The Use of a GUS Transformant of Trichoderma Harzianum, Strain T3a, to Study Metabolic Activity in the Spermosphere and Rhizosphere Related to Biocontrol of Pythium Damping-off And Root Rot     

Helge Green  Nina Heiberg  Kirsten Lejbølle  Dan Funck Jensen 《European journal of plant pathology / European Foundation for Plant Pathology》2001,107(3):349-359

The activity of Trichoderma harzianum in the spermosphere and rhizosphere of different plant species was studied by use of a beta-glucuronidase (GUS) transformant (strain T3a). Hereby, direct observation of micro-habitats supporting metabolic activity of T. harzianum is reported. Germination of conidia and mycelial growth were not supported by exudates from healthy roots of various ages. Instead, growth and activity of T. harzianum depended on access to dead organic substrates such as seed coats, decaying roots, and wounds, including those caused by infecting pathogens. A correlation between the GUS activity of T. harzianum and the biomass of Pythium ultimum in infected roots was established. On the basis of our observations, we suggest that the biocontrol ability of T. harzianum involves competition with the pathogen for substrates including the seed coat, and wounded or infected root tissue.  相似文献   

A new isolate of the nematophagous fungus Duddingtonia flagrans a biological control agent against free-living larvae of horse strongyles     

Silvina Fernández A  Henningsen E  Larsen M  Nansen P  Grønvold J  Søndergaard J 《Equine veterinary journal》1999,31(6):488-491

An experiment was carried out in 1997 to test the efficacy of an isolate of the microfungus Duddingtonia flagrans against free-living stages of horse strongyles under conditions in the field and to assess the eventual effect of the fungus on the normal degradation of faeces. Faecal pats were made from faeces of a naturally strongyle infected horse, which had been fed fungal material at a dose level of 106 fungal unit/kg bwt. Control pats without fungi were made from faeces collected from the same animal just before being fed fungi. Faecal cultures set up for both groups of faeces to monitor the activity of the fungus under laboratory conditions showed that the fungus significantly reduced the number of infective third-stage larvae (L3) by an average of 98.4%. Five faecal pats from each batch of faeces were deposited on pasture plots at 3 times during spring-summer. The herbage around each pat was sampled fortnightly to recover L3 transmitted from faeces. The results showed that the herbage infectivity around fungus-treated pats was reduced by 85.8-99.4%. The remaining faecal material at the end of each sampling period was collected, and the surviving L3 were extracted. Significantly fewer larvae were recovered from the fungus-treated pats. Analysis of wet and dry weight of the collected pats, as well as their organic matter content, were performed to compare the degradation of faeces of both groups. The results indicated that the presence of the fungus did not alter the degradation of the faeces.  相似文献   

Spontaneous vaginal rupture in pregnant ewes     

Mosdøl G 《The Veterinary record》1999,144(2):38-41

Seventeen cases of spontaneous, partial or total vaginal rupture, in pregnant ewes, involving the dislocation and herniation of the intestines and uterus, were studied. Four of them also had a uterine torsion, and three of these recovered after treatment. In the remaining 13 cases the condition of the uterus was unknown. The lesion always consisted of a dorsolateral tear in the vagina with a partial or total perforation of the wall close to the uterine cervix. The affected animals were all in normal body condition. Their average age was just under five years, and most were carrying twins. Most cases occurred approximately one week before expected lambing. None of the cases was observed to have a vaginal prolapse before the vaginal rupture. Histological examination of one case revealed scar formation in the vaginal wall close to the rupture, which appeared to be due to an earlier inflammatory process or injury. The circulatory disturbance in the reproductive organs caused by the uterine torsion potentially weakens the vaginal wall. This weakness, in combination with excessive tenesmus resulting from increased tension in the uterine ligaments, and in some cases possibly with a lower vaginal resistance due to previous scarring, may be of aetiological significance in spontaneous vaginal rupture.  相似文献   

A pharmacokinetic study including some relevant clinical effect of medetomidine and atipamezole in lactating dairy cows     

Ranheim B  Arnemo JM  Ryeng KA  Søli NE  Horsberg TE 《Journal of veterinary pharmacology and therapeutics》1999,22(6):368-373

Medetomidine is the most potent and selective alpha2-agonist used in veterinary medicine and its effects can be antagonized by the alpha2-antagonist atipamezole. The pharmacokinetics of medetomidine and atipamezole were studied in a cross-over trial in eight lactating dairy cows. The animals were injected intravenously (i.v.) with medetomidine (40 microg/kg) followed by atipamezole i.v. (200 microg/kg) or saline i.v. after 60 min. Drug concentrations in plasma were measured by HPLC. After the injection of atipamezole, the concentration of medetomidine in plasma increased slightly, the mean increment being 2.7 ng/mL and the mean duration 12.1 min. However, atipamezole did not alter the pharmacokinetics of medetomidine. It is likely that the increase in medetomidine concentration is caused by displacement of medetomidine by atipamezole in highly perfused tissues. The volume of distribution at steady state (Vss) for medetomidine followed by saline and medetomidine followed by atipamezole was 1.21 and 1.32 L/kg, respectively, whereas the total clearance (Cl) values were 24.2 and 25.8 mL/min x kg. Vss and Cl values for atipamezole were 1.77 mL/kg and 48.1 mL/min x kg, respectively. Clinically, medetomidine significantly reduced heart rate and increased rectal temperature for 45 min. Atipamezole reversed the sedative effects of medetomidine. However, all the animals, except one, relapsed into sedation at an average of 80 min after injection of the antagonist.  相似文献   

A retrospective evaluation of a Bovine Herpesvirus-1 (BHV-1) antibody ELISA on bulk-tank milk samples for classification of the BHV-1 status of Danish dairy herds     

Nylin B  Strøger U  Rønsholt L 《Preventive veterinary medicine》1999,47(1-2):91-105

Bulk-tank milk samples analysed in a Bovine Herpesvirus-1 (BHV-1) blocking ELISA are still in use in the Danish BHV-1 programme as a tool to classify dairy herds as BHV-1 infected or BHV-1 free herds. In this retrospective study, we used data from the Danish BHV-1 eradication campaign to evaluate performance characteristics of the BHV-1 blocking ELISA in 1039 BHV-1-seropositive and 502 repeatedly BHV-1-negative dairy herds using the results of blood testing of the individual animals as the true infection status. At a cut-off value of 30% blocking reaction, the herd-level relative sensitivity and relative specificity were 82 and 100%, respectively. The herd-level relative sensitivity depended on the within-herd prevalence of seropositive cows and the cut-off value in the assay, but not on the time interval (up to 90 days) between the collection of the bulk-tank milk sample and the individual serum samples. The BHV-1 blocking ELISA on bulk-tank milk could detect seropositive herds (few), with prevalence proportions as low as one seropositive cow out of 70 cows.  相似文献   

Toxicological studies of phenoxyacetic herbicides in animals     

N E Bj?rklund  K Erne 《Acta veterinaria Scandinavica》1966,7(4):364-390

  相似文献   

Effects of processing on availability of starch for digestion in vitro and in vivo; I Extrusion cooking of wheat flours and starch     

I. Björck  N.-G. Asp  D. Birkhed  I. Lundquist 《Journal of Cereal Science》1984,2(2):91-103

  相似文献   

Effects of growth hormone and feeding level on endocrine measurements,hormone receptors,muscle growth and performance of prepubertal heifers     

Vestergaard M  Purup S  Frystyk J  Løvendahl P  Sørensen MT  Riis PM  Flint DJ  Sejrsen K 《Journal of animal science》2003,81(9):2189-2198

Prepubertal Friesian heifer calves (n = 24, initial BW = 195 +/- 5 kg) were assigned to a 2 x 2 factorial block design and used to evaluate the effects of daily GH treatment (0 or 15 mg/d) at either a low or a high feeding level in a 5-wk treatment period on endocrine measurements, hormone receptors, muscle growth, and overall performance. In the pretreatment period, a low feeding level was employed for all calves. During the treatment period, animals at the low feeding level had free access to a roughage-based mixture, whereas animals at the high feeding level had free access to a concentrate mixture and were offered 2 kg/d of the roughage-based mixture. Blood samples were collected weekly starting 3 wk before treatment. Longissimus (LM) and supraspinatus (SS) muscles were obtained at slaughter. Metabolizable energy intake was 81% higher, digestible CP intake was 140% higher, and ADG was 115% higher (all P < 0.001) at the high vs. low feeding level. Feed (DMI, ME, and protein) intake was not affected by GH treatment, but ADG was 18% higher (P < 0.13) in GH-treated than in control heifers at both feeding levels. Although of different magnitudes, the muscle anabolic effects of GH treatment and high vs. low feeding level were additive, and both treatments increased carcass weights (P < 0.02 and P < 0.001, respectively), LM (P < 0.05 and P < 0.001), and SS (P < 0.06 and P < 0.003). The anabolic effect of GH treatment was similar in both muscles, whereas the effect of feeding level was most pronounced in LM. Overall, GH treatment increased plasma GH, IGF-I (both P < 0.001), and IGFBP-3 (P < 0.02); however, GH treatment increased total IGF-I, free IGF-I, and IGFBP-3, and decreased IGFBP-2 mainly at the high feeding level (GH x feeding level interaction; P < 0.02, 0.01, 0.03, and 0.10, respectively). The high feeding level increased insulin, free and total IGF-I, and IGFBP-3 (all P < 0.001), but decreased GH and IGFBP-2 (both P < 0.001). High feeding increased type-1 IGF receptor density (P < 0.02), mainly in LM, in accordance with the largest anabolic response in this muscle, whereas GH treatment had no effect on type-1 IGF receptors. The results suggest that in skeletal muscle, the anabolic effects of exogenous GH are related to endocrine changes in the GH-IGF axis, whereas the effects of feeding level also seem to rely on IGF receptor density in the muscles.  相似文献   

Risk factors associated with faecal shedding of verocytotoxin-producing Escherichia coli O157 in eight known-infected Danish dairy herds     

Rugbjerg H  Nielsen EM  Andersen JS 《Preventive veterinary medicine》2003,58(3-4):101-113

A risk-factor study was performed in eight dairy herds found to excrete verocytotoxin-producing Escherichia coli (VTEC) O157 in a former prevalence study. Associations between excretion of VTEC O157 and management factors such as housing and feeding were analysed in a generalised linear mixed model. The animals were stratified in three age groups and sampled four times during 1 year. The risk of excreting VTEC O157 was higher among weaned calves than non-weaned calves. Among the calves aged 1–4 months, the risk was reduced if the calf had suckled colostrum from the mother or if the calf had stayed >2 days with the mother after calving. Calves aged 5–24 months that had been moved within the last 2 weeks had a higher risk, but risk was reduced if fed barley silage. Cows fed grain or molasses had a higher risk of excreting VTEC O157.  相似文献   

A Bayesian approach to the accuracy of clinical observations     

Baadsgaard NP  Jørgensen E 《Preventive veterinary medicine》2003,59(4):189-206

The accuracy of clinical observations was estimated using Bayesian latent-class models with two or more independent tests. Four veterinarians carried out systematic independent clinical examinations on 155 pigs in three herds. Based on the results of binary recordings of clinical observations on dullness, poor body condition (PBC), skin lesions, lameness, respiratory disease, and diarrhea, a latent disease state for each clinical disease was estimated using Gibbs sampling.

The accuracy of the clinical observations differed for the four observers and for different clinical signs. Population parameters were estimated from a Bayesian hierarchical model, and the accuracy of a random observer was calculated. We concluded that the accuracy of the veterinarians in this study substantiated the need to pursue more-precise definitions of the clinical findings and that larger sample sizes would be needed to provide reasonable variance estimates. Finally, we concluded that the uncertainty in the clinical decision-making process (starting with the clinical examination) needs to be represented fully.  相似文献