Parasites/Treatments/FAMCHA/Fecal Exams

This page explains the worm’s life cycle .

It dicusses the differnent wormers and their dosages.

The FAMCHA and how to use it.

It explains how to do your own fecal exam.

Internal Parasites  by The Biology of the Goat

The Secret Lives of Goat Parasites

Goat owners mount a significant effort to eliminate infections of parasites which can cause harm and misery to their goats. If, for only a short time, the worry over parasites can be set aside in favor of a closer look at their life history, interesting, even mysterious discoveries can be learned.The relationship of internal parasites to the host is often complex. Larvae can go through phases in which one stage bears no resemblence to another. Some parasites require more than one different species of host, while others can alternate between free-living or parasitic forms.

Adults of internal parasites must live and take nourishment in some organ of the host and then find a way to infect other hosts. With few exceptions, the egg once laid, exits the host, hatches in the often hostile environment, then the juvenile larvae must find a way to get inside another host to develop to the adult stage.

Direct Life Cycles

The life cycle of a nematode worm, such as Haemonchus contortus which causes so much trouble for goats and their owners, is an example of a simple, direct type of life cycle which requires only one host.

The adult, female worm lays eggs which leave the goat’s intestinal tract with the feces. The first-stage larvae hatch out and feed on soil microbes and bacteria. When the first-stage larva grows large enough it matures into the second stage. The somewhat rigid, protective outside membrane called the cuticle must be shed so the larva can grow. The second stage continues to eat and when the time comes to molt to the third stage, the larva does not shed its protective cuticle, but retains it. The third stage larva then has two protective cuticles called a sheath which helps it survive in the environment. However, the two membranes completely encloses the larva which prevents its ability to eat.

The third-stage larvae spend the next few months working a short way up moist grass every morning, waiting patiently for a goat to come along and eat it.When the sun gets too hot and the grass dries out, the larvae crawl back down to the cooler, moist surface to wait for another day.

If the larva is lucky enough to be ingested by the goat, the third cuticle is shed with the help of digestive enzymes in the rumen allowing the fourth stage larva to emerge by the time it reaches the fourth stomach. After feeding at the lining of the stomach wall or small intestine for a short time, the fourth stage develops into the adult stage and begins mating and laying eggs shortly after.
View an animation of the life cycle of H. contortus

Another type of nematode parasite which usually does not cause the goat much trouble has a more fascinating life cycle. Males and females of Strongyloides papillosus, the intestinal thread worm, live freely in the soil almost everywhere in the world. They feed, mate and lay thin-shelled eggs which produce more free-living worms. This free-living worm also goes through four larval stages, but does not require a animal host.


However, under certain conditions, some of the second-stage larva will molt into an infective form of third stage larvae. The anatomy of the esophagus is the only obvious difference between infectious and non-infectious third stage larvae. Infectious larvae called filariform have a long, cylindrical-shaped esophagus like all infectious nematodes. The esophagus of the free-living or rhabditiform S. papillosus is shorter, wide at the mouth end with narrow portion which opend into a bulb shape. There are valves between the portions.

Why the larva decide to become infectious is not well understood. Since more infective forms are produced when the environment conditions are unfavorable, it’s tempting to imagine that the young larvae somehow know that they need to spend time safe and sound inside a warm mammal. It’s more likely though that both forms are produced in the egg stage but environmental conditions favor the survival of one over the other.

Infective third stage larve can enter the goat by being swallowed on feed and then continues in nearly the same development path inside the goat as H. contortus. However, unlike H. contortus third stage larvae, S. papillosus has no protective outer sheath so cannot resist drying in the environment.

More typically, infective S. papillosus third-stage larva burrow through the skin of the goat, usually in the area of moist skin between the hooves. This can cause itching and the inflammation can lead to invasion of foot rot bacteria. The larvae enter the blood stream where they are carried to the lungs. They work their way out of the lung tissue into the alveoli, migrate up the bronchi to the trachea where they are coughed up and swallowed to continue on to the adult stage in the intestine.

Eggs laid by parasitic adult S. papillosus leave with the feces and then can hatch into either the free-living or more infective forms. What makes this parasite even more unusual is that the infective parasitic worms that live in the goat’s intestines are all females. Parasitic males are unknown. The females are self-fertilizing hermaphrodites, producing fertile eggs without the help of males. These parasitic females are much longer than the free-living forms and in heavy infections can be seen with the naked eye in fresh feces.

View an animation of the life cycle of the intestinal thread worm


Indirect Life cycles

Other parasites that infect goats require a different species of animal or insect to complete some stage of its life cycle. The goat tapeworm, Moniezia expansa which lives in the intestine, expels packets of eggs onto the pasture. A tiny mite must come along and eat the egg which will then hatch inside of the mite as a larval form. The goat accidently ingests the mite carrying the tapeworm larva while feeding. When the mite is digested, the tapeworm larvae escapes, attaches to the lining of the intestine then develops into the adult form.

View an animation of the life cycle of Moniezia tapeworm

The large liver fluke, Fasciola hepatica which infects goats, sheep and cattle also require an intermediate host to develop through stages that have little resemblance to one another.

The adult fluke lives in the bile ducts of the liver, laying eggs which travel out of the host with the feces. The eggs hatch in water into the first-stage, cilia-covered miracidium which swims about looking for the right species of snail to play the role as intermediate host.

The miracidium actively attacks the surface of the snail injecting a sporocyst into its body. Each sporocyst produces 5 to 8 redia, the third larval stage, which live and feed on the snail’s tissue. Each redia produces many fourth-stage larvae called cercariae. This stage leaves the snail, uses a tail-like structure to swim around until it finds a plant stem where it attaches, loses its tail and secretes a protective coating. There the encysted cercaria waits to be eaten by a goat so that it can continue to its adult stage and begin the process again.

View an animation of the life cycle of Fasciola hepatica


Click image for a larger view

Surival Mechanisms

The eggs or larvae of parasites play a passive role in infection. They can’t do much else but wait for the right host to come along and ingest it or in the case of the liver fluke miracidium swim around with the hope that the right snail will cross its path. This is a hit-or-miss way of continuing the life process and in natural conditions the odds are against larvae suriving long enough to find the correct host.

The strategy that some adult parasites use to insure that their species will continue to exist is to produce huge numbers, in some cases hundreds of thousands, of eggs in their short lifetime. This represents probably the highest reproduction rate of all living animals.

Eggs and larvae are protected from the environment with thick shells or cuticles. Larvae of some parasites use intermediate hosts to gain acess to the definitive host, remaining safe from environmental pressures inside an arthropod or snail.

S. papillosus goes out of its way to make certain that its species survives either by living and pairing freely in the soil or parasitically in the gut of the goat without the need for males to produce fertile eggs.

While we may wish that all internal parasites would vanish to make our and the life of our goats’ easier, it does give us something to pause and think about. Considering the obstacles that parasites must overcome to reproduce themselves, in finding new hosts, surviving the harsh environment, then add to that our increasing arsenal of effective anti-parasiticides, it is amazing that they are able to survive and do as well as have. THis article by The Biology of the Goat.

What type wormer is Best?

Ivermectin (Ivomec) is a clear wormer

dosage is 1cc=50 pounds

Kills lungworms, gastrointestinal worms, roundworms, larvae, lice, and manage mites. Used on extermal parasites too.

withhold milk consumption for 36 days!

 

Alvendazole 11.36% (Valbazen) is a white wormer

dosage is 3cc=50 pounds

Kills lungworms, gastrointestinal worms, roundworms, stomach worms, tape and flukes.

withhold milk consumption for 5 days

DO NOT GIVE TO PREGNANT DOES!

 

Fenbendazole (Safe Guard, Panacur) is a white wormer

this wormer has a wide resistance and some breeders thinks it is a waste of time and money. Use your judgement. Follow instructions on bottle.

Kills lungworms,gastrointestinal worms, roundworms, stomach worms, tape and fluke worms.

Safe on pregnant Does.

Levamisole (Tramisole & Levasol) is a clear wormer

dosage is 1cc=50 pounds

kills Lungworms and roundworms

Safe in Pregnant Does

Toxic: do not overdose

Cydectin (Moxidectin, Quest equine)

dosage is 1cc=20-25 pounds

kills Lungworms, gastroinstesinal worms, roundworms, lice, manage mites. Exteranl worms.

 

 

 

FAMCHA

The top 2 pictures are the way they should lookNot much pink here. Goat needs some intervention or it may not be around much longer.

How To Do Your Own Fecal Exams

How to do your own fecal exams
 Goats can be host to a variety of internal parasites. Parasitic worms lay eggs, more correctly called oocytes, which are passed out through the feces. The small parasitic protozoa which causes coccidiosis produce oocysts which infect other goats. We can determine what types of parasites a goat has by examining the feces which contain the microscopic eggs. To keep many parasites in check, monitoring egg counts can tell you if your worming protocol is working. In addition, different parasites respond better to one class of wormer than another. Knowing what your goats carry or if they carry any parasites at all is helpful for tailoring a treatment. In this laboratory you will learn an easy method for looking for parasite eggs right in your own home.
How to do your own fecal exams

Supplies you will need

The most important piece of equipment you need is a microscope. You can get a good student scope with a monocular eyepiece for under $200. Avoid toy microscopes, they will not be of much use. Greatscopes.com has good information to help you choose a microscope and has some affordable ones you can buy. A microscope with 10X and 40X power will work for fecal exams and many other things.

At the same time you buy your microscope be sure to get some slides and cover slips. Many online companies, including greatscopes.com sell kits that include an eyedropper which will come in handy. You can wash and reuse slides and cover slips many times if you are careful with them. Be sure to rinse with distilled water so they are sparkling clean.

You might enjoy purchasing a few prepared specimens that you can use to practice looking through your microscope. These specimens can also be educational for your youngsters.

You will need a small vial that holds about 12cc of liquid and is narrower than a cover slip for floating the fecal sample. Your veterinarian uses a special fecal vial for dog and cat samples and you can usually buy one from them. Be sure to tell them that you only want the vial, you are going to do your own exam, so they don’t charge you for a full fecal test. You can clean and reuse them.

Finally it will help to have a good book that has clear photographs of parasite eggs so you can identify what you see in the microscope. Veterinary Parasitology by William J. Foreyt has good photos and covers life cycles and treatments for parasites found in most species of domestic animals.

Making a Floatation Solution

We take advantage of specific gravity in order to view the eggs of parasites.  Specific gravity is defined as the density of one fluid compared to water so it is sometimes called relative density.  Pure water has been assigned a specific gravity of 1. We compare the density of all other solutions to water.  Anything with a density of less than 1 will float in water and anything with a density of greater than 1 will sink in water.

Parasite eggs have a specific gravity of about 1.1 to 1.2.  If you put eggs in water they will sink.  In order to make the eggs float we need a solution that has a specific gravity that is higher than 1.2.  Fecal debris has a specific gravity of 1.3 or higher.  If the floatation medium has too high a specific gravity then the debris will float along with the eggs which will make the eggs hard to see and the high concentration will distort the eggs.

We make a dense solution by dissolving sugars or salts in water. If compounds that are denser than water are dissolved in water the specific gravity increases. In laboratories a commercial solution of sodium nitrate is used which has a specific gravity of about 1.25, making it ideal for floating parasite eggs.  Sugar can be used but it is sticky and it is hard to get the specific gravity above 1.2 therefore larger eggs will not float.  Regular table salt is the least desirable because it corrodes equipment and forms crystals which distorts the eggs.  In addition, the specific gravity of table salt can never go above 1.2 so larger eggs will not float.

There is one very common salt, called magnesium sulfate, which is found in most homes and is inexpensive to buy.  Commonly called Epsom Salt, magnesium sulfate works very well for a floation solution since it has a specific gravity of 1.296.

To make a solution start with a clean, glass quart jar and fill it about half full of warm water.  Begin adding epsom salt, about a quarter cup at a time, stirring until each addition is completely dissolved.  Keep doing this until the salt no longer dissolves.  You will see a few crystals at the bottom.  Your quart jar will be almost full by then.  Let the jar sit overnight and you will notice that most of the crystals will have dissolved.  If you add a little more epsom salt the crystals will not dissolve and your solution will be called super-saturated.  However, you don’t have to do that, the solution will be concentrated enough to work.  Keep the solution well sealed and it will last for months.

Preparing the sample

The best sample is one that is very fresh, taken directly from one goat.  When your goat stands up from resting she will usually give you a good sample.  Gather about 4 or 5 pellets and put them in a small glass jar.  Add about 1/4 cup of your floatation solution and mash up the pellets using a small spoon or wooden tongue depressor.  You can either let the debris settle a bit and then use your eyedropper to collect fluid from the top or you can strain the debris using a piece of cheese cloth or a tea strainer.  If you use a tea strainer dedicate it to your fecal exams and do not use it for human food.

If you use one of these fecal vials first make sure that the green part is snapped all the way down inside the holder.  Pour the strained fluid into the vial until it is almost full.  Using your eyedropper continue filling the vial, drop by drop, until there is a slight bulge of fluid above the top of the vial.

Gently set the cover slip straight down on the top of the vial.  Some of the liquid will leak out around the edge.

Wait about 15 to 20 minutes.  It takes time for the microscopic eggs to travel the long distance to the top of the fluid.  They will stick to the cover slip when they get to the top.  Don’t wait too long because the salt solution will begin to dry which will distort your eggs.

When the time is up, lift the cover slip straight up and set it on a glass microscope slide.  Give the cover slip a very gentle tap with your finger nail, which will squish out excess fluid.  Now you are ready to see if you have any parasite eggs in your sample.

 

Set the slide on the microscope stage. On some microscopes you will have to move the slide around with your fingers.If your microscope has a mechanical stage, like the one shown at the left, you will use the mechanical adjustment knobs to move the slide right, left, forward, and back. Mechanical stages are easier to use if you want to scan the whole slide which you will want to do if you want to estimate an egg count.Start with the lowest power which is usually 10X.  Move the stage with the course focus knob to just below the tip of the lens while watching from the side so you don’t break the cover slip.Then, while looking through the eyepiece, focus down until you can clearly see the level of the fluid between the cover slip and slide.  This can take some practice.  It helps to have the corner of the cover slip in view then focus down a little bit or find a bit of debris and focus on it.You may need to adjust the amount of light coming through the sample by opening or closing the diaphragm under the stage.  You will need more light at the higher power.Once you are in focus, begin to scan the slide for something interesting.  To scan the entire slide start at one corner, move all the way to the other side, adjust to the left or right a little then scan again all the way back to the other end.  When you locate an interesting object at the lower power, switch to the 40X lens.  Simply rotate the 40X lens into place and it will be positioned over the sample.  Switch back to the 10X and look around some more.Have fun!

This information was taken from  Goat Biology