Johne's disease in goats

Johne's disease in goats

Johne's disease in goats


You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

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

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!