| characterisation of macrocyclic lactone resistance in two field-derived isolates of cooperia oncophora. | the anthelmintic sensitivity of two field-derived isolates (designated fi001 and fi004) of cattle nematodes from beef farms in scotland were investigated in a controlled efficacy test (cet). efficacies of ivermectin pour-on (ivm-po), ivm injectable (ivm-inj) and moxidectin pour-on (mox-po) formulations were assessed. in each group, five helminth-naïve calves were infected experimentally with 50,000 third stage larvae from either isolate and administered with anthelmintic at the manufacturers' re ... | 2012 | 22884912 |
| assessing resistance against macrocyclic lactones in gastro-intestinal nematodes in cattle using the faecal egg count reduction test and the controlled efficacy test. | the main objective of the present study was to evaluate the accuracy of the faecal egg count reduction test (fecrt) to assess the resistance status of ivermectin (ivm)-resistant isolates of the cattle nematodes ostertagia ostertagi and cooperia oncophora, using the controlled efficacy test (worm counts) as a reference. the second objective was to investigate whether both ivm-resistant isolates showed side-resistance against moxidectin (mox) under controlled conditions. thirty male holstein calve ... | 2012 | 22647465 |
| seasonal occurrence of infective nematode larvae in california high sierra pastures grazed by cattle. | worm-free holstein calves were used to assess the seasonal variation in numbers of nematode infective larvae on herbage at 2 commercial cow-calf ranches in the sierra nevada mountains. both ranches used herefords as their basic breed. one ranch near sattley, california, is at an elevation of approximately 1,500 m above sea level, whereas the study area on the 2nd ranch near susanville is at an elevation of approximately 1,250 m above sea level. worm-free tracer calves were allowed to graze for a ... | 1984 | 24049905 |
| resistance against gastrointestinal nematodes in crioulo lageano and crossbred angus cattle in southern brazil. | gastrointestinal nematode (gin) infection is a major cause of production losses in cattle. this study was carried out to evaluate the natural resistance against nematode infection in crioulo lageano and crossbred angus male calves. crioulo lageano is a local cattle breed in the state of santa catarina, in southern brazil. ten weaned calves of each breed were grazed together on pasture and naturally infected with nematodes between july 2009 and december 2010. once every 28 days, we collected feca ... | 2013 | 23177359 |
| comment on bloemhoff et al., 2015. prevalence and seasonality of bulk milk antibodies against dictyocaulus viviparus and ostertagia ostertagi in irish pasture-based dairy herds. vet. parasitol. 209, 108-116. | | 2015 | 26391821 |
| association between dictyocaulus viviparus status and milk production parameters in dutch dairy herds. | the objective of this study was to estimate the association between dictyocaulus viviparus bulk tank milk (btm) test results and milk production and milk composition parameters in adult dutch dairy cattle herds. bulk tank milk samples were collected in august and november 2013, and elisa tests were performed. two hundred btm positive (btm+) and 200 btm negative (btm-) herds were selected based on their btm test result of november 2013, obtained from a list of farms that participated in the dutch ... | 2015 | 26298745 |
| prevalence and seasonality of bulk milk antibodies against dictyocaulus viviparus and ostertagia ostertagi in irish pasture-based dairy herds. | infections with dictyocaulus viviparus and ostertagia ostertagi nematode parasites are of importance to bovine health and production in temperate areas across the world. losses due to these parasites in dairy herds can be considerable due to decreased milk productivity and fertility. however, information on current epidemiological patterns in irish dairy herds is limited. bulk milk samples were collected from a total of 319 dairy farms across the republic of ireland. the d. viviparus samples wer ... | 2015 | 25709092 |
| parasite control practices on pasture-based dairy farms in the republic of ireland. | dictyocaulus viviparus, ostertagia ostertagi (nematode parasites), and fasciola hepatica (trematode parasite) result in productivity losses on dairy farms and impact on animal health through clinical and sub-clinical disease. parasite control in livestock systems is largely based on the use of chemoprophylactic agents (anthelmintics), grazing management, or a combination of both. the objective of this study was to document current parasite control measures employed by irish dairy farmers in a pr ... | 2014 | 24924698 |
| exposure to pasture borne nematodes affects individual milk yield in swedish dairy herds. | the association between exposure to gastrointestinal nematode (gin) parasitism, indicated by elevated individual optical density ratio (odr) to ostertagia ostertagi, and individual milk production was analysed in dairy cows. the multivariable analysis also accounted for other sources of variation than exposure to gin parasitism. intra- and inter-herd variation in parasite exposure was also evaluated. organic and conventional herds located in south-east sweden (13 herds per system) were visited d ... | 2012 | 22459108 |
| climate-driven longitudinal trends in pasture-borne helminth infections of dairy cattle. | helminth parasites of grazing ruminants are highly prevalent globally and impact negatively on animal productivity and food security. there is a growing concern that climate change increases helminth disease frequency and intensity. in europe, these concerns stem from case reports and theoretical life cycle models assessing the effects of climate change scenarios on helminth epidemiology. we believe this study is the first to investigate climate-driven trends in helminth infections of cattle on ... | 2016 | 27771256 |
| climate influences assemblages of abomasal nematodes of sheep on steppe pastures in the east of algeria. | it is a common view that assemblages of parasitic nematodes are influenced by climatic conditions; however, there are only a few articles available regarding those that infect farm animals. we investigated the relationship between climate variables and infection with abomasal trichostrongyles in 335 1-year-old rams grazed on steppe pastures in eastern algeria. abomasa were collected from 12 local slaughterhouses located in four climatic areas (from humid to arid) and the worms extracted, identif ... | 2016 | 27905269 |
| [a comparative analysis of various antigenic proteins found in haemonchus contortus--a review]. | many innovative researches on the development and introduction of recombinant vaccines against many economically important parasites were carried out in the 20th century. research continues to hold promise with the development of immunological and molecular approaches for control of these parasites and in this regard it has already been seen that blood-sucking parasites such as haemonchus contortus and ostertagia ostertagi are susceptible to control by vaccines containing "novel" or "concealed" ... | 2015 | 26710767 |
| characterization of ostertagia ostertagi annexin-like proteins at different developmental stages. | ostertagiosis remains an economically important parasitic disease in cattle in the temperate regions of the world. repeated exposures to ostertagia ostertagi in calves cause significant pathology in the abomasum but elicit little protective immunity. the larvae use the host's gastric glands as a niche for development, where the parasite completes its parasitic stages, while in the gastric glands, the larvae must down-regulate the host inflammatory immune responses. annexin (anx) a1, commonly fou ... | 2017 | 28378195 |
| economic modelling of grazing management against gastrointestinal nematodes in dairy cattle. | grazing management (gm) interventions, such as reducing the grazing time or mowing pasture before grazing, have been proposed to limit the exposure to gastrointestinal (gi) nematode infections in grazed livestock. however, the farm-level economic effects of these interventions have not yet been assessed. in this paper, the economic effects of three gm interventions in adult dairy cattle were modelled for a set of flemish farms: later turnout on pasture (gm1), earlier housing near the end of the ... | 2017 | 28288768 |
| a multi-country study to assess the effect of a treatment with moxidectin pour-on during the dry period on milk production in dairy cows. | a randomized clinical study was conducted in a total of 45 commercial dairy farms in france (14 farms), germany (28 farms) and the uk (3 farms) to evaluate the effect of an anthelmintic treatment on milk yield in the subsequent lactation. a total of 1287 animals with suspected exposure to ostertagia ostertagi were included in the study. animals were treated during the dry period (7-77days before parturition) with moxidectin pour-on (cydectin(®) 0.5% pour-on, zoetis; 638 animals) or left untreate ... | 2017 | 28259556 |
| modelling the consequences of targeted selective treatment strategies on performance and emergence of anthelmintic resistance amongst grazing calves. | the development of anthelmintic resistance by helminths can be slowed by maintaining refugia on pasture or in untreated hosts. targeted selective treatments (tst) may achieve this through the treatment only of individuals that would benefit most from anthelmintic, according to certain criteria. however tst consequences on cattle are uncertain, mainly due to difficulties of comparison between alternative strategies. we developed a mathematical model to compare: 1) the most 'beneficial' indicator ... | 2016 | 27915061 |
| confirmation of ivermectin resistance in ostertagia ostertagi in cattle in new zealand. | six suspected cases of ivermectin resistance in ostertagia spp. in cattle were investigated after routine anthelmintic efficacy testing on commercial farms. on four farms a comprehensive faecal egg count reduction test (fecrt) was undertaken using oral formulations of ivermectin (0.2mg/kg), albendazole (10mg/kg) and levamisole (7.5mg/kg) while on two farms only ivermectin was tested. the proportions of ostertagia spp. in the untreated control and post-treatment larval cultures were used to appor ... | 2016 | 27809969 |
| abomasal mucosal immune responses of cattle with limited or continuous exposure to pasture-borne gastrointestinal nematode parasite infection. | it has been well documented that cattle raised on pasture are slow in weight gain when compared to those fed with grain. inflammation in the digestive system commonly caused by pasture-transmitted gastrointestinal (gi) nematode parasites that could negatively impact feed conversion has never been compared in cattle raised with no pasture exposure (npe, uninfected), limited pasture exposure (lpe, exposure until weaning), or continuous pasture exposure (cpe, life time exposure). in the present stu ... | 2016 | 27809966 |
| a stochastic model to investigate the effects of control strategies on calves exposed to ostertagia ostertagi. | predicting the effectiveness of parasite control strategies requires accounting for the responses of individual hosts and the epidemiology of parasite supra- and infra-populations. the first objective was to develop a stochastic model that predicted the parasitological interactions within a group of first season grazing calves challenged by ostertagia ostertagi, by considering phenotypic variation amongst the calves and variation in parasite infra-population. model behaviour was assessed using v ... | 2016 | 27573532 |
| a simulation model to investigate interactions between first season grazing calves and ostertagia ostertagi. | a dynamic, deterministic model was developed to investigate the consequences of parasitism with ostertagia ostertagi, the most prevalent and economically important gastrointestinal parasite of cattle in temperate regions. interactions between host and parasite were considered to predict the level of parasitism and performance of an infected calf. key model inputs included calf intrinsic growth rate, feed quality and mode and level of infection. the effects of these varied inputs were simulated o ... | 2016 | 27514906 |
| host protective asp-based vaccine against the parasitic nematode ostertagia ostertagi triggers nk cell activation and mixed igg1-igg2 response. | the mucus-dwelling parasite ostertagia ostertagi is one of the most important gastrointestinal nematodes in cattle. our group has previously demonstrated the protective capacity of a vaccine against this parasite based on a native activation-associated secreted protein asp1 (nasp) in combination with the saponin adjuvant quila. the aim of the current study was to analyse the effect of both antigen and adjuvant on the cellular and humoral vaccine-induced immune responses by comparing the native a ... | 2016 | 27403891 |
| explaining variability in first grazing season heifer growth combining individually measured parasitological and clinical indicators with exposure to gastrointestinal nematode infection based on grazing management practice. | the objective of our study was to explain the variability of average daily weight gain (adwg) due to gastrointestinal nematode (gin) infection for 291 non treated first grazing season (fgs) heifers, from 12 independent groups in the western part of france, by combining parasitological and clinical indicators at individual level and grazing management indicators at group level. parasitological indicators were faecal egg count (fec), anti ostertagia ostertagi antibody level (ostertagia odr), and p ... | 2016 | 27369576 |
| the level of embryonation influences detection of ostertagia ostertagi eggs by semi-quantitative pcr. | the internal transcribed spacer 2 (its2) is a candidate diagnostic marker of the pathogenic cattle nematode ostertagia ostertagi. the aims of this study were: (i) to document and quantify how the development of o. ostertagi eggs affects its2 copies under different storage conditions, and (ii) to suggest optimal storage conditions for faecal samples in a diagnostic pipeline that involves detection and semi-quantification by real-time semi-quantitative polymerase chain reaction (qpcr). | 2016 | 27357701 |
| sesquiterpene lactone containing extracts from two cultivars of forage chicory (cichorium intybus) show distinctive chemical profiles and in vitro activity against ostertagia ostertagi. | the study investigated direct anthelmintic effects of sesquiterpene lactones (sl)-containing extracts from forage chicory against free-living and parasitic stages of ostertagia ostertagi. freeze-dried leaves from chicory cultivars 'spadona' and 'puna ii' were extracted using methanol/water. total sl were further fractionated by solid-phase extraction and resulting extracts were characterised by high-performance liquid chromatography (hplc). o. ostertagi eggs from faeces of mono-infected calves w ... | 2015 | 27120066 |
| anthelmintic resistance in gastrointestinal nematodes of dairy cattle in the macalister irrigation district of victoria. | to report anthelmintic resistance in gastrointestinal nematode parasites of cattle on commercial dairy farms in the macalister irrigation district of gippsland, victoria. | 2016 | 26814160 |
| the relation between input-output transformation and gastrointestinal nematode infections on dairy farms. | efficiency analysis is used for assessing links between technical efficiency (te) of livestock farms and animal diseases. however, previous studies often do not make the link with the allocation of inputs and mainly present average effects that ignore the often huge differences among farms. in this paper, we studied the relationship between exposure to gastrointestinal (gi) nematode infections, the te and the input allocation on dairy farms. although the traditional cost allocative efficiency (c ... | 2016 | 26499290 |
| anthelmintic resistance to ivermectin and moxidectin in gastrointestinal nematodes of cattle in europe. | anthelmintic resistance has been increasingly reported in cattle worldwide over the last decade, although reports from europe are more limited. the objective of the present study was to evaluate the efficacy of injectable formulations of ivermectin and moxidectin at 0.2 mg per kg bodyweight against naturally acquired gastro-intestinal nematodes in cattle. a total of 753 animals on 40 farms were enrolled in germany (12 farms), the uk (10 farms), italy (10 farms), and france (8 farms). animals wer ... | 2015 | 26448902 |
| applying a kinetic method to an indirect elisa measuring ostertagia ostertagi antibodies in milk. | indirect enzyme-linked immunosorbent assays (elisas) are frequently run as endpoint elisas (e-elisas). however, kinetic elisas (k-elisas) have certain advantages over e-elisas. the objective of this study was to understand the relationship between e-elisa and k-elisa results. specifically, to determine whether it was possible to run both k-elisa and e-elisa on the same plate and establish an appropriate time interval for k-elisa measurements. a normalization method for k-elisa slopes (slope rati ... | 2015 | 26130849 |
| resistance of gastrointestinal nematodes to the most commonly used anthelmintics in sheep, cattle and horses in spain. | the objective of this study was to evaluate the status of anthelmintic resistance (ar) in ruminants and horses in spain. the efficacy of commonly used macrocyclic lactones (mls) - ivermectin (ivm) and moxidectin (mox) - was measured in sheep, cattle and horses. in addition, albendazole (abz) and levamisole (lev) were evaluated in sheep and oxibendazole (oxi) and pyrantel (pyr) in horses. efficacy was evaluated based on the difference between the arithmetic mean pre- and post-treatment faecal egg ... | 2015 | 26112062 |
| controlling nematodes in dairy calves using targeted selective treatments. | with increasing concerns of anthelmintic resistance in cattle nematode populations worldwide, there is a need to explore alternative approaches to nematode control. one alternative approach is the use of targeted selective treatments (tst) where only individual animals are treated instead of the entire group. this study reports the findings of a tst approach in dairy calves conducted over their first grazing season (fgs) to control both gastrointestinal nematode and lungworm challenge. ninety-si ... | 2015 | 25770853 |
| rapid selection for β-tubulin alleles in codon 200 conferring benzimidazole resistance in an ostertagia ostertagi isolate on pasture. | resistance to benzimidazoles (bzs) is widespread in sheep nematodes and increasing in those of cattle. several reasons including the predominant use of pour-on anthelmintics and lack of scales in field conditions lead to under-dosing of cattle and therefore to increased selection pressure. in an field experiment the frequency of bz-resistance associated allele (tac) in codon 200 in the β-tubulin isotype 1 gene of ostertagia ostertagi was monitored over one grazing season (approximately 30 weeks) ... | 2015 | 25725546 |
| the parasitic phase of ostertagia ostertagi: quantification of the main life history traits through systematic review and meta-analysis. | predictive models of parasite life cycles increase our understanding of how parasite epidemiology is influenced by global changes and can be used to support decisions for more targeted worm control. estimates of parasite population dynamics are needed to parameterize such models. the aim of this study was to quantify the main life history traits of ostertagia ostertagi, economically the most important nematode of cattle in temperate regions. the main parameters determining parasite density durin ... | 2014 | 25229178 |
| annual variation in serum antibody concentrations against gastrointestinal nematodes in beef calves from semi-arid rangelands of western canada. | sera from calves originating on a 17,000 ha ranch in southeastern alberta, were collected over three consecutive years (2008-2010) at weaning and analysed for the presence of anti-ostertagia antibodies using the svanovir(®)ostertagia ostertagi-ab elisa kit. faecal samples taken at the same time were analysed for presence of nematode eggs using the modified wisconsin faecal flotation technique. mean optical density ratio (odr) values for all calves were similar in 2008 and 2010 while the 2009 val ... | 2014 | 25086494 |
| a stochastic frontier approach to study the relationship between gastrointestinal nematode infections and technical efficiency of dairy farms. | the impact of gastrointestinal (gi) nematode infections in dairy farming has traditionally been assessed using partial productivity indicators. but such approaches ignore the impact of infection on the performance of the whole farm. in this study, efficiency analysis was used to study the association of the gi nematode ostertagia ostertagi on the technical efficiency of dairy farms. five years of accountancy data were linked to gi nematode infection data gained from a longitudinal parasitic moni ... | 2014 | 24731629 |
| analysis of the mucosal immune responses induced by single and trickle infections with the bovine abomasal nematode ostertagia ostertagi. | the purpose of this study was to provide more information on the kinetics of the immunological changes occurring in the abomasal mucosa after single and trickle infections with the bovine parasite ostertagia ostertagi. the time course analysis of gene expression revealed that the major changes coincided with the emergence of adult worms from the gastric glands. these changes consisted of a simultaneous upregulation of th1- and th2-type cytokines. in addition, a single o. ostertagi infection elic ... | 2014 | 24372091 |
| analysis of cell hyperplasia and parietal cell dysfunction induced by ostertagia ostertagi infection. | infections in cattle with the gastric nematode ostertagia ostertagi are associated with decreased acid secretion and profound physio-morphological changes of the gastric mucosa. the purpose of the current study was to investigate the mechanisms triggering these pathophysiological changes. o. ostertagi infection resulted in a marked cellular hyperplasia, which can be explained by increased transcriptional levels of signaling molecules related to the homeostasis of gastric epithelial cells such as ... | 2013 | 24330735 |
| serological evidence of ostertagia ostertagi infection in dairy cows does not impact the efficacy of rabies vaccination during the housing period. | nematode infections modulate the immune reaction of humans and livestock and may impair immune responses to non-parasitic antigens such as those present in vaccines. in this study, the relationship between antibodies directed against ostertagia ostertagi, the economically most important nematode infection of cattle in temperate regions, and the magnitude and the kinetics of the antibody response to rabies vaccination was investigated in a commercial dairy herd of 46 cows. during the stabling per ... | 2013 | 24075620 |
| quality of milk of cows in the first lactation vs. presence of anti-ostertagia antibodies in their milk. | invasions of gastrointestinal nematodes in dairy cows may affect animals productivity. the most frequently detected internal parasite of dairy cattle is ostertagia ostertagi. the objective of this study was to determine o. ostertagi invasion extensiveness in selected herds of dairy cattle, with special consideration to cows being in the first lactation, and to analyze the milk yield and contents of basic constituents of milk originating from sero-positive cows. five herds of dairy cattle (403), ... | 2013 | 23971192 |
| the association between ostertagia ostertagi antibodies in bulk tank milk samples and parameters linked to cattle reproduction and mortality. | in western europe, gastrointestinal nematodes are widespread in dairy cattle. this study was carried out to evaluate the relationship between optical density ratio (odr) measured on bulk tank milk with an indirect ostertagia ostertagi elisa and reproduction/mortality parameters. data were collected between 2008 and 2010 from monitoring carried out on 1643 dairy herds (normandy, western france). odr values of 3 samples from each farm taken from november 2008 to 2010 were averaged and then transfo ... | 2013 | 23806747 |
| presence of ostertagia ostertagi antibodies in bulk tank milk from cattle herds in northern spain. | the objective of this survey was to investigate the ostertagia ostertagi infection status of cattle dairy herds from northern spain through measurement of antibody concentration in the bulk tank milk (btm). in addition, management and performance data were collected to determine possible relationships with btm o. ostertagi antibody levels. btm samples were collected in 118 dairy cattle farms from five northern spain autonomic communities in the autumn of 2009 and spring of 2010. the o. ostertagi ... | 2013 | 23806745 |
| predicting the effect of anthelmintic treatment on milk production of dairy cattle in canada using an ostertagia ostertagi elisa from individual milk samples. | gastrointestinal nematodes, such as ostertagia ostertagi and several species of cooperia, are ubiquitous in temperate climates and have been shown to have detrimental effects on production in adult dairy cattle. a published meta-analysis demonstrated that overall, producers lose approximately 0.35 kg of milk per parasitized cow per day. enzyme-linked immunosorbent assays (elisas) have the ability to quantify nematode infections in cattle, and thus, could be used to estimate the amount of milk pr ... | 2013 | 23647705 |
| structure of ostertagia ostertagi asp-1: insights into disulfide-mediated cyclization and dimerization. | the cysteine-rich secretory/antigen 5/pathogenesis-related 1 (cap) protein superfamily is composed of a functionally diverse group of members that are found in both eukaryotes and prokaryotes. the excretome/secretome of numerous helminths (parasitic nematodes) contains abundant amounts of cap members termed activation-associated secreted proteins (asps). although asps are necessary for the parasitic life cycle in the host, the current lack of structural and functional information limits both und ... | 2013 | 23519657 |
| do the changes in the behaviours of cattle during parasitism with ostertagia ostertagi have a potential diagnostic value? | we investigated the magnitude of temporal changes in activity, posture and feeding behaviour of cattle infected with ostertagia ostertagi, and their reversal after treatment with an anthelmintic. twenty-six, 3-month-old, holstein-friesian bulls were allocated to one of three treatment groups. bulls in two of those (groups p and pa) received 100,000 larvae on three occasions (days 0, 7 and 14) and the remaining animals served as controls (c). the pa group also received an anthelmintic on day 31. ... | 2013 | 23218221 |
| the effects of acute versus chronic health challenges on the behavior of beef cattle. | the changes in behavior associated with a (subclinical) acute and a chronic health challenge were investigated to assess their potential value for the development of an early disease detection system in beef cattle. the hypothesis was that acute challenges would lead to acute but transient changes in behavior, whereas the converse would be the case during chronic challenges, with changes taking longer to develop, but being more persistent. for this purpose, holstein-friesian beef bulls were chal ... | 2012 | 22745185 |
| characterization of a novel aspartyl protease inhibitor from haemonchus contortus. | aspartyl protease inhibitor (api) was thought to protect intestinal parasitic nematodes from their hostile proteolytic environment. studies on ostertagia ostertagi, ascaris suum and brugia malayi indicated that aspins might play roles in nematode infection. in a recent study, proteins differentially expressed between free-living third-stage larvae (l3) and activated l3 (xl3) of haemonchus contortus were identified by 2d-dige. api was found downregulated in xl3 when compared with l3. however, the ... | 2017 | 28420411 |
| herd-level prevalence of selected endemic infectious diseases of dairy cows in great britain. | to implement appropriate and effective disease control programs at the national level, up-to-date and unbiased information on disease frequency is needed. the aim of this study was to estimate the prevalence of selected endemic infectious diseases in the population of dairy herds in great britain. bulk milk tank (bmt) samples from 225 randomly selected dairy farms, stratified by region and herd size, were tested for antibodies against bovine viral diarrhea virus (bvdv), bovine herpesvirus type 1 ... | 2017 | 28843682 |
| anthelmintic effects of forage chicory (cichorium intybus) against free-living and parasitic stages of cooperia oncophora. | chicory shows great promise as an anthelmintic forage for grazing ruminants that can reduce reliance on anti-parasitic drugs. recently, we reported potent anthelmintic effects of chicory-based diets in infected cattle with significant reductions in worm burdens of the abomasal nematode ostertagia ostertagi, whilst no apparent activity was observed against the small intestinal parasite cooperia oncophora. to explore this discrepancy, we investigated direct anthelmintic effects of forage chicory a ... | 2017 | 28807295 |
| establishment rate of cattle gastrointestinal nematodes in farmed red deer (cervus elaphus). | red deer can be infected with some gastrointestinal nematodes (gin) of cattle but it is unknown to what extent. an indoor study was conducted to determine the establishment rate of cattle gin in young deer. five young calves and 5 young red deer were used. they were effectively treated with anthelmintics when housed and then infected 2 weeks later. after four weeks they were killed for total worm counts. establishment rates were assessed comparing worm counts to the infective dose which were ide ... | 2017 | 28807276 |
| the use of nemabiome metabarcoding to explore gastro-intestinal nematode species diversity and anthelmintic treatment effectiveness in beef calves. | next-generation deep amplicon sequencing, or metabarcoding, has revolutionized the study of microbial communities in humans, animals and the environment. however, such approaches have yet to be applied to parasitic helminth communities. we recently described the first example of such a method - nemabiome sequencing - based on deep-amplicon sequencing of internal transcribed spacer 2 (its-2) rdna, and validated its ability to quantitatively assess the species composition of cattle gastro-intestin ... | 2017 | 28797791 |
| economic assessment of ostertagia ostertagi and fasciola hepatica infections in dairy cattle herds in germany using paracalc(®). | the aim of the current study was to estimate economic costs of ostertagia ostertagi and fasciola hepatica infections in dairy cattle herds in germany using the online calculation programme paracalc(®). following a questionnaire, survey data were available from 464 farms in 14 federal states. on those farms bulk tank milk (btm) samples and additionally up to six serum samples collected from first season grazing calves were analysed, using a commercially available elisa (boehringer ingelheim svano ... | 2017 | 28576343 |
| [anthelmintic resistance in ruminants: development, diagnostics, and procedures]. | anthelmintic resistance of gastrointestinal nematodes in small ruminants, but also in cattle and horses, is now found worldwide. the reason for increasing anthelmintic resistance is, in particular, the extensive use of all the anthelmintic agents available on the market. a non-targeted use leads to the selection of naturally occurring resistance genes within parasite populations. the most practical method for evaluating the efficacy of an anthelmintic is the fecal egg-count reduction test. to re ... | 2017 | 28765867 |
| modelling the impacts of pasture contamination and stocking rate for the development of targeted selective treatment strategies for ostertagia ostertagi infection in calves. | a simulation study was carried out to assess whether variation in pasture contamination or stocking rate impact upon the optimal design of targeted selective treatment (tst) strategies. two methods of tst implementation were considered: 1) treatment of a fixed percentage of a herd according to a given phenotypic trait, or 2) treatment of individuals that exceeded a threshold value for a given phenotypic trait. four phenotypic traits, on which to base treatment were considered: 1) average daily b ... | 2017 | 28408216 |
| unusual population genetics of a parasitic nematode: mtdna variation within and among populations. | very little is known about the distribution of genetic variance within and among populations of parasitic helminths. in this study we used mitochondrial dna (mtdna) restriction fragment analysis to describe the population genetic structure of ostertagia ostertagi, a nematode parasite of cattle, in the united states. estimates of within-population mtdna diversity are 5 to 10 times greater than typical estimates reported for species in other taxa. although populations are genetically differentiate ... | 1992 | 28564029 |