Parasite Control for Goats

8/2/2019 Parasite Control for Goats

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Parasite Control for GoatsMeet the Enemy

byThe Southern Consortium for Small Ruminant Parasite Control

Part 1 of series

Part 2 Managing the Barberpole Worm Part 3 Integrated Parasite Management With FAMACHA Part 4 Dewormers and Dewormer ResistancePart 5 Alternative dewormers -Do they work?Part 6 Doing Your Own Research and Fecal Egg Counts

Internal Parsites (worms) cause more goats to die in the Southeastern U.S. than thetotal of the next three leading causes of goat deaths according to necropsy records fromKentucky State University. Controlling worms in goats is much more complex thancontrolling other goat diseases. Many other diseases can be controlled by simplemanagement practices and vaccination. Many goat producers in the past havecontrolled worms solely by the use of dewormers, but now goats still die due to theworms developing resistance to the dewormer and some goat producers in the humidSouth have gone out of the goat business because no dewormer was effective againstthe worms in their goats. Goats have a lower immune response to worms than mostother animals and therefore have greater problems with worms. There is a lot ofdisinformation on controlling worms which increases the problem. Our knowledge on

controlling worms in sheep and goats has quadrupled in the last decade due toresearch in Australia, New Zealand and South Africa and therefore many animalprofessionals may not be current on the recent developments. In fact, some of our oldgood management practices to control worms have been found to not be good and insome cases harmful.

This is the first of a series of articles which will appear in the Goat Rancher over thenext several months. The articles are written and reviewed by the consortium memberswhich include a number of parasitologists with an interest in small ruminants and anumber of small ruminant scientists so that the articles contain the most up to date andaccurate information on parasites.

This first article is an introduction to worms in sheep and goats. The next articlediscusses the life cycle of a goat worm and how we can use that knowledge reducetheir numbers. The third article describes dewormers and the correct use of dewormersand focuses on the problem of dewormer resistance and what can be done. The fourtharticle describes the FAMACHA system for reducing dewormer resistance and selectingmore resistant animals. The final article describes alternative (non-chemotherapeutic)methods for controlling worms and what supporting data is available.
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The purpose of this series of articles is to teach the producer to assemble his or herworm control program, using applicable management practices as the first line ofdefense against worms and using dewormers only when management is not enough tocontrol worms. Using this program, we can reduce the use of dewormers, reduce therate at which worms develop dewormer resistance and select for animals which have

genetic resistance against worms. This will enable the goat business to be sustainablein the face of dewormer resistance.

Although there are more than 15 species of worms identified in goats, we will discussthe most economically important worms and parasites in goats and list some usefulsources for further information. The most common worms in goats are gastrointestinalnematodes because they are nematodes which live in the digestive tract, predominantlythe stomach and small intestine. In this first paper, we discuss several other wormsincluding the tapeworm, the deer brain worm as well as coccidia and liver flukes whichare other types of internal parasites in goats which can be important at times.

Worms are a normal part of the animal's ecosystem. A low level of worms is desirableto keep the animal's immune system active against worms. However, excessive wormscauses disease. Excessive worms are caused by such things as a depressed immunesystem, consuming too many worm larva, filth and lack of sanitation, rainfall, closegrazing etc. Worms function in the ecosystem to keep animals from overrunning theecosystem when production conditions are good and they also prevent all animals fromstarving when there is a shortage of food. One cannot eradicate worms on your farm;you have to learn how to live with them and use management to control them to levelswhich do not harm animal production.

The most common worm (especially in the Southeastern US) that causes the majority of

deaths as well as depressed animal performance is the Barber pole worm (scientificname Haemonchus contortus). In figure 1 is a picture of a fresh barberpole worm withred and white stripes like a barber pole. The red stripe is the gut which is filled withblood which he has sucked from the animal that he infects. The white stripe is theuterus which contains eggs. This pretty well describes the barber pole worm; he is ablood sucking-egg laying machine. He sucks about half to one drop of blood per dayand produces 1,000-6,000 eggs per day. The barberpole worm can multiply rapidlyunder good conditions because of the large number of eggs that they lay. Since hesucks a half to one drops of blood per day, 1000 worms can suck two ounces of bloodper day, two quarts in a month, which is why your goat will die from a heavy infection.The goat can make blood fast enough to replace that consumed by a low level ofbarberpole worm infection, but as the infection gets worse, the goat is unable to makecomponents (red blood cells and blood protein) of blood fast enough to replace lostblood and the goat starts getting low on blood components. A low level of red bloodcells (a component of blood) is called anemia ( a thin layer of blood is pale because ofthe loss of red blood cells). The percent red blood cells in the blood can be measuredin the laboratory to determine the extent of anemia. You can determine if an animal hasanemia by looking at the color of the mucous membranes of the animal. Mucousmembranes are areas of tissue where the capillaries are close to the surface of the skin


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and the color of the skin reflects the color of a thin layer of blood. When an animalbecomes anemic these mucous membranes change from a healthy pink to a lighter pinkand then if the anemia is severe, the mucous membranes will be white as a sheet ofpaper. When mucous membranes become white, the animal is critically low on bloodand needs dewormed immediately. It must be remembered that other conditions that

cause blood loss such as liver flukes or lice can also cause anemia. Mucousmembranes that are easily observed are located on the inside of the lower eyelid(touching the eyeball), the gums (hard to see in animals with pigmentation in the mouth)and inside the vulva (often checked at goat dairies). A low level of blood protein alsocauses edema, due to a shortage of blood proteins to pull fluid back into the circulatorysystem. Edema is often seen as a pouch of fluid under the lower jaw. Angora goatsmay also get edema on the floor of the chest. When an animal gets edema, he isseverely low on blood components and needs dewormed promptly.

The barber pole worm is a tropical worm; he likes a warm climate and therefore,predominates in the South, although he can cause major problems in northern areas,

but for a shorter period of time. These worms require rain to infect small ruminants andtherefore are much less of a problem in the West or any location where there is lessthan 25" of rain per year. The barber pole worm also has a short generation interval,being able to complete a generation as quick as 4 weeks which enables him to developdewormer resistance quicker than for most other worms.

The barber pole worm is relatively large, and can easily be seen with the naked eye.He is about the diameter of paper clip wire and about an inch long. The barberpoleworm pierces the stomach lining and establishes connections to small blood vessels tosuck blood. If you open up the true stomach (abomasum) of a goat that has died fromworms, you will see some floating free, but most are attached to the stomach and they

may look like hair growing on the inside of the stomach. The barberpole worm will loseits coloration as it is exposed to air. The average lifespan of a worm in the stomach is 6months, but they can live longer than a year. The animal's immune system is constantlyfighting against the worms and may suppress egg production of the worm or cause it todie prematurely. The immune system on some occasions may have a hyperimmuneresponse and eliminate most of the worms in the animal. There are barber pole wormsin sheep and cattle. But the strain in cattle will not infect sheep or goats (and vice versa)except under unusual circumstances.

There are two temperate species gastrointestinal nematodes which are important ingoats and sheep. These are the Bankrupt worm (scientific name Trichostrongyluscolubriformis) and Brown stomach worm (scientific name Telodorsagia circumcinctaformerly known as Ostertagia). Although these worms do not kill as many goats as thebarberpole worm, under some circumstances they can cause important productionlosses as well as death of the goat. Many of the management practices which suppressthe barberpole worm will also suppress these worms. Since these worms are bestadapted to temperate conditions, they are more of a problem in the fall and winter ascompared to the barber pole worm which dominates in the summer. The mainsymptoms of a bankrupt worm or brown stomach worm infection is diarrhea , a slow


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growing animal, a rough haircoat and an unthrifty animal. In the next article in thisseries, we will be discussing the life cycle of the gastrointestinal nematodes mentionedabove with emphasis on management techniques that can be utilized to help control theparasites.

The tapeworm is another worm that causes goat problems. It seldom kills goats, butcauses poor performance, especially among young animals and may give them a pot-bellied appearance. Occasionally diarrhea is a symptom of tapeworms. Tapewormsegments can be readily observed in feces as they look like grains of rice making thisparasite easy to diagnose. The general tapeworms that infect goats will infect sheepand occasionally cattle. Tapeworms are located in the small intestine and can grow tobe several feet long. Tapeworms absorb nutrients from the digestive tract and thereforedecrease nutrition available for the goat. The immune system of mature animals usuallykeeps the tapeworm suppressed.

The tapeworm eggs are consumed by a grass mite (like a chigger) and the egg

develops to an infective stage in the body cavity of the mite over a 1 to 4 month period.The goat then eats grass on which the mite is crawling and becomes infected. It takes40 days from the time a goat consumes infected grass mites until the tape wormsegments appear in feces. Pasture areas that are infected usually remain infected forsome time although the mites may be killed by winter weather. Tapeworms are more ofa problem under intensive production systems. If young animals get infected in apasture, the general recommendation for cleaning the pasture up is to not graze apasture for a year (make hay or graze with another species of animal). Tapeworms arenot killed by all dewormers, but is controlled by the Benzamidole group of dewormers.Valbazen is one of the more popular dewormers used for tapeworm control.

Coccidiosis is a common goat parasite that appears when animals are stressed orsanitation is lacking. It mainly causes diarrhea, but unlike cattle, blood is seldom seenin the feces. Coccidia are normally present at low numbers in the digestive tract of theanimal, but the infection level is low and the immune system is able to prevent themfrom causing disease. Coccidiosis is a disease of stress and filth. The main route ofinfection is the consumption of feces due to uncleanliness. The animal is usuallystressed, depressing the immune system. Coccidiosis is most commonly seen in justweaned kids due to stress, lack of a mature immune system and fecal contamination.Stressing animals by shipping is also a major cause coccidiosis. Animals oftenconsume the infective stage coccidia from feces, such as fecal contamination in thefeed trough or water trough. Moisture whether by rain or humidity increases the timethat infective coccidia live. Therefore, keeping the goat's environment clean and dry willhelp prevent coccidiosis.

During times of stress, a medicated feed containing Rumensin or Deccox can be fedwhich is quite effective at preventing coccidiosis. Occasionally coccidiosis will still occurdespite feeding medicated feed, but fewer animals will be affected. Animals should betreated when diarrhea first starts if coccidiosis is suspected ( history of stress) becausedelaying treatment can result in scarring of the intestine and an poor-doing animal for


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life. Coccidia are not observed when feces are examined under a microscope in earlystages of disease, but they are very numerous later on. Coccidiosis may be treatedwith Corid (Amprolium) or Albon (Sulfadimethoxine). If Corid is used at too high a dose,or for too long a time, animals may develop a thiamine deficiency calledpolioencephalomalacia (animals behave like they are drunk) which can be readily

treated with thiamine and removal of the Corid treatment.

The meningeal worm or deer brain worm causes partial paralysis in goats, sheep andllamas that are exposed to the parasite by deer. The parasite occurs in deer and doesnot cause clinical symptoms as it does in goats. The larvae are passed in deer fecesand are ingested by a variety of snails and slugs where they develop into infectivelarvae over a 3-4 week period. The snails or slugs are consumed by grazing goats.Inside the goat, the larvae penetrate the intestine and migrate to the spinal cord throughthe abdominal cavity over a 10 day period. The larva gets lost in migrating from thespinal cord to the brain because the goat anatomy is different from the deer. They endup destroying brain tissue causing differing degrees of paralysis. Symptoms of the

brain worm include paralysis of one or more limbs, excessive tail twitching, circling,abnormal head position, blindness, inability to get up, toe dragging, being in a dog-sitting position or difficulty or exaggerated movement of limbs when walking. Thedisease usually occurs in the fall and winter. There is no treatment for the brain wormthat is very effective. Sometimes it is treated with high doses of various dewormers(fenbendazole and ivomec) and steriods, but treatment is often not effective.

Since the parasite is carried by deer and uses a snails or slugs as the infectiveintermediate host, prevention consists of discouraging deer from using the pasture andmaking the environment unfavorable for snails and slugs. As goats clear the cover froman area, deer will visit that area less frequently. Guard dogs may chase deer away from

pastures. A number of snails may serve as intermediate host and some may be sosmall (1/4") as to be overlooked. Snails prefer water, and so swampy areas are goodhabitat for snails. Therefore, fencing goats out of areas that often have water can helpon prevention. Slugs and some snails prefer organic matter, leaf piles and compost.These areas may be cleaned up if the area is not extensive. Guinea hens and Muscovyducks are reputed to be effective at controlling snails and slugs and may aid inprevention of the deerworm. Some producers deworm goats every 30 days from 30days after the grazing season until a hard freeze to prevent the deerworm. Ivomec andfenbendazole (Safeguard, Panacur) are the most common dewormers used for thispurpose. This will likely create dewormer resistance, but for many people, thesedewormers do not work for roundworms. One producer used a low dose of Rumatel fedevery day in a minimal amount of corn and appeared to be effective.

Liver flukes may be caused by the common liver fluke and less commonly by the largeAmerican liver fluke (also called the deer fluke). The flukes invade the liver and causeinternal bleeding. A goat with high numbers of flukes will have an acute infection, wherethe animal stops eating, has pale mucous membranes, gradually does not get up andoften dies within days. With fewer numbers of flukes, the symptoms may be milder andis called a chronic infection. The animal will have a poor appetite, lose weight for longer


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than a month, poor body condition, rough hair coat, rapid heartbeat, pale mucousmembranes and sometimes edema, especially bottle jaw.

Liver flukes can infect wildlife, cattle sheep and goats and even man. The fluke layseggs in the bile duct of the animal it infects and the eggs end up in the feces. The

infective larva develop inside the egg over a 2-3 week period which then infect snails.These are the common pond snails which are in or around water and may range form1/4" to nearly 3" in length. The larvae further develops in the snail over 5-7 days andthen becomes a true infective larvae which leaves the snail and attaches to grass wherethe goats may consume it. Once consumed, the fluke further develops and penetratesthe intestine on its way through the abdominal cavity to the liver. Once in the liver, itstarts consuming the liver. Prevention includes fencing off ponds or marshy areas in thepasture. Muscovy ducks and guinea hens may be used to control snails.

The snails are mainly active from January/February through May/June depending onenvironmental conditions. Thee snails burrow into the mud and become dormant

through the hot summer months and the rest of the year. Because of this pasturecontamination peaks late summer, early fall, withpeak incidence of clinical disease inlate fall, early winter. Control of the liver fluke is dependent on the stage of the larvae,which depends on the time of the year. Chlorsulon and valbazen is effective late in theyear when flukes are mature. Chlorsulon is the only product that is effective againstimmature flukes, in early stages of infection as well as mature flukes. Consult localveterinary expertise for the time of the year to treat for flukes.

Lungworm infections results in respiratory distress such as painful breathing, chroniccoughing, unthriftiness and death. There are several kinds of lungworms that live in thelungs of animals. Infection usually happens during the cooler months of the year. One

kind of lung worm has a direct life cycle, the larvae are coughed up, go out in the feces,develop to infective worms in one to two weeks. The infective stage is killed by hardfreezes or hot dry summer. These larvae can live a long time in a cool dampenvironment. These larva develop into adults a month after being consumed. Severalother kinds of lung worms have an indirect life cycle, that is they spend part of their livesdeveloping in many species snails and slugs. Fortunately, these worms are easilycontrolled with the drug Fenbendazole (Panacur or Safeguard). Other dewormers suchas levamisole and Ivomec are effective on some species of lung worms, but ineffectiveon other species.

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Parasite Control for GoatsManaging the Barberpole Worm


Part 2 of Series

Part 1 Parasite Control for Goats: Meet the EnemyPart 3 Integrated Parasite Management With FAMACHA Part 4 Dewormers and Dewormer ResistancePart 5 Alternative dewormers -Do they work?Part 6 Doing Your Own Research and Fecal Egg Counts

The previous article was an introduction to the major worms affecting goats and sheep.This article develops our understanding of the biology of the worm, how sheep andgoats become infected and using that knowledge to develop management practices tohelp control the worm.

While this article is targeted to the Barberpole worm (Haemonchus contortus), the mosteconomically important worm of sheep and goats, most principles apply to the othermajor roundworm of goats and sheep, the Bankrupt worm or Black scour worm(Trichostrongylus colubriformis). We need to remember that the parasite game is agame of numbers; how many worms does your goat have. A few worms areacceptable, maybe even good, because they keep the immune system active against

roundworms, but too many worms will cause lost production, sickness and even death.So, we want to reduce numbers at whatever stages of the life cycle we can, realizingthat something out of control at another stage may overwhelm the good that we havedone at another stage. We have to look at our whole parasite program. The next articlewill be devoted to developing a parasite control program to include FAMACHA, asystem of scoring the color of the eye mucous membranes (inner surface of lowereyelid). After that, there will be an article on dewormer resistance and selection ofdewormers. The last article will cover alternative dewormers.
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Goats and sheep get infected with worms by picking up infective larva on pasture thathave developed from eggs in the fecal pellets. Eggs are laid by worms in the truestomach or upper small intestine and flow with the digesta until it becomes a pellet;undigested residues with the eggs trapped in the residues. Basically, kids and lambsare not infected with roundworms when they are born as may happen with dogs and

other species, rather, kids and lambs pick up their first worms from larvae on thepasture. Since they graze little in early life, it may take several weeks for them to pick uptheir first worms. The first stage in the life cycle of the Barberpole worm is the hatchingof the egg in the fecal pellets. The number of eggs available to hatch per acre isimportant in that if there are few eggs, even with a 100% hatch rate, there will be fewinfective larvae. Conversely, with many eggs per acre, even with a poor hatch anddevelopment success rate, there will be many infective larvae and parasites will bemore of a problem.

The number of eggs per acre is affected by two factors, stocking rate and how manyeggs the worms in each goat is producing (how many worms the goat has). High

stocking rates such as 10-12 animals per acre will produce many more eggs per acrethan two animals per acre. It is thought that if you have a stocking rate less than twoanimals per acre, stocking rate is not a major contributor to pasture contamination. Theother factor is the number of worms (and eggs produced by them) produced peranimal. For example, if we have slightly wormy animals with 400 eggs per gram in theirfeces, pasture contamination will slowly build. However, if our parasite problem is badand a few animals die due to worms, the average fecal egg count of the herd may be 4-10,000 eggs per gram, which very rapidly leads to a high level of pasturecontamination. Even when we do deworm, the animal, there are so many infectivelarvae on pasture that animals will need to be dewormed again in 3 - 4 weeks becausethey are picking up so many larvae from the pasture. We need to think about pasture

contamination as part of our parasite management.

Older parasite management strategies realized the importance of pasture contaminationand prevented it by frequent deworming during critical times (usually lactation andsummer grazing) which helped to reduce pasture contamination, but such a strategy isnow recognized to increase dewormer resistance of the worms due to the frequentdeworming. This management strategy is not an acceptable practice because of theincrease in dewormer resistance (means that the dewormer that we are using will notkill worms after a short period of time). Also, we can reduce pasture contamination byselecting animals with low fecal egg counts and monitor the level of worm infection ofanimals with FAMACHA or fecal egg count and deworming animals when needed toavoid heavy pasture contamination. It has been shown that 15% of the wormiestanimals contribute 50% of the total eggs on a pasture and 30% of the wormiest animalscontribute 75% of the eggs. Culling of these animals will result in a marked reduction inpasture contamination and consequent parasite problems for the whole herd.

TableEffect of pasture contamination (eggs per acre) and hatch rate on infective larvae


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400 eggs 95% hatch = 380 larvae6,000 eggs 25% hatch 1,500 larvae

Managing pasture for goats and sheep is different from cattle in that instead ofmaximizing forage or animal production being the management objective, the

management objective becomes controlling parasites. Pasture rotation can reducepasture contamination, especially if there is a long enough rest period for infective larvato die. Grazing sheep or goat pastures with cattle or horses will reduce infective larvasince the infective larva die after being consumed by cattle or horses. Levels of infectivelarva can also be reduced by making hay or tillage. Incorporation of one or more ofthese management practices into your pasture rotation program, it will help you reducethe level of infective larvae on pastures.

Two conditions are required for worm eggs to hatch and develop to larvae, they arewarmth, and moisture (rain, dew, humidity). The Barberpole worm likes it warm with86oF is the ideal temperature for hatching eggs and developing infective larvae which

will result in infective larvae being available in as little as 6 days. Eggs will still hatch upto 100oF, but with a reduction in hatching rate. Barberpole worm eggs do not hatch anddevelop when temperature is less than 50oF however, the Bankrupt worm will hatch atlower temperatures, which is the reason that they are greater problems in cooler timesof the year. This is the reason why there are fewer Barberpole worm problems inwinter. In the southeastern US, the winters are not cold enough to kill worm larvae, butthe cold weather does slows down hatching and rate of development and reducespasture contamination and consequent worm problems. However, remember that youranimals still have worms from the larvae that they picked up prior to cool weather andinfective larvae are still out there on the forage for a period of time.

The major environmental effects on worms are caused by temperature andmoisture (rain, humidity or irrigation). Moisture is essential for the eggs todevelop to infective larva. This is why worms are little problem in drier climatesand a big problem in wetter climates.

Moisture is required for the egg to hatch and develop. The fecal pellet has sufficientmoisture in it for the eggs to hatch and develop. In fact, we hatch worm eggs in thelaboratory by suspending a cheesecloth bag of fecal pellets in a quart jar with a littlewater in the bottom (humidity 100%) at room temperature (75oF) for a week or so andthe larva are fully developed and ready to be used to infect animals. Underneath somesod pastures such as Bermudagrass, the microenvironment is humid and not as hot asthe outside temperature, resulting in ideal egg hatching conditions during the summer.In drier areas or when the weather is dry, the pellet crusts over and as the pellet driesfrom the outside in, the developing larvae move towards the center of the pellet where itis more moist. Dry conditions will reduce the success rate of hatching and especiallyhot, dry conditions. This is the reason why worms are less of a problem during drought(except when animals graze down close to the ground). If the pellet is in open pasture


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and exposed to the sun, the pellet will be heated over 100oF and the longer suchconditions prevail, more eggs and larvae will die in the pellet.

The egg, under conditions of warmth and humidity hatches in the pellet to a first stagelarva abbreviated L1. This larva cannot infect your goat, but must grow and develop

through several larval stages to become an infective larva. The first stage larva wiggleshis way through the fecal pellet, eating bacteria and growing. Then it molts, this issomewhat like a snake shedding his skin and becomes a second stage larva (L2). Thesecond stage larva does much the same thing as the first stage larva, wiggling his waythrough the fecal pellet, eating bacteria and growing. The second stage larva thenmolts to become a third stage larva (L3) which is the infective stage larva that your goatwill pick up from pasture. This will happen as quick as 6 days in temperate regions and4 days in tropical regions. However, this molt is an incomplete molt. The skin onlypartially comes off and slips down the worm's body. This is a good news/bad newssituation. The good news is that the larvae has a second skin which makes him moreresistant to drying out (L1 and L2 are susceptible to being killed by drying out). The bad

news is that the partially shed skin covers his mouth which prevents him from eating.This means that he must live off his body stores until he gets into your goat. If his bodystores run out before he gets into your goat, he dies. These larva are very small, like thethickness of spider web and about as long as the period at the end of this sentence, soyou cannot see them with your eye. If you have a good magnifying glass and knowwhat you are looking at, you can see the larvae (look like eyelashes).

Larva may be killed in the feces by nematophagus (worm trapping) fungi, literally funguswhich parasitize nematode larvae (worms are also called gastrointestinal nematodes).The fungus forms loops that look like an Easter basket handle and as the larva wiggleshis way through the fecal pellet, he goes through the loop which traps him. The fungus

then kills the larva and uses its body to reproduce more fungus. These fungi arenormally present in feces at a low levels and do reduce larval numbers to a smalldegree. However, research on feeding high levels of fungal spores to animals greatlyreduced the number of infective larva and thus is effective in reducing pastureinfectivity. But, the fungal spores must be fed every day to be effective. Hopefully acommercial product will be developed from this technology. In addition, the forage,sericea lespedeza appears to reduce hatch rate and development of larvae in the feces,also aiding in reducing pasture contamination. A similar reduction in hatch rate andlarval development has been observed for a number of plants, many of which containtannin. However, there are many types of tannins and not all are effective against wormeggs and larva.

Since the larva is cold-blooded, his metabolism runs slow in cold weather, his bodystores will last a long time, and he may survive as long as 180 days. However, when itis hot (summer), his metabolism goes much faster, burning up the body stores and maysurvive only 30-40 days. There are several studies on grazing systems to avoidparasites using rotation grazing. A study on native species range in the US(Oklahoma) utilized 14 pastures and moved animals every 5 days with a 65 day restperiod during the summer. Animals were fenced in with temporary electric fencing


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which was moved every 5 days. Fecal egg counts of goats remained low throughoutthe summer and pasture contamination was low. Animals were moved before any L3infective larvae had developed and the infective larvae that did develop later, diedduring the 65 day rest period since the weather was hot. Forage quality remained goodsince this was a native tallgrass pasture. If improved grasses are used in this grazing

system, the forage quality would be too low at the end of 65 days to be nutritious toanimals. Therefore, some modifications would be suitable for utilizing such improvedgrasses. Grazing cattle or horses 3 to 4 weeks after the goats would help in that theywould pick up goat and sheep worms which would not infect them as they have differentworm parasites. Goats would follow the cattle or horses in 3 to 4 weeks. Another optionis to make hay on the pasture which may eliminate most of the larvae. When the larvaeare baled up with the hay, they will eventually die when they run out of body stores.

And, since hay bales often generate heat, the larva can die from the high temperature.A grazing system in the tropics used a 3.5 day grazing period (moved animals offpasture before there were any L-3 infective larva) and 31.5 days of rest (larva ran out ofbody stores in hot tropical weather). This was a 10 pasture grazing system on alfalfa.

Using these types of grazing systems, it would be possible to raise goats and/or sheepwith little use of dewormers.

Tillage is another way to reduce larval contamination on pastures. If larvae are buriedunder an inch of soil, most will die. If annual pastures such as winter wheat, or ryegrassor summer sudangrass are grazed, tillage between grazing seasons will kill manyinfective larvae from the previous grazing season, creating a pasture with reducedinfectivity.. Several chemicals have been investigated for use in killing larva on pasturesand to date, no product has proven effective. Pasture rotation, at appropriate intervals,may reduce the number of infective larvae your goat consumes. However, worms arenot effectively reduced by a 4 pasture rotation system when animals graze one week in

each pasture. This is because the 3 week rest period is just enough time for infectivelarvae to build up to maximum levels and not long enough for larvae to die. .Trees canincrease parasite problems because they provide shade, humidity and cause animals tocongregate (more feces, grass grazed close to ground, more mouths to pick up infectivelarvae). Rotation grazing with a long rest period reduces problems caused by trees.Barns and watering areas can concentrate animals and also have a similar effect totrees.

Management factors that reduce worm problems1. Pasture rotation, especially with a long rest period2. Grazing pastures with cattle or horses3. Harvesting hay4. Tilling soil on annual pastures5. Grazing browse

Once the larva reaches the infective stage, he has a problem: He can't very well get intoa goat to infect him it is still in the fecal pellet since goats don't generally go aroundeating fecal pellets. The fecal pellet has a hard crust on it by a week after the goat


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produced it and the larva can't penetrate this crust to escape. The pellet needs to bebroken up so the larva can escape. Generally, rain soaks the pellet, softening the crustmaking it easier to be broken up. Two inches of rain in a month's time is sufficient toenable larvae to escape. The goat's feet may also break open the pellet as well as fowlor wildlife. If the pellets are broken up shortly after the goat dropped it, the pellet will dry

out and the L1 and L2 larvae and eggs in the pellet will quickly die. However, if thepellet is broken open when there are infective L3 larvae present, they will be released toinfect the goat. After being released from the pellet, the infective larvae travel on a filmof water (from dew or rain). The larvae cannot swim, but wiggles and drifts whereverthe film of water takes them. Larvae may be carried up a pasture plant or under plantresidues such as a fallen leaf. They only go as far as the film of water takes them,usually only two to three inches up the plant. The infective larva rests on the plantwhere the moisture has taken it so it can then be consumed with the plant by grazinganimals. The infective larvae can live on the plant until they run out of body stores. Ifthe larvae in the pellet is not released, they can survive in the pellet until they run out ofbody stores. So, that can be a month or more before rain comes along to release

them. A heavy rain can cause the release of a month's accumulation of infective larvae,resulting in a sudden, dramatic increase in infective larva on the pasture. Very hottemperatures especially when it is dry can result in a high mortality rate for the infectivelarvae, reducing pasture infectivity. Generally, larvae accumulate over the summergrazing season, making for greater parasite problems in mid- and late- summer if thereis adequate moisture. This is one reason why kids born early in the kidding seasonoften do better and wean heavier than kids born late in the kidding season.

Since the larva do not go very high up the plant, when goats consume browse, they pickup very few larvae since they are eating higher than the larvae and therefore, usuallyhave very few worm problems. Conversely, when pastures are grazed short, goats and

sheep consume many larvae, resulting in major worm problems. On some pasturessuch as bermudagrass, goats will patch graze i.e. have favorite spots where the pastureis grazed down to less than 3 inches high. This will result in a heavy worm infectioneven though most of the pasture is greater than 3 inches high. The solution to patchgrazing is rotation grazing.

Once the infective larva has been consumed by a sheep or goat, it molts to a fourthstage larva. This larva may suck blood and further develop into an adult wormcomplete with sex organs and mate, producing eggs in about three weeks, or it maybecome arrested in development (arrested fourth stage larva), kind of like hibernatingin the stomach. One caution with fecal egg counts, if the animal suddenly picks up alarge number of infective larva, they are sucking blood but there will not be any eggsshowing up in the feces until 3 or 4 weeks later. So negative or low fecal egg counts donot always mean no or few worms. Since it takes at least a week for the egg to hatchand develop to infective larvae and then at least three weeks to develop to maturity andlay eggs after ingestion by the goat or sheep the generation interval is 4-5 weeks for theBarberpole worm. This is the reason why deworming every 4-6 weeks is so effective atdeveloping dewormer resistance, because each generation of worms is selected fordewormer resistance. Also, the 4-5 week generation interval is why the Barberpole


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worm can build its population numbers so explosively under good environmentalconditions (warm temperatures and frequent rain or irrigation).

The arrested form of the larvae is a survival mechanism, enabling the Barberpole wormto survive the winter in cold environments. The eggs produced by worms during the

winter do not hatch due to cold temperatures. Many of the worms in the animal that arelaying eggs will die of old age over the winter. The average life span of an adult worm is4-6 months, but some may live longer. A strong immune response by the animal cancause early death of the worms. Worm and fecal egg counts will often be low in thespringtime. The arrested larvae are in reserve, safely nestled down in the glands in thestomach where they do not trigger an immune response. The arrested larva requires ahigher dose of the benzamidole class of dewormers (Panacur, Safeguard, Synanthic,Valbazen) to kill them. Since these dewormers were less effective on arrested worms, itwas a common recommendation in years past to deworm again two weeks after the firstdeworming when the arrested larvae developed and took the place of the worms thatwere killed. Sequential dewormings are not needed with other classes of dewormers

such as ivermectin (Ivomec), moxydectin (Cydectin) or levamisole (Tramisol, Levasoleor Prohibit) are used because they are effective at killing arrested larva of theBarberpole worm.

The main trigger for the arrested form to develop into an adult is kidding or lambing.The exact mechanism for triggering the development of the arrested worms is notknown, although, longer day length, kidding, lactation and green grass are all supportedby scientific evidence. This is the reason for the recommendation to deworm aroundkidding/lambing time. By deworming at this time, you may eliminate most of thearrested larva as well as active worms (depending on the dewormer resistance status ofthe worms; worms and larvae that are resistant to the dewormer used will survive) and

start the kidding season with very low level of pasture contamination. In addition, thelactating animal is very susceptible to worm infection (from grazing) during this timebecause lactation depresses the doe's or ewe's immune system.

The immune system is the first line of defense against worms. The immune system hasgenetic and environmental components that determine its effectiveness at suppressingworms. Since fecal egg counts are moderately heritable, one can make progress overseveral generations by selecting animals for low fecal egg counts. Genetics of the herdcan also be improved by simply culling the worst animals each year as identified byFAMACHA eye scores. Since the buck contributes more than 50% of the geneticmaterial to the herd, his genotype is very important. Not only should his fecal eggcounts or FAMACHA scores be evaluated, but the fecal egg count or FAMACHA scoresof his sons and daughters. Culling animals with high fecal egg counts or highFAMACHA scores can not only improve the herd genetics for resistance to worms, butalso substantially reduce the number of infective larvae on the pasture, thus reducingworm problems for the whole herd.

The major environmental components of the immune system are nutrition and stress. Itis well known that stress depresses the immune system. This includes stress such as


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other sickness (coccidiosis, pneumonia, pinkeye etc.), shipping, putting with a newgroup of animals (need to establish pecking order) etc. Nutrition includes adequateprotein and energy as well as minerals and vitamins. When animals suffer from poornutrition, nutrients going to the immune system are diverted to other body functions sothe animal may survive, but this makes the animal more susceptible to disease and

parasites. There are many examples in the literature of protein and/or mineralsupplementation decreasing fecal egg counts, likely by boosting the immune response.

The animal's immune system is the first line of defense against worms. Someanimals are more resistant than others to worms due to genetics. However, theimmune system must be fueled by good nutrition. The immune system can bedepressed by disease or stress, making the animal more vulnerable to worms.

To summarize, here are a list of environmental conditions that increase worm problemsand when these conditions occur, you need to be concerned about worms so that youdo not lose animals.

1. Temperatures warmer than 50oF.2. More than two inches of rain in a month.3. Long residence time on the same pasture4. Grazing close to the ground5. Stressed animals either by undernutrition, disease, shipping etc.6. Stocking rate greater than five animals per acre.

To summarize, here is a list of things the manager can do to help his goats fight worms

1. Pasture rotation, especially with long rest periods

2. Grazing browse or eating high off the ground3. Using good nutrition4. Grazing cattle or horses with sheep or goats5. Making hay6. Tillage of pastures7. Monitoring parasite infection using FAMACHA or fecal egg counts8. Culling animals with the most parasite problems9. Deworming around kidding time

The next article will show how to incorporate these management practices into aparasite control program.

A good reference on management to control parasites is a publication by ATTRA,Managing Internal Parasites in Sheep and Goats. It can be obtained by calling 1-800-346-9140 or can be printed fromATTRA's web site.
http://attra.ncat.org/attra%E2%80%91pub/parasitesheep.htmlhttp://attra.ncat.org/attra%E2%80%91pub/parasitesheep.html


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Parasite Control for GoatsIntegratedParasite Management With FAMACHA


Part 3 of Series

Part 1 Parasite Control for Goats: Meet the EnemyPart 2 Managing the Barberpole Worm Part 4 Dewormers and Dewormer ResistancePart 5 Alternative dewormers -Do they work?Part 6 Doing Your Own Research and Fecal Egg Counts

The objective of this article is to help you develop an integrated parasite managementprogram for your farm that is sustainable i.e. enables you to stay in the goat or sheepbusiness for the long term despite some dewormer resistance. In warm, humid areas ofthe US, producers are being forced out of the goat business due to managementpractices leading to severe dewormer resistance. When you have a climate that isgood for worms and no available dewormer kills the worms, the goats/sheep will die andcontinue to die until the producer goes out of business.

Most people think a parasite control program consists of (1) how frequently do wedeworm, (2) which dewormer to use and (3) how much to use. This strategy has led usto high levels of dewormer resistance in the worm population, resulting in frustration,

and animal deaths. We know that it is possible to have a parasite management planthat requires reduced or even no use of dewormer drugs, which is important to anyonewho wants to stay in the goat or sheep business, but especially so to those raising anorganic, chemical free or natural product. It is also important if a high level of dewormerresistance exists on a particular farm.

An integrated parasite management program consists of several components. The firstis to identify the parasite that are causing the problem, which in the Southeastern USwill be the Barberpole worm (Haemonchus contortus). In other drier and cooler areas,the Barberpole worm may be a minor or less severe problem. In cooler climates andtimes of the year, the Bankrupt worm (Trichostrongylus colubriformis) and the Brownstomach worm (Teledorsagia circumcincta) will be more important. In some geographicareas the thread-necked intestinal worm (Nematodirus species) can be a problem.Clinical symptoms of the Barberpole worm is anemia since he sucks blood which can bemonitored by FAMACHA . Clinical symptoms of the other worm species are usuallydiarrhea and fecal egg counts are the only available tool to monitor these other species.

The second step of integrated parasite control is to understand the biology of theparasite, which was presented in the second article of this series. Factors such as
http://www.wormx.org/SCSRPC/Publications/part1.htmhttp://www.wormx.org/SCSRPC/Publications/part2.htmhttp://www.wormx.org/SCSRPC/Publications/part4temp.htmhttp://www.wormx.org/SCSRPC/Publications/part4temp.htmhttp://www.wormx.org/SCSRPC/Publications/part5.htmhttp://www.wormx.org/SCSRPC/Publications/part6.htmhttp://www.wormx.org/SCSRPC/Publications/part1.htmhttp://www.wormx.org/SCSRPC/Publications/part2.htmhttp://www.wormx.org/SCSRPC/Publications/part4temp.htmhttp://www.wormx.org/SCSRPC/Publications/part5.htmhttp://www.wormx.org/SCSRPC/Publications/part6.htm


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temperature and moisture are important since they are required for the eggs to developto infective larvae and therefore determine how many infective larvae are available foryour animal to pick up.

The third step is to develop a set of management practices to suppress the kind(s) of

parasite that are applicable to your production system. This was also covered in thesecond article and included such practices as rotation grazing, making hay, tillage, notgrazing close to the ground, managing for lower stocking rates, grazing browse andselecting for resistant animals. Write down what practices you plan to use and thenhave the discipline to follow your plan. Making hay may be a viable managementpractice to reduce the level of infective larvae during the spring when grass growth isoften excessive. If making hay is not possible, it may be possible to graze cattle orhorses on the pastures following goats. If you don't own cattle you may be able to leasesome, borrow a few from a neighbor or graze stocker calves. Some sort of rotationgrazing system to help out not only with parasite management but also foragemanagement. Electric fencing can be used to readily subdivide pastures, but requires

management if it is to be successful. If you use summer annual pastures (such assudan/sorghum, sudan or millet) these pastures start out without infective larvae(assuming that they were clean tilled) and keep the animal grazing high off the ground,they will pick up few infective larvae. You may be able to lease or borrow some pasturethat is brushy or weedy and clean it up while grazing pasture that is uninfected withlarvae and keep your animals grazing high above the level of infective larvae. You maybe able to incorporate sericea lespedeza into your pasture program since it has beenshown to suppress worms. You may have a neighbor that wants to control sericealespedeza, you may be able to use your sheep or goats to graze it for control at verylittle cost.

If worms have caused you problems in the past, you need to do something different ifyou plan to survive in the sheep/goat business. This may mean doing some things thatyou have never done before or you may need to do things differently than you havedone them before. Solutions requires creativity and thinking outside of the box. Youmay have to learn some new skills or team up with another person for help on theproblem. You may have to learn to use electric fence for rotation grazing or grazing anarea that goats have not grazed on before. You may need to keep fewer goats if yourun out of forage resulting in the animals grazing closer to the ground.

The fourth part of integrated parasite management is monitoring the degree of infectionand applying control (deworming) only when the level of infection of an animaldepresses production. This may be done by monitoring fecal egg counts or byevaluating animals at regular intervals with the FAMACHA chart. The latter is moreconvenient, but is only applicable when the Barberpole worm is the target parasite.Fecal egg counts (FEC) can be used to monitor the level of worm infection in a herd. Ifthe herd is small, all animals may be sampled whereas in a larger herd, a portion (10-20%) of animals are sampled. The same animals should be sampled at each time.When temperate species worms predominate (cooler climates and at cooler times of theyear) fecal egg counts in conjunction with body condition and fecal consistency


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(temperate worms cause diarrhea in varying degrees) will need to be used. Fecal eggcounts have a disadvantage in being more expensive and time consuming thanFAMACHA. Information about the FEC of a few individuals is extrapolated to the wholeherd and if they are high, the whole herd must be dewormed, a procedure thatincreases dewormer resistance as compared to selective deworming individuals with

the FAMACHA system. One should deworm animals only when they need to bedewormed, not because it is that time of the year or because you are working theanimals anyway or just to be sure there are no worm problems. The exception to thiswould be strategic deworming around kidding time to get arrested worms and slowdown the rate of infection for lactating animals since they are more susceptible toworms. In sheep breeds that have significant resistance to worms, this may not benecessary. When temperate species of worms predominate (cooler climates and atcooler times of the year) fecal egg counts are very important since the FAMACHAprocedure will not diagnose those worms.

Reducing the use of dewormers will reduce the rate of development of dewormer

resistance in the worm population on your farm. The next article will cover the selectionand proper use of dewormers. Each time a goat or sheep is dewormed, it should berecorded. Worms, like wealth are not equally distributed among all individuals. A smallportion of your animals (20-30%) will carry a major portion of the worms (70-80%),presumably because their immune system is genetically weak for resisting worms.These animals are producing most of the eggs and larvae for infecting the rest of theherd. If we identify and cull these animals, we will substantially reduce our wormproblems. By recording when each animal is dewormed, those that need dewormed themost frequently are the ones carrying the most worms and should be culled. Fecal eggcounts are moderately heritable in sheep and goats (heritability =.30). This level ofheritability means that a good portion of the differences in worm levels within individuals

in a herd or flock is due to genetic differences. We can make significant progress inselecting for resistance to worms over several generations. The Katahdin Hair SheepInternational is working on a protocol to measure worm resistance in lambs and produceEPD's (expected progeny difference) for fecal egg counts. There is potential for asimilar program to be used in the goat industry.

The next step is evaluation of how your parasite control management program isworking. If very many animals need dewormed in any year, you should determine why.Refer to information in article two of this series. Once the reasons are identified,modify your parasite control program accordingly. As your parasite managementprogram gets better and your genetic base of the flock or herd becomes more resistantto worms, less deworming will be necessary. However, continue to be cautious,because weather conditions change within a year and from year to year, and canincrease parasite challenge. The introduction of new animals can create an additionalchallenge. Management changes related to pasture management, stocking rate, planeof nutrition may increase worm problems, even resulting in the death of animal(s) if webecome complacent.


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Five steps of Integrated Parasite Control

1. Identify worm(s) causing animal production problems (morbidity, mortality andreduced production). In the Southeast US, it will be the Barberpole worm.2. Learn as much as you can about the biology of the worm causing problems so

that you can utilize management practices which suppress parasite reproductionand development.. Evaluate the impact of your standard management practiceson worms and revise as necessary.3. Plan what management practices applicable to your operation. Stick to yourplan unless it is obviously not working.4. Evaluate the worm status of animals. Use either fecal egg counts or theFAMACHA system. Deworm only animals those that need to be dewormed.5. Re-evaluate your worm problems and determine which management needs tobe changed to control worms. Revise your parasite control plan for next year.

The use of fecal egg counts is a necessary tool of a parasite control program. It is thebest and quickest way to determine if your dewormer is/isn't working. It is also the onlyway to really tell the level of infection of the Brown stomach worm or the Bankrupt wormsince these worms do not cause anemia (they do cause diarrhea though) which ismonitored through the FAMACHA system. You can learn to do your own fecal eggcounts rather easily. There are instructions on how to do this on these web sites:www.SCSRPC.org and http://www2.luresext.edu/goats/training/herdhealthI.html (scrollto bottom).

The easiest way to monitor the need for deworming is to use the FAMACHA chart if theBarberpole worm is the problem species. The FAMACHA chart was developed in South

Africa in response to dewormer resistance that was causing major problems in sheepproduction systems. The name of the chart is an acronym from the name of a famousSouth African parasitologist Dr. Fafa Malan with chart added to get FAMACHA.

Although originally developed for use in sheep and it was successfully validated for usein goats in the USA through research support from Southern SARE. The validationexercise did include sheep as well as goats and involved several of the institutions thatare currently a part of SCSRPC. This parasite management tool consists of a colorchart for comparison of eye mucous membrane color and rules for proper use of thechart. Figure 1 shows a picture of the FAMACHA chart (actual chart is in color).
http://www.wormx.org/SCSRPC/Files/Files/RKJMMcMaster.pdfhttp://www2.luresext.edu/goats/training/herdhealthI.htmlhttp://www.wormx.org/SCSRPC/Files/Files/RKJMMcMaster.pdfhttp://www2.luresext.edu/goats/training/herdhealthI.html


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figure 1

FAMACHA is an important tool in an integrated parasite management program. Itidentifies animals that have a high enough level of the Barberpole worm infection toreduce animal productivity. Only those individuals need to be dewormed. Since theBarberpole worm sucks blood, the of resultant degree of anemia. will cause lostproduction or even death of the animal. Anemia is reflected in the color of the mucous

membranes i.e. a healthy reddish-pink color reflecting no anemia, whereas pale mucousmembranes reflect a degree of anemia. By monitoring the degree of anemia,(using eyemucous membrane color as an indicator) we can identify animals that need to bedewormed to prevent a loss in animal production and to prevent death. Usually only aportion of the animals in a herd need dewormed (animals to right of arrow as shown infigure 2). The remainder of animals are not dewormed which reduces the developmentof dewormer resistance which will be discussed in the next article. This also reducesdewormer expense.

figure 2

Mucous membranes that are readily observed are located on the inside of the eyelid,the gums (difficult to gauge anemia in animals with pigmented gums) and inside thevulva (often checked by dairy goat people when animals are being milked on a milk

stand). The FAMACHA system was developed based on the eye mucous membrane,which is on the inside of the lower eyelid where it touches the eyeball. It is convenientto see the membrane by holding the animal=s head, slightly pressing down on the top ofthe eyeball (causes third eyelid to stay out of way), and pulling down on the skinimmediately below the eyeball. The lower eyelid will roll out and can be readilycompared to the FAMACHA chart. By using a series of color chips to match mucousmembrane color, we can determine the degree of anemia and consequently, whetheran animal needs to be dewormed. Since the Bankrupt worm and Brown stomach worm


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do not suck blood, FAMACHA will not bean effective indicator for controlling thesespecies of worms. These worms are more prevalent during cooler times of the year andneed to be monitored with fecal egg counts or monitoring animals for diarrhea. Yourlocal veterinarian or animal extension specialist should be able to help you identify timesof the year when these worm species are more prevalent.

The FAMACHA chart was originally brought into the US by the Southern Consortium forSmall Ruminant Parasite Control. The agreement was that the chart could only be soldto Extension Educators, agricultural teachers and producers who had completed hands-on training following the specified curriculum (Some exceptions made for veterinariansand Extension Specialists who already had the prerequisite training). Training sessionsare posted to the website (www.scsrpc.org) as well as further information about theFAMACHA chart. Most states have qualified trainers which can be identified throughyour state sheep or goat extension specialist. Some trainers are listed on the SCSRPCweb site.

The FAMACHA chart is small enough to be fastened to the back of the hand for readycomparison when the lower eyelid is pulled down. The chart is calibrated for observingthe eye of the animal in direct sunlight (the type of light may affect appearance of color,ask any woman about the effect of different kinds of light on makeup). Animals shouldbe observed in direct sunlight and matched to the chart. Color memory is not as goodas a person thinks (why do women take swatches of fabric to the store for matching?)Therefore, the chart should always be used for matching colors. If the animal's eyecolor is in between two chips, score as the lighter chip (higher number).

When scoring eyes, one should remember that some environmental factors can affecteye color and make the eye appear redder and make the animal not appear anemic.

Factors include hot and/or dusty conditions which can irritate the eyes, infectious eyediseases (pink eye) and fever. In addition, remember that there can be other causesof anemia besides the Barberpole worm and deworming will not fix those anemias.Other causes includes liver flukes (most likely a problem in the Gulf Coast andNorthwestern States), sucking lice, nutritional deficiency, bacterial and viral infections.

The frequency of checking eyes will vary with how suitable environmental conditions arefor the Barberpole worm and age and class of the animal. Young animals need to bechecked every two weeks because they are more susceptible to worms. In the spring,such as around kidding time, one may only check every 3-4 weeks, but when theweather warms up and you have rain (ideal conditions for the Barberpole worm are 85oFand two or more inches of rain in a month's time), you may need to check as frequentlyas weekly. Many producers will only need to check every two weeks except when it iswarm and rainy when they need to go to weekly eye examination. With large herds ofgoats, a random sample may be checked (don=t forget that animals that are anemic areoften at the end of the line because they move slower due to anemia) and if 80% are 1and 2's and there are no 4's or 5's then the herd is assumed OK. If there are 4's and 5'sor more than 10% of the herd is a 3, then the whole herd should be examined.


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Sheep or goats that score a 4 or 5 (pale) need to be dewormed and the rest turned backto the pasture. However, when over 10% of the flock are dewormed, the 3's should alsobe dewormed because pasture contamination is building and the 3's will needdewormed shortly. The flock should be rotated to a new pasture since present pasturehas become highly contaminated with infectious larvae. In addition, pregnant animals,

lactating animals and animals under a year of age should be dewormed when they are3's since their immune system is not fully functional. Animals with bottle jaw (swellingunder the chin caused by edema) should be dewormed and animals that lag behind therest of the herd or those that look wormy should be dewormed.

It is important to know that the dewormer that you are using works. The best way todetermine this is to take a fecal sample before deworming on several animals thendeworm those animals. Take another fecal sample 7-14 days later on the same animalsfor a fecal egg count. There should be less than 15% of the eggs in the second fecalcount as compared to the first count. If there are more than 15% of the eggs in thesecond fecal egg count as compared to the first one, the dewormer is not effective in

your herd or flock. The dewormer should be changed and be sure to verify that the newdewormer is working for your sheep/goats. The next article in this series will coverselection of a dewormer.

To get the most out of this program, records should be kept on which animals aredewormed. Records may be as simple as recording eartag numbers or names anddates animals were dewormed. It is beneficial to be able to identify the animals thatrequire the most deworming. These animals are candidates for culling. These animalsneed culled because they are producing most of the eggs (and infective larvae) forinfecting other animals in the herd. Remember, 20-30% of the animals produce 70-80%of the eggs on a pasture. In addition, culling of these animals will improve the genetic

base of the whole herd for resistance to the Barberpole worm. Several methods ofmarking animals are available to identify animals that were dewormed if there is not anindividual animal identification. The ear may be notched each time the animal isdewormed or a wire tie may be placed around the cannon bone of the front leg with thetail of the tie cut off much like a bangel. The animals that accumulate the most wire tiebangels in a season or ear notches are candidates for culling.

Another record keeping tool that can be used is shown in Figure 3. It is a FAMACHAblock histogram. It shows the proportion of animals in each FAMACHA score categoryat each time animals are checked. By keeping this record, a pattern will develop over

time of what is happening in the herd as far as infection levels. That can providebackground information for development/modification of the parasite control program.By watching changes in the relative proportion of FAMACHA categories of the herd,

one can tell when animals need ti be checked more or less frequently.


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figure 3

Since the determination of whether an animal needs to be dewormed is by comparisonto the color chart, you need to protect the chart from fading. The chief cause of thecolor chart fading is sunlight, just as sunlight causes stop signs to fade. When theFAMACHA card is not being used, it should be stored in a dark area such as in a bookor dark colored folder to exclude sunlight. Probably the worst place to put the card is onthe dash of the pickup with the sun beating down on it. Despite your best efforts, thecolors will eventually fade. It is recommended that the card be replaced every year sothat you are sure that the colors are true. Replacement cards can be obtained fromwhoever you obtained the first card or from www.scsrpc.org web site.

Troubleshooting Barberpole worm problems

Routinely monitor sheep/goats for parasite infection level using FAMACHA chart.

Do only a few individuals (less than 20% of the herd) need dewormed?Keep up with regular monitoring.Do some individuals require the most deworming?

Solution, cull individuals requiring the most deworming because they have more wormsand are causing most of the pasture contamination for other animals.

Do more than 20% of the herd need dewormed?Has it been longer than 8 weeks since those animals were dewormed?

Keep up with regular monitoring and realize that level of pasture contamination maybe building.

Less than 8 weeks since those animals were previously deworming?


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Possible causes:a. Sheep or goats are picking up a many infective larva from the pasture which may beheavily infected with larva such as by having many animals on it a long time or havingwormy animals on it during times of good rainfall. The solution is to move animals toanother less infected pasture (deworm only animals that need to be when moving

pastures). The old pasture will need to be without goats or sheep at least 6 weeks toreduce contamination. It can be cut for hay or grazed with a cattle or horses to reducecontamination.

b. Goats/sheep may be grazing close to the ground picking up many larva, causingworm problems. This can happen if the pasture is grazed low, or animals may grazefavorite patches such as in bermuda grass or specific areas where their favorite plantsare. The solution is to move animals to another pasture or reduce animal numbers orsupplement animals so that they don't need to graze close to the ground. Patchgrazing can be reduced by high stocking density in a rapid rotation grazing system.

c. Animal's immune system may be suppressed by lactation, shipping, poor nutrition(protein, energy and minerals) or other stress. Solution is to make sure animals havegood nutrition (protein, energy, vitamins and minerals) and reduce stress. Sincelactation suppresses the immune system, deworming around lambing/kidding time willhelp reduce worm problems. It is important to plan to use pastures which have a lowlevel of infective larvae (such as pastures that have been rested a long period of time)for animals around kidding/lambing time and lactation.


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Parasite Control for GoatsDewormers and Dewormer Resistance


Part 4 of Series(Temporarily Unavailable)

Part 1 Parasite Control for Goats: Meet the EnemyPart 2 Managing the Barberpole Worm Part 3 Integrated Parasite Management With FAMACHA Part 5 Alternative dewormers -Do they work?Part 6 Doing Your Own Research and Fecal Egg Counts
http://www.wormx.org/SCSRPC/Publications/part1.htmhttp://www.wormx.org/SCSRPC/Publications/part2.htmhttp://www.wormx.org/SCSRPC/Publications/part3.htmhttp://www.wormx.org/SCSRPC/Publications/part5.htmhttp://www.wormx.org/SCSRPC/Publications/part6.htmhttp://www.wormx.org/SCSRPC/Publications/part1.htmhttp://www.wormx.org/SCSRPC/Publications/part2.htmhttp://www.wormx.org/SCSRPC/Publications/part3.htmhttp://www.wormx.org/SCSRPC/Publications/part5.htmhttp://www.wormx.org/SCSRPC/Publications/part6.htm


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Parasite Control for GoatsAlternative dewormers -Do they work?


Part 5 of Series

Part 1 Parasite Control for Goats: Meet the EnemyPart 2 Managing the Barberpole Worm Part 3 Integrated Parasite Management With FAMACHA Part 4 Dewormers and Dewormer ResistancePart 6 Doing Your Own Research and Fecal Egg Counts

There has been a great increase in interest in alternative dewormers ie. substances

used to control worms which are not commercially available drugs or pharmaceuticals.This has been especially true with the continued development of dewormer resistanceby worms. Sometimes these are called non-chemical dewormers, but also wouldinclude organic dewormers, herbal dewormers, and natural dewormers. Specificsubstances to be discussed include tannins (including sericea lespedeza), copper oxidewire particles, diatomaceous earth and herbal preparations. There is some significantscientific data on the several alternative dewormers, but data on herbal dewormers isscarce. The SCSRPC has coordinated research on sericea lespedeza and copperoxide wire particles and accumulated data from several trials. One characteristic ofmany alternative dewormers is not only the lack of data, but also the lack of consistentdata when data is available. For example, in the study of copper oxide wire particles in

sheep, the copper oxide wire particles were fairly effective in sheep in all locations, butdata in goats were not as consistent, in fact, in three trials at one location, they had littleeffect, but were effective in a number of studies conducted in three other locations.

Alternative dewormers need to be studied at several locations, with sheep and goatsand with different classes of animals ie. kids vs. yearlings vs. mature does. There is notmuch money available to fund this kind of research which is why we have so little dataand understanding of these alternative dewormers. There is a USDA funded study onherbal dewormers for sheep and goats at Lincoln Univesity in Missouri that isprogressing. In addition, when one gets into the many different combinations of herbaldewormers that can be used, the research becomes too large to be accomplished.Hearsay data is not very good and in some cases, very few animals were tested. In thenext article in this series, we will discuss how to do your own research to see if thedewormer (alternative or conventional) that you use is working in your animals.

Tannins

Condensed tannins have been shown to suppress fecal egg counts and reduce wormsin the digestive tract. Tannins are a large group of polyphenolic compounds that differin many physical characteristics. Some tannins such as in sericea lespedeza and other
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plants have been shown effective in suppressing worms whereas tannins in oaks andother plants do not appear to possess those characteristics. There is an excellentsummary of research on sericea lespedeza for worm control by ATTRA (Tools forManaging Internal Parasites in Small Ruminants: Sericea lespedeza,http://www.attra.org/attra-pub/sericea_lespedeza.html). Some work has been done

overseas with sainfoin, birdsfoot trefoil, dock and chicory (tannin-containing plants thatgrow in the US) showing that they too effectively suppress worms. There are severalstudies that have been done overseas with tannin containing plants, most of which donot grow here or have a very limited area of adaptation (Sulla, big trefoil). One studyshowed that the tannins in some types of browse are effective in suppressing worms.

Goat Eating Sericea Lespedeza

Even as much research as has been done on sericea lespedeza here in the US, there isso much that we dont understand other than it works both as fresh forage and as adried product (hay, meal, pellets). Feeding in the short term reduces fecal egg countsby half, and longer term feeding appears to kill a portion of the worms in the animal. Inaddition, fecal egg hatch may be reduced and larval development and motility affected.When goats are grazed on a solid stand of lespedeza or a mixed lespedeza stand(goats do have a strong preference for sericea lespedeza in the middle of summer) andunder both scenarios, worm control was such that dewormers were not needed, even inkids. When animals were grazed on alternate weeks on sericea lespedeza, there was asignificant reduction in fecal egg counts, but not as much as for animals grazing sericealespedeza alone. We do not know if a pasture containing 20% sericea lespedeza will

help suppress worms. Can we supplement with sericea lespedeza hay to animals for10 days each month (or some such scenario) and get a useful reduction in fecal eggcounts? There appear to be some differences in potency of some improved varieties ofsericea lespedeza. To summarize, we know that sericea lespedeza works (we assumeit is tannins in the plant), but we need to figure out more ways to apply that knowledgeto our goat production systems.
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Sericea lespedeza is a legume plant that grows throughout most of theSoutheastern and Eastern US. It is adapted to warm climates and is quitedrought tolerant, tolerant of low fertility and low soil pH (as low as 4.5). It wasformerly planted for erosion control and used for revegetating strip mines. It isspread by wildlife and is a long-lived perennial plant. It is too well adapted in

Kansas where it has been declared a noxious weed. Sericea lespedeza will notbecome invasive as long as it is grazed by sheep or goats (it does not produceseed when moderately defoliated) . Cattle often only eat the plant when it isyoung, because as it matures, the stems become coarse and tough, the tannincontent increases and cattle avoid it because the tannins are bitter (cattlemenhate the plant because of this). However, goats and to a lesser extent sheep cantolerate the bitterness of the tannins and consume it well. Improved selections ofsericea lespedeza such as AU grazer are more palatable to cattle and mitigate theobjections of cattlemen. Get assistance from your County Extension Service orNatural Resource Conservation Service to identify the plant or you can seepictures of the plant on the web at http://plants.usda.gov/java/profile?

symbol=LECU . You may be able to locate natural stands in your area and beable to rent them cheaply for grazing. There is information on planting sericealespedeza at www.scsrpc.org.

Tannin containing plants may work several ways to reduce fecal egg counts. They havea high level of protein and the protein and tannins interact to improve protein nutrition ofanimals. Protein supplementation has been shown to suppress fecal egg counts insheep and goats most likely due to stimulation of the immune system and tannincontaining plants may work in this way. Also, these plants grow high off the ground andanimals grazing these plants should pick up fewer infective larvae which are on the

lower two to three inches of the plant. There is some research that shows that tanninsmay bind to the cuticle skin of worms and cause damage to it. There are many otherproposed mechanisms by which tannins may work, but the important thing is that wehave identified some tannin-containing plants that do suppress worms and we candevelop this knowledge into application. In addition, there is potential that we mayidentify other tannin containing plants that suppress worms.

There are a number of varieties of annual lespedezas which were formerly thought tonot have tannins, but this needs to be reexamined as we now have better tests fortannins. These plants may be helpful for parasite control even if they are proved to nothave tannins since they have high levels of protein and tend to grow high off theground. There are also native lespedezas which grew in the tallgrass prairie andgenerally rare now on most native range sites. These plants could be useful sincesome have proven to have tannins.

Copper Oxide Wire Particles

Copper sulfate was found to be effective in controlling the Barberpole worm in the early1900's and has been used in many deworming solutions since. One drawback was that
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it typically required 100 cc of solution since copper sulfate is caustic and must be madeup in a dilute solution. Copper oxide wire particles (COWP) were developed as a slowrelease form of copper to treat copper deficiency in Australia and New Zealand. Oneresearcher working with COWP to supply copper observed a reduction in symptoms ofworms in the treated animals and in 1990 some New Zealand researchers studied the

effect of copper oxide wire capsules on worms. They observed that COWP wereeffective at removing only the Barberpole worm. Since our major worm during thesummer in the Southeast U.S. is the Barberpole worm, COWP should be effective as adewormer at this time of year. There have been a number of studies conducted in bothsheep and goats in the US in recent years and there is a good summary written by

ATTRA (Tools for Managing Internal Parasites in Small Ruminants: Copper WireParticles at http://www.attra.org/attra-pub/copper_wire.html).

The work is very clear for sheep; administration of 1-2 grams COWP in a gelatincapsule for ewes or 1.0 g for lambs will reduce fecal egg counts 50-90% and seems tobe more effective in growing animals. One must be careful with repeated use of COWPin sheep due to the potential for copper toxicity. However, COWP administration wasrepeated 4 times during the summer without toxicity. COWP is an effective dewormerfor sheep when the Barberpole worm is the predominant species and details on its usein the ATTRA publication listed above.

COWP have been shown to be effective in goats although in three studies at onelocation it did not appear to be effective because the Barberpole worm was not theprimary worm.. However at other locations and multiple studies, COWP was aneffective dewormer in goats. Since goats are more tolerant of copper, there is lessconcern about repeated use of the COWP capsules than for sheep. Basically, doses ofCOWP from 0.5 to 2.0 g appeared useful in reducing fecal egg counts from 50-80% ingoats and appeared to be more effective in kids than in adults. A recent study onpregnant goats shows promise for the use of COWP incorporated in the feed (fed onlyonce) to reduce fecal egg counts. For details on the use of COWP as a dewormer, referto the above ATTRA publication.

Trace Mineral Bolus
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There have been two experiments at one location using a slow dissolving trace mineralbolus (Small-Trace for sheep, Agrimin Ltd., not available in the U.S.) as a treatment forworms in adult goats. In one experiment, there was a 75% reduction in fecal egg countand in the other study, there was over 50% reduction in fecal egg count. This wasthought to be an effect of the copper oxide in the bolus. The bolus seemed to have

some beneficial effects in reducing reinfection for 4-6 weeks. Research remains to bedone in sheep. The high level of copper may limit the capsule to being used onceduring the worm season with sheep.

Copper sulfate was used for deworming sheep before dewormer drugs were available.Copper sulfate was recommended for control of stomach worms (Barberpole worm) insheep with 100 cc of a 1 % solution being given to a yearling or adult sheep and halfthat amount to a 3 month old lamb (USDA Farmers Bulletin 1330, 1925; there areseveral revisions of this bulletin). For tapeworms, they recommended 1% coppersulfate with 1% of snuff or powdered tobacco. The tobacco was steeped in waterovernight and the copper sulfate added . The dose was 50cc for lambs and twice this

amount for a full grown sheep. Other state experiment station bulletins recommendedcopper sulfate treatment for worms in sheep, often after an overnight fast. Studies atone location showed that 1 1/2% copper sulfate was effective at controlling theBarberpole worm in sheep (AVMA 43:163, 1937). A more recent study (2008) showedthat a copper sulfate drench (following fasting ) caused a 60% fecal egg countreduction in ewes that had just been weaned. However, in another study where coppersulfate was incorporated in the feed for one day, it was not effective as a dewormer.Repeated use of copper sulfate has potential to cause copper toxicity in sheep althoughsome reports indicated its use on a monthly basis for a year. Higher concentrations ofcopper sulfate in the drench (than 1.5%) are caustic. One source reported success withfeeding a 3.3% mixture of copper sulfate in the salt which appeared promising for

several months until sheep died from copper toxicity. When they reduced theconcentration in the salt to 2%., it was ineffective at controlling worms. More researchis needed on copper sulfate.

Tobacco and Nicotine Sulfate

Tobacco and nicotine sulfate have been recommended in old USDA and StateExperiment Station Bulletins for control of parasites. Data and dose are sometimessketchy in older literature as are quantitative results. It was recommended for control ofintestinal worms (bankrupt worm and brown stomach worm). It must be rememberedthat nicotine sulfate is a nerve paralyzing toxin with which one hopes to use enough ofthe drug to paralyze the worm (causing him to turn loose and go out the digestive tract)without using too much, paralyzing (and killing) the animal. The margin of safetybetween an effective dose and killing the animal is not very wide, so one must be verycareful when using this chemical as a dewormer. Most workers used 1-1.5% solutionof 40% nicotine sulfate with 100 cc being given to a yearling or adult sheep and half thatamount to a 3 month old lamb. It was often used in a mixture with copper sulfate (seeabove). It must be emphasized that using these compounds can be toxic to thesheep/goat. If you insist on experimenting with copper sulfate and/or nicotine sulfate,


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use them with a few cull animals that you wont mind losing if you do have a problemwith toxicity.

Diatomaceous Earth

Diatomaceous earth is fossilized unicellular marine or fresh water algae called diatoms.It is used as a food ingredient (read the labels on processed foods) and in swimmingpool filters. There are cautions about using the swimming pool grade for feedinganimals in that it can be contaminated with heavy metals whereas the food grade mustbe proven to have non toxic levels of heavy metals. Diatomaceous earth has beenused for many years for control of various pests from grain weevils to houseflies. Goatproducers that use it for deworming control often mix it with the mineral supplement orin the feed. Most claims are that it extends the time between dewormings althoughsome claim that it kills worms in goats. There have been 4 or 5 scientific studies andthe data consistently show that diatomaceous earth does not kill worms in goatsalthough one study did show that at a very high level (5% of the diet), it had a slight

effect. There is speculation that it may help fecal pellets to dry out faster which couldreduce the success of eggs developing into infective L3 larvae. Research conducted onthis aspect has not been conclusive. It is very difficult to study the claim thatdiatomaceous earth increases the time between dewormings.

Herbal Dewormers

A problem with herbal dewormers is that active ingredients may vary with the stage ofmaturity, environment (including soil that it is grown in, fertility, moisture and daylengthpattern), processing and/or extraction procedure and variety of plant. If you look atherbal supplements in the pharmacy, the FDA has required manufacturers to

standardize the products based on a major active ingredient i.e. Garlic is standardizedbased on concentration of allicin, a bioactive ingredient in garlic. When you buy driedcooking garlic for deworming sheep or goats, you have little idea of the concentration ofallicin in it. This is the problem for other herbals because the active ingredient may beso low it is nearly zero in one plant material source and another source of plant materialmay contain higher than average level of active ingredient. Another problem is thatcommon names do not always refer to the same plant. For example, wormwoods referto plants of the genus Artimesia which includes several species, some of w

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Parasite Control for Goats