Dr Meducci vet's blog: May 2011

Blood sampling in animals

1:54 AM | Labels: blood sampling in animals

I was recently coming from the farm trip and the thing I enjoyed while working is blood sampling. Honestly, bleeding program is the most exciting activity for me; to see the blood oozing out from vein to the tube and you can't help the satisfied feeling because you have done it. However, I have only learn to do venipuncture to animals such as sheep, goat and cattle. I have not put a try on other animals (it'll be pleasure to practice) and here's some information about blood sampling technique in animals.

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Equipments

1. Needle

Needle size : The smaller the number, the bigger the lumen

Needle and needle sheath

2. Holder

Holder: To direct the blood from the needle to the vacutainer

3. Vacutainer tube

Containers containing coagulant (commonly used in veterinary medicine)

Red top: Contain clot activator and gel for serum seperation
Orange top: Contain thrombin (a rapid clot activator) for STAT serum testing

Containers containing anticoagulant (Commonly used in veterinary medicine)

Green top: Contain sodium heparin or lithium heparin for plasma determination
Purple top: Contain ethylenediaminetetraacetic acid (EDTA) strong anticoagulant used for full blood count and blood films.

Where to take the blood??

1.Sheep and goat: Jugular vein

2. Cattle: Coccygeal vein and jugular vein

Coccygeal vein

Jugular vein

3. Pigs: External jugular vein and marginal ear vein

Jugular vein

Marginal ear vein

4. Horse: Jugular vein

5. Cats: Jugular vein and medial saphenous vein

Jugular vein

Saphenous vein

6. Dog: Jugular vein and cephalic vein

Jugular vein

Cephalic vein

7. Poultry: Wing vein

Wing vein bleeding

8. Elephant: auricular (ear) vein, cephalic vein, saphenous vein

Saphenous vein

Auricular vein

9. Rabbit, rat or mice : Marginal ear vein, jugular vein, cephalic vein, saphenous vein

10. Iguana (or some cold-blooded animal) : Ventral tail vein

Ps: When time comes, I'll post the blood sampling procedure

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Parasitlogy; McMaster Technique for fecal egg count

12:58 AM | Labels: fecal egg count, McMaster technique, parasitology

Aim: To check the effectiveness of the anthelmintics by counting the estimate number of the worm's eggs.

Fecal egg count using modified McMaster technique is currently the main measurement used for selection for parasite resistance.

Equipments

2 beakers or plastic equipment
Weighing scale
Measuring cylinder
Mortar and pastle
Filter
Spatula
Pipette
Saturated salt solution
McMaster slide
Compound Microscope
Animal feces

Procedure

1. Weigh 3 grams of faeces and place into a container.

scales and container into which faeces are being placed

** Feces must be fresh. Wear gloves.

2. Add 45ml saturated salt solution

flotation fluid being added to container

3. By using mortar and pastle grind off the feces (to remove the fiber) and filter the solution into another beaker.

pouring solution from one beaker to the second beaker

4. Stir the solution by using spatula and leave for 2-3 minute (to allow the fiber to become sedimentary at the bottom of the beaker

5. Pipette the solution and fill the first compartment of the McMaster slide

** the second compartment may be filled by other sample

for example: 1st compartment = sample A

2nd compartment = sample B

6. Observe the McMaster slide under the compound microscope at 10x10 mag

** Do not use 40x and 100x because the objective will break the thick upper part plate of the McMaster slide.

7. Identify and count all eggs within the area of both chambers

8.The number of eggs per gram can be calculated as follows:

Count the number of eggs within the grid of each chamber, ignoring those outside the squares. For example:

Sample A Sample B

*Read from the first left row down to the second row up to the third row and next..

Calculation

Sample A

12 eggs x 100 epg = 1200 epg

*100 epg is the times factor for the McMaster technique

Sample B

15 eggs x 100 epg = 1500 epg

Interpretation of the results

More than 3000 epg, the animals must be given anthelmintics or change the deworming drugs because the higher the epg numbers indicates the worm's resistance against the anthelmintic drugs.

Eggs are produced only by fertile adult female (or hermaphrodite) worms and will, therefore, be absent in immature or single sex infections
The daily output of eggs by fertile females is influenced by host-physiological factors such as stress or lactation ( increased ) or immunity ( decreased )
Chemotherapy can also affect egg-production e.g. corticosteroids ( increased ) or sub-lethal anthelmintic doses (decreased)
Some food-stuffs may have a similar effect e.g. tannin-rich forages (decreased )
The concentration of eggs (per gram of faeces) is influenced by the daily volume of faeces being produced by the host, the rate of passage by the ingesta through the intestine, and the distribution of eggs throughout the faecal mass.
Some types of eggs are heavier than others and may not float well in solutions of lower specific gravity (e.g. Fasciola)
Some eggs from different species are indistinguishable (particularly trichostrongylids and strongylids). This complicates clinical interpretation as some species (e.g. Haemonchus) produce many more eggs per day than others (e.g. Ostertagia).

Ruminant eggs (commonly found)

Trichuris ovis

Length 70-80 µm
Width 30-42 µm
Thick-walled
Lemon-shaped with polar plugs
Granular contents, no blastomeres

Nematodirus battus egg

Nematodirus battus

Length 164 µm
Width 72 µm
Shell thin, brown, parallel sides

Nematodirus filicollis

Length 150 µm
Width 75 µm
Shell thin, colourless

Nematodirus helvetianus

Length 212 µm
Width 97 µm
Shell thin, colourless

Toxocara vitulorum egg

Toxocara vitulorum

Length 69-95 µm
Width 60-77 µm
Subglobular
Thick albuminous shell
Granular contents
Pitted surface to shell

Monieza

Monezia

(M. expansa and M. benedeni)

Fasciola Hepatica

Length 130-145 µm
Width 70-90 µm
Regular ellipse
Thin shell
Operculum at one pole
Granular yellowish-brown contents filling whole egg

Paramphistomum

Length 160 µm
Width 90 µm
Operculum on one pole
Pale grey to greenish colour

Strongyle

Approximately 80 µm long
Thin-shelled
Broad ellipse
Barrel-shaped side walls
Blastomeres present, number vary

Source: The RVC/FAO Guide to Veterinary Diagnostic Parasitology

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Restraining domestic animals

4:55 AM | Labels: Animal's restrain

A continuation from yesterday's farm work. I found a good web source that shows how to restrain domestic animals in various ways. Some I have seen in the farm and some not, but it's good to know it all though. :)

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Occasionally, livestock must be restrained for examination and treatment. Restraining animal with care to ensure safety and minimum of stress.

Cattle and water buffalo restraining