Sheep, in contrast to other livestock species, are characterized by interior-. External parasites particularly at risk. In section statistics, strains with internal parasites are in first place as cause of loss in sheep. Developmental stages of parasites can regularly be detected in more than 50% of the fecal samples of sheep taken by the Sheep Health Service of the LWK NRW in clinically inconspicuous farms. In this case, the feces of the animals may well be unremarkable.
If sheep (Fig. 1) show a dull, open wool despite good feed supply, individual sheep appear conspicuously tired (apathetic) and doughy swellings between the mandibular branches are noticeable in individual animals, several (at least 5) individual fecal samples should be sent immediately to a veterinary examination institute for parasitological examination. After targeted treatment, the laryngeal edema can begin to subside as early as two to three days later. A significant increase in the vitality of the sheep can be expected. Since benzimidazole resistance was also detected in our region in a dissertation last year, fecal samples should be sent in again about 10 days after the use of this group of active substances for parasitological examination in order to check the success of the treatment.
2. Pasture Coccidiosis
2. 3-month-old Texel lamb severely impaired in development due to coccidia
In the first weeks of life, primarily during housing with high stocking density and moist bedding, ewe lambs are regularly infected with unicellular, microscopic parasites, so-called. Coccidia, confronted. Due to the warm and humid weather of the last few weeks, the sheep health service of North Rhine-Westphalia was also able to identify the so-called. "pasture coccidiosis" in lambs has also been observed to increase. It leads to pulpy diarrhea from the age of 4 weeks, whereby the inflammation of the intestinal mucosa is not infrequently accompanied by strong urging. Depending on the intensity of infestation and the duration of exposure, coccidia can lead to growth depression and developmental disorders – as in the severely underweight, approximately three-month-old Texel lamb pictured (Fig. 2). Parasitological examination of fecal samples can identify pathogens. Timely, targeted treatment of ewe lambs with a special preparation that is exclusively effective against coccidia helps to avoid economic losses.
3. + 4. Lip Grind Infection
3. Malignant labial form of lipgrind
4. Genital form of lip scab on the udder of a ewe
Even in well-managed herds, massive inflammatory, pustular changes on the skin and mucous membranes in the area of the head, nose (Fig. 3) and/or on the udder skin and teats (Fig. 4) occur sporadically. This "lip bark infection" is caused by a so-called. ORF virus induced.
In the mild form, the symptoms disappear after 14 days. The malignant form of lip scab is characterized by severe inflammation of the mucous membrane of the mouth with cheesy deposits. Affected sheep may die as a result of reduced feed and water intake associated with severe pain. In the case of inflammation of the udder skin, the teats are usually also affected, so that the supply of the lambs is endangered and udder inflammation develops as a consequence.
Unfortunately, Listeria vaccines are not available, and treatment is limited to symptomatic measures to combat secondary bacterial infections.
The viral infection can also lead to vesicular changes in humans if skin lesions are present, leaving scars as they heal. As this is a zoonosis, gloves should always be worn when handling diseased sheep.
5. MAEDI infection
5. Mouth breathing of a MAEDI-infected older Cameroon ewe
If sheep lose weight from the age of 2-3 years despite good feed intake, show coughing under stress (Fig. 5) and, in advanced stages, severe respiratory distress (mouth breathing), a MAEDI infection must be considered. Due to breed disposition, Texel, dairy and Cameroon sheep are particularly at risk. As a rule, in contrast to the "sheep snot", the animals do not show increased nasal secretion and increased rectal temperature. Retrovirus infection can be detected by blood serology or pathologic-anatomic examination. Treatments are not possible. In a rehabilitation procedure, one separates from the affected, d. h. clinically conspicuous and all seropositive, i. d. R. healthy appearing animals. Whose offspring. healthy appearing animals and their offspring.
6. Listerosis
6. Central nervous disorders caused by listeria after feeding poor grass silage
When sheep are fed poor-quality silage or. Central nervous symptoms can occasionally be observed in sheep and goats if the pens are not cleaned regularly. The bacterium responsible is "Listeria monocytogenes", which causes u. a. leads to a purulent meningitis, which is only treatable in the early phase of the disease by high antibiotic administration. In the case of the so-called. "Listerosis" individual sheep (Figure 6) initially separate from the flock, appear apathetic, show drowsiness, turning movements, increased salivation, lacrimation, trembling of the lips, and after a few days come to rest. With sufficient water intake, they die in a lateral position after 10-14 days at the latest. Vaccines are unfortunately no longer available for prophylaxis. When feeding silage to sheep, scrupulous attention should be paid to perfect quality; silage residues should be regularly removed from troughs and troughs.
7. Abortions
7. Chlamydia abortion with characteristic changes of the egg membranes
Abortions can occur in sheep both on non-infectious (z. B. Drifting by dogs, impact during rank fights, mycotoxins etc.) as well as due to infectious factors. While in practice one often has to rely on conjecture (temporal assignment, exclusion of specific pathogens) to clarify the first-mentioned cause complex, the so called "MAEDI" cause complex can be identified. "Viral abortion" as the most common infectious cause of abortion is relatively easy to detect (Figure 7). In the case of an initial infection with the pathogen Chlamydophila abortus, which belongs to the bacteria, more than 50% of the sheep can abort the foetus. give birth to weak lambs. Preferably affected are firstlings in the last third of gestation. If postpartum retention does not lead to complications, the sheep will resume breeding a few weeks later. The pathogen is preferably detected by microscopic examination of freshly collected egg skin material. Pathogen-typical are yellow-gray, flaky changes in the area of the egg membranes. Prophylactically, the use of a commercially available live chlamydia vaccine should be scheduled in time before the ram is used for the following lambing period. In an early phase of the infection, an attempt can be made, in cooperation with the veterinarian, to stop the spread of the pathogen in the herd by using tetracyclines.
8. Inflammation of the conjunctiva and corneas
8. Mainly during summer grazing, infectious inflammations of the eyelid conjunctiva can be. Corneal mange is a serious health problem in small ruminants. Initially, there is an inflammation of the conjunctiva, usually bilateral, accompanied by strong lacrimation, blinking and photophobia (Fig. 8). Later, the inflammation spreads to the cornea, vessels sprout, the secretion becomes purulent and the cornea becomes completely opaque. Microbiological examination of eye swabs reveals the presence of either Chlamydia, Mycoplasma or Moraxella. Insects are thought to have a vector function in the rapid spread of the disease in the herd. Visual disturbances lasting several weeks often affect a high percentage of the animals in a herd; the movement restrictions can be so severe that the herd loses its cohesion and can no longer be herded. For treatment, in smaller herds antibiotics are applied locally to the eye after resistance testing, in larger herds the active substances must be administered by injection. As an accompanying measure, it is recommended to house the animals or at least provide shaded pastures, as UV radiation has a negative effect on the healing process.
9. Sheep mange
9. Pasteurella-induced inflammation of the respiratory tract (so-called. "Sheep snot")
Sporadic, dry cough and serous-purulent nasal discharge (Fig. 9) are the leading symptoms of the so-called. "sheep mange", which in recent years has been observed not only in unfavorable stable climatic conditions (warm, humid stables with high concentrations of harmful gases) but also on farms with good management during the grazing period in summer weather conditions. All age groups are affected, although meat sheep breeds such as Texel and Blackheads appear to be more susceptible. In the bacteriological examination of nasal swabs of acutely ill, untreated animals, the bacterium "Mannheimia haemolytica" can be regularly detected. It cannot be excluded that a viral infection is primarily responsible for the disease process. The use of antibiotically active substances in accordance with the antibiogram curbs the clinical manifestations and prevents irreparable lung damage. A commercially available inactivated vaccine, which is used in time before lambing in (healthy) dams as well as in lambs a few weeks old with revaccination after 3-4 weeks, at least alleviates the course of the disease.
10. Mange
10. Head mange provoked by sarcoptes mites in a Texel ram
Sheep mange is caused by parasites invisible to the naked eye, so-called "sheep snot". caused by mites. A distinction is made between head mange, body mange and foot mange. Economically important are the head and cornea inflammations. Sarcoptic mange (Fig. 10). The body or foot mange. Psoroptic mange. The pathogen enters the flock via latently infected sheep or contaminated objects (hurdles, shearing machines, common pastures). Outside the animal body, the mites remain infectious for about seven weeks. Clinically, restlessness, itching resp. Scouring on solid objects – associated with stringy wool loss – in the foreground. Whereas head mange is characterized by inflammatory changes in the skin areas around the eyes, ears, forehead and the bridge of the nose, body mange affects the torso and the back of the nose in particular. the lateral chest wall is affected. On closer inspection, the skin, which is swollen with inflammation, shows washboard-like changes (allergic reaction) and is not infrequently blood-scoured. For microscopic detection of the pathogen in the laboratory, a skin scraping must be taken deeply at the transition from the healthy to the diseased skin. Both sheep baths and injectables containing avermectin are suitable for treatment. In order to avoid relapses, a second treatment after 10-14 days is strongly recommended for both treatment methods.
11. Moderhinke
11. Beginning detachment of the claw horn from the claw bone as a result of moderhinke
Moderhinke is caused by the interaction of two pathogens, whereby the bacterium "Dichelobacter nodosus", which is divided into several groups and serovars, is of primary pathogenic importance. Depending on the degree of inflammatory processes on the horn of the sole and wall of the forelimbs and/or hindlimbs and the damage to the dermis, the affected sheep show varying degrees of lameness of the supporting legs.
In extreme cases, sheep are no longer able to move due to extreme pain. In particularly severe cases (Fig. 11), the claw shoe is completely detached from the vascular and nerve-conducting dermis and the claw bone.
The rehabilitation of an affected herd requires a period of several months and can only be achieved by consistent hoof care, d. h. Removal of defective claw material during multiple follow-up examinations. Corrections possible at weekly intervals. Through the use of a commercially available vaccine or. The use of a herd-specific vaccine can additionally promote the healing process or reduce the risk of infection. New infections are reduced. At present, it is being examined whether the use of claw baths, which has been practiced up to now and is undoubtedly indispensable, is permissible under pharmaceutical law.
12. Pseudotuberculosis
12. Abscessed posterior ear lymph node in a Boer goat after pseudotuberculosis infection
Pseudotuberculosis, which appears clinically from the age of 1 to 2 years, is chronic in nature and is caused by the pathogen "Corynebacterium pseudotuberculosis" caused. The bacterial disease is also called "caseating lymphadenitis" denotes. Outside the organism, the germ, which is very sensitive to common disinfectants, retains its infectivity for weeks in soil, feces or water. Direct sunlight should kill it within 24 hours.
Transmission occurs mainly as a dirt and smear infection through direct contact via small skin injuries, for example during shearing, tail docking. The goat or sheep owner usually first notices an up to fist-sized, usually unilateral swelling of the paired skin lymph nodes (Fig. 12). This includes especially the posterior ear lymph node, but also the mandibular lymph node, the nuchal lymph node located in front of the scapula, the popliteal lymph node and the lymph node in the udder area.
These superficially located lymph nodes increase in size within a few weeks, usually on one side, with the little painful circumferential proliferations feeling hard at the beginning and taking on a doughy consistency in an advanced phase with a diameter of up to 10 cm, so that the abscess capsule can be easily pressed in with a finger. Finally, the abscess breaks open and a viscous, or even crumbly or concentrically layered mass of pus is released. The abscess content has a yellowish-gray color and is odorless.
While the general condition of the small ruminants is hardly affected at the beginning, the animals become increasingly thin after several months of illness. In the case of infestation of the internal lymph nodes, d. h. especially of the laryngeal and pulmonary lymph nodes as well as the mediastinal lymph nodes, swallowing and breathing difficulties, tympany and occasionally abortions occur. However, these changes in the internal lymph nodes do not become apparent until the animal is dissected. Further spread of the pathogen to the liver, spleen, kidney, brain and spinal cord can lead to isolated deaths.
Diagnosis is based on the detection of the pathogen by bacteriological examination of the abscess contents. To identify already infected, but clinically still inconspicuous animals, a serological examination of the herd by means of an ELISA test is recommended. a recovery of the animals after splitting of the mature abscess. Antibiotic treatment for several days is not to be expected. Clinically ill and serologically positive animals must be removed from the herd. After eradication of the reactors, follow-up testing is required.
There is the possibility of using a herd-specific vaccine, which promises the establishment of a resilient immunity, reduces the risk of infection in not yet infected animals and must be applied until the last infected animal has left the herd.
13. CAE
13. Symptomatic for CAE infections in goats: bilateral thickened carpal joints with simultaneous poor nutritional status
The CAE ( CaprineArthritis Encephalitis) of goats, like MAEDI infection of sheep, is caused by a retrovirus.
The most common manifestation of CAE in older goats is a slowly progressive (chronic), rarely acute, inflammation, or a progression of the disease. Swelling in the area of the joints, tendon sheaths and bursa. Preferably affected are the carpal joints, often wrongly called "knee joints" (Figure 13). In the advanced stage, the animal owner notices that the animals, which have a marked drop in milk yield, alternately relieve the limbs by lifting them and audibly grind their teeth as an expression of pain when standing. The mobility of the animals decreases, the lying phases are extended, the goats become thin due to a lack of feed intake resp. The animals die off as a result of the pain and finally come to rest after weeks or months.
In addition, the virus also provokes chronic mastitis, which is accompanied by nodular hardening in the glandular parenchyma and pneumonia.
CAE viruses cause changes in the brain and spinal cord of goat lambs up to 4 months of age. This so-called. Encephalomyelitis first manifests itself as hind hand weakness, which appears as overkilling in the fetlock joint.
As with MAEDI, treatment of this slow virus infection is not possible. The rehabilitation essentially corresponds to the procedure already described for the control of the MAEDI infection of sheep.
14. Bluetongue
14. Apathetic merino sheep after bluetongue infection: upper and lower lip swollen, acute inflammation of the nasal mucosa with bloody discharge
All photos: Dr. Wilfried Adams
Bluetongue (BT) is a notifiable, virus-related disease that affects sheep, cattle and wild ruminants.
The virus is transmitted from animal to animal by relatively small, 1-3 mm blood-sucking mosquitoes.
Orbi virus serotype 8 (24 different serotypes are described) has been detected; this serotype has only been detected in the sub-Saharan region to date. On which ways he came to Germany resp. It is not yet clear how the virus could have reached the Netherlands.
The classic picture of bluetongue in sheep (Figure 14) is characterized by several days of high fever after an incubation period of 2-12 days, associated with redness and swelling of the mucous membranes of the nose, lips, mouth, and larynx. The leading symptoms, d. h. the strong swelling and blue coloration of the tongue, which can be observed in some animals, gave the disease its name. On the mucous membrane of the mouth, preferably in the vicinity of the dental necks. The hard palate can be diagnosed with ulcerative changes. The animals salivate more, the secretion can be mixed with blood and pus. As a result of swelling and crusting in the area of the nostrils, respiratory problems set in. Painful inflammation of the coronet band can lead to lameness, although, in contrast to fashion limp, all limbs are usually affected at the same time. Abortions and weak lambs were also registered. Bucks experience fertility problems after surviving BT infection, but most of these are reversible, d. h. the ability to fertilize is restored after several months. Since the nightly stabling of the animals and the use of insecticide-containing preparations have obviously shown unsatisfactory effects, one was forced last year to limit oneself to the application of symptomatic measures in order to reduce the suffering of the animals and to keep the economic losses within reasonable limits.
According to the veterinary investigation offices, no cases of bluetongue have yet been detected in sheep, goats or cattle in NRW this year, despite the warm, humid weather and a few suspected cases based on the clinical biIde, which could be supported with evidence of the virus.
Vaccination against bluetongue has now been completed for sheep in NRW. The coming weeks will show whether specific immunization using an inactivated, monovalent BTV-8 vaccine in combination with field virus antibodies will be able to intercept the infection with all its unpleasant side effects in this and the following years.