unless co-formulated with clavulanic acid
What are the differences between different generations of cephalosporins?
Second generation: Broadest spectrum included gram +ve (inc Staphylococci), good anaerobic activity and reasonable gram negative.
Third generation: Should be reserved for difficult gram -ve
When should third generation cephalosporins be used?
Difficult gram negative infections.
Example of a bacteriostatic drug that works by inhibiting protein synthesis. How is this group of drugs separated?
Tetracyclines. Separated into water soluble tetracyclines (oxytetracyclines) and lipid soluble
Example of a lipid soluble tetracyclines
Doxycycline. More lipid soluble so can penetrate prostate and blood bronchus barrier. Eliminated in faeces so safer in liver failure
What drug would you use for prostatitis in a patient with kidney disease
Needs to be lipid soluble and eliminated in faeces i.e. lipid soluble tetracycline = DOXACYCLINE
How do aminoglycosides work? What bacteria are they BEST against? Which bacteria do they have NO ACTION against?
Cause a mis-reading of mRNA is BACTERIOCIDAL. Concentration dependent.
Gram negative aerobic antibacterial actions. No action against anaerobes. NEED OXYGEN TO ENTER CELL.
Spectrum of macrolides/lincosamides
Narrow spectrum. Mainly Gram POSITIVE. Also good against mycoplasma.
Both are bacteriostatic and work by inhibiting protein synthesis
Sides effects of erythromycin
Vomiting in dogs
In which species does trimethoprine cause immune-mediated reactions?
Dobermanns, Pinschers. Trimethoprine is a potentiated sulphonamides (bacteriocidal) and has a short half life.
Is BROAD spectrum (not difficult gram -ve or serious anaerobic infections)
Which group do fluoroquinoles have NO action against
Anaerobes. Fluronquinoles can cross the BBB.
Should be reserved for difficult gram -ve
When should chloramphinicol be used? When is it contraindicated?
Bacteriostatic. Imbhibits bacterial protein synthesis.
Broad spectrum, including anaerobes. Excellent tissue penetration.
Do not use in animals with poor hepatic function as it causes irreversible hepatic enzyme inhibition.
Which group do fluoroquinoles have NO action against
Anaerobes. Fluronquinoles can cross the BBB.
Should be reserved for difficult gram -ve
When should chloramphinicol be used? When is it contraindicated?
Bacteriostatic. Imbhibits bacterial protein synthesis.
Broad spectrum, including anaerobes. Excellent tissue penetration.
Do not use in animals with poor hepatic function as it causes irreversible hepatic enzyme inhibition.
Why do we need to be careful of antimicrobial residues in food?
Some people have penicillin allergies = very dangerous.
Dairy wants no antibiotics in milk as affects cheese product (i.e. kills required natural bacteria)
Global antimicrobial resistance
Which bacteria do dairys want in the milk to aid cheese production
Lactococci, Lactobacilli or Streptococci. All gram positive
Two different types of mastitis tube
- Dry Cow Tube (MUCH LONGER LASTING)
Much LONGER withdrawal period - Lactating tubes
What does the cascade say are withdrawal times in milk and milk if not specifically specified?
Milk: 7 days
Meat: 28 days
Which products cannot be used in animals for human consumption
- Enrofloxacin (baytril) in birds producing eggs for human consumption
- Chloramphincol (aplastic anemia) very lipophillic
- Metronidazole. Carcinogenic. Not for food producing animals
Fluroquinoles are USELESS against
Obligate anaerobes. GREAT for gram negative aerobes
Ideal fibre length in diet.
Why is this important?
2-4cm to prevent SORTING i.e. make the TMR homogenous
Cow comfort essential; most chewing when lying (14hrs/day).
Minimum trough space per cow. What else needs to be checked around the trough
60cm.
Check for sharp edges/ physical condition. Fresh food or old food?
Dry matter should always be calculated.
What is the formula to ESTIMATE this?
This formula cannot be used in _____-
Dry Matter. How much are the cows actually eating. Can be estimated.
DMI= 0.025BW + 0.1 milk yield.
Can’t use the formula in DRY COWS
Explain how secondary fermentation of the silage occurs
Silage in anaerobic. When exposed to air = secondary fermentation = spoilage and heating.
Can produce MYCOTOXINS
Look after silage face
What causes grass staggers?
Magnesium deficiency
How can you help prevent bloat when turning out to grass each day?
‘Buffer feed’ e.g. silage/hay
What is the cow comfort index?
85% lying down 1 hour before feeding
Milk fat % is determined by
Low milk fat can indicate
Fibre level. Spring grass can be low in fibre.
SARA may cause low bilk milk fat
Milk protein is determined by ___
Energy. Difficult to correct quickly.
Check ME in feed, check palatability (+++ Mollasus?)
When should BCS remain CONSTANT?
During the dry period. Should NOT loose weight here as causes excessive fat mobilisation (therefore fatty liver).
Dry off at same BCS they should calve at (around 3.0)
Why should the dry cows be split into two groups
Calving already a stressful time. 14 days before calving move into TRANSITIONAL group and change onto new food/ calving environment.
Reduce associated stress
When doing metabolic profiling which cows do you a) WANT to include b) NOT WANT to include?
Include: Early lactation (20Days Post calving
The intake value should ideally be above
100.
Why is the target pH. What affects this value
Target: 3.5-5.5. Higher pH acceptabele at high dry matter
DM: 20g/kg, pH 4.2
Ammonia level and DRY MATTER
Which of the VFA’s are gluconeogenic?
Proprionate (almost as effective as acetate at causing depression)
Which has more effect on VFI - water drunk with food or water in the plant material?
Water in the plant material can have a significant effect in reducing intake.
Water drunk with dry food has LITTLE effect on VFI
Does transit time increase or decrease with size of particle?
Larger particle = Longer transit time
Ruminant plasma glucose concentration is normally about _____ of non- ruminants
HALF that
The thermostatic theory is most likely in which species….
Poultry.
Thermostatic theory: Animals eat to maintain body temperature. Not a good theory for ruminants as rumen is exothermic
For beef and pigs, the DMI is around ___% of bodyweight
2%
in dairy cows: 0.025 x BW + 0.1 Milk Yield
What are the two sources of energy in forages
Cell contents (sugars, starches, proteins)- readily digestible and avaliable Cell walls: contains cellulose, lignin. Less digestible. Slowly available
What is neutral detergent fibre?
Why is it an important measure?
Main measure of fibre in the diet. Components of the cell wall e.g. lignin, cellulose (structural components)
The amount of NDF in the diet is a measure of the DRY MATTER INTAKE
Energy requirement for a dairy cow
5MJ/litre
+ Maintance = 65MJ for 650kg cow.
If pregnant extra 40MJ
Relevance of oak in cattle?
Oak poisoning can lead to GI signs and reduced intake = FATAL.
Normally happens after a storm when green oats fall from trees
Example of anti-nutritional factor affecting ruminants
Protease inhhibitors inhibit trypsin, chemotropism. Found in legumes such as beans and peas but also in cereals and potatos. Impaired growth, poor food utilisation and longer transit times
Ammonia nitrogen has consistantly decreased silage ____-
DM intake
What mineral deficiency might result in Pica
Pica = deprived appetite
Phosphorous is most common.
Can also be due to CNS disease
Clinical signs of Magnesium deficiency
‘Grass staggers; Sensititve to sound/hand clap. Ears twitching, collapses, champing of jaws, muscle tremor
How should magnesium deficiency be treated?
STAND BEHIND COW, Administer Ca boroglutinate with Mg hypophosphate into MILK VEIN.
Prevention is better ADD Magnesium flakes to water or bolus dry cows. Avoid K fertiliser when it is a known problem
Severe hypocalcemia would be then the blood concentration is less than
<1.2mmOL.
Urgent disease IV
Give some SC to act as reservoir
Lateral recumbancy, decreased cardiac output, muscle flaccidity
Potential adverse effects when treating hypocalcimia
Atrial systole –> Cardiac arrest if administered IV too quickly.
Measure HR during treatment
How to prevent milk fever
Low calcium in dry cow ration. High calcium in milk cow ration Mg supply (required for some absorption co-factors) Drench at calving if at risk e.g. twins -Older, fatter, channel breeds
Hows suffering from hypophospatemia are said to be
‘Happy Downers’
Difficult to diagnose- if no response to calcium or magnesium,. Give Fostons IV.
Check there aren’t any other reasons for being a downer cow (mastitis/broken leg).
What does DCAB stand for (in ruminant nutrition)
Dietary cation anion balance.
Cations: Na and K (Cat-ions are POSITIVE)
Anions Cl and S (Are negative)
What should the DCAB balance be?
Anions should be more than cations.
I.e. more negative than positive
(Na+K) - (Cl+S) < -200!!
How is this ideal -200mmol/kg be achieved?
Decrease K in diet or ADD anions to diet, magnesium chloride, magnesium sulphate.
Add anionic salts but are very unpalatable and can decrease palatability
What should the ruminants pH be?
Aim for 5.5 to 6.5.
If it drops below 5. TOO MANY ANIONS ARE BEING ABSORBED
How are epigenetics and obesity in horses related
Horses future is predetermined.
Pre-programming determined by maternal diet
Equine metabolic syndrome is the horse preparing itself for a
poor diet in later life
____increases with obesity.
________decreases with obesity
Tumour Necrosis Factor (TNF) increases with obesity.
Adiponectin decrease with obesity. Normally adiponectin decreases insulin resistance
Obesity results in what three things
- Chronic inflammation
- Insulin resistance (see adiponectin)
- Decreased blood flow = Laminitis
For obese horses what is better
a) 1 large meal or
2) Several smaller meals
Several smaller meals is better as prevents peaks in insulin.
How does soaking hay help provide ‘nutritional support’ to obese horses?
Soaked hay has half the calories BUT also results in loss of nutrients (leach into water)
HR must be above 80bpm/ 30 minutes/ per 24hrs
Problems associated with obesity in DOGS and CATS
CATS: Hepatic lipodosis, D.mellitus, urethral obstruction
DOGS: Pancreatitis, Degren orthopaedic disorders.
-Respiratory
-Orthopaedic
- Neutrological
How does the composition of senior diets compare to junior diets.
Senior diets contain MORE protein and LESS calories.
Don’t need as much for maintenance
BCS range for dogs
Should be recorded every consultation 1-9
Weekly weight loss should not exceed ___% of body mass per week
2% / week is the maximum rate of loss that should be achieved.
In dalmations protein is somethings restricted. Why is this and why might it be detrimental?
To prevent urolithiasis.
In growing dogs this protein restriction can lead to dilated cardiomyopathy
Deficiency in taurine in cats can lead to
Dilated cardiomyopathy or retinal degeneration. This is normally seen when unsupplemented vegetarian diets are being offered
Too much protein, not enough energy will change urea in what way
too much protein, not enough energy will INCREASE urea
Which three areas do you examine on a horse for BCS
0-5 BCS
- Neck - nuchal ligment run along neck/supraorbital fossa ABOVE EYES
- Middle (shoulder blades to hips)
- Bottom (hips, pelvis, hind quarters)
What would you expect for a horse with a BCS of 3
No fat above nuchal ligament Hollow above eyes Ribes easily felt but not seen. Hand forms a slight cup along backbone Pelvic bones felt bit not seem Rump is in an upside down C.
