The
old shepherds remember rainy years that especially in late autumn many
sheep in their flocks, especially dzviskite, abortion. Initially
abort single sheep, but after a week or two abortions as frequent wave
and covering up to 30-40 per cent of pregnant animals. They become fearful disaster for the herd. Appeared predominantly in November and December in the Polish regions of South Bulgaria.
Several adverse factors provoke these enzootic abortion. They
are damp and rainy autumn in which the sheep are moving, and even sleep
with wet wool scarce grazing, lack of extra nutrition, hypovitaminosis
or poor quality feed, chaotic mixture of different herds and older
sheep, particularly dzviski performance of abortions in the first fold itself, in which contact pregnant sheep infected with large amounts of conditional pathogens. Undoubtedly, these enzootic abortions are infectious in nature, but provoke, unlock and develop several critical disadvantages.
It has been shown that various infectious agents involved in the pathogenesis of enzootic abortion. But the most famous and common causes that determine and some clinical distinctions between them caused by abortion are few.
The most famous is Salmonella abortion caused by Salmonella abortus bovis. It occurs mainly in mid-pregnancy. Abortion
occurs quickly discarded fetuses half-naked, maceration, which is an
indication that they had been dead a long time in his mother's womb. The placenta is completely degenerated. Often normal lambs born from the affected flock showed diarrhea. Antibiotic
treatment does not stop abortions quickly, because real infectious
process in the fetus has already passed, while the abortion is just a
consequence of it. Against Salmonella abortion is used vaccine must be administered in early pregnancy. Very often, however, salmonella infection is only a secondary complication of a viral infection (pestiviruses). In such cases re-examination of aborted fetuses only a single isolate Salmonella.
Another common abortion in sheep is chlamydial. It was discovered in the country as early as 1959 by Haralambiev and Ognyanov. There are typical clinic. Causes of late abortions are often stubbornly retained placenta. Placenta itself is highly edematizirana yellow-gray deposits on the part of the cotyledons. Fetus itself is worn, strigose. And
some of the placenta normal sheep were born there, although small
deposits, suggesting that the infection is local, more widespread, but
could not cause abortion. Prophylactic treatment with antibiotics of the tetracycline group is effective if performed in the early stages of pregnancy. In England, Hungary and other countries that vaccination against abortion, which proved effective.
Previously unknown to the country, but my data quite common, abortion is caused by sheep pestiviruses. It is associated with a disease called by the English Borderova disease. The virus is actually a variant of the virus mucosal disease in cattle and is quite prevalent among sheep as a latent infection.
Causes and bearing intra-uterine infections and diseases in newborn lambs depending on the time of infection and field strain. Frequent uterinni infections lead to fetal death, abortion or the birth of urodstva immature lambs. Abortions
occur in the middle or late pregnancy and are often accompanied by
lesions in aborted fetuses - crooked limbs and bones, absence of
mandible megatsefaliya and others. This is typical of Borderovata disease. Born uterinno infected lambs are underdeveloped, with tousled hair rights. Since the CNS is infected, these lambs display their legs twitching and trembling. The English called these lambs sheykeri.
Since
pestiviruses induces immunosuppression Borderovata disease often is
accompanied by secondary infections - salmonella, campylobacter, etc.
Borderovata disease is demonstrated by immunofluorescence with
conjugated serum against swine fever. For the control and prevention of this infection can be used vaccine against mucosal disease or swine fever.
Another infection that causes abortion in sheep is listeriynata. Listeria serotypes have many, but one of them (6 s) which was discovered by Dr. Ivanov, mainly cause abortions among sheep. So he called listeria Ivanov. These abortions affect mostly young sheep and appear periodically. Their clinical signs similar to those of salmonellosis abortion. For the prevention of abortions listeriynite has developed a vaccine that has proven effective. So its patent was bought by Norway and other countries.
Appear sporadically abortions caused by other etiologic agents - Q fever (R. Burnett), tests for campylobacter and others. But they are rare and sporadic. There are also severe, generalized infections accompanied with mass abortions. These are the foot and mouth, brucellosis, bluetongue, etc. But they must be considered separately.
Against
enzootic abortion in sheep in addition to specific vaccines and
antibiotics are crucial general zoo-prophylactic measures. The
most important are: stopping the indiscriminate mixing of herds of
sheep before and during the whole pregnancy, use of healthy rams happen
in season; adequate nutrition; later grazing in wintry days with
pre-feeding, warm pens littered with thick, high hygiene etc. But most importantly prevent abortions take place in the common fold, next to other pregnant sheep. This leads to massive contamination and to unavoidable consequences. At the first early signs of abortion sheep must be isolated in a separate room. Placenta, fruit skins and water should be burned or buried and decontaminated. In enzootic abortion should be made continuous disinfection of the pen.
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