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1.
J. W. PLANT K. H. WALKER H. M. ACLAND G. P. GARD † 《Australian veterinary journal》1983,60(5):137-140
Homogenised tissues or tissue culture supernatant fluid containing a noncytopathic pestivirus obtained from a lamb with a neurologic form of border disease, were inoculated into ewes at different stages of pregnancy. Foetal death occurred in 9 ewes of those inoculated between 19 and 47 days of pregnancy while 3 ewes did not lamb. Eight of the foetuses were aborted between 77 and 132 days of pregnancy; of these 6 were autolysed or mummified and one had arthrogryposis. The one full-term dead lamb had a hairy birth coat and lissencephalic micrencephaly. Foetal death occurred in only 7 of 14 ewes inoculated between 57 and 72 days of pregnancy. Four of these ewes aborted between 77 and 108 days of pregnancy and 3 gave birth to full-term, dead, hairy lambs. The remaining 7 ewes gave birth to live hairy lambs with severe inco-ordination. All lambs carried to term and aborted foetuses or lambs that could be examined had a range of intracranial malformations including focal leucomalacia, micrencephaly, hydranencephaly, porencephaly, lissencephaly and cerebellar hypoplasia. Some lambs also had skeletal abnormalities including arthrogryposis, scoliosis and brachygnathia inferior. The pestivirus isolate used in these trials produced more severe effects on the ovine foetus than previously observed in similar inoculation trials using pestivirus isolates from border disease lambs without nervous signs. 相似文献
2.
G. P. GARD B.V.SC. PhD. HELEN M. ACLAND B.V.SC. J. W. PLANT B.V.SC. 《Australian veterinary journal》1976,52(2):64-68
A condition in Australian sheep resembling border disease was transmitted by the inoculation of pregnant ewes with material from affected lambs. This material contained mucosal disease virus (MDV). Twenty-two lambs comprising 6 from uninoculated control ewes, together with 11 with hairy coats and 5 with normal coats from inoculated ewes, were observed from 7 to 182 days after birth. Nine of the lambs from inoculated ewes died during the experiment from a variety of causes. Glial cell abnormalities were observed in control and affected lambs, but only 4 of the 11 hairy lambs were judged to have abnormal glial cells. There were no consistent histopathological findings indicative of MDV infection. MDV was recovered from tissues of all 11 hairy lambs, but not from any of the lambs with normal coats. The hairy lambs appeared to be immunologically tolerant to the virus. Susceptible sheep in contact with the hairy lambs were infected with MDV. It is suggested that a condition in Australian lambs characterised by hairiness of the birth coat and poor viability is due to foetal infection with a mucosal disease virus. 相似文献
3.
The transmission of mucosal disease virus (MDV) from infected ewes and their lambs to susceptible sheep was investigated. MDV was recovered from the amniotic fluid of an infected pregnant ewe and from the blood, nasal swabs and urine of hairy lambs. MDV infection was transmitted either at lambing, from infective foetal fluids or lambs, or later as a result of contact with a surviving with a hairy lamb and either aborted or gave birth to an infected hairy lamb. Adult sheep and 12-months-old sheep were less readily infected than were newborn lambs. Pregnant ewes were infected by contact with a hairy lamb and either aborted or gave birth to an infected hairy lamb. A method to minimise spread of the infection in the field is suggested. 相似文献
4.
J. W. PLANT B.V.SC HELEN M. ACLAND B.V.SC G. P. GARD B.V.SC Ph.D. 《Australian veterinary journal》1976,52(2):57-63
A condition resembling border disease has been transmitted by the inoculation of pregnant ewes with material from affected lambs. Forty-nine merino ewes, mated to merino rams 7 to 87 days previously, were inoculated with an homogenate of brain, spinal cord and spleen from affected lambs. Mummified foetuses, abortions and stillbirths were observed, and lambs with hairy birth coats were born to ewes inoculated between days 12 to 70 of gestation. A mucosal disease virus (MDV), present in the original material, was recovered from the aborted foetuses and lambs. Attempts to induce passive protection using bovine anti-serum to the C24V strain of MDV were not successful. The condition was also transmitted by inoculation of pregnant ewes with a cell culture supernatant prepared from tissue cultures that had been inoculated with an organ homogenate pool. MDV was present in the supernatant and was recovered from aborted foetuses and lambs. It is suggested that a condition in sheep in Australia resembling border disease is due to the infection of the pregnant ewe by a mucosal disease virus. 相似文献
5.
I.M. Parsonson Mary Lou O&#x;Halloran Y.C. Zee W.A. Snowdon 《Veterinary microbiology》1979,4(4):279-292
Bovine viral diarrhoea-mucosal disease (BVD) virus has been incriminated as a cause of abortion, hairy birth coat and unthriftiness in sheep. Intravenous inoculation of 40 ewes 34 to 45 days pregnant with the V/TOB strain of virus produced death in two of four foetuses 9 days after inoculation and in all but one of 31 foetuses between 11 and 56 days. The highest levels of virus in placentomes and foetal tissues occurred between 9 and 15 days after inoculation and in foetal fluids between 11 and 18 days. Virus was not detected in any foetus later than 21 days after inoculation. Groups of 10 ewes infected between 59 and 62 days (Group B) and 70 and 76 days (Group C) of gestation had 73% and 62%, respectively, of abortions or perinatal foetal deaths. Birth weights of lambs born to infected ewes in groups B and C were significantly lower than those born to uninfected control ewes. Virus was recovered consistently from the cotyledons of the foetal membranes of live lambs, and irregularly from the tissues of full term foetuses that were dead at birth but on no occasion from mummified foetuses. There were no specific gross or microscopic lesions in tissues selected from aborted foetuses and the results highlight the difficulties associated with the diagnosis of BVD abortions and perinatal death of foetuses under field conditions. 相似文献
6.
Twenty-eight pregnant ewes were inoculated IV with approximately 6 X 10(8) nonclassified, anaerobic, flagellated bacteria (NAFB) that had been isolated from an aborted lamb. Abortion occurred in 3 of the ewes and 1 ewe gave birth to a weak lamb. The remaining 24 ewes and 3 other ewes inoculated orally with NAFB did not develop clinical signs of illness. Suppuration and vasculitis were seen in the placentas of the 3 aborted lambs, 1 of which had necropurulent hepatitis indistinguishable from that usually attributed to Campylobacter fetus infection. The NAFB was isolated from fetal placenta, abomasal content, or internal organs of 2 aborted lambs and the weak lamb. A morphologically similar organism was seen in the abomasal content of the other aborted lamb, but the organism did not grow on bacteriologic culture medium. Therefore, in susceptible pregnant ewes, NAFB can cause fetal placentitis and hepatitis and subsequent birth of weak lambs or abortion. 相似文献
7.
Studies on transmission of maedi virus to lambs 总被引：4，自引：0，他引：4
L Sihvonen 《Acta veterinaria Scandinavica》1980,21(4):689-698
Lambs born to 5 ewes in 3 successive years were studied for presence of maedi virus and its antibodies. In the middle of the first-year pregnancies the ewes and the only ram of the colony were inoculated with maedi virus. No antibodies or viraemia could be detected in the lambs at birth. After sucking colostrum, antibodies appeared in the lambs of the ewes which themselves were seropositive, and reached their peak in a few days. Maternal antibodies disappeared within 12 weeks in all the lambs. Neutralizing antibodies were demonstrated in the colostrum and their content declined rapidly after lambing. Virus was isolated from the milk of 2 ewes in the third year of the studyIn the first year the spread of maedi virus was demonstrated to only 1 of the lambs, but in the other 2 years maedi virus was detected in tissues of half of the lambs sacrificed at 3–12 weeks of age. It was concluded that lambs born to chronically infected ewes are readily infected, indicating excretion of virus by ewes. The study yielded no information on the specific routes of transmission, except for the finding of the virus in milk of 2 ewes in the third year of the study. No evidence was obtained of transplacental transmission of maedi. 相似文献
8.
M. FLANAGAN A. J. WILSON K. F. TRUEMAN M. A. SHEPHERD 《Australian veterinary journal》1982,59(1):18-20
Eleven maiden Merino ewes, free of antibody to bluetongue virus serotype 20 (BTV-20) in agar gel immunodiffusion and serum neutralisation tests, were mated once with a ram. Ten ewes were inoculated with BTV-20 35 to 42 days after service, and one ewe was left as an uninoculated control. One of the inoculated ewes and the control ewe remained uninfected throughout the experiment. Eight of the remaining 9 ewes showed clinical signs ranging from mild to moderate, and the other showed no clinical signs of infection. BTV-20 viraemia was detected in ewes between days 3 and 11 post inoculation, and the serum antibody response was followed. The control ewe and 5 of the 9 infected ewes were pregnant when examined 90 to 97 days after service. Each of these animals produced a normal lamb. There was no evidence of abortion in the remaining 5 ewes, and no transplacental transfer of virus was detected in the lambs of the 5 infected ewes. At necropsy, 46 days after the birth of the last lamb, no gross or microscopic lesions were observed in either the ewes or lambs. 相似文献
9.
D Sweasey D S Patterson C Richardson J W Harkness I G Shaw W W Williams 《The Veterinary record》1979,104(20):447-450
Pregnant Dorset horn gimmers inoculated with a non-cytopathic strain of the border disease virus produced "hairy shaker" lambs that were individually affected to a varying degree. Surviving lambs were observed for a period of up to 20 weeks when neurological signs were seen to gradually disappear. During this time live virus was isolated from a wide variety of sites in nearly all of the infected lambs. The infected animals grew at a significantly slower rate compared with the controls, particularly during the first 15 weeks. Several morphological defects are described the most consistent being the decreased weight of the central nervous system. By 20 weeks body-weights were about 20 per cent lower and carcase quality scores were reduced. An assessment is made of the economic losses attributable to BD taking into consideration carcase quality at 20 weeks and the perinatal losses. 相似文献
10.
Pregnant ewes were supplemented with dl-alpha-tocopheryl acetate, either as a single intramuscular dose (500 mg two weeks before lambing) or perorally (150 mg daily during 3-4 weeks before lambing). Ewes without such a supplementation were controls. The vitamin E supplemented ewes had nearly twice as high vitamin E (alpha-tocopherol) concentrations as the unsupplemented control ewes at lambing both in serum and in colostrum. The vitamin E concentration in colostrum was 5-11 higher than in milk 1 week after lambing. Both supplementations somewhat increased the vitamin E serum concentration of the newborn lambs, but the increase was negligible in comparison with the effect produced by the consumption of colostrum. All lambs had very low serum concentrations at birth. The lambs from the supplemented ewes had significantly higher serum values than the control lambs 24 h after birth. The ewes had somewhat higher selenium status at birth than their offsprings when evaluated by glutathione peroxidase (GSH-Px) in the erythrocytes. It seems reasonable that nutritional muscular degeneration may arise in newborn lambs with a normal selenium status if their vitamin E status is critical, either because of an inadequate consumption of colostrum or because of a vitamin E deficient diet during pregnancy with a low vitamin concentration of colostrum as a consequence. 相似文献
11.
Forty yearling Brucella-free ewes were inoculated with Brucella ovis by the conjunctival route in mid or late first pregnancy. Only a few ewes excreted B ovis during pregnancy and gave birth to stillborn lambs, but most of them excreted the organism at lambing or during lactation. One of the 11 lambs which were born alive but died before they were weaned was found to be infected postmortem. In contrast, none of the 46 surviving lambs which were reared in isolation until adulthood, was found to be infected. At weaning, the 40 ewes were mated again with five Brucella-free rams. Although many of the ewes excreted B ovis, none of the rams was found to be infected when necropsied after mating. Most of the ewes that became pregnant, all having excreted B ovis during their first pregnancy, cleared the infection during the second pregnancy. However, three remained persistently infected and excreted B ovis in their milk throughout the second lactation. None of the lambs born to these three ewes was found to be infected when necropsied at weaning. 相似文献
12.
P. W. Physick-Sheard J. B. Hopkins R. D. O'Connor 《The Canadian veterinary journal. La revue veterinaire canadienne》1980,21(2):53-60
An outbreak of nervous disease and abnormally hairy fleece was observed among newborn lambs in a closed flock of sheep in southern Ontario. The outbreak was investigated and found to closely parallel syndromes described in the British Isles and Australia and variously referred to as border disease, hypomyelinogenesis congenita and hairy shaker syndrome. Clinically affected lambs represented only a portion of the animals affected, considerable losses being caused by reproductive failure in the ewes and suboptimal performance in subclinically affected lambs. Sheep from the affected flock showed a strong serological response to the causative agent of bovine virus diarrhea/mucosal disease. The episode appeared to be chronologically related to the introduction of beef heifers from a sales barn. The paper discusses the results of clinico-epidemiological investigation of the outbreak in the light of current knowledge of border disease-like syndromes. 相似文献
13.
A 2 x 2 factorial arrangement of treatments with 78 mature ewes was used to evaluate the effects of supplementing the pregnant ewe's diet with high levels of minerals and vitamin E on immunoglobulin G (IgG) absorption by the lamb and whether any altered efficacy of IgG absorption was due to the colostrum or to the lamb. The ewes were estrus-synchronized in October and housed in wk 10 of gestation. In the final 7 wk of gestation, a grass silage-based diet, offered ad libitum, was supplemented with 500 g of a 19% CP concentrate, and from 1 wk later until lambing, half the ewes was offered 48 g of a mineral/vitamin supplement containing 6.5 g of Ca, 4.9 g of P, 5.9 g of Mg, 4.0 g of Na, 790 mg of Zn, 3.5 mg of Se, 40 mg of I, 200 mg of Mn, 20 mg of Co, and 40 IU of vitamin E. At birth, the lambs were allocated to one of four treatments in a 2 x 2 factorial arrangement, with lamb origin and colostrum origin as the two factors. The lambs born to ewes not offered the mineral supplement were fed colostrum obtained from their own dams or from ewes in the mineral-supplemented treatment, whereas lambs born to ewes given supplemental minerals were fed colostrum obtained either from their dams or from ewes in the control treatment. The ewes were milked at 1, 10, and 18 h postpartum and the lambs were fed using a stomach tube. A 5-mL blood sample was taken from each lamb at 24 h postpartum for IgG analysis. The level of fecal adhesion to the upper tail/rump area of the lamb was subjectively scored at 72 h postpartum. There was no difference in gestation length, lamb birth weight, colostrum yield, or IgG production (P = 0.16 to 0.82). When ewes were fed supplemental minerals, the serum IgG content of the progeny was lower than in their control counterparts (6.8 vs. 16.1 g/L; P < 0.001), regardless of whether the lamb received colostrum from ewes with or without access to supplementary minerals. The difference in serum IgG concentrations at 24 h postpartum was a direct reflection of a compromised efficiency in IgG absorption. The progeny of ewes with access to minerals had higher (P < 0.05) levels of fecal adhesion, which was not related to the origin of the colostrum, indicating altered digestive function in these lambs. We conclude, using the sheep as a model, that high mineral intakes in late pregnancy not only lower serum IgG concentrations in the lamb, but also that high mineral intakes result in the neonate being preprogrammed at birth so that it is born with a compromised ability to absorb colostral IgG. 相似文献
14.
Transmissible congenital demyelinating encephalopathy of lambs 总被引：2，自引：0，他引：2
Twenty-two fetal lambs were inoculated in utero with tissue suspension prepared from lambs born with weakness, incoordination and clonic tremor. Clinically, affected newborn lambs had clonic tremor, were generally weak and had abnormally pigmented hairy fleece. The inoculation resulted in a disseminated encephalomyelitis with secondary teratologic changes in a significant number of fetuses. The mononuclear inflammatory changes were most obvious 14 days after inoculation, after which there was rapid resolution. Changes seen at birth were chronic astrocytosis with neuron loss in the spinal cord and cerebellar dysplasia. Single radioimmunodiffusion studies showed consistently low IgG in infected fetuses and high IgG in lambs at birth. 相似文献
15.
Throughout pregnancy, 30 primiparous Finn cross ewes were given a low Zn (less than or equal to 1 ppm) semi-purified diet. A 100-g hay supplement was fed three to seven times/week. Supplemental Zn (20 ppm) was provided in the drinking water of 14 ewes. At parturition, lambs were removed from ewes before suckling. Viable lambs not taken for tissue analysis were given 200 ml cow colostrum and raised on an artificial feeder. Throughout gestation, unsupplemented (-Zn) ewes gained less weight and had lower plasma Zn levels than Zn-supplemented (+Zn) ewes. One -Zn ewe was not pregnant, three aborted, one resorbed, one delivered mummified twins at term and two delivered malformed lambs. Average weight of lambs born to -Zn ewes d 136 or later (excluding mummified twins and one weighing less than 20% as much as its twin) was 1.8 +/- .6 (SE) kg. Only three lambs born to -Zn ewes were vigorous enough to put on the artificial feeder; none survived. One +Zn ewe was not pregnant. Of 23 lambs born to the remaining +Zn ewes, five were used for tissue analysis, two lambs of triplets were born dead, twins born d 138 died at birth. One twin died 6 d after birth. The 14 remaining lambs were weaned in good health. Average birth weight of +Zn lambs was 3.3 +/- 1.0 kg. Increased salivation was seen in -Zn ewes after 6 wk of low Zn intake.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
16.
J L Zaugg 《American journal of veterinary research》1987,48(1):100-103
Seventeen mature, pregnant, anaplasmosis-susceptible and 3 anaplasmosis-carrier ewes were used in Anaplasma ovis in utero transmission studies. Susceptible ewes were arbitrarily allotted to 3 groups, 4 each in groups A and C and 9 in group B, and were inoculated with whole blood from a carrier ewe. Each group was Anaplasma-exposed once during one of the thirds of pregnancy. In all ewes, resulting parasitemias were low and anemias were mild. Three carrier ewes comprised group D. Blood samples were obtained once during gestation from each fetus at various stages of development for evaluation and inoculation into splenectomized lambs. Blood obtained from neonates before nursing was also evaluated for Anaplasma presence. Parasitemia was not detected in any fetus or neonate; however, 3 of 16 splenectomized lambs inoculated with fetal or neonate blood developed acute anaplasmosis. Dams of fetuses/neonates with infective blood had been Anaplasma-exposed during their 2nd or last 3rd of pregnancy. Infective Anaplasma agents crossed the placental barrier as early as 130 days of gestation. 相似文献
17.
R C Cutlip H D Lehmkuhl S C Whipp A W McClurkin 《American journal of veterinary research》1982,43(1):82-85
Fetuses of 20 pregnant ewes at 4 gestational periods (45, 55, 85, and 100 days) were inoculated with ovine progressive pneumonia virus. Fourteen of 16 fetuses exposed to virus before gestational day 80 were either resorbed or expelled, whereas 10 of 15 fetuses exposed to virus after day 80 were normal at birth. Three of the 9 expelled fetuses and 1 of 2 newborn lambs had accumulations of lymphoid cells in the lungs. Virus was readily isolated from the tissues of expelled fetuses and newborn lambs. Lambs did not have precipitating antibody to the virus at birth, but 3 to 5 lambs had specific antiviral antibody at 18 months of age. 相似文献
18.
OBJECTIVE: To identify and describe the occurrence of neurological lesions that could have an effect on lamb mortality. PROCEDURE: The central nervous system was investigated macroscopically (n = 92) and microscopically (n = 72) in lambs dying in the perinatal period during 3 years in flocks of adult Corriedale ewes. The central nervous system was removed intact and samples of cerebral cortex, basal ganglia, thalamus, hippocampus, mesencephalon, cerebellar cortex, medulla oblongata, and cervical spinal cord were scored microscopically for the severity of neuronal dead, cytotoxic and perivascular oedema, and haemorrhage. RESULTS: Neurologic findings between birth and 6 days included haemorrhages in meninges, brain congestion and oedema, neuronal ischemic necrosis, intraparenchymal haemorrhages in medulla oblongata and cervical spinal cord, parasagittal cerebral necrosis, and periventricular leukomalacia. No significant lesions were found in anteparturient deaths or in those aged between 7 and 16 days. Oedema was more severe in the brain than in other regions of the central nervous system. Ischaemic neurons first appeared 24 hours post partum, increased linearly in number between 48 hours and 5 days post partum, and had a laminar distribution in the cerebral cortex, indicating a hypoxic-ischemic encephalopathy. Haemorrhages were most severe in the gray matter of medulla oblongata and cervical spinal cord, suggesting trauma due to instability of atlantoaxialis joint. CONCLUSION: Lesions in the central nervous system can explain most deaths at birth and within 6 days of birth. The lesions were hypoxic-ischemic and appeared to be related to birth injury. 相似文献
19.
The objective of the experiment was to determine the effectiveness of copper oxide wire particles (COWP) in pregnant ewes and safety to lambs. COWP have been used recently as an anthelmintic in small ruminants to overcome problems associated with nematode resistance to chemical dewormers. Doses of COWP (相似文献
20.
T S Kellerman L Prozesky R A Schultz C J Rabie H van Ark B P Maartens A Lübben 《The Onderstepoort journal of veterinary research》1991,58(4):297-308
During 1987 when cob rot was rife, perinatal losses were reported in flocks and herds that had been exposed to diplodiosis. The affected lambs or calves were either stillborn or died soon after birth. Dosing trials at the Onderstepoort Veterinary Research Institute involving 82 ewes revealed that 66% of the offspring of dams exposed to cultures of Diplodia maydis (= Stenocarpella maydis) in the second trimester of pregnancy and 87% of lambs of ewes exposed in the third trimester were born dead or died soon afterwards. A status spongiosus similar to that of the field cases was present in the white matter of the brains of all the affected lambs. The lambs of ewes that had shown nervous signs and those of ewes that had not shown such signs were equally affected. The experiments also clearly demonstrated that foetuses were much more susceptible to diplodiosis than the adults, e.g. in the third trimester 87% of the lambs were affected compared to only 44% of the dams. No perinatal mortalities were recorded in the group exposed to the culture in the first trimester. Ewes developed significant resistance to intoxication after initial exposure to the culture and both the length of gestation and birth mass of the affected lambs were less than those of their untreated counterparts. 相似文献