Bovine viral diarrhea virus (BVDV) 1b: predominant BVDV subtype in calves with respiratory disease   总被引：1，自引：1，他引：0       下载免费PDF全文

Robert W. Fulton  Julia F. Ridpath  Jeremiah T. Saliki  Robert E. Briggs  Anthony W. Confer  Lurinda J. Burge  C. W. Purdy  Raymond W. Loan  Glenn C. Duff    Mark E. Payton 《Canadian journal of veterinary research》2002,66(3):181-190

The prevalence of bovine viral diarrhea virus (BVDV) infections was determined in 2 groups of stocker calves with acute respiratory disease. Both studies used calves assembled after purchase from auction markets by an order buyer and transported to feedyards, where they were held for approximately 30 d. In 1 study, the calves were mixed with fresh ranch calves from a single ranch. During the studies, at day 0 and at weekly intervals, blood was collected for viral antibody testing and virus isolation from peripheral blood leukocytes (PBLs), and nasal swabs were taken for virus isolation. Samples from sick calves were also collected. Serum was tested for antibodies to bovine herpesvirus-1 (BHV-1), BVDV1a, 1b, and 2, parainfluenza 3 virus (PI3V), and bovine respiratory syncytial virus (BRSV). The lungs from the calves that died during the studies were examined histopathologically, and viral and bacterial isolation was performed on lung homogenates. BVDV was isolated from calves in both studies; the predominant biotype was noncytopathic (NCP). Differential polymerase chain reaction (PCR) and nucleic acid sequencing showed the predominant subtype to be BVDV1b in both studies. In 1999, NCP BVDV1b was detected in numerous samples over time from 1 persistently infected calf; the calf did not seroconvert to BVDV1a or BVDV2. In both studies, BVDV was isolated from the serum, PBLs, and nasal swabs of the calves, and in the 1999 study, it was isolated from lung tissue at necropsy. BVDV was demonstrated serologically and by virus isolation to be a contributing factor in respiratory disease. It was isolated more frequently from sick calves than healthy calves, by both pen and total number of calves. BVDV1a and BVDV2 seroconversions were related to sickness in selected pens and total number of calves. In the 1999 study, BVDV-infected calves were treated longer than noninfected calves (5.643 vs 4.639 d; P = 0.0902). There was a limited number of BVDV1a isolates and, with BVDV1b used in the virus neutralization test for antibodies in seroconverting calves' serum, BVDV1b titers were higher than BVDV1a titers. This study indicates that BVDV1 strains are involved in acute respiratory disease of calves with pneumonic Mannheimia haemolytica and Pasteurella multocida disease. The BVDV2 antibodies may be due to cross-reactions, as typing of the BVDV strains revealed BVDV1b or 1a but not BVDV2. The BVDV1b subtype has considerable implications, as, with 1 exception, all vaccines licensed in the United States contain BVDV1a, a strain with different antigenic properties. BVDV1b potentially could infect BVDV1a-vaccinated calves.  相似文献   

Evidence for transplacental transmission of canine distemper virus: two case reports   总被引：1，自引：0，他引：1  

S Krakowka  A Confer  A Koestner 《American journal of veterinary research》1974,35(9):1251-1253

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Hindlimb lameness caused by systemic lymphosarcoma in a Warmblood mare     

D. K. Moser  H. W. Jann  A. W. Confer  R. J. Bahr  C. Kuzma 《Equine Veterinary Education》2014,26(8):416-419

Equine lymphosarcoma is rare but has been reported in mediastinal lymph nodes, cutaneous nodules, the gastrointestinal system and peripheral lymph nodes. This report describes the clinical presentation of lymphosarcoma characterised by weight shifting, reluctance to ambulate or peripheral oedema. This case is extremely atypical in clinical presentation and justifies the need for consideration of lymphosarcoma when formulating a differential diagnosis of lameness with atypical presentation.  相似文献   

Effects of fertilization and incubation factors on the quality and yield of scallop, Pecten fumatus Reeve, larvae     

M P Heasman  W A O'Connor  AW Frazer 《Aquaculture Research》1996,27(7):505-513

Variable quality and yield (percentage development from eggs) D-veligers of the scallop, Pecten fumatus Reeve, prompted assessment of fertilization and incubation protocols. Various sperm to egg ratios were tested on eggs suspended in sea water at different densities. Ratios of 1000:1 led to the highest D-veliger yield when eggs were incubated in suspension at one per millilitre. With increasing egg densities, the addition of 1000 sperm per egg led to increasing average numbers of sperm visible at the periphery of each egg, indicating that fewer sperm were necessary for fertilization at higher egg densities. The time period and temperature over which released gametes were stored before fertilization were also found to significantly affect D-veliger yield. Decreasing gamete storage temperature from 26 to 14^oC increased D-veliger yield, as did a reduction in the gamete storage period from 6 to 1 h. The incubation of embryos at densities in the 5-50 ml^-1 range did not affect D-veliger yield. A significant increase in total bacterial counts in the culture water occurred with increasing embryo stocking densities. However, presumptive Vibrionaceae counts did not increase significantly with increasing embryo stocking densities. In a comparison of the viability of self- and cross-fertilized embryos and larvae, fewer self-fertilized embryos developed to D-veliger stage; however, percentage survival, although highly variable, did not differ significantly in subsequent larval rearing. Cross-fertilized larvae had attained a significantly larger size by day 7.  相似文献   

Cytotoxin (leukotoxin) production by Pasteurella haemolytica: requirement for an iron-containing compound   总被引：9，自引：0，他引：9  

M J Gentry  A W Confer  E D Weinberg  J T Homer 《American journal of veterinary research》1986,47(9):1919-1923

In studies of Pasteurella haemolytica type 1 cytotoxin, filter-sterilized culture supernatants from organisms grown in RPMI-1640 tissue culture medium generally have been used. Supplementation of the medium with 7% bovine fetal serum was shown to be necessary for maximal cytotoxin production, as measured by percentage of bovine peripheral blood leukocytes that were killed. The serum-induced increase in cytotoxicity could not be explained simply by a greater percentage of increase in the number of viable organisms produced in the enriched medium. There also was no correlation between encapsulation of the organisms and cytotoxin production. Several natural iron-containing proteins including transferrin, lactoferrin, conalbumin, and hemoglobin stimulated cytotoxin production in lieu of bovine fetal serum, leading to the conclusion that one function of serum supplementation may be to increase the medium's iron concentration. A number of additional iron-containing and iron-chelating compounds were tested, with the conclusion that the iron concentration of the growth medium, as well as the presence of a suitable carrier molecule, may be critical for efficient cytotoxin production by P haemolytica.  相似文献   

Causes of perinatal mortality in farmed fallow deer (Dama dama)     

AW ENGLISH  RC MULLEY† 《Australian veterinary journal》1992,69(8):191-193

The causes of perinatal mortality in farmed fallow deer in the Camden region of New South Wales were determined between 1982 and 1987. The results of 144 necropsies on fawns showed that ante-parturient and parturient deaths occurred in 33 (22.9%) of cases, with post-parturient deaths accounting for 99 (69.8%), and undiagnosed causes the remaining 12 (8.3%). The most common cause of post-parturient death (43.1%) was exposure/starvation of fawns that had birthweights lower than the average for surviving fawns on these same farms (3.01 kg and 4.12 kg, respectively). These results provide good evidence of the correlation between low birthweight and perinatal mortality in fallow deer on Australian deer farms.  相似文献   

Evaluation of health status of calves and the impact on feedlot performance: assessment of a retained ownership program for postweaning calves   总被引：1，自引：1，他引：0       下载免费PDF全文

Robert W. Fulton  B. J. Cook  D. L. Step  Anthony W. Confer  J. T. Saliki  Mark E. Payton  Lurinda J. Burge  R. D. Welsh    K. Shawn Blood 《Canadian journal of veterinary research》2002,66(3):173-180

The objective of this study was to evaluate animal health status at entry to a feedlot against feedlot performance and carcass value. There were 24 herds represented by 417 calves in a retained ownership program. The health status at entry was represented by the levels of serum antibody to infectious bovine rhinotracheitis virus (IBRV), bovine viral diarrhea viruses 1 and 2 (BVDV1a, BVDV2), parainfluenza 3 virus (PI3V), bovine respiratory syncytial virus (BRSV), Mannheimia haemolytica, and Pasteurella multocida, as well as by the presence of virus in nasal swabs and blood leukocytes and the presence of bacteria in nasal swabs. The presence or absence of viruses or bacteria at entry did not predict subsequent illness. However, there were predictors of illness severity (number of treatments) and performance parameters of feedlot performance. Herds with a low morbidity rate had higher levels of BVDV1a antibodies than herds with a high morbidity rate. On both an individual-animal and a herd-average basis, calves with low levels of antibody to BVDV1a and BVDV2 had increased total treatment costs. Also, for individual animals and the herd as a whole, low levels of antibody to P. multocida, BVDV1a, and BVDV2 were related to decreased net value to owner (carcass value minus total feedlot cost). Calves treated twice or more had lower levels of antibody to BVDV1a than those treated once or not at all. Differences in herd morbidity rate and treatment costs were more related to appropriate timing of vaccine (last dose at or near delivery of calf) or lack of a 2nd dose of killed vaccine. This was best illustrated by the levels of antibody to BVDV1a. The results of this study were used to formulate recommendations for the subsequent year.  相似文献   

Experimental infection of domestic cats (Felis domesticus) with Cytauxzoon manul from Pallas' cats (Otocolobus manul)     

Joyner PH  Reichard MV  Meinkoth JH  Milne VE  Confer AW  Kocan AA  Hoover JP 《Veterinary parasitology》2007,146(3-4):302-306

In a random, blind study, six domestic cats were assigned to two treatment groups that received either sterile water or dexamethasone by subcutaneous injection prior to intravenous inoculation with Pallas' cat (Otocolobus manul) blood infected with Cytauxzoon manul. A seventh domestic cat served as a control and was inoculated only with sterile water. Cats were monitored for clinical signs consistent with cytauxzoonosis, and periodically screened for hemoparasitemia. All domestic cats (6/6) that received Pallas' cat blood infected with C. manul developed a low but detectible parasitemia by 9 days post-inoculation, yet remained clinically healthy. All domestic cats (7/7) were subsequently challenged with Cytauxzoon felis and developed clinical signs typical of cytauxzoonosis within 5 days post-challenge. Affected animals were euthanized and cytauxzoonosis was confirmed by histopathology. While inoculation of domestic cats with Pallas' cat blood infected with C. manul induced a parasitemia, it did not cause disease or provide protection against challenge with C. felis. Further studies are warranted to determine the potential for interspecies transmission and disease with C. manul.  相似文献   

Lathyrus hirsutus (Caley Pea) Intoxication in a Herd of Horses          下载免费PDF全文

T.C. Holbrook  L.L. Gilliam  F.P. Stein  S.E. Morgan  A.L. Avery  A.W. Confer  R.J. Panciera 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(1):294-298

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Evaluation of diagnostic tests used for detection of bovine viral diarrhea virus and prevalence of subtypes 1a, 1b, and 2a in persistently infected cattle entering a feedlot     

Fulton RW  Hessman B  Johnson BJ  Ridpath JF  Saliki JT  Burge LJ  Sjeklocha D  Confer AW  Funk RA  Payton ME 《Journal of the American Veterinary Medical Association》2006,228(4):578-584

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