The specific gravity hydrometer is an essential tool for any parasite testing lab. Whether conducting regular or infrequent FEC’s fecal egg counts (also referred to as WEC worm egg count), the fecal flotation solution must be inspected routinely with a specific gravity hydrometer.
Specific gravity means the weight of an object in comparison to an equal volume of water. The specific gravity of the fecal flotation solution must be higher than the specific gravity of the parasite eggs in order to float them. The specific gravity of water is 1.000 and most parasite eggs are in the range of 1.05 – 1.24. The most common parasites that threaten livestock are below 1.2
There are five main flotation solutions used for floating parasite eggs:
- Sodium nitrate 1.2 SG
- Zinc sulfate1.2 SG
- Magnesium sulfate 1.2 SG
- Sodium Chloride (salt) 1.2 SG
- Sugar 1.27 SG
Of these sugar has the greatest specific gravity of 1.27. Sugar has limitations though. It is sticky and messy to deal with, a preservative must be added and it can distort or burst the eggs. Parasitologists and veterinarians differ on their preference and opinions of flotations solutions. For livestock generally a specific gravity of 1.2 is sufficient.
The specific gravity of Sodium Chloride or salt (commonly used in fecal flotation for helminths) is 1.2 SG as seen in this image of a hydrometer floating in salt water.
Finding the right hydrometer for sale can be daunting as they are hard to find and there are many that are sold for other purposes and liquids. We hope to make this easy by offering hydrometers for sale at a reasonable price with world wide shipping.
FEC Source is now offering an inexpensive, easy to use specific gravity hydrometer for sale on our website http://fecsource.com/shop/ . We also have for sale a 100mL cylinder for use with the for sale hydrometer. Other useful testing supplies can be purchased through our website FECSource.com . Please inquire at info@FECsource.com for more information. Or call us toll free at (844) VETSLIDES.