(Continued from Part 1. This concludes the article.)
The test is performed with the freshest stool you can get. You can corral the animal, get your gloves on and get in the rectum to get some pellets out, or any number of less stressful ways to get your sample. I just walk into the field and walk behind the sheep or lamb I want a sample from. They routinely walk away and I follow them until they get a little antsy and they will give you what you need in short order. You are not trying to spook them, just be a little annoying so they stay at the slow halting walk so you can spot the pellets and pick them up. You will need two grams (probably two pellets in an adult and four in a lamb) of stool which you place into the 50cc tube. Add 30cc of flotation fluid and then break up the pellets in the fluid to make a slurry. I do this with a flat screwdriver. Technically you are supposed to use 28cc but the line on the tube is at thirty. Let it sit for 5-10 minutes. You will need to strain the slurry into another clean test tube and will need to press the solids within the strainer to drain your effluent through. I have been using the same disposable #10 scalpel blade for the past 5 years. You can now use your pipette to suck up some of the slurry and place it onto the chambers on the slide. I squeeze and eject the contents of the slurry in the pipette ten times before placing on the slide. This mixes the slurry in the tube. Why ten? No good reason. I just do it the same way every time with every test.
The same can be said for 28cc vs. 30cc of flotation fluid, how you break up the pellets, time that you wait before you strain. Do it the same way every time. Apples to apples as they say.
The slides are unique in that they have an elevated cover slip which allows for effluent that you created to stay within the space on the slide via surface tension. You place the pipette at the opening and fill the chamber completely. If you make a mistake or blow in an air bubble, just wash the slide and try again. You have 30cc of slurry and you are only putting about 1cc into each chamber so you have plenty. Lay the slides down and wait about 10-15 minutes which will allow your eggs to float to the upper glass of the chamber while the debris sinks to the bottom. That’s where the specific gravity comes in. The eggs have a specific gravity of around 1.2 and debris at 1.3+.Continue reading“Combating Sheep Flock Parasites – Part 2, by Mike V.”
