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Johne's disease in goats

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Johne’s DiseaseQ&Afor Goat Owners


The National Johne’s Education Initiative recognizes Dr. Elisabeth Patton andDr. Gretchen May with the Wiscons<strong>in</strong> Department of Agriculture, Trade andConsumer Protection and Dr. Elizabeth Mann<strong>in</strong>g with the University ofWiscons<strong>in</strong>-Madison Johne’s Information Center for their contributions to thispiece. Some photos have been provided by the Johne’s Information Center,University of Wiscons<strong>in</strong>-Madison, http://johnes.org.


1Q: What is Johne’s <strong>disease</strong>?A: Johne’s (“YO-knees”) <strong>disease</strong> is a fatal gastro<strong>in</strong>test<strong>in</strong>al <strong>disease</strong>of <strong>goats</strong> and other rum<strong>in</strong>ants (<strong>in</strong>clud<strong>in</strong>g cattle, sheep, elk, deer, andbison) that is caused by the bacterium Mycobacterium avium subspeciesparatuberculosis (MAP). Also known as paratuberculosis, this <strong>in</strong>fection iscontagious, which means it can spread <strong>in</strong> your herd.The MAP organism is most commonly passed <strong>in</strong> the manure of <strong>in</strong>fectedanimals. The <strong>in</strong>fection usually spreads from adult <strong>goats</strong> to kids and occurswhen a young animal swallows the organism via water, milk or feed thathas been contam<strong>in</strong>ated by manure from <strong>in</strong>fected animals. Most ownersare taken by surprise when the <strong>in</strong>fection is diagnosed, and learn too latethat the <strong>in</strong>fection has taken hold <strong>in</strong> multiple animals <strong>in</strong> a herd.Due to lack of test<strong>in</strong>g and report<strong>in</strong>g, it is not known how widespreadJohne’s <strong>disease</strong> is <strong>in</strong> <strong>goats</strong> <strong>in</strong> the United States. The <strong>in</strong>fection has beenconfi rmed, however, <strong>in</strong>many goat herds throughoutthe country—<strong>in</strong> milk,meat, heritage and otherbreeds—and it is a problem<strong>in</strong> most other goat-rear<strong>in</strong>gcountries as well. The costsof this <strong>in</strong>fection range fromeconomic losses—due toreduced production and<strong>in</strong>creased cull<strong>in</strong>g for meatand milk animals—toemotional losses—forthose whose <strong>goats</strong> aremore pets than agricultural<strong>in</strong>vestments.There is no cure for Johne’s<strong>disease</strong>, and there is not anapproved vacc<strong>in</strong>e for <strong>goats</strong> <strong>in</strong> the United States to help protect them from<strong>in</strong>fection. Therefore, prevention is the key to control.


2Q: How do I know if my herd has Johne’s <strong>disease</strong>?A: A goat that appears perfectly healthy can be <strong>in</strong>fected with MAP.Although <strong>goats</strong> become <strong>in</strong>fected <strong>in</strong> the fi rst few months of life, manyrema<strong>in</strong> free of cl<strong>in</strong>ical illness until months or years later. When <strong>goats</strong>fi nally do become ill,the symptoms arevague and similar toother ailments: rapidweight loss and,<strong>in</strong> some cases,diarrhea. Despitecont<strong>in</strong>u<strong>in</strong>g to eatwell, <strong>in</strong>fected <strong>goats</strong>soon becomeemaciated and weak.S<strong>in</strong>ce the signs ofJohne’s <strong>disease</strong> aresimilar to those forseveral other <strong>disease</strong>s—parasitism,A goat show<strong>in</strong>g symptoms of Johne’s <strong>disease</strong>.dental <strong>disease</strong>,Caseous Lymphadenitis (CLA) and Capr<strong>in</strong>e Arthritis-EncephalitisVirus (CAEV)—laboratory tests are needed to confi rm a diagnosis.When an animal with signs of Johne’s <strong>disease</strong> is discovered, it is verylikely that other <strong>in</strong>fected animals—even those that still appear healthy—are <strong>in</strong> the herd. Control of the <strong>in</strong>fection requires that you and yourveter<strong>in</strong>arian address it <strong>in</strong> the whole herd and not just on an <strong>in</strong>dividualanimal basis.


3Q: Why do <strong>goats</strong> with cl<strong>in</strong>ical signs of Johne’s <strong>disease</strong>lose weight and become weak?A: When an animal is <strong>in</strong>fected with MAP, the bacteria reside <strong>in</strong>the last part of the small <strong>in</strong>test<strong>in</strong>e—the ileum—and the <strong>in</strong>test<strong>in</strong>al lymphnodes. At some po<strong>in</strong>t, the <strong>in</strong>fection progresses as bacteria multiply andtake over more and more of the tissue. The goat’s immune systemresponds to the bacteria with <strong>in</strong>fl ammation that thickens the <strong>in</strong>test<strong>in</strong>alwall and prevents it from absorb<strong>in</strong>g nutrients. As a result, a goat <strong>in</strong> thecl<strong>in</strong>ically ill stage of Johne’s <strong>disease</strong> <strong>in</strong> effect starves to death. At thisstage the organism may also spread beyond the gastro<strong>in</strong>test<strong>in</strong>al tract,travell<strong>in</strong>g <strong>in</strong> the blood to muscles or other major organs such as the liveror lungs.Top: Thickened <strong>in</strong>test<strong>in</strong>al mucosa caused by Johne’s <strong>disease</strong>.Bottom: Th<strong>in</strong>, pliable, normal <strong>in</strong>test<strong>in</strong>e


4Q: How do <strong>goats</strong> become <strong>in</strong>fected?How is MAP spread <strong>in</strong> a herd?A: Johne’s <strong>disease</strong> usually enters a herd when an <strong>in</strong>fected, but healthylook<strong>in</strong>g,goat is purchased. With MAP hid<strong>in</strong>g <strong>in</strong> its small <strong>in</strong>test<strong>in</strong>e, this<strong>in</strong>fected goat sheds the organism <strong>in</strong> its pellets and <strong>in</strong>to the environment—perhaps onto pasture or <strong>in</strong>to water shared by its new herdmates. Goatsare at risk when they repeatedly swallow the organism, especially whenthey are young (less than 6 months old). If the doe is <strong>in</strong>fected, her offspr<strong>in</strong>gcan become <strong>in</strong>fected even before they are born (<strong>in</strong> utero transmission).The organism is also shed <strong>in</strong> an <strong>in</strong>fected doe’s milk and colostrum.Kids are most susceptible to <strong>in</strong>fection with MAP and often become<strong>in</strong>fected through <strong>in</strong>gestion ofmanure conta<strong>in</strong><strong>in</strong>g MAP—such as from suckl<strong>in</strong>g manuresta<strong>in</strong>edteats, swallow<strong>in</strong>g milkthat carries MAP or eat<strong>in</strong>gfeed, grass or water conta<strong>in</strong><strong>in</strong>gMAP-contam<strong>in</strong>ated manure.Bottle-fed kids can also become<strong>in</strong>fected if the milk wascontam<strong>in</strong>ated. Heat treatmentused to control CAE <strong>in</strong> milkis not sufficient to kill MAPorganisms.S<strong>in</strong>ce <strong>goats</strong> usually producemore than one kid per birth<strong>in</strong>g,Johne’s <strong>disease</strong> can spread swiftly through a herd, especially if the<strong>in</strong>fection rema<strong>in</strong>s undetected for several kidd<strong>in</strong>g seasons.While there seems to be age-related resistance to Johne’s <strong>disease</strong>, someolder <strong>goats</strong> may become <strong>in</strong>fected, particularly when their immune systemsare suppressed for other reasons.Johne’s <strong>disease</strong> can be transmitted from one rum<strong>in</strong>ant species toanother—for example from cows to <strong>goats</strong>, <strong>goats</strong> to sheep, etc.


5Q: When do <strong>in</strong>fected animals shed the bacteria?A: Infected <strong>goats</strong> shed MAP <strong>in</strong> their manure on and off throughout theirlives. The older the animal, the more likely that shedd<strong>in</strong>g occurs as the <strong>in</strong>fectionprogresses. As <strong>goats</strong> enter the latter stages of <strong>in</strong>fection and cl<strong>in</strong>icalsigns beg<strong>in</strong> to appear, the <strong>in</strong>fective organism is shed more often andmore heavily.Q: Is it difficult to f<strong>in</strong>d out if my herd has Johne’s <strong>disease</strong>?A: Sometimes. Johne’s <strong>disease</strong> is often mistaken for <strong>in</strong>test<strong>in</strong>alparasitism, chronic malnutrition, environmental tox<strong>in</strong>s, cancer and CLA—particularly <strong>in</strong> <strong>goats</strong> that have <strong>in</strong>ternal abscesses. Many herds rotateparasite treatments for several rounds before test<strong>in</strong>g for Johne’s <strong>disease</strong>and determ<strong>in</strong><strong>in</strong>g this is the reason their <strong>goats</strong> are so th<strong>in</strong>. In addition,some of the common laboratory tests for Johne’s <strong>disease</strong> may be diffi cultto <strong>in</strong>terpret.If Johne’s <strong>disease</strong> issuspected but has notbeen confi rmed <strong>in</strong> aherd, a necropsy of agoat with symptomsof the <strong>disease</strong> may behelpful <strong>in</strong> determ<strong>in</strong><strong>in</strong>gif the <strong>in</strong>fection is <strong>in</strong> aherd. This necropsymay reveal enlarged<strong>in</strong>test<strong>in</strong>al lymph nodesand a thickened, corrugated<strong>in</strong>test<strong>in</strong>al tract.A complete necropsy of a goat suspected of hav<strong>in</strong>g Johne’s <strong>disease</strong>should <strong>in</strong>clude culture of the <strong>in</strong>test<strong>in</strong>e and adjacent lymph node as wellas microscopic exam<strong>in</strong>ation of these tissues to give you the greatestconfi dence <strong>in</strong> the diagnosis.


6Q: How can I help keep Johne’s <strong>disease</strong> out of my herd?A: Buyers beware! The most common way that the <strong>in</strong>fection is <strong>in</strong>troducedto a herd is through the purchase of an animal from an <strong>in</strong>fectedherd. S<strong>in</strong>ce many people rais<strong>in</strong>g <strong>goats</strong> are unaware of Johne’s <strong>disease</strong>,both the seller and buyer are usually shocked when the diagnosis is made.In short, it is easier to keep MAP out of a herd than to control the <strong>disease</strong>once MAP sneaks <strong>in</strong>.Practices that can help prevent the <strong>in</strong>troduction of Johne’s <strong>disease</strong> <strong>in</strong>toa herd are:■ Ma<strong>in</strong>ta<strong>in</strong> a closed herd. Don’t buy Johne’s <strong>disease</strong>.■■If you br<strong>in</strong>g animals <strong>in</strong>to the herd, purchase animals only fromherds that have tested for Johne’s <strong>disease</strong>. Ideally, purchaseonly from herds that have had a negative whole-herd test <strong>in</strong> thelast year. If this is not possible, you are better off buy<strong>in</strong>g fromsomeone who is aware of the <strong>in</strong>fection, has tested for it andcan provide accurate records on the <strong>disease</strong> <strong>in</strong> their herd thanto purchase an animal from someone who has never heard ofJohne’s <strong>disease</strong>.If no diagnostic test<strong>in</strong>g has been conducted <strong>in</strong> the source herd,at least closely evaluate the body condition of all the adultanimals, discuss the history of cl<strong>in</strong>ical signs <strong>in</strong> any animals <strong>in</strong>the herd over the past few years with the seller and test theadult animal to be purchased.


7■ If the animal to be purchased is less than a year old, test itsdam s<strong>in</strong>ce <strong>in</strong>fected young animals are unlikely to test positivefor the <strong>in</strong>fection.■■■Avoid graz<strong>in</strong>g <strong>goats</strong> on pastures where MAP-<strong>in</strong>fected rum<strong>in</strong>antshave grazed. Graze young <strong>goats</strong> on such a pasture only afterit has rested for a year. To date, MAP <strong>in</strong>fection of free-rang<strong>in</strong>grum<strong>in</strong>ants such as deer or elk is uncommon, and currentlythese species are not believed to be an important source of<strong>in</strong>fection to farmed rum<strong>in</strong>ants.Do not br<strong>in</strong>g <strong>in</strong> other species that are susceptible to Johne’s<strong>disease</strong>: sheep, cattle, other rum<strong>in</strong>ants.Do not board or borrow other people’s <strong>goats</strong>, as this can<strong>in</strong>troduce the <strong>in</strong>fection <strong>in</strong>to your herd.Q: How can I control Johne’s <strong>disease</strong> once it hasentered my goat herd?A: S<strong>in</strong>ce there is no cure for Johne’s <strong>disease</strong>, control of the <strong>in</strong>fectionis critical. Control of Johne’s <strong>disease</strong> takes time and a strong commitmentto management practices focused on keep<strong>in</strong>g young animals away fromcontam<strong>in</strong>ated manure, milk, feed and water. A typical herd clean-upprogram may take a number of years. The basics of control are simple:new <strong>in</strong>fections must be prevented, and animals with the <strong>in</strong>fection mustbe identifi ed and removed from the herd.Your State Designated Johne’s Coord<strong>in</strong>ator can help you undertake anon-farm risk assessment that evaluates your operation, your resourcesand your goals. An on-farm risk assessment highlights current managementpractices that may put your herd at risk for spread<strong>in</strong>g Johne’s<strong>disease</strong> and other <strong>in</strong>fections. At the completion of a risk assessment, yourveter<strong>in</strong>arian can work with you to develop a management plan designedspecifically for you and your herd that will m<strong>in</strong>imize the identified risksfor <strong>disease</strong> transmission. (An on-farm risk assessment is part of theJohne’s <strong>disease</strong> course for goat producers at www.vetmedce.org.)


8Most control plans follow basic rules of sanitation to block transmissionof the <strong>in</strong>fection with<strong>in</strong> the herd. Management recommendations <strong>in</strong>clude:■■■■■■■■■■■■Keep kidd<strong>in</strong>g areas as manure free as possible. Use deep,fresh bedd<strong>in</strong>g or sunny pastures with m<strong>in</strong>imal manure.If feasible, clean the udders of dams before kids nurse.Use milk and colostrum from test-negative animals.Be aware that colostrum purchased from another goat herd orcow herd may be contam<strong>in</strong>ated. Pasteurization needs to be at145°F (63°C) for 30 m<strong>in</strong>utes for batch pasteurization, or 162°F(72°C) for 15 seconds for flash pasteurization to kill MAP <strong>in</strong> milk.Kid suspect or test-positive does <strong>in</strong> an area separate from thetest-negative does.Move young animals and their mothers to “clean” pastures assoon as possible after kidd<strong>in</strong>g.Wean early and put young <strong>goats</strong> on uncontam<strong>in</strong>ated pastures.Keep water sources clean, particularly those used by kids.Use waterers designed to m<strong>in</strong>imize fecal contam<strong>in</strong>ation.Raise all feeders and avoid feed<strong>in</strong>g on the ground.Use diagnostic tests to identify <strong>in</strong>fected animals and removethem from the herd.Necropsy sick or cull animals to determ<strong>in</strong>e if your herd is<strong>in</strong>fected with MAP.If your herd has had numerous cases of Johne’s <strong>disease</strong>,discuss depopulation with your veter<strong>in</strong>arian or, at a m<strong>in</strong>imum,immediately remove all test-positive animals and their last-bornkid. Do not allow kids to be exposed to milk or manure from<strong>in</strong>fected animals.Remember: Prevent<strong>in</strong>g Johne’s <strong>disease</strong> is much less costly thancontroll<strong>in</strong>g it.


9Q: How can I clean contam<strong>in</strong>ated equipment, stallsand fields?A: The MAP organism is very hardy <strong>in</strong> the environment: It resistsheat, cold, dry<strong>in</strong>g and dampness. Although the majority of organisms dieafter several months, some will rema<strong>in</strong> for many months. In fact researchshows that MAP can survive—at low levels—for up to 11 months <strong>in</strong> soiland 17 months <strong>in</strong> water. MAP has also been recovered from grassesfertilized with MAP-contam<strong>in</strong>ated manure. This is why pastures and fi eldsknown to be contam<strong>in</strong>ated with MAP should not be used for kids, calvesor lambs for at least one year after last exposure.Feed and water<strong>in</strong>g equipment that may have become contam<strong>in</strong>atedshould be washed and r<strong>in</strong>sed. When clean<strong>in</strong>g a water trough, sedimentand slime from the sides and bottom should not be dumped onto groundthat will be grazed by young<strong>goats</strong> as the sediment andslime may be contam<strong>in</strong>atedwith MAP.Dis<strong>in</strong>fectants labeled as“tuberculocidal” may beused as directed for clean<strong>in</strong>gtools, implements andsome surfaces. Thesedis<strong>in</strong>fectants, however, canbe <strong>in</strong>activated by organicmaterial—such as dirt andmanure—and therefore arenot effective on dirtysurfaces, wood surfaces,soil or even cement fl oors.Compost<strong>in</strong>g of manureand used bedd<strong>in</strong>g canreduce the number of liv<strong>in</strong>gMAP organisms.


10Q: Should I test my herd for Johne’s <strong>disease</strong>?A: If you have <strong>goats</strong> with a normal appetite that have become th<strong>in</strong>and are not respond<strong>in</strong>g to treatment, talk to your veter<strong>in</strong>arian. The culpritmay be Johne’s <strong>disease</strong>.Remember: S<strong>in</strong>ce Johne’s <strong>disease</strong> is a herd problem, test<strong>in</strong>g shouldfocus on the herd and not just a s<strong>in</strong>gle animal.Diagnostic test<strong>in</strong>g for Johne’s <strong>disease</strong> can help to:1. Determ<strong>in</strong>e if MAP <strong>in</strong>fection is present <strong>in</strong> your herd.2. Estimate the extent of MAP <strong>in</strong>fection <strong>in</strong> your herd.3. Control MAP <strong>in</strong> an <strong>in</strong>fected herd.4. Make a diagnosis for a sick animal.5. Check if MAP is present <strong>in</strong> the environment.6. Meet a pre-purchase or shipp<strong>in</strong>g requirement.7. Demonstrate to potential buyers that your animals are lowrisk for Johne’s <strong>disease</strong> (test-negative).Once your veter<strong>in</strong>arian knows your goals <strong>in</strong> test<strong>in</strong>g for Johne’s <strong>disease</strong>,a test<strong>in</strong>g plan that best meets your needs can be put <strong>in</strong> place. This planshould outl<strong>in</strong>e the type of test, when to test, which animals to focus on,the cost of test<strong>in</strong>g, how to <strong>in</strong>terpret the results and what actions to takebased on test results.Decide how you plan to use your test results before you collect thesamples.


11Q: What diagnostic tests are available?Which one is best?A: Although there is no one “best test” for Johne’s <strong>disease</strong> <strong>in</strong> <strong>goats</strong>,the best test<strong>in</strong>g plan is one developed by you and your veter<strong>in</strong>arians<strong>in</strong>ce you know your operation best—its goals, resources, other animalhealth issues.Diagnostic tests for Johne’s<strong>disease</strong> look for eitherthe organism that causesJohne’s <strong>disease</strong> (MAP) orthe animal’s response to<strong>in</strong>fection.Tests that look for theorganism <strong>in</strong>clude cultureand PCR, with manuresamples tested. Individualanimals can be tested ora laboratory can poolmanure samples frommultiple animals andprovide owners witheffective Johne’s <strong>disease</strong>surveillance for a fractionof the cost of <strong>in</strong>dividualculture or PCR.The animal’s bodyresponds to <strong>in</strong>fection bymak<strong>in</strong>g antibodies. Tests that measure antibody levels are the ELISA formilk and blood samples.Due to the biology of MAP <strong>in</strong>fection, older <strong>goats</strong> are much more likelyto shed MAP or produce antibody. Therefore, diagnostic tests are lessreliable for <strong>goats</strong> that are less than 18 months old.


12Test<strong>in</strong>g approaches that have worked well for other goat herds <strong>in</strong>clude:Test<strong>in</strong>g Purpose Option A Option BConfirm presence ofMAP <strong>in</strong> a herd.Determ<strong>in</strong>e number of<strong>goats</strong> that are <strong>in</strong>fected.Control or eradicateMAP <strong>in</strong> an <strong>in</strong>fected herd.Diagnose a sick goator goat with weight lossand diarrhea.Culture 5 – 10environmental fecalsamples collected athigh goat traffi c areas onthe farm.Blood test (ELISA*) alladult <strong>goats</strong>.Blood test (ELISA*)<strong>goats</strong> after their secondkidd<strong>in</strong>g or older.If previous cases havebeen seen <strong>in</strong> the herd:ELISA.*(Fecal culture if CLA isa problem <strong>in</strong> the herdor if the herd has beenvacc<strong>in</strong>ated for CLA.)Us<strong>in</strong>g ELISA* or fecalculture, test the oldestor th<strong>in</strong>nest <strong>goats</strong>—10% or more of the herd.Collect fecal samples forthe lab to test by pool<strong>in</strong>gfor culture. For everypositive pool, samplesare retested <strong>in</strong>dividually.Collect fecal samples forthe lab to test by pool<strong>in</strong>gfor culture. For everypositive pool, samplesare retested <strong>in</strong>dividually.If MAP has never beenconfirmed <strong>in</strong> the herd,use fecal culture.*Use commercial ELISA kit approved by the USDA for small rum<strong>in</strong>ants to limit the chance of false-positive results due tocross-react<strong>in</strong>g antibodies from other types of <strong>in</strong>fections.Test samples should be submitted to a laboratory that has passed anannual “check test” demonstrat<strong>in</strong>g their competency. These labs arelisted here:http://www.aphis.usda.gov/animal_health/lab_<strong>in</strong>fo_services/approved_labs.shtml


13Q: Where can I f<strong>in</strong>d more <strong>in</strong>formation aboutJohne’s <strong>disease</strong>?A: The University of Wiscons<strong>in</strong> School of Veter<strong>in</strong>ary Medic<strong>in</strong>e’sJohne’s <strong>disease</strong> website—www.johnes.org—addresses all aspects ofJohne’s <strong>disease</strong> for multiple species, <strong>in</strong>clud<strong>in</strong>g <strong>goats</strong>. The site has an“Ask An Expert” feature that allows you to submit your own questionsand receive a personalized response from an expert.The University of Wiscons<strong>in</strong> School of Veter<strong>in</strong>ary Medic<strong>in</strong>e also offers afree onl<strong>in</strong>e course for goat producers. Simply go to www.vetmedce.org,click on “Courses” <strong>in</strong> the lower left hand corner of the homepage. Onceon a new page, click on “Johne’s Disease.” At the next new page, clickon “Johne’s Disease Courses for Producers” followed by click<strong>in</strong>g on“0017—Johne’s Disease for Goat Producers.”To learn more about Johne’s <strong>disease</strong> <strong>in</strong> <strong>goats</strong>, please contact yourState animal health regulatory agency or your State Designated Johne’sCoord<strong>in</strong>ator. Contact <strong>in</strong>formation for your State’s Johne’s <strong>disease</strong>program is available onl<strong>in</strong>e at www.johnes<strong>disease</strong>.org when you clickon “State Contacts.”


This <strong>in</strong>formation is provided by13570 Meadowgrass Drive, Suite 201Colorado Spr<strong>in</strong>gs, CO 80921Ph: 719.538.8843www.animalagriculture.org

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