One man's quest to ranch American bison in Virginia.
Bison fecal egg counting: Part 2
Get link
Facebook
Twitter
Pinterest
Email
Other Apps
This post gives a basic description of the method and materials I use to run modified McMaster fecal egg counts on samples collected from my bison herd. A description of why people run these test and how I collect the samples can be found in my previous blog post.
Most of the items I use to run my modified McMaster egg counts. Not pictured are the samples of bison poop, latex gloves, and paper cups used to hold the samples. Yes, I realize I misspelled "flotation" on this graphic, but I'm not going to redo it.
To conduct a modified McMaster egg count on a sample of bison poop I first use the scale to measure out 2 grams of the sample into a paper cup. I then use a veterinary syringe to add 28 mL of flotation solution to the cup and allow the poop to dissolve into the solution. There are recipes you can find on the Internet for making your own flotation solution, but I feel that the commercially available solutions are preferable because they offer greater consistency between batches of solution. Once the poop has dissolved into the solution the mixture is then poured through a piece of cheesecloth into a second paper cup.
A closeup photograph of my McMaster microscope slide. The slide consists of two separate chambers with grid markings that help guide you while you are counting eggs.
As soon as the liquid has drained through the cloth a pipette is used to transfer a portion of it to the McMaster slide, which is then allowed to sit for about five minutes. During this wait period the eggs, which are less dense than the flotation solution, will float up to the top of the slide chambers while most of the other fecal particles sink to the bottom. At this point the slide is ready for the microscope.
The microscope I purchased for these analyses is the Celestron Model # 44104 Advanced Microscope. This microscope comes with a 4x, 10x, and 40x objective lenses (I only use the 4x and 10x for counting eggs) and 10x and 12.5x eyepieces. To view the slide through the microscope I've opted to replace the eyepieces that came with the microscope with a Celestron Model # 44421 Digital Microscope Imager, which I plug into a USB port on my computer. By using this imager in conjunction with a media player, such as VLC, I am able to view the microscope slide on my computer screen rather than having to squint through the microscope eyepiece. This digital imager has the added benefit of allowing me to capture photographs or videos of what I am seeing (see above video).
One of the photographs I captured from sample four. This sample had the largest number of eggs I've seen yet.
The basic procedure in the modified McMaster technique is to count the parasite eggs you can see within the grid markings of a chamber. When I am using a 4x microscope objective, the eggs are large enough to clearly identify as I scan up and down the grid columns by moving the microscope's mechanical stage.
A photograph of the fecal egg count results from five samples I tested yesterday.
Once all the eggs visible within the grid markings of one chamber are counted and recorded, the same procedure is done with the second chamber. The egg counts for each chamber are then added together and multiplied by 50 to give the estimated number of Eggs Per Gram (EPG). Some time in the next few weeks I will treat the bison with an anthelmintic and then run another egg count to see if the anthelmintic is working.
Since we started fencing the perimeter of our ranch in 2014, I've strove to increase the rate at which I am able to fence an area. Among the most recent improvements has been a t-post pusher which is mounted to our tractor's front-end loader bucket. This device is very simple, but has already saved us countless hours of work. The following photographs illustrate how I use the post pusher. Aiming: The loader is first positioned with the end of the pusher is close to the ground. I then maneuver the tractor until the end of the pusher is in alignment with the marked post location. This is how the lined up pusher looks from the driver's seat of the tractor. Yes, I know the loader has an issue with the hydraulics cover. Loading: Once the pusher is aligned, I place the tractor in park, raise the loader arm and insert a t-post into the open end of the pusher. Tilting: Correct placement of the t-post is dependent aligning the post along three axises,
For those of you who are unfamiliar with agricultural equipment, a cultipacker is an implement used to compress soil. There are several reasons a farmer may use a cultipacker, but, for me, the primary purpose for the cultipacker is to pack down soil that has just been planted with grass seed. This should greatly improve seed germination in newly planted bison pasture. Five truck tire rims welded together form the shape of the cultipacker. Technically this is really more of a cultipacker-roller hybrid as the ridged portions on the roller should be more closely spaced on a true cultipacker. A thick piece of steel tube runs through the center of the rims, which I'll explain later in this post. For added weight each tire rim was filled with concrete after it was welded in place. A photograph of the roller portion of the cultipacker completed and waiting for the concrete to cure. The length of steel tube that runs through the center of the roller is welded to the
Face flies beginning to appear a few days after my initial treatment with AiM-L VetCaps. I unfortunately don't have any photos of the original mob of flies, which was much worse. Since the forth of July an insect called the face fly ( Musca autumnalis ) has plagued our ranch and caused me a considerable amount of stress. It was a week ago, on the forth, while doing a routine check on the herd, that I noticed that the bison appeared to be greatly agitated by a surprisingly high number of the flies. While the sight of flies or other small insects buzzing around grazing animals is nothing unusual, this was something different. The flies flocked in groups around the eyes and nose of each animal so incessantly that the bisons' natural defenses appeared to be ineffective. All the blinking, ear flapping, tail wagging, snorting, rolling in soil, and rubbing on trees had little effect. No matter how many times they did these things the flies would just briefly fly up into the
Comments
Post a Comment