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1.
Rodger SM Maley SW Wright SE Mackellar A Wesley F Sales J Buxton D 《The Veterinary record》2006,159(23):768-772
To investigate the potential role of endogenous transplacental transmission of Toxoplasma gondii, 31 seropositive ewes presumed to be persistently infected with the parasite and 15 seronegative ewes were mated and monitored throughout pregnancy and lambing. Antibody titres were determined in precolostral sera from the liveborn lambs and in thoracic fluid from the dead lambs. A PCR for the B1 gene of T gondii was applied to the placentas from all the ewes and to the brains of the stillborn lambs. Samples of brain, lung, liver, spleen and heart from the dead lambs were examined by histopathology. No evidence of toxoplasmosis was detected by histopathology or PCR in any of the samples, but low titres of antibody to T gondii were detected in two liveborn, healthy offspring of a seropositive ewe by the immunofluorescent antibody test (3.2 per cent of pregnancies and 4.1 per cent of lambs in the seropositive group). Antibody to specific antigens of T gondii was demonstrated in sera from these two lambs by Western blotting. 相似文献
2.
3.
Intrauterine transmission of ovine progressive pneumonia virus 总被引：2，自引：0，他引：2
Ovine fetuses, newborn lambs, and ovine colostrum were examined for ovine progressive pneumonia virus. The lambs and colostrum were also examined for specific antibody. Virus was isolated from 1 fetus, from 2 newborn lambs, and from most samples of colostrum. The fetus was about 100 days old and was carried by a seronegative ewe in contact with seropositive sheep. Both newborn lambs were carried by seropositive ewes. One lamb was dead at birth; the other lamb was normal and had not nursed. Antibody specific for the virus was present in the colostrum of 12 of 14 seropositive ewes and in the serum of 8 of 11 lambs that had nursed seropositive ewes, but not in the serum of lambs that had not nursed. 相似文献
4.
E. Simensen P. S. Valle S. Vatn 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):194-201
Abstract Factors influencing rate of barren ewes, number of lambs born per pregnant ewe, and autumn live weight of the lambs were studied in 627 Norwegian sheep flocks based on herd level data from the Norwegian Sheep Recording System and a mailed questionnaire to the sheep farmers. The following factors were significantly associated (P<0.05) with rate of barren ewes: breed, herd average lambing date, type of production/age of farmer, routines for treatments for parasites, and housing type. Number of lambs born per pregnant ewe was significantly associated with rate of barren ewes, herd average lambing date, breed, percentage grass silage of total roughage, and no separation of gimmers during the housing period. Corrected autumn live weight of the lambs was significantly associated with breed, flock size, lambs born per pregnant ewe, no separation of gimmers during the housing period, and type of summer pasture. 相似文献
5.
H Waldeland 《Acta veterinaria Scandinavica》1977,18(2):237-247
The contents of toxoplasma antibodies were estimated by a micro-modification of the dye test for up to 3 years after the initial stage of infection both in ewes which had aborted and in ewes with normal pregnancies. During the first 2 years the titres in ewes which had aborted were significantly higher than in ewes with normal pregnancies. The investigation indicated that dye test titres ≥ 1/512 usually occur during the first stage of infection, and are mainly found in ewes with clinical toxoplasmosis.The dye test titres in lambs due to antibodies transferred with the colostrum were up to 4 twofold dilutions higher than in their dams during the first 2 days after birth. Later the titres declined, and at the age of about 2 months only 3 of 29 lambs had higher titres than their dams. After the age of about 3 months maternally derived antibodies were not detected.The contents of toxoplasma antibodies in sheep with listeric encephalitis were nearly the same as found by a serological survey of the local sheep population. The examination indicated that the dye test titres in sheep are little influenced by conditions that may affect the defence mechanism.Sheep with haemoglobin type B had significantly higher dye test titres than sheep with the haemoglobin types A and AB when examined less than about 6 months after they had acquired the infection. No association was found between the susceptibility to toxoplasma infection and the haemoglobin type. kw|Keywords|k]toxoplasma infection; k]antibody formation; k]sheep {fn1|This work was supported by grants from The Norwegian Research Council for Science and for the Humanities.} 相似文献
6.
Scheer-Czechowski P Vogt HR Tontis A Peterhans E Zanoni R 《Schweizer Archiv für Tierheilkunde》2000,142(4):155-164
Maedi-Visna is a lentiviral disease of sheep with a worldwide distribution. The transmission of the virus occurs primarily via colostrum and milk from the infected ewe to its newborn lamb but also horizontally between sheep. The most obvious clinical symptoms are progressive dyspnea and emaciation. In this prospective study an eradication based on serological testing and removing of seropositive animals was performed in 24 flocks of sheep of the breed "Walliser Schwarznasenschafe" leading to a reduction of the seroprevalence from 36% to 1% within two years. The control group consisted of 21 flocks of sheep. Lambs of seropositive ewes had a 7.6 times higher risk to seroconvert within their first two years of life compared to those of seronegative ewes. The dynamics of the spread of the infection were studied in birth cohort groups. Cohort animals of seropositive ewes showed an obvious trend to seroconvert slowly. Seropositive ewes had a significantly lower reproduction rate and their lambs suffered from significantly higher death and lower growth rates, probably due to a reduced milk production, resulting in economic losses. 相似文献
7.
Hallstein Grnstl 《Acta veterinaria Scandinavica》1979,20(2):168-179
Listeriosis in sheep. Listeria monocytogenes excretion and immunological state in healthy sheep. Acta vet. scand. 1979, 20, 168–179. — The excretion of Listeria monocytogenes (Lm) in the faeces and milk, and humoral and cell mediated immunity against Lm, were examined in a sheep flock where no cases of listeriosis had occurred during the last 3 years. The investigation was carried out during the indoor season. During the first part of the season 2 of the 10 pregnant, 8 months old lambs excreted Lm in the faeces, but none of the 106 ewes, 2–10 years old. At lambing the organism was isolated from the faeces of 6 of the 10 1 year old lambs and from 64% of the ewes, and from the milk of 1 of the lambs and 41% of the ewes. Nearly all the isolates (98.5%) belonged to serotype 1.Antibody titres against Lm were found in sera and whey by an indirect haemagglutination method. The titres were higher for the ewes than for the hoggs and seemed to be influenced by the number of foetuses the animals carried.Cell mediated immunity was determined by a skin test where delayed hypersensitivity against an antigen prepared from Lm, was measured. Animals fed grass silage had a stronger reaction than animals fed hay, and a stronger reaction was found in animals with ≥ 3 foetuses than in the remainder.The investigation indicates that even in a healthy sheep flock all the animals may be exposed to Lm, and the majority may be latent carriers and excrete this organism in the faeces and milk during periods of stress. 相似文献
8.
D E Behymer R Ruppanner E W Davis C E Franti C M Les 《American journal of veterinary research》1985,46(5):1141-1144
An epidemiologic study was done on a ranch in northern California on a flock of ewes that had a history of abortions, mummified fetuses, weak or stillborn lambs, and failure to conceive. Of 56 ewes tested, 33 (59%) had serum agglutinating antibodies against Toxoplasma gondii, with an unusually high proportion of high titers. Over a 2-year-period, reproductive problems were higher (39% to 42%) among the seropositive ewes than among the seronegative ewes (9% to 33%). Of 89 sera received from persons and 7 species of animals on the ranch, 44 (49%) were found to be seropositive to T gondii, including seropositive members of a family of 6. The rancher's wife and teenage daughter, both of whom were involved with lambing, had serum titers exceeding 4,096. Other members of the family not involved with lambing were seronegative by the indirect hemagglutination test. The 2 infected persons are known to have come in contact with placentas, birth fluids, fetuses, and colostrums from these infected ewes. 相似文献
9.
Pleuropneumonia in swine caused by Haemophilus parahaemolyticus. A study of the epidemiology of the infection 总被引：15，自引：0，他引：15
Haemophilus parahaemolyticus infection was studied in a herd with continuous production, i.e., continuous introduction of stock to replace animals delivered for slaughter. None of 30 seronegative pigs contracted the infection when exposed to contact with two pigs that were seropositive after inoculation with H. Parahaemolyticus three weeks earlier. After aerosol infection had been applied in the building an acute outbreak with a morbidity rate of 100 per cent developed in less than 24 hours. Following recovery the majority of the 16 pigs present became seropositive, and when 30 seronegative pigs were introduced 7 weeks later, antibody response occurred in three of them. The persistence of H. parahaemolyticus in pigs that had been infected during the acute outbreak was confirmed at slaughter, in that the organism was re-isolated from the tonsils of 2 of these pigs. Most serum titres persisted for several months, but some animals showed just a transient antibody response. 相似文献
10.
Tittarelli M Di Ventura M De Massis F Scacchia M Giovannini A Nannini D Caporale V 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2005,52(9):403-409
The authors studied the persistence of infection in 46 ewes experimentally infected with Brucella melitensis biovar 3 and monitored through three subsequent reproductive cycles. The entire experimental period lasted for 151 weeks. Infection of ewes and elimination of Brucella in milk, or its presence in vaginal discharges, persisted throughout the duration of the trial, as demonstrated by recurrent elimination of Brucella in milk and vaginal discharges. Brucella melitensis was recovered from the tissues of one ewe killed at the end of the trial. The strain was recovered from vaginal swabs and milk following parturition in the third reproductive cycle from an ewe that had aborted in the first cycle but was not pregnant in the second cycle. From a public health point of view, the periodical recovery of Brucella from the milk during the entire trial period illustrated that brucellosis in sheep remains a continuous occupational risk and a significant public health problem for consumers of fresh milk and milk products. That risk may persist for at least 3 years following the initial infection of the flock. Lamb antibody titres became negative in all lambs within 5 months after birth. This suggested that serological tests on lambs may have no practical diagnostic significance if performed during the first 5 months of life. Nevertheless, the birth of three infected lambs suggested that the phenomenon of latent carrier state may represent another way for B. melitensis to persist in a flock. 相似文献
11.
Alvarez V Daltabuit-Test M Arranz J Leginagoikoa I Juste RA Amorena B de Andrés D Luján L Badiola JJ Berriatua E 《Research in veterinary science》2006,80(2):226-234
A recent large-scale experimental study showed that bottle-feeding ovine colostrum from seropositive ewes results in high MVV-seroconversion in lambs. In contrast, relatively few lambs that naturally suckled colostrum from seropositive dams seroconverted as a result of it. Furthermore, lambs fed uninfected bovine colostrum readily seroconverted when mixed with ovine-colostrum lambs indicating that horizontal MVV transmission between lambs was efficient. MVV-infection was further investigated in the same samples using two PCR tests targeting sequences in the long-terminal repeats (LTR) and POL MVV genes. PCR-tests confirmed previous serological findings. However, the LTR-PCR was more sensitive and allowed detecting infection earlier than the other tests, including 5-8% of new-born lambs from seropositive dams, providing more evidence that prenatal MVV-infection may be more important than considered. The degree of agreement between PCR and antibody tests in individual samples was low up to 6 months of age and moderate at 10 months-old. Nine percent of lambs were always PCR-negative but seroconverted and 19% of lambs were PCR-positive at least once and did not seroconvert. However, seroconversion was associated with increasing number of times lambs were PCR-positive and ovine colostrum-fed lambs were more frequently PCR-positive than other lambs. The significance of these findings in terms of MVV-infection, epidemiology and control is discussed. 相似文献
12.
Prevalence and effect of subclinical ovine progressive pneumonia virus infection on ewe wool and lamb production 总被引：3，自引：0，他引：3
G D Snowder N L Gates H A Glimp J R Gorham 《Journal of the American Veterinary Medical Association》1990,197(4):475-479
The prevalence of infection with ovine progressive pneumonia (OPP) virus and its effects on ewe wool and lamb production were investigated in a flock of 2,976 ewes of 6 breed types (Rambouillet, Targhee, Columbia, Polypay, 1/4 cross Finnsheep, and 1/2 cross Finnsheep). Prevalence of seropositivity was significantly (P less than or equal to 0.01) lower among Rambouillet and Targhee breeds (44 and 42%, respectively), intermediate in Polypay, Columbia, and 1/4 cross Finnsheep (approximately 53%), and higher among 1/2 cross Finnsheep (62%). Seropositivity increased with age in all breed types from 11% at 1 year of age to 93% at greater than or equal to 7 years of age. Lateral disease transmission is indicated by linear increase of seropositivity prevalence with increasing age, including that in sheep greater than 6 years old. Subclinical infection with OPP virus had no apparent detrimental effect on number of lambs born, lamb viability, birth weight, number of lambs weaned, or growth rate of single and twin lambs, compared with findings for noninfected sheep in the same flock. Mature ewe body weight and grease fleece weight did not differ between subclinically infected seropositive and seronegative ewes. Subclinical infection with OPP virus does not appear to have an adverse economic effect on ewe wool and lamb production. Culling rate attributable to clinical manifestation of infection with OPP virus must be accurately determined before the true effects of virus infection on production can be determined and an eradication program can be recommended. 相似文献
13.
Alvarez V Arranz J Daltabuit-Test M Leginagoikoa I Juste RA Amorena B de Andrés D Luján LL Badiola JJ Berriatua E 《Research in veterinary science》2005,78(3):91-243
Maedi-visna virus (MVV) seroprevalence associated with consumption of colostrum from seropositive ewes was investigated in 276 housed lambs from birth to 300 days-old. At birth, lambs were allocated to five experimental groups according to the maternal MVV-serological status, source and mode of feeding colostrum (bovine or ovine and bottle fed or suckled from the dam) and type of horizontal MVV-exposure (raised with the dam or separately with other lambs). The risk of being seropositive at 300 days-old was associated with feeding ovine colostrum from seropositive ewes and increased with intake of bottle-fed ovine colostrum and was higher in lambs separated from their dams and raised with other experimental lambs compared to lambs raised with their dams. Approximately 75-87% of ELISA-positive results in lambs that had ovine colostrum was attributable to colostrum itself. However, approximately only 16% of naturally raised and 29-61% of bottle-fed ovine colostrum lambs were ELISA-positive as a result feeding ovine colostrum. These results confirm that ovine colostrum from seropositive ewes can be a major source of MVV but its overall contribution to seroprevalence in natural conditions is relatively low, and shows that horizontal MVV transmission can be an important source of infection in new-born lambs. 相似文献
14.
In a Swedish sheep flock comprising 202 ewes and 13 rams, a pair of twin lambs born in the spring of 1990 demonstrated signs of border disease (BD) and were persistently infected (PI) with border disease virus (BDV). Investigation showed that BDV had been introduced in the preceding tupping period 5-6 months earlier by a bought-in ewe which, on the basis of immunoperoxidase- and polymerase chain reaction techniques, was shown to be PI with BDV. Only 7 of the ewes, all of which had been in close contact with the PI ewe, seroconverted during the subsequent gestation. Apart from the PI twin lambs the losses caused by BDV were restricted to 2 barren ewes. The twin lambs, the PI ewe and lambs from the other 4 ewes that seroconverted were removed from the flock. The flock was thereafter free from an ongoing infection with BDV as shown by the absence of seroconversion.In addition, 5 heifers in late pregnancy most probably seroconverted to bovine virus diarrhoea virus (B VDV) when kept in close contact with the same PI ewe during the winter of 1989-90. When these heifers were reintroduced to the BVDV-free dairy herd from which they originated, their serum antibody titres ranged between 1:250 and 1:1250. Neither these heifers - nor their calves–caused any spread of the infection in the herd, as indicated by the absence of seroconversion in 70 cows. The present investigation shows that in the control of both BDV in sheep and BVDV in cattle, it is important to ensure that the risk of transmission of pestivirus between the 2 species is minimized. 相似文献
15.
Influence of selenium on antibody production in sheep 总被引：3，自引：0，他引：3
Three experiments were carried out, using sheep fed a marginally low selenium diet, to study the effect of selenium supplementation on the antibody response to tetanus toxoid and on the serum IgG concentration. Six groups of three six-month-old lambs were fed a basal diet containing 0.13 mg Se kg-1 supplemented with either 0.1, 0.5 or 1.0 mg Se kg-1, as sodium selenite or as selenomethionine. These animals generally showed enhanced antibody response to tetanus toxoid, parainfluenza-3 virus and Corynebacterium pseudotuberculosis, and their total serum IgG concentrations were higher than in unsupplemented control animals although few responses were statistically significant. In two field studies significantly higher titres to tetanus toxoid were detected in ewes injected with 100 mg selenium as barium selenate, although no influence on serum IgG concentrations was detected. Lambs from selenium supplemented ewes had significantly higher titres to tetanus toxoid than lambs from ewes in the control group. Dietary vitamin E supplementation had a similar effect on the antibody response to tetanus toxoid in ewes, though no additive effect was seen when vitamin E was given together with selenium. 相似文献
16.
Three rams were infected with tick-borne fever eight months after infection with toxoplasma. There was no clinical evidence of reactivation of the latent toxoplasma infection and semen samples from the rams were not infective to mice. Semen samples from 77 apparently normal rams were tested for toxoplasma infection by passage through mice; none of the samples produced patent infections in mice. Two rams with chronic toxoplasma infection were repeatedly mated with seronegative ewes. None of the ewes showed serological evidence of acquired infection and all lambed satisfactorily. 相似文献
17.
The antibody response of 20 pregnant ewes to oocyst infection with Toxoplasma gondii was determined by the latex agglutination test (LAT) and compared with the indirect fluorescent antibody test (IFAT) and a commercially available indirect haemagglutination test (IHAT). The LAT and IFAT showed a similar rapid response with antibody first appearing by two to three weeks after infection and titres that correlated closely (r = 0.81, P less than 0.001). The IHAT response was slower and less consistent up to seven weeks after infection. The LAT response was biphasic in seven of the sheep. Sera were fractionated using a minicolumn gel filtration technique and specific IgM and IgG titres determined by LAT. IgM titres peaked three weeks after infection and IgG titres exceeded IgM titres at a mean time of 4.7 weeks after infection (range 3 to 7). Eleven sheep exhibited fetopathy with abortion/parturition 12 to 53 days after infection; in nine of them IgG titres exceeded IgM at that time. A non-specific anti-toxoplasma reaction associated with IgM antibody occurred at low titre in one sheep. The results indicate that used from a dilution of 1/64 the LAT is a sensitive, reliable and rapidly responsive serological test for toxoplasma infection in ewes and it may be utilised with sample fractionation techniques to determine IgM titres. It is suggested that the best time to examine ewe sera to assist diagnosis of toxoplasma abortion is one week after abortion. While the determination of specific IgM titres in ewe sera may assist epidemiological studies and, sometimes, diagnosis, in the majority of aborting ewe sera it is unlikely to aid diagnosis. 相似文献
18.
In October 1998, two abortions associated with Coxiella burnetii occurred in a group of 34 pregnant ewes in the sheep flock belonging to INRA Tours-Nouzilly. The flock was kept in groups of approximately 40 ewes, which were housed together in the same accommodation. The prevalence of C burnetii infection in the groups was investigated by using ELISA and PCR tests, which revealed a high prevalence of C burnetii. The ewes were treated with oxytetracycline to reduce the shedding of C burnetii and to prevent further abortions. Nevertheless, five abortions attributed to C burnetii occurred in January and March 1999 in three groups of ewes, and 24 of the ewes still shed the bacteria into their vaginal tracts. In addition, a serological study was carried out during the first year of life of the female lambs born in 1999 and 2000; 12 per cent of 113 lambs born in 1999 were seropositive for C burnetii by ELISA, and half of the ELISA-positive lambs were born either to serologically positive ewes or to dams that excreted the pathogen into their vaginal tracts. However, all the 150 lambs born in 2000 were ELISA-negative, suggesting that the preventive measures undertaken had suppressed both the abortions and the shedding of C burnetii, and reduced the transmission of the agent. 相似文献
19.
This study describes responses to artificial infection with Haemonchus contortus in ewes and lambs of 50% Dorset, 25% Rambouillet, and 25% Finn-sheep ancestry and provides estimates of genetic parameters for measures of parasite resistance. One hundred ninety-eight ewes out of 64 sires, and 386 lambs out of 25 sires were evaluated in autumn and spring of 2 yr. Ewes were dewormed shortly after weaning their lambs and lambs were dewormed at about 120 d of age. One week after deworming, ewes and lambs were dosed with approximately 10,000 infective larvae of H. contortus. After infection, BW, fecal egg counts (FEC), and packed cell volume (PCV) were measured weekly for 7 wk in lambs kept in drylot and fortnightly for 11 wk in ewes on pasture. Summary traits were defined as initial PCV, mean BW across all times, and means for PCV (MPCV) and log-transformed FEC (MLFEC) at wk 3 to 7 after infection for lambs and wk 3 to 11 after infection for ewes. Ewes and lambs did not lose weight overall in any year or season, but there was no consistent effect of year or lambing season on mean LFEC or mean PCV during infection in either ewes or lambs. Yearling ewes were less resistant to infection than older ewes, with lower PCV (P < 0.05) and higher LFEC (P < 0.05). During infection, PCV was positively correlated with BW and negatively correlated with LFEC in both ewes and lambs. In lambs, heritabilities were 0.39 (P < 0.01) for PCV, 0.10 (P < 0.05) for LFEC across all measurement times, and 0.19 (P < 0.01) for three measures of LFEC taken at the peak of infection. Heritability estimates for ewes were 0.15 (P < 0.05) for PCV and 0.31 (P < 0.01) for LFEC. Repeatabilities for LFEC and PCV across measurement times were moderate in ewes and lambs. Correlations between dam and lamb records for MLFEC were generally low, suggesting different mechanisms of resistance in lambs and nonlactating ewes. Ewes with higher genetic merit for growth as lambs were less resistant to infection as adults, but genetic merit for fertility and prolificacy were not related to parasite resistance. Lambs with higher genetic merit for body weight were more resistant to infection. Selection for resistance to H. contortus is therefore possible and should not adversely affect growth of lambs and fertility of ewes in this production environment. 相似文献
20.
Attempted venereal transmission of Chlamydia psittaci in sheep 总被引：2，自引：0，他引：2
Attempts were made to transmit Chlamydia psittaci, the causal agent of enzootic abortion of ewes, in three different ways. Ten ewes were inseminated artificially with freshly collected semen containing 10(5) CELD50 chlamydia. Serological evidence of infection was found two weeks before parturition in nine ewes and the organism was recovered from three of them. By six weeks post partum antibody titres had fallen and were negative in six ewes. Twenty-four hours after service two groups of 10 ewes were infected intravaginally with 10(8) CELD50 and 10(3) CELD50 chlamydia respectively. Positive complement fixation titres were present in the first half of pregnancy in all the ewes in the high dose group but not the low dose group. None of the ewes showed evidence of infection at parturition. Fourteen ewes were served by four rams which had been intravenously infected with 10(8) CELD50 chlamydia four to six days earlier. Following service seroconversion occurred but titres became negative again by late pregnancy. No microbiological evidence of infection was detected in any of the ewes at parturition but complement fixation titres were positive in 12 of 14 ewes sampled six weeks post partum. The 14 ewes were sampled during their pregnancies the next year and none showed any evidence of chlamydial infection. It is concluded that venereal transmission of C psittaci is biologically feasible in sheep, but that under normal systems of flock management in Britain it is unlikely to contribute greatly to the epidemiology of enzootic abortion of ewes. 相似文献