DIY egg counting
- Mix faecal sample well and weigh out 3g into a plastic bag
- Add 42ml of saturated salt solution
- Mash up the sample – make sure no lumps of faecal material remain
- Pour mixture over a tea strainer into a plastic beaker. Squeeze out the moisture and discard the debris
- Mix the liquid well (but don’t stir in circles as this will collect eggs in the center!)
- Fill plastic pipette with liquid and load the McMaster chambers
- Leave to stand for 2 minutes (this allows eggs time to float to the top of the chambers)
- Examine under the microscope and count the number of strongyle and Nematodirus eggs under both of the grids…see below for pictures of the eggs
When you are ready to count, focus the microscope on the air bubbles in the sample (see picture below) – these float to the same level as the eggs so you will know where to look!
To calculate the eggs per gram of faeces:
Add the number of eggs counted in each grid and multiply by 50.
Example: there were 6 eggs in grid one and 4 eggs in grid two… (6+4) x 50 = 500 eggs per gram
All equipment needs to be rinsed thoroughly with water between egg counts (no detergent needed).
What you will need
- A compound microscope (40X magnification)
- McMaster slide
- Tea strainer
- Graduated syringe
- Pasture pipette
- Plastic beaker
- Weigh balance
- Saturated salt solution
What you might see...
Below are pictures of eggs you might come across in your samples. It is interesting to note what you see but faecal egg counts are normally done to count strongyle eggs (1) and Nematodirus eggs (2).
1. Strongyle egg
2. Nematodirus egg
3. Tapeworm egg (monezia)
5. Strongyloides – Be careful! These are different from strongyles… the eggs are smaller and have a larvae (tiny worm) visible inside the egg shell.