i) 18-Nov-13 Flashcards
Difference between antiseptic and disinfectant
ANTISEPTIC: is a chemical agent that either kills or inhibits pathogenic microorganisms. Applied to the skin DISINFECTANT: Germicidal chemical that kills microorganisms on inanimate objects.
Define sepsis
Presence of pathogens or their toxic products in the tissues of a patient
Complete elimination of microbial viability, including spores by physical/chemical means is known as
Sterilisation
What are Halsteads principles? When were these proposed??
19th century. 1. Gental tissue handling 2. Accurate haemostasis 3. Preservation of vascularity 4. Surgical asepsis 5. No tension on tissues 6. Approximation of tissues 7. Obliteration of dead space
Three types of hand washing chemicals
- Chlorhexidine 2. Povidone- iodine 3. Ethyl alcohol (70%)
How does chlorhexidine work? Why is it favoured by farm vets?
Broad spectrum vs bacteria. Variable vs virus’. NOT against spores. Kills by: Precipitation of cellular contents and alteration in cell proliferation Instant kill and some residual activity. Favoured by FARM VETS as not inactivated by organic matter
Clorhexidine is toxic in 3 ways….
Ototoxic, corneal, neurotoxic (do not apply directly!!)
Povidone-iodine action. What is the required contact time? What decreases its action time?
Broad spectrum (bac, virus NOT SPORES). Inhibition of protein synthesis Required contact time is 2 minutes. Action time decreased by organic matter + hard water.
Can chlorhexidine and Povidone-iodine be used together?
No, they inactivate each other. Alcohol enhances their action
Which of the antiseptics is best around open wounds?
Povidone-iodine. Avoid alcohol
Is closed gloving or open gloving more sterile?
CLOSED GLOVING is MORE sterile. Use OPEN gloving for urinary catheter etc.
Method for ‘scrubbing up’ the patient
Inside out. Minimum 5 minutes contact time
If using the 4 drape method, where should the first one be placed?
In the field immediately infront of the surgeon. Then work in circular pattern clockwise
Which part of the surgeon is not considered to be sterile?
Not below waist OR BACK
NRC four classifications of contamination
- Clean 2. Clean-contaminated 3. Contaminated 4. Dirty
Entry to the gastrointestinal/ urogenital/bilary tract without contamination would be described as which of the 4 NRC classifications
Clean contaminated Also minor break in aseptic technique (glove puncture)
Gross spillage into the body cavity from GIT would be which of the NRC four classifications
Contaminated, also entrance to urogenital/bilary if infected. Fresh traumatic wound or major break in aseptic technique
When would a surgery be classed as dirty
Perforated viscus. Pus encountered Faecal contamination. Major break in sterile
What are the important principles of antimicrobial prophylaxis
- Administer BEFORE SURGERY 2. Maintain MIC at surgical sire Decrease number of bacteria to a level that host immune system can cope with. If longer surgery HAVE TO GIVE IV throughout surgery.
By which method should prophalactic antimicrobials be given?
Intravenous. Additional dose given 1/2x t1/2 If SC= Too slow to have any effect. No proven effect if given after surgery
Fluroquinoles should NOT be used as a first line of antimicrobial. What do they have NO EFFICACY against?
Fluroquinoles have NO EFFICACY against anaerobes. Are GOOD against gram negative.
Metronidazole is great against
Anaerobes (poor against others)
A safe minimum standard for steam sterilisation is
13 minutes at 120 degrees. Thermal destruction of bacteria is time and temperature dependent. The presence of moisture means bacterial death occurs at a lower temperature in a shorter period of time
Dry heat requires more or less time that moist heat sterilisers
Dry heat requires more time. 160 degrees for 120 minutes
Items damaged by heat e.g. fibre-optic equipement cannot be sterilised by temperature. What can be used?
ETHYLENE OXIDE, is capable of destroying all known bacteria, spores, fungi and larger fibres. It inactivates cellular DNA. 12 hours in polythene liner at room temperature. HYDROGEN PEROXIDE
When should (cold sterilisation) disinfectants not be used
Should not play a part in critical instruments. (Those used below the skin)
Metzenbaum sissors
Mayo sissors
Different types of haemostatic forceps
Mosquioto, Kelly, Carmalt
(in order of increasing size)
Two types of diathermy
Monopolar
Bipolar (electric field between the two). Less traumatic, effective in a wet field
What is a Esmarch bandage?
Type of bandage used for haemostasis.
Wrap bandage distally to proximally to remove blood. Can upwrap a distal portion while the proximal portion is occuluding the vessel
Types of thumb forceps
Adson, Adson Brown, DeBakey
The needle holders with sissors at the bottom are known as
Olsen-Hegar
What is the 7 step herd/flock investigation process?
- Define/Refine problem
- History
- Distance examination
- Clinical examination
- Ancillary aids
- Analysis/ Decision Making
- Reporting back/ further monitoring
What is involved in the indivudal animal exam?
Age, BCS, Temp, HR, RR, rumination rate, Hydration status, mucus membranes
Definition of poor thift
Failure to gain weight AS EXPECTED
Poor body condition score
Is very common and VERY EXPENSIVE
How does the feed conversion ratio vary between poor thift animals and normal?
Feed conversion ratio is HIGHER for poor thift animals/
It takes more dry matter to convert into a kg of weight
When is economic cost of poor thift most significant?
At key times of the year
-Matings- decrease conception rates/ ovulation rates
Early pregnancy: Decreased placental development
Late pregnancy: Increased risk of metabolic disease
Lactation: Decreased milk production
WELFARE
Whole group causes of poor thift
Under feeding (quantitity)
Under feeding (quality)- trace element deficiency
If normal appetite: Maldigestion/Malabsorbtion (nematodes, fluke, coccidosis)
What can be used to see if nutrition is adequate in a herd
Milk yield, BCS, calving-conception interval, forages testing
What are the three GI worms of sheep visible by eye?
HOT 2-1-0.5
Haemoncus
Ostertagia
Trichostrongylus
What is the condition ‘Pine’
Cobalt deficinecy
Can cause pale mucous membranes
Makes PGE worse/ dirrrhoea
TE deficiency can be described as PRIMARY or SECONDARY. Explain the differences
Primary: Soil/Plant deficiency
Secondary: Lack of absorption in the animal
Which TE are more commonly involved in
a) Primary deficiency
b) Secondary deficiency a
Primary (soil/plant): Co, Se, I, Cu
Secondary (Absorption in animal): Cu
(Cu binds to Mo in rumen)
Why is Cobalt a trace element?
How do difficient animals present?
Co is an essential part of VitB12 (incorportated into vit B 12 by rumen microbes)
Vit B12 is part of a co-enzyme involved in propionate –> Glucose pathway
If deficient = shortage of glucose. Therefore POOR THIFT of growing animals
Can does a severely Co deficient animal present?
Anemia, Eye discharge.
Usually seen in weaned lambs. Often associated with concurrent parasitism
Before checking TE, what is it important to observe?
Adequate nutrition, parasites? LOOK AT FIELD.
TEST ANIMALS NOT SOIL
What is the function of VitE/ Selenium.
How do deficient animals present?
Protects against free radicals i.e. don’t know.
WHITE MUSCLE DISEASE (2-6 weeks)
i.e. if calf that won’t stand = WARNING SIGN.- tip of ice berg
Poor growth rates
Why do animals require Cu?
How do deficient animals present?
Cu is essential part of many enzymes (myelin formation), tyrosinase (pigmentation)
Swayback (lambs born to deficient ewes/deer)
Deficient animals: Poor thift, diarrhoea poor coat colour.
Brown rings around eyes!! Tyrosinase/.
Where is the trace element, Cu stored?
Liver, so can take biopsy to see if appropriate storage.
Liver Cu levels deplete over winter.
A lamb is born with a swelling by its neck. What TE is the most likely to be deficient?
Iodine. Required for synthesis of thyroid hormones.
If deficient = hyperplasia of thyroid tissue.
Could also be bottle jaw (but probably too young) which is oedema due to protein loss= parasitism
A young sheep has an abnormal gait. What TE defiency could be causing this?
Cu = sway back in lambs- important in myelin formation
OR
Selenium - white muscle disease (also affects diarphram= dyspnoea??)
Cu deficiency also =- spontaneous fractures
How do you diagnose TE deficiency?
TEST ANIMAL, NOT SOIL
TE stored in body?
YES= Test storage site (e.g. Cu in Liver)
NO= Sample blood (Se)
If variation = sample lots (Cu, Co) . No variation = only few samples (Se)
Co most commenly affects
Weaned lambs
Se most commonly affects
Any species
Cu normally affects
Cattle
What is good practice when treating TE deficencys in a herd
Keep a control group (ideally 1/2) to check effectiveness
Important first step when investigating sudden death?
Define the problem.
Observational skills = v.v. important
Is it really sudden death?
Infectious causes of sudden death include:
Infectious: Septicaemia/ Toxemia
Common; usually bacterial.
Predisposed by management factors: CLOSTRIDIAL DISEASES
Stocking density= Salmonellosis
Recent flooding= Leptospirosis
Three unvaccinated yearing dairy-bred bullocks at grass died in a week.
What further tests would you consider
What is the most likely diagnosis?
Would take history, vaccination, management, changes in MM colour- if congested = enterotoxemia
Clostridal enterotoxamia
How long before lambing should ewes be vaccinated with a booster against clostridial diseases?
How long do maternal antibodies against clostridial diseases last for in the lamb?
Ewe: Sensitiser + Booster THEN booster 4-6 weeks before lambing
MDA last for 10-12 weeks (if adeuate clolostrum). Clostridal vaccines are effective in the face of maternal antibody
If grass has recently been cut for silage and cows are put out to graze it; what do you need to CHECK?
If there are marshy areas around the outside edge of the field with longer grass cows will preferentially graze this and may result in high metacercaria numbers ingested
= acute fascioliasis
Similar with Haemonchus
= anamia
Which plants are toxic to cows?
Yew, Oleander, Oak, PA containing (e.g. Ragwort)
Easier diagnosis as all affected cows in same field.
Common after storms especially acorns falling down.
What is the significance of this plant?
Is Oleander. Toxic to cows
Over supplmentation of which mineral results in sudden death
Over supplmentation of Selenium (or Cu!)
Diagnosis: Blood Se levels
Lead (car batterys), Cyanide (peach seeds)
What is the most common cause of sudden death in beef cattle (as reported by VLA in 2008)
Hypomagenesium!
52% of sudden death
Thiamine deficiency in cows causes sudden death due to ______
Cerebro-cortical necrosis consistant with thiamine deficiency (vit B1)
Which stage of the Fasiola life cycle is ingested by cows?
Metacercaria then immature fluke migrates to liver. Mature fluke develops in liver.
Majority of parasites life IN REFUGIA i.e. ON PASTURE
What are the four main nematodes that affect ruminants and WHERE ARE THEY FOUND?
Ostertagia, Hamonchus = ABOMASUM
Treichostrongulus, Nematodirrus (at lambing time!) = SMALL INTESTINE
Fasiola hepatica is an example of a __-
Trematode
= 12 WEEK LIFE CYCLE
Adults are responably immune, the exceptions are…
- Goats
- Immuno-compromised
- PPRI (after lambing - 1-3 weeks after lambing!!!)
- Horses= cyathostomins
- Liver fluke
Arrested over-wintered parasites start to resume develop in which season?
Spring. e..g. arrested ostertagia and cyathostomins.
SPRING: MAIN THREATS:
Nematodirus battus, overwintered eggs
Type 2 Ostertagiasis (young cattle)
Larval cyathosomins
FEC limited value
What are the main parasite threats in summer
All nematodes (calves, lambs, goats)
Parascaris
Cyathostomins
When would you expect lambs/goats to get infected with a) ostertagia b) trichostrongylus
Ostertagia: Summer
Trichostrongulus: Autumn
Main parasite threats in WINTER
Chronic fascioliasis - adults
What are the SCOPS Guidlines? Which is the most important?
- Work out a control strategy with vet/ advisor
- Use effective quarentine strategies
- Test for AR on farm
- Adminsiter anthelmintics effectively
- Use anthelmintics only when necessary = MOST IMPORTANT. ONLY TREAT FEC WORTH TREATING
- Select appropriate anthelmintic for task
- Adopt strategies to preserve sucseptible worms on the farm
- Reduce dependent on anthelmintics
How is Gross Margin calculated?
What do they NOT take into account of?
Gross Margin: Output- Variable costs
Gross Margin does NOT take into account of fixed costs
Partial budgeting is based on
Partial budgeting is based on additional costs and additional benefits
Costs: new costs (e.g. vaccine/discinfectant) / revenues forgone (salvage value of animals with disease)
Benefit: Costs saved/ new revenue
Difference between Macromolecules and Trace Elements. INCLUDE EXAMPLES
Macrominerals: Required in 10s of Grams/ day
e.g. Ca, Mg, P,
Trace Elements: Required in grams/ day
e.g. Co, Zn, Se, Cu,
