Investigation of bovine venereal campyloacteriosis in beef cow herds in New Zealand     

McFadden AM  Heuer C  Jackson R  West DM  Parkinson TJ 《New Zealand veterinary journal》2005,53(1):45-52

AIMS: To determine regional prevalences of beef cow herds in New Zealand positive for Campylobacter fetus subsp venerealis antibodies in samples of vaginal mucus tested using an immunoglobulin (Ig) A enzyme-linked immunosorbent assay (ELISA), and to examine the suitability of the IgA ELISA for detecting infection with C. fetus subsp venerealis under field conditions in New Zealand. METHODS: Vaginal mucus samples (n=1,230) collected from beef cow herds (n=125) throughout New Zealand (approximately 10 samples/herd) were tested for antibodies to C. fetus subsp venerealis using an IgA ELISA. Test results were compared between herds classified as having low, medium and high fertility based on pregnancy test results interpreted in relation to the duration of the mating period used. In addition, a small number of samples were collected from dairy cows that were mated using artificial insemination (AI) and had no contact with breeding bulls. The influence of putative risk factors for the spread of venereal disease and the effect of sample quality on the status of herds according to test results was assessed using multivariate logistical regression. Preputial washings from 54 bulls from nine herds classified as low fertility in which mucus samples from > or =3 cows were IgA antibody-positive were cultured for the presence of Campylobacter spp, and isolates of C. fetus subspecies were characterised using a polymerase chain reaction (PCR) test. RESULTS: One or more mucus samples was positive to the IgA ELISA in 70% of all herds tested. The prevalence of IgA antibody- positive individuals was >20% in most regions of New Zealand and did not differ significantly for cows from herds classified as high, medium or low fertility (28%, 26% and 23%, respectively; p=0.39). No relationship was found between mucus antibody status and age of breeding group, herd size, herd fertility, number of herds that female replacements or breeding bulls were sourced from, whether a serving ability test (SAT) was used to assess bulls, or the quality of samples submitted to the laboratory. Campylobacter fetus subsp venerealis was not cultured from any of the 54 bulls sampled. Four other species of Campylobacter and related organisms were cultured, viz Arcobacter cryaerophilus, Campylobacter jejuni, Campylobacter fetus subsp fetus and Helicobacter cinaedi. CONCLUSIONS: The specificity of the IgA ELISA as a diagnostic test for C. fetus subsp venerealis was found to be unsatisfactory under New Zealand conditions. It is possible that an immunological response by cows to Campylobacter species other than C. fetus subsp venerealis caused cross-reactivity in the IgA ELISA. The results do not support the hypothesis that C. fetus subsp venerealis is widespread in New Zealand.  相似文献   

Validation of a bulk tank milk antibody ELISA to detect dairy herds likely infected with bovine viral diarrhoea virus in New Zealand     

Thobokwe G  Heuer C  Hayes DP 《New Zealand veterinary journal》2004,52(6):394-400

AIMS: To assess the sensitivity and specificity of a bulk tank milk (BTM) antibody enzyme-linked immunosorbent assay (ELISA) to detect likely infection of a dairy herd with bovine viral diarrhoea virus (BVDV). The ELISA was subsequently used to estimate the prevalence of likely infected herds in parts of the North Island of New Zealand. METHODS: BTM samples from 724 randomly selected dairy herds in the Waikato, Bay of Plenty and Northland regions of New Zealand were tested for BVDV antibodies. From this group, 20 herds were again randomly selected from each of the quartiles of the ELISA percentage inhibition (%INH) result. From each participant herd, serum from 15 randomly selected calves aged 6-18 months and 15 cows was collected and tested using an indirect blocking ELISA for BVDV antibodies. RESULTS: Among serum results from calves from 50 herds available for analysis, 34 (68%) herds were classified as likely non-infected (0-3 seropositive among 15 calves) and 16 (32%) as likely infected (5-15 seropositive among 15 calves). Receiver-operator characteristic (ROC) analysis identified an optimal cut-off for BTM of 80%INH associated with 81% sensitivity and 91% specificity for likely herd infection. The prevalence of BVDV antibodies in cows within herds and %INH for BVDV in bulk milk were positively correlated (p<0.01). The association between bulk milk %INH and the prevalence of BVDV antibodies in calves was stronger than the same association in cows. Based on the threshold of 80%INH, the 95% confidence interval (CI) for prevalence of likely infection in the 724 herds in the Waikato, Bay of Plenty and Northland regions of New Zealand was 12-17%. Vaccination against BVDV was not significantly associated with the likely infection status of the herd based on prevalence of BVDV antibodies among calves. CONCLUSION: An ELISA test result for BVDV antibodies in BTM >/=80%INH can be used as a threshold to indicate the presence of likely infection with BVDV in dairy herds in New Zealand, with 81% sensitivity and 91% specificity.  相似文献   

Irrigation interval as a factor in the salt tolerance of eggplant     

J. Shalhevet  Bruria Heuer  A. Meiri 《Irrigation Science》1983,4(2):83-93

  相似文献   

Application of modelling to determine the absence of foot-and-mouth disease in the face of a suspected incursion     

Heuer C  French NP  Jackson R  Mackereth GF 《New Zealand veterinary journal》2007,55(6):289-296

AIM: To use disease modelling to inform a response team about the number of animals per herd/flock to be examined, and the start date and duration of clinical surveillance required to be confident that foot-and-mouth disease (FMD) was not present on an island in New Zealand with a population of approximately 1,600 cattle, 10,000 sheep and a small number of pigs, goats and alpacas. METHODS: Because the probability of detecting clinical disease in (the) primary case(s) in larger herds and flocks was extremely low, deterministic and stochastic mathematical SLIR (susceptible, latent, infectious, recovered) models for the transmission of infection were constructed to estimate the date when clinical lesions in herds and flocks would be detected with 95% confidence. Surveillance targeted the first wave of infections following a suspect index case. RESULTS: If 70 cattle in herds of about 400 cattle were examined it was estimated it would take approximately 13 (90% stochastic range 9-19) days from first exposure before it would be possible to achieve 95% confidence for detecting clinical signs for a low-virulence virus, and 9 (7-14) days for a high-virulence virus. The duration of sufficiently accurate clinical detection was 17 (15-19) days and 13 (12-14) days for low- and high-virulence viruses, respectively. A sample of 70 sheep from flocks of >1,000 would be required to achieve clinical detection at about the same time but with a shorter period of detection than for cattle. The duration of effective detection could be increased by examining a larger sample in most sheep flocks, however the small size of many cattle herds in the study population limited the confidence of detecting group-level disease in cattle, therefore necessitating repeated herd inspections. The model suggested that group-level detection was not feasible if it was based on elevated body temperature alone because of short durations of fever in infected animals. CONCLUSION AND CLINICAL RELEVANCE: Simulation modelling is a useful and powerful tool for informing ongoing surveillance activities in the face of an exotic disease incursion. Results of modelling suggested to start clinical inspection activities at 4 days and to continue regular inspection twice a week for about 35 days after the date of first exposure, to satisfy the required 95% confidence threshold of clinical detection of FMD in cattle herds and sheep flocks.  相似文献   

All-fish gene constructs for growth hormone gene transfer in fish     

Benzion Cavari  Yunhan Hong  Bruria Funkenstein  Boaz Moav  Manfred Schartl 《Fish physiology and biochemistry》1993,11(1-6):345-352

In order to develop all-fish expression vectors for microinjection into fertilized fish eggs, we have prepared the following constructs: rainbow trout metallothionein a/b and the gilthead seabream growth hormone cDNA (ptMTa-gbsGHcDNA, ptMTb-gsbGHcDNA), carp β-actin gilthead seabream GH cDNA (pcAβ-gsbGHcDNA). The inducible metallothionein promoters a and b were cloned from rainbow trout, and the constitutive promoter β-actin was isolated from carp. The metallothionein promoters were cloned by using the PCR technique. The tMTa contains 430 bp, while the tMTb contains 260 bp (Hong et al. 1992). These two promoters were introduced to pGEM-3Z containing the GH cDNA of Sparus aurata to form ptMTa-gsbGH and ptMTb-gsbGH, respectively. The carp cytoplasmic β-actin gene was chosen as a source for isolating strong constitutive regulatory sequences. One of these regulatory sequences in pUC118 was ligated to GH cDNA of S. aurata to form the pcAβ-gsbGHcDNA. Expression of the constructs containing the metallothionein promoters was tested in fish cell culture and was found to be induced effectively by zinc. The ptMTa gsb-GH cDNA construct was microinjected into fertilized carp eggs, and integration in the genome of carp was detected in the DNA isolated from fins at the age of two months.

---

Résumé Afin de développer des vecteurs d'expression de poisson, entièrement homologues, destinés aux microinjections dans des oeufs fertilisés, les constructions suivantes ont été préparées: promoteurs de la metallothionine, a ou b, de truite arc-en-ciel d'une part, et promoteur de l'actine β de carpe d'autre part, associés à l'ADNc de l'hormone de croissance de daurade royale (ptMTa-gsbGH cDNA, ptMTb-gsbGH cDNA, et pcAβ-gsbGH cDNA). Les promoteurs de la metallothionine ont été clonés en utilisant la technique de la RCP. La tMTa comprend 430 pb. tandis que la tMTb en comprend 260 (Hong et al. 1992). Ces deux promoteurs ont été insérés dans pGEM-3Z qui contenait l'ADNc de GH de Sparus aurata, pour former, respectivement, ptMTa-gsbGH et ptMTb-gsbGH. Le gène de l'actine cytoplasmique β de carpe été choisi comme source d'isolement de séquences régulatrices fortement constitutives. Une de ces séquences régulatrices a été liguée à l'ADNc de GH de S. aurata dans pUC118, pour réaliser la construction pcAβ-gsbGH cDNA. L'expression des constructions contenant les promoteurs de la metallothionine a été tentée dans des cultures de cellules de poisson, où elle a été effectivement induite par le zinc. La construction ptMTa-gsbGH cDNA a été microinjectée dans des oeufs fertilisés de carpe. Son intégration dans le génome de carpe a pu être détectée dans l'ADN isolé à partir de nageoires d'animaux agés de 2 mois.

  相似文献   

Crop water stress index derived from multi-year ground and aerial thermal images as an indicator of potato water status   总被引：1，自引：0，他引：1  

Ronit Rud  Y. Cohen  V. Alchanatis  A. Levi  R. Brikman  C. Shenderey  B. Heuer  T. Markovitch  Z. Dar  C. Rosen  D. Mulla  T. Nigon 《Precision Agriculture》2014,15(3):273-289

Potato yield and quality are highly dependent on an adequate supply of water. In this study, 3 years of information from thermal and RGB images were collected to evaluate water status in potato fields. Irrigation experiments were conducted in commercial potato fields (Desiree; drippers). Two water-deficit scenarios were tested: a short-term water deficit (by suppressing irrigation for a number of days before image acquisition), and a long-term cumulative water deficit. Ground and aerial images were acquired in various phenological stages along the potato growing season. Effects of irrigation treatments were recorded by thermal indices and biophysical measurements of stomatal conductance (SC), leaf water potential, leaf osmotic potential and gravimetric water potential in soil. Canopy temperature was delineated from the thermal images with and without fused information from the RGB image. Crop water stress index (CWSI) was calculated, using three forms of minimum baseline temperature: empirical, theoretical and statistical. An empirical evaluation of maximum baseline temperature of Tair + 7 °C was used in all CWSI forms examined. Statistical tests and comparison of CWSI with biophysical measurements were performed to evaluate the responses to irrigation treatments. The results indicated a high correlation of CWSI with SC from tuber initiation to maturity based on ground and aerial data (0.64 ≤ R² ≤ 0.99). Similar trends of increasing CWSI from well to deficit-irrigated treatments were found in all three growing seasons. The results also showed that CWSI may be calculated based merely on thermal imagery data.  相似文献   

Small amounts of ammonium (NH$ _4^+ $) can increase growth of maize (Zea mays)          下载免费PDF全文

Jessey George  Luke Holtham  Kasra Sabermanesh  Sigrid Heuer  Mark Tester  Darren Plett  Trevor Garnett 《植物养料与土壤学杂志》2016,179(6):717-725

Nitrate (NO$ _3^ - $ ) and ammonium (NH$ _4^+ $ ) are the predominant forms of nitrogen (N) available to plants in agricultural soils. Nitrate concentrations are generally ten times higher than those of NH$ _4^+ $ and this ratio is consistent across a wide range of soil types. The possible contribution of these small concentrations of NH$ _4^+ $ to the overall N budget of crop plants is often overlooked. In this study the importance of this for the growth and nitrogen budget of maize (Zea mays L.) was investigated, using agriculturally relevant concentrations of NH$ _4^+ $ . Maize inbred line B73 was grown hydroponically for 30 d at low (0.5 mM) and sufficient (2.5 mM) levels of NO$ _3^ - $ . Ammonium was added at 0.05 mM and 0.25 mM to both levels of NO$ _3^ - $ . At low NO$ _3^ - $ levels, addition of NH$ _4^+ $ was found to improve the growth of maize plants. This increased plant growth was accompanied by an increase in total N uptake, as well as total phosphorus, sulphur and other micronutrients in the shoot. Ammonium influx was higher than NO$ _3^ - $ influx for all the plants and decreased as the total N in the nutrient medium increased. This study shows that agriculturally relevant proportions of NH$ _4^+ $ supplied in addition to NO$ _3^ - $ can increase growth of maize.  相似文献   

Distribution of root-knot nematode species and their virulence on vegetables in northern temperate agro-ecosystems of the Pakistani-administered territories of Azad Jammu and Kashmir     

Tariq-Khan  Muhammad  Munir  Anjum  Mukhtar  Tariq  Hallmann  Johannes  Heuer  Holger 《植物病害和植物保护杂志》2017,124(3):201-212

Journal of Plant Diseases and Protection - Root-knot nematodes (RKN) are yield devastating plant pathogens. Objective of this study was to investigate the distribution of RKN and their threat to...  相似文献