Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| economics of gastrointestinal parasitism of cattle. | understandably, cattle are raised for profit, as beef and/or dairy. anything that negates that equation results in a loss to the producer and to the livestock economy. thus, parasites negatively affect the economy of the industry. worldwide, gastrointestinal nematode parasites, especially ostertagia ostertagi, and those of the respiratory tract (dictyocaulus viviparus) have a potentially major impact on herd health. in the past 10-15 years, anthelmintic (ah) drug development and the strategic us ... | 1997 | 9460211 |
| comparative efficacy of ivermectin pour-on, albendazole, oxfendazole and fenbendazole against ostertagia ostertagi inhibited larvae, other gastrointestinal nematodes and lungworm of cattle. | an experiment was conducted to evaluate the current efficacy of albendazole (abz), oxfendazole (oxf) and fenbendazole (fbz) compared with ivermectin pour-on (ivm-po) against inhibited early fourth-stage larvae (iel4) of ostertagia ostertagi, other gastrointestinal nematodes and lungworm of cattle during spring in louisiana. twenty-five crossbred beef heifer calves of 235 kg average weight and 10-12 months of age were acquired in late winter and grazed for 9 weeks on pasture contaminated with o. ... | 1997 | 9477494 |
| the efficacy of eprinomectin against induced infections of immature (fourth larval stage) and adult nematode parasites in cattle. | eprinomectin is a new endectocide of the avermectin chemical group developed for use in cattle. to establish its effectiveness against cooperia spp., dictyocaulus viviparus, haemonchus contortus, nematodirus helvetianus, oesophagostomum radiatum, ostertagia ostertagi, trichostrongylus axei and trichostrongylus colubriformis (immature infections only), six trials were conducted in europe at two trial sites. in each trial, animals were artificially infected with a number of nematode species and tr ... | 1997 | 9477498 |
| persistence of the efficacy of pour-on and injectable moxidectin against ostertagia ostertagi and dictyocaulus viviparus in experimentally infected cattle. | the persistence of the efficacy of moxidectin 0.5 per cent pour-on and moxidectin 1 per cent injectable against ostertagia ostertagi and dictyocaulus viviparus in calves was studied in two experimental trials. in the first trial two groups of seven calves were treated with either the pour-on or the injectable formulation, while a third group remained untreated. all the animals were infected daily from monday to friday with infective stages of o ostertagi and d viviparus between the day of treatm ... | 1997 | 9023906 |
| efficacy of a topical formulation of eprinomectin against endoparasites of cattle in new zealand. | two controlled studies involving 24 cattle were conducted in new zealand to determine the efficacy of a topical, non-flammable formulation of eprinomectin against induced and naturally acquired nematode infections. in trial 1, nematode infections were induced on day -5 with third-stage larvae of cooperia spp., haemonchus contortus, ostertagia ostertagi and trichostrongvlus colubriformis so that the nematodes would be at the fourth larval stage when the cattle were treated. in trial 2, cattle had ... | 1997 | 16031938 |
| genetic markers for strongylid nematodes of livestock defined by pcr-based restriction analysis of spacer rdna. | twenty-four species of parasitic nematode (order strongylida) from sheep, goats, cattle or pigs were characterised using a polymerase chain reaction-linked restriction fragment length polymorphism technique (pcr-rflp). the ribosomal (r)dna region spanning the first internal transcribed spacer (its-1), 5.8s rrna gene and the second internal transcribed spacer (its-2) (designated its) was amplified from genomic dna by polymerase chain reaction (pcr), digested separately with four restriction endon ... | 1998 | 9588237 |
| the effect of different infection levels on acquired resistance to gastrointestinal nematodes in artificially infected cattle. | the objective of this study was to evaluate the effect of different infection levels of ostertagia ostertagi and cooperia oncophora in a simulated 'first grazing season' on the resistance of calves to an artificial challenge infection. the infection levels were determined by the infection schedules and the chemoprophylaxis used. thirty six 7-11-month old holstein-friesian bull calves were randomly divided into four groups. the animals of group b received an ivermectin sustained release bolus (is ... | 1998 | 9637217 |
| demonstration of shared carbohydrate epitopes in intestinal proteins of some bovine gastrointestinal nematodes. | the presence of shared carbohydrate intestinal epitopes in bovine gastrointestinal nematodes was demonstrated. proteins were extracted from the intestinal tissue of a laboratory strain of adult haemonchus placei and used to produce monoclonal antibodies (mab). analysis of this detergent extract by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed 7-9 bands ranging from approximately 39 to 298 kda. the mabs reacted with periodate-sensitive epitopes and, in western blots, recogniz ... | 1998 | 9645850 |
| effects of preventive anthelmintic treatment on acquired resistance to gastrointestinal nematodes in naturally infected cattle. | the objective of this study was to investigate the influence of different types of chemoprophylaxis in first season grazing calves on their resistance against a natural reinfection with ostertagia ostertagi and cooperia oncophora in the second grazing season. thirty helminth-naive crossbred calves were randomly divided in three groups of 10 animals. the animals of group b received an ivermectin sustained release bolus on day 0. the calves of group d were treated on days 0 and 56 with a subcutane ... | 1998 | 9650866 |
| the effect of repeated moves to clean pasture on the build up of gastrointestinal nematode infections in calves. | the build up of gastrointestinal nematode infections was followed in two grazing experiments. both experiments included four groups of six calves, a permanently housed non-infected control group and three groups which were grazed from may to october. one of these was moved to aftermath in the beginning of july, the second in the beginning of july and august and the third in the beginning of july, august and september. the build up of gastrointestinal nematode infections was followed by performin ... | 1998 | 9653993 |
| quantitative characterization of texture used for identification of eggs of bovine parasitic nematodes. | this study investigates the use of texture, i.e. the grey level variation in digital images, as a basis for identification of strongylid eggs. texture features were defined by algorithms applied to digital images of eggs from the bovine parasitic nematodes, ostertagia ostertagi, cooperia oncophora, and oesophagostomum radiatum. the resulting data served to establish classification criteria by linear discrimination analysis, and the criteria were subsequently evaluated by cross-validations. from ... | 1998 | 9687600 |
| comparisons of two polymorphic species of ostertagia and phylogenetic relationships within the ostertagiinae (nematoda: trichostrongyloidea) inferred from ribosomal dna repeat and mitochondrial dna sequences. | the first internal transcribed spacer dna (its-1) (rdna) and the mitochondrial (mt) dna-derived cytochrome oxidase i gene (cox-1) were enzymatically amplified, cloned and sequenced from 6 nominal species of ostertagiinae as well as haemonchus contortus and haemonchus placei. the portion of the cox-1 gene analyzed was 393 base pairs (bp) in length and contained 33 within species polymorphic base changes at 28 synonymous sites. the its-1 rdna consensus sequences ranged from 392 bp (ostertagia oste ... | 1998 | 9714215 |
| identification and semi-quantitation of ostertagia ostertagi eggs by enzymatic amplification of its-1 sequences. | a region within the first internal transcribed spacer (its-1) of the ribosomal dna repeat of ostertagia ostertagi has been identified that is 408 base pairs (bp) in length and is comprised of a 2 x 204 bp repeat. universal polymerase chain reaction (pcr) primers which span this region, as well as a portion of the 5.8s rdna, generate a 1011 bp fragment using genomic dna from o. ostertagi. however, these same primers generate only a 600 bp (approximate) fragment using dna from haemonchus contortus ... | 1998 | 9763315 |
| persistence of the efficacy of doramectin against ostertagia ostertagi and cooperia oncophora in cattle. | the persistence of the efficacy of doramectin injectable against ostertagia ostertagi and cooperia oncophora was evaluated in two studies in calves. in both, the calves were allocated to six groups of six. calves in the first control group (c1) and first treated group (t1) received a daily infection of 200 l3 of o ostertagi and 200 l3 of c oncophora; the calves in groups c2 and t2 received a daily infection of 1000 l3 of each species, and groups c3 and t3 received 10,000 l3 of each species per d ... | 1998 | 9823606 |
| characterization of protective immune responses in local lymphoid tissues after drug-attenuated infections with ostertagia ostertagi in calves. | in the present study, cell-surface markers and cytokine gene expression of lymphocytes from the local lymph nodes were studied 9 days after primary infection with ostertagia ostertagi in previously naive calves or in calves previously immunized with multiple, chemically attenuated infections. changes in lymphocyte populations were assessed by flow cytometry utilizing monoclonal antibodies specific for bovine cell-surface markers. changes observed in the percentages of lymphoid populations after ... | 1998 | 9877071 |
| evaluation of a micro method for the routine determination of serum pepsinogen in cattle. | estimation of serum pepsinogen concentration in cattle is used to aid the detection of clinical or subclinical infections with the abomasal nematode ostertagia ostertagi. an inexpensive, simple micro method for the routine determination of pepsinogen concentration in bovine serum samples is described which is based on the hydrolysing effect of serum on buffered bovine albumin substrate. comparison of this assay with a macro method, based on the same principle, gave almost identical results in th ... | 1998 | 9915153 |
| experimental inoculations with ostertagia ostertagi or exposure to artificial illumination alter peripheral cortisol in dairy calves (bos taurus). | a series of experiments were conducted on dairy calves (bos taurus) to assess, by way of circulating cortisol, the impact of a parasitic infection as a systemic stressor. the first study was designed to assess the effects of chronic stress on dairy calves resulting from a large bolus inoculation of the nematode parasite, ostertagia ostertagi. peripheral cortisol concentrations and adrenal cortical competency to adrenocorticotropic hormone (acth) challenge were utilized as indicators of chronic s ... | 1998 | 11253801 |
| study on the inductive factors of hypobiosis of ostertagia ostertagi in cattle. | two experiments were carried out to determine the causes producing the ostertagia ostertagi hypobiosis phenomenon in cattle. in the first experiment, the effect of time on third-stage larvae in the environment was studied during a 2-year period. three experimental paddocks contaminated with o. ostertagi eggs at different times of the year were used, and the levels of hypobiosis were recorded by using 'indicator' and 'tracer' calves. the results suggest that time as such is not a hypobiosis-induc ... | 1999 | 10206103 |
| the distribution of pepsinogen within the abomasa of cattle and sheep infected with ostertagia spp. and sheep infected with haemonchus contortus. | the effect of nematode infections on the production of pepsinogen by ruminants was investigated immunohistochemically and biochemically. abomasal tissues were collected from parasite-naive cattle and sheep, from sheep infected with predominantly ostertagia circumcincta, sheep infected experimentally with haemonchus contortus and cattle infected with ostertagia ostertagi. pepsinogen was also assayed biochemically in homogenates of fundic mucosae from sheep infected with predominantly o. circumcin ... | 1999 | 10321586 |
| larval migration inhibition activity in abomasal mucus and serum from calves infected with ostertagia ostertagi. | the present study investigated whether abomasal mucus from calves naturally infected with gastrointestinal nematodes possessed larval migration inhibition (lmi) activity in vitro, and whether lmi activity was greater in mucus from previously immunised animals, compared to primary infected and uninfected calves. lmi activity was also assessed in serum from calves during both natural and artificial ostertagia ostertagi infections, in an attempt to monitor the development of acquired immunity. both ... | 1999 | 10333468 |
| anthelmintic treatment of dairy cows and its effect on milk production. | the results of more than 80 experiments on gastrointestinal parasitism and the impact of anthelmintic treatment on milk production in dairy cattle were reviewed. abattoir surveys of culled dairy cows, faecal egg counts in milking cows, and serological tests and worm counts in cull cows in milk production studies were collated to assess the level of parasitism in dairy herds. the studies were divided into four general categories: induced infections in previously uninfected cattle; naturally infec ... | 1999 | 10378289 |
| persistent efficacy of doramectin pour-on against artificially induced infections of nematodes in cattle. | two studies were conducted to determine the persistent efficacy of doramectin pour-on against an artificial, trickle challenge of mixed nematodes in calves. in each study, 42, 4-8 months old calves were randomly assigned into four groups of 10 animals each (t1-t4), plus two larval-viability monitor animals. all animals were treated with fenbendazole (10 mg kg(-1)) 14 days prior to the start of the study to clear any existing infection. doramectin pour-on at 500 microg kg(-1) was used on each ani ... | 1999 | 10384905 |
| differences in the second internal transcribed spacer (its-2) of eight species of gastrointestinal nematodes of ruminants. | genetic differences in the nucleotide sequence of the second internal transcribed spacers (its-2) among trichostrongylus axei, trichostrongylus colubriformis, ostertagia ostertagi, cooperia oncophora, cooperia punctata, nematodirus helvetianus, nematodirus filicollis, and haemonchus contortus are described. the its-2 sequences of the 8 species ranged between 230 and 241 base pairs in length. sequence similarities between the different genera varied between 60% and 80%. identities between the dif ... | 1999 | 10386433 |
| use of a pre-selected epitope of cathepsin-l1 in a highly specific peptide-based immunoassay for the diagnosis of fasciola hepatica infections in cattle. | a peptide-based indirect elisa to detect cattle antibodies against fasciola hepatica was developed and evaluated for its sensitivity and specificity. an immunogenic antigen released in vitro by f. hepatica was purified. after purification the sequence of the first 20 n-terminal aa of this protein showed considerable homology with cathepsin l-like proteinase. based on its homology with cathepsin-l1, we further focused on this protein for diagnostic purpose. predicted b-cell epitopes of cathepsin- ... | 1999 | 10404262 |
| effect of duddingtonia flagrans against ostertagia ostertagi in cattle grazing at different stocking rates. | the efficacy of an isolate of the nematophagous fungus duddingtonia flagrans against gastrointestinal nematodes of cattle was examined at 2 dose levels on 2 permanent pastures, with high and low stocking rates, respectively. thirty calves, experimentally infected with ostertagia ostertagi, were divided into 3 comparable groups and allocated to 3 similar paddocks in each of the 2 trials. two of the 3 groups received fungal material once per day during the initial 2 months, either at high dose (10 ... | 1999 | 10446709 |
| the efficacy of two isolates of the nematode-trapping fungus duddingtonia flagrans against dictyocaulus viviparus larvae in faeces. | a series of experiments was carried out to examine the effects of two different isolates of the nematode-trapping fungus duddingtonia flagrans to reduce the number of free-living larvae of the bovine lungworm, dictyocaulus viviparus. a laboratory dose-titration assay showed that isolates ci3 and troll a of d. flagrans significantly reduced (p < 0.05 to p < 0.001) the number of infective d. viviparus larvae in cultures at dose-levels of 6250 and 12,500 chlamydospores/g of faeces. the larval reduc ... | 1999 | 10488731 |
| the effect of simulated rainfall on the efficacy of doramectin pour-on against nematode parasites of cattle. | two studies were conducted with doramectin topically administered at 500 microg/kg body weight to assess retention of therapeutic efficacy against nematode infections of cattle before, and after, simulated rainfall. in the first study, 50 heifers, with patent nematode infections, were allocated to one of five treatment groups. an untreated control group and one doramectin-treated group were not exposed to simulated rainfall. simulated rainfall was applied at a rate of 25.4 mm of water in 35 min ... | 1999 | 10536979 |
| the helminths of ranch calves in the north-eastern mountain grassland of south africa. | the cumulative total helminth parasite burdens of ranch calves during their first seven months of life on the north-eastern mountain grassland of south africa were determined during two consecutive years. trichostrongylus axei was the most abundant nematode parasite followed by cooperia spp. and ostertagia ostertagi. haemonchus spp. occurred in relatively low numbers and its development was significantly inhibited. the total helminth parasite burdens of the calves ranged from 681 to 7,269 with a ... | 1999 | 10689707 |
| relationships between bulk-tank antibodies to ostertagia ostertagi and herd-management practices and measures of milk production in nova scotia dairy herds. | monthly bulk-tank milk samples were obtained from 415 nova scotia dairy herds in each of the months of july-september 1998 and tested using an indirect microtitre elisa against a crude saline-extract, whole-worm ostertagia ostertagi antigen. elisa results (optical densities (ods)) were consistent across months (r=0.85) but there was considerable variation among herds. a questionnaire was sent by mail to all producers; information on management factors that would potentially influence parasite bu ... | 1999 | 11018736 |
| persistent efficacy of topical eprinomectin against nematode parasites in cattle. | six studies were conducted to evaluate the persistent efficacy of eprinomectin pour-on against experimental challenges with infective nematode larvae in calves. in each study, calves were randomly assigned to one untreated group and up to four test groups, which were treated with eprinomectin at 500 microg/kg body weight at weekly intervals before single bolus challenge. the calves were necropsied approximately 4 weeks after challenge infection for nematode recovery. eprinomectin pour-on provide ... | 2000 | 11097305 |
| proteinases released in vitro by the parasitic stages of the bovine abomasal nematode ostertagia ostertagi. | host tissue penetration, feeding and immune evasion by helminth parasites may be mediated by both mechanical processes and histolytic products released by the parasite. the aim of this study was to investigate potential histolytic products released during in vitro maintenance of exsheathed third (l3) and 4th larval stage (l4) and adult ostertagia ostertagi. therefore, the ph optima, substrate specificity, molecular size and inhibitor sensitivity of in vitro released (ivr) proteinases were analys ... | 2000 | 11155935 |
| identification of ostertagia ostertagi specific cells in bovine abomasal lymph nodes. | to investigate the contribution of different bovine cell subpopulations in the development of in vitro induced responses by ostertagia ostertagi third larval antigen extract (l3), bovine abomasal lymph node cell suspensions were depleted of specific cell populations. the depleted cell suspensions were subsequently assayed for their proliferative responses to o. ostertagi l3 antigen extract. proliferative responses to o. ostertagi l3 antigen extract were restricted to a cd2+ cd4- cd8- cell popula ... | 2000 | 10690930 |
| evaluation of the persistent efficacy of doramectin and ivermectin injectable against ostertagia ostertagi and cooperia oncophora in cattle. | the persistent efficacy of doramectin and ivermectin injectable against moderate and high infection levels of ostertagia ostertagi and cooperia oncophora were evaluated in cattle. calves were allocated to six groups of six animals. on day 0 animals of groups i1/i2 and d1/d2 were treated with 0.2mg/kg ivermectin and doramectin injectable, respectively. animals of the c1, i1 and d1 groups received a daily (moderate) infection of 1000 l3 of o. ostertagi and 1000 l3 of c. oncophora, and animals of t ... | 2000 | 10729646 |
| identification of abundant mrnas from the third stage larvae of the parasitic nematode, ostertagia ostertagi. | reverse transcriptase-pcr (rt-pcr) was carried out on total rna prepared from the third-stage larvae (l3) of ostertagia ostertagi in order to clone and characterize the major transcripts expressed in this larval stage, as an initial investigation of arrested larval development in the parasite. distinct bands were visible on an agarose gel and four of these were cloned and sequenced. three of the bands represented multiple transcripts, while the fourth band encoded the enzyme gtp cyclohydrolase i ... | 2000 | 10769181 |
| evaluation of immunization with gut membrane glycoproteins of ostertagia ostertagi against homologous challenge in calves and against haemonchus contortus in sheep. | peanut and cona lectins were used as ligands to isolate glycoproteins from detergent extracts of adult ostertagia ostertagi membranes. as judged by their profiles following sds-page, these fractions closely resembled the equivalents from haemonchus contortus which are derived from the nematode intestinal cell microvillar membranes and which are highly protective when used as antigens. groups of calves were immunized with the peanut and cona binding fractions of ostertagia, either as separate or ... | 2000 | 10792763 |
| nematode parasites of adult dairy cattle in the netherlands. | abomasa, blood samples and faecal samples for examination of nematode infections were collected from 125 dairy cows during the period november 1997-october 1998. of these, 12 had no grazing history and were, therefore, excluded from this study. from the remaining 113, 88.5% had nematode eggs in the faeces. larval identification of the positive cultures showed that ostertagia spp. larvae were most frequent (97%), followed by trichostrongylus spp. (29%), oesophagostomum spp. (23%), cooperia puncta ... | 2000 | 10799842 |
| ostertagia ostertagi challenge of calves vaccinated with haemonchus placei intestinal homogenate. | the protective capacity of vaccination with haemonchus placei whole gut homogenate against challenge with the non-blood-feeding nematode ostertagia ostertagi was evaluated in calves. ten helminth-free calves were randomly assigned to two groups. group 1 received 100microg h. placei intestinal homogenate in the adjuvant 5% dextran sulfate/pbs, while group 2 received the adjuvant alone. injections were administered subcutaneously on days 0 and 28. all calves were challenged with approximately 26,1 ... | 2000 | 10828516 |
| the immune response and the evaluation of acquired immunity against gastrointestinal nematodes in cattle: a review. | the present review discusses the immune responses to gastrointestinal nematodes in cattle and the different immunological and parasitological parameters used to assess acquired immunity. measuring acquired immunity to gastrointestinal nematodes in cattle (e.g. for the evaluation of candidate parasite vaccines) is hampered by the limited understanding of bovine immune responses against gastrointestinal parasites. in this paper the available data on protective immunity against gastrointestinal nem ... | 2000 | 10874708 |
| hypobiosis induction alters the protein profile of ostertagia ostertagi (nematoda: trichostrongylidae). | the appearance of variations in the protein profile of ostertagia ostertagi (stiles, 1892) infective larvae (l3), which were induced by hypobiosis triggering factors, was evaluated by means of sds-page and densitometric analysis. area integration analyses of their protein profiles was carried out between 66 and 77 kda. important quantitative variations were identified in the protein levels of the induced larvae, where a 5.25 fold increase compared to the control was observed. two 75.4 and 70 kda ... | 2000 | 10945738 |
| persistent efficacy of topical doramectin and eprinomectin against ostertagia ostertagi and cooperia oncophora infections in cattle. | 2000 | 10958538 | |
| survival of infective ostertagia ostertagi larvae on pasture plots under different simulated grazing conditions. | this study was carried out to examine the survival of infective ostertagia ostertagi larvae (l(3)) on pasture under different simulated conditions of grazing, i.e. mixed grazing of cattle and nose-ringed sows, or grazing by cattle alone. standardised pats of cattle faeces containing o. ostertagi eggs were deposited on three types of herbage plots, which were divided into zone 1: faecal pat; zone 2: a circle extending 25cm from the edge of the faecal pat; zone 3: a circle extending 25cm from the ... | 2001 | 11267755 |
| a multiplex pcr assay for differentiating economically important gastrointestinal nematodes of cattle. | a multiplex polymerase chain reaction (pcr) test was developed for identifying gastrointestinal (gi) nematodes that commonly infect cattle. this assay was developed using adult-derived genomic dna and shown capable of discriminating parasite eggs from the feces of experimentally-infected animals at both the species and genus levels. sequence data from internal (its) and external (ets) transcribed spacers of the ribosomal dna (rdna) repeats as well as the 3'-end of the small subunit rdna and 5'-e ... | 2001 | 11390072 |
| development of a copro-antigen capture elisa for detecting ostertagia ostertagi infections in cattle. | the present study reports on the development of a copro-antigen capture elisa for detecting ostertagia ostertagi infections in cattle. the elisa was based on polyclonal rabbit antibodies, which recognize o. ostertagi excretory/secretory antigens (es). es antigens are released by the metabolic active stages of the parasite in the abomasum, and passed in the faeces of the host. the detection limit of pure es material was 30 ng ml(-1) in sample buffer and 125 ng ml(-1) in faecal extract. the test w ... | 2001 | 11390075 |
| a field survey on the status of internal parasites in calves on organic dairy farms in southwestern sweden. | infections with internal parasites are one of the most important causes of reduced productivity in first-grazing season cattle (fgsc). in conventional herds, nematode infections can be controlled by prophylactic anthelmintic treatments, but this is prohibited in organic production. the purpose of this investigation was to monitor the status of internal parasitism on 15 organic cattle enterprises in southwestern sweden during the 1997 and 1998 grazing seasons, and to estimate the benefits of some ... | 2001 | 11470179 |
| role of the bovine immune system and genome in resistance to gastrointestinal nematodes. | gastrointestinal nematode infections of cattle remain a constraint on the efficient raising of cattle on pasture throughout the world. most of the common genera of parasites found in cattle stimulate an effective level of protective immunity in most animals within the herd after the animals have been on pasture for several months. in contrast, cattle remain susceptible to infection by ostertagia for many months, and immunity that actually reduces the development of newly acquired larvae is usual ... | 2001 | 11516579 |
| vaccination against gastrointestinal nematode parasites of ruminants using gut-expressed antigens. | to date, proteins isolated from the surface of the gut of gastrointestinal nematodes, particularly haemonchus contortus, have generally proved to be useful protective antigens and several are being progressed towards recombinant protein-based vaccines. this paper describes the properties of some of the most promising antigens and summarises their performance in laboratory and field based trials. the antigens described include contortin, h11, h-gal-gp, gpi and cysteine proteinases. in addition, t ... | 2001 | 11522403 |
| inactivation of eggs and larvae of the cattle nematodes ostertagia ostertagi and cooperia oncophora after passage in pigs. | the study investigated the effect of gastrointestinal passage in pigs on free-living stages of bovine nematodes. two landrace x yorkshire pigs, a and b, were fed fresh eggs of ostertagia ostertagi and cooperia oncophora while two other pigs, c and d, were fed third stage larvae (l3) of the same parasites. faeces from the pigs were collected for 48 h after ingestion. in pigs a and b, 15 and 66% of the eggs were recovered after passage, respectively. however, only 0.003 and 0.002% of the ingested ... | 2001 | 11587842 |
| genomic tools to improve parasite resistance. | the natural genetic variability of the ruminant immune system provides a feasible means to control gastrointestinal (gi) parasite infection without anthelmintics. however, the paradigm of traditional selection has not been effectively applied to the moderately heritable traits of parasite resistance (h approximately equal to 0.3) due to the difficulty and expense of gathering accurate phenotypes in a commercial production setting. these characteristics make host traits related to gi nematode inf ... | 2001 | 11707308 |
| titration of subcutaneously administered eprinomectin against mature and immature nematodes in cattle. | eprinomectin has been approved for use as a topically applied endectocide for beef and dairy cattle. to determine if eprinomectin has utility as an injectable anthelmintic, it was titrated at 0.05, 0.1, and 0.2 mg/kg s.c. against adult (trial 1) and at 0.05, 0.1, 0.14, and 0.2 mg/kg s.c. against immature (trial 2) stages of lung and gastrointestinal nematodes in cattle. in trial 1, every dose of subcutaneously delivered eprinomectin showed maximal or near-maximal (> or = 99%) efficacy against ha ... | 2001 | 11780839 |
| abomasal and small intestinal nematodes from captive gazelles in spain. | the abomasal and small intestinal helminth fauna of three species of captive gazelles (gazella dama mhorr, g. cuvieri and g. dorcas neglecta) kept in captivity in almería (southeast spain) have been studied, and the following species were identified: nematodirus spathiger, n. filicollis, n. helvetianus, camelostrongylus mentulatus, trichostrongylus vitrinus, t. probolurus, t. colubriformis, ostertagia ostertagi, o. harrisi, teladorsagia (ostertagia) circumcincta, and t. (ostertagia) davtiani. ca ... | 2001 | 11818055 |
| evaluation of a strategic deworming program in dairy heifers in quebec based on the use of moxidectin, an endectocide with a long persistency. | two different deworming strategies based on the use of moxidectin, a broad spectrum endectocide with persistency against ostertagia ostertagi, were evaluated in grazing dairy heifers. eighty-four heifers unexposed to parasitic infection were randomly allocated to 3 different groups: untreated (group 1), treated at 3 and 10 weeks after turnout with 0.5 mg/kg/body weight (bw) of topical moxidectin (group 2), or treated at turnout and 10 weeks later with 0.5 mg/kg/bw of topical moxidectin (group 3) ... | 2001 | 11195520 |
| [forming of gastro-intestinal nematodes fauna of free ranging european bison in bialowieza primeval forest during last 17 years (1984-2001)]. | 28 european bison of both sexes and in different age shot in białowieza primeval forest in january 1984, (10 animals), january 1992 (10 animals) and in january and the beginning of february 2001 (8 animals) have been necropsied. the examined animals in mentioned years were of similar age. there were examined abomasa and duodena of shot animals. all necropsied bison were infected with gastro-intestinal nematodes. the highest intensity of infection with nematodes of abomasum was found in 1992 year ... | 2002 | 16894720 |
| effects of ostertagia ostertagi and omeprazole treatment on feed intake and gastrin-related responses in the calf. | infection with the bovine abomasal nematode, ostertagia ostertagi, results in a loss of acid-secreting parietal cells and an increase in gastric ph. the effects of an experimental infection with ostertagia and/or daily treatment with omeprazole (omp) at 2mgkg(-1) bodyweight for four consecutive days (experiment days 24-27, inclusive) on voluntary feed intake, blood and tissue gastrin concentrations, abomasal g-cell numbers, gastric ph, and blood cholecystokinin (cck) and pepsinogen concentration ... | 2002 | 11983304 |
| a bulk tank milk survey of ostertagia ostertagi antibodies in dairy herds in prince edward island and their relationship with herd management factors and milk yield. | the objective of this study was to quantify the relationship of the levels of antibodies to ostertagia ostertagi in bulk-tank milk samples from prince edward island (pei) dairy farms to milk production and to herd-management practices potentially related to gastrointestinal nematode infections. the milk samples were obtained from 289 to 322 dairy farms during 2000; production and management data were available from 197 and 200 farms, respectively. cow exposure to pasture and whole-herd anthelmin ... | 2002 | 12058571 |
| vaccination of calves against ostertagia ostertagi with cysteine proteinase enriched protein fractions. | cysteine proteinase enriched fractions obtained by thiol-sepharose chromatography of ostertagia ostertagi membrane-bound protein extract (s3-thiol) or total adult excretory-secretory (es-thiol) products were tested in a vaccination experiment to evaluate their protective efficacy against o. ostertagi in cattle. calves were vaccinated three times and subsequently challenged with a trickled infection of 25,000 infective larvae in total over 25 days (1000 l3/day, 5 days/week). geometric mean cumula ... | 2002 | 12060320 |
| a longitudinal study of gastrointestinal parasites in canadian dairy farms. the value of an indirect ostertagia ostertagi elisa as a monitoring tool. | the general objective of this study was to evaluate a crude ostertagia ostertagi antigen enzyme-linked immunosorbent assay (elisa) for monitoring gastrointestinal parasites in lactating dairy cattle. a longitudinal study of gastrointestinal parasites in lactating dairy cows was carried out in 38 herds in four provinces of canada (prince edward island, quebec, ontario and saskatchewan) from september 1999 to october 2000. bulk tank milk, cow milk, serum and fecal samples were collected monthly or ... | 2002 | 12127251 |
| effect of gastrointestinal nematode and liver fluke infections on weight gain and reproductive performance of beef heifers. | spring born, crossbred beef heifers (n=372) were utilized over four years to measure reductions in body weights, reproductive performance and calf weights caused by gastrointestinal nematodes (primarily ostertagia ostertagi) and the bovine liver fluke (fasciola hepatica) and to differentiate losses attributable to each type of parasitism. each year, weaned heifers were allotted to one of the four treatment regimens: group 1, untreated controls; group 2, treated for nematodes; group 3, treated fo ... | 2002 | 12127252 |
| evaluation of the repeatability of a crude adult indirect ostertagia ostertagi elisa and methods of expressing test results. | an indirect enzyme-linked immunosorbent assay (elisa) for the detection of antibodies against ostertagia ostertagi using a crude adult worm antigen was evaluated using serum and milk samples from adult cows, as well as from bulk tank milk. within and between plate repeatabilities were determined. in addition, the effects of factors such as antigen batch, freezing, preserving of the samples and somatic cell counts (sccs) of the samples were evaluated. raw optical densities (ods) and normalized va ... | 2002 | 12383627 |
| identification of potential protective antigens of ostertagia ostertagi with local antibody probes. | the identification of protective helminth antigens remains the most important challenge in the development of parasitic vaccines. to identify protective antigens of ostertagia ostertagi, an important abomasal parasite of cattle, parasite-specific local antibodies from the abomasal mucus and from the draining lymph nodes were collected from calves immunized with multiple infections and from 'primary infected' animals. with these probes, western blots of extracts and excretion/ secretion (e/s) mat ... | 2002 | 12403327 |
| a novel cathepsin b active site motif is shared by helminth bloodfeeders. | this study compared specific protein sequence motifs present within cathepsin b-like cysteine proteases from a number of helminth parasites. we have focused our efforts on cathepsin b-like proteases of haemonchus contortus, caenorhabditis elegans, schistosoma mansoni, schistosoma japonicum, ostertagia ostertagi, and ancylostoma caninum. the goal of this work is to correlate specific features, or proposed roles, of the cathepsin b-like proteases with primary sequence motifs discovered within the ... | 2002 | 12427461 |
| the effect of eprinomectin treatment at calving on reproduction parameters in adult dairy cows in canada. | a clinical trial was carried out in two provinces of canada to investigate the effect of treatment with eprinomectin at calving on production parameters in adult dairy cattle in 1999-2000. one of the objectives of this study was to evaluate the impact of treatment on reproductive performance as measured by: calving-to-conception interval, calving-to-first service interval and number of services per conception. the ability of an indirect elisa using a crude adult ostertagia ostertagi antigen to p ... | 2002 | 12450687 |
| evaluation of gastro-intestinal nematode parasite control strategies for first-season grazing cattle in sweden. | a three-year grazing experiment (1998-2000) was conducted with first-season grazing cattle (fsgc) on improved pastures in central-eastern sweden. comparison was made between five groups with 10 calves in each group where four of these were set stocked and either (1) untreated, (2) ivermectin bolus treated, (3) subjected to biological control with the nematophagous fungus duddingtonia flagrans, or (4) treated with a copper wire particle bolus. the fifth treatment was an evasive grazing strategy, ... | 2003 | 12531294 |
| [helminth infection in cattle from schleswig-holstein (germany) after one grazing season]. | fifteen holstein-friesian bulls which grazed together for one season (april to november) in schleswig-holstein were necropsied after housing for 2 to 6 weeks. the approximately 12-month old bulls weighed 378 to 491 kg at slaughter and did not receive any anthelmintic on pasture. the most prevalent species of the gastrointestinal tract was ostertagia ostertagi (prevalence; geometric mean worm count; minimum-maximum) (100%; 1,355; 130-4,590) followed by cooperia (c.) oncophora (86.7%; 343; 20-14,8 ... | 2003 | 12592928 |
| identification of excretory-secretory products of larval and adult ostertagia ostertagi by immunoscreening of cdna libraries. | excretory-secretory (es) products of ostertagia ostertagi, an abomasal nematode of cattle, are considered to be important for the development and survival of the parasite within the host. to gain insight in the composition of these es products of both larval (l3, l4) and adult life stages of ostertagia cdna libraries of the parasite were immunoscreened with polyclonal rabbit serum raised against these es products. this approach led to the identification of 41 proteins, amongst which are structur ... | 2003 | 12615319 |
| protein disulphide isomerase of ostertagia ostertagi: an excretory-secretory product of l4 and adult worms? | a pepstatin a-agarose column was used in an attempt to purify a previously described antibody-degrading aspartyl proteinase from excretory-secretory material from the l4 and the adult stages of the bovine abomasal nematode ostertagia ostertagi. however, no aspartyl proteinase activity was detected in the eluted fractions (l4pepst and adpepst). screening of cdna libraries with polyclonal antibodies raised against l4pepst and adpepst showed that a protein disulphide isomerase (ost-pdi2) was presen ... | 2003 | 12633650 |
| activation-associated secreted proteins are the most abundant antigens in a host protective fraction from ostertagia ostertagi. | 2003 | 12706806 | |
| dose confirmation of moxidectin 0.5% pour-on against adults and fourth-stage larvae of various cooperia spp. and trichostrongylus colubriformis in louisiana. | thirty-five castrate or intact holstein male calves, ranging in weight from 122 to 210kg, were used in the study. on study days -15 and -14, all study calves were treated with fenbendazole 10% paste at 10mg/kg to remove existing nematode infections. all cattle had zero egg counts on day -1. experimental infections of a mixed species inoculum were administered to all calves on day 0. the inoculum consisted of cooperia spp. (primarily c. punctata, but also c. pectinata, c. spatulata, c. oncophora ... | 2003 | 12809755 |
| current research and future prospects in the development of vaccines against gastrointestinal nematodes in cattle. | vaccination is being considered as the most feasible alternative for anthelmintic drugs to control gastrointestinal nematode infections in cattle. however, despite the identification of several candidate protective antigens, no vaccines against gastrointestinal nematode parasites are currently available. the main problems that hamper the development of nematode vaccines in ruminants are that vaccination with recombinant nematode proteins produced in bacterial or eukaryotic expression systems did ... | 2003 | 12901605 |
| multispecies and multiple anthelmintic resistance on cattle nematodes in a farm in argentina: the beginning of high resistance? | there are very few resistance records on cattle nematodes. south american successive records have been increasing rapidly since the year 2000. in argentina, increasing dissatisfaction based on the exclusive use of macrocyclic lactones has prompted the use of benzimidazoles in the pampean region. the studied farm is located in the argentina humid pampas and had apparently poor results after anthelmintic treatments. evaluation of resistance was firstly based on faecal egg reduction after treatment ... | 2003 | 12911862 |
| probable multigeneric resistance to macrocyclic lactone anthelmintics in cattle in new zealand. | to establish the efficacy of topical formulations of eprinomectin and abamectin against naturally acquired abomasal and small intestinal nematode infections in cattle purchased from a north island bull-beef property. | 2003 | 16032313 |
| benzimidazole-resistant beta-tubulin alleles in a population of parasitic nematodes (cooperia oncophora) of cattle. | three anthelmintic classes with distinct mechanisms of action are commercially available. selection of nematode populations resistant to all these drugs has occurred, particularly in trichostrongyloid parasites of sheep. anthelmintic resistance in cattle parasites has only recently been recognized and appears to be less pronounced, even though very similar species infect both hosts. to understand the bases for differences in the rate of resistance development in sheep versus cattle parasites, it ... | 2003 | 14630425 |
| inhibition of bovine t lymphocyte responses by extracts of the stomach worm ostertagia ostertagi. | lowered immune responses during bovine ostertagiosis have been reported in both in vivo and in vitro assay systems. in the present study we have employed three different life cycle stages of the nematode ostertagia ostertagi to determine if products of this economically important parasite inhibit in vitro proliferation of con a-stimulated cells from uninfected animals. we have demonstrated an inhibitory effect upon the growth of con a-stimulated lymphocytes after addition of fourth stage larval ... | 2004 | 15041095 |
| milk antibodies against ostertagia ostertagi: relationships with milk igg and production parameters in lactating dairy cattle. | the present study was carried out to evaluate the relationship between milk optical density ratios (odrs) from an indirect ostertagia ostertagi elisa, total milk igg levels and milk production and then establish a correction factor to adjust odr. five hundred and sixty composite milk samples collected from 358 cows on four dairy herds in june and august 2002 were used in this analysis. the average odr was 0.34. a positive correlation was found between odr and igg values in milk, days in milk, ag ... | 2004 | 15063942 |
| vaccination with an ostertagia ostertagi polyprotein allergen protects calves against homologous challenge infection. | as an alternative to antihelminthic drugs, we are exploiting vaccination to control infections with the abomasal nematode ostertagia ostertagi in cattle. our focus for vaccine targets is excretory-secretory (es) products of this parasite. one of the most abundant antigens in larval and adult ostertagia es products is a protein homologous to nematode polyprotein allergens. we found that the ostertagia polyprotein allergen (opa) is encoded by a single-copy gene. opa comprises three or more repeate ... | 2004 | 15102812 |
| interrelationships among physicochemical properties, absorption and anthelmintic activities of 2-desoxoparaherquamide and selected analogs. | the interrelationships between physicochemical properties, absorption and potency of 2-desoxoparaherquamide and five analogs, representing a new anthelmintic class, were evaluated in in vitro and in vivo assays. at ph 7.5, rates of drug absorption by the gastrointestinal nematode haemonchus contortus and jird small intestine, parameterized by the permeability coefficient, p(e), ranged from 1.2-2.4 x 10(-4) cm/min (nematode) to 2.5-5.5 x 10(-3) cm/min (jird). in the jird intestine, absorption was ... | 2004 | 15189303 |
| validation of the protective ostertagia ostertagi es-thiol antigens with different adjuvantia. | intramuscular immunization of calves with an excretory-secretory antigen fraction enriched for cysteine proteinase activity (es-thiol) and quila as adjuvant induces a protective immune response against the abomasal nematode ostertagia ostertagi. the objectives of the present study were to confirm the protective capacity of es-thiol in combination with quila, to test al(oh)(3) as adjuvant for vaccination against o. ostertagi and to look for correlations between protection and immunological effect ... | 2004 | 15198644 |
| parasites of domestic and wild animals in south africa. xlv. helminths of dairy calves on dry-land kikuyu grass pastures in the eastern cape province. | successive pairs of approximately 4-month-old friesland bull calves, raised under worm-free conditions, were exposed to helminth infection for 14 days on dry-land kikuyu grass pastures at 28-day to monthly intervals, on a coastal farm in a non-seasonal rainfall region of the eastern cape province. with the exception of one pair of calves exposed for 28 days, this procedure was repeated for 28 consecutive months from december 1982 to march 1985. the day after removal from the pastures one calf of ... | 2004 | 15732456 |
| helminths in a giraffe (giraffa camelopardalis xgiraffa) from a zoo in spain. | a pregnant female cape giraffe (giraffa camelopardalis giraffa) died from an unknown cause in the aitana zoo, alicante, spain. neither clinical signs nor macroscopic lesions were observed at necropsy. the alimentary tract was removed and examined for parasites. a total of 2 724 nematodes were found, including camelostrongylus mentulatus, trichostrongylus axei, ostertagia ostertagi, teladorsagia circumcincta, teladorsagia trifurcata, marshallagia marshalli, trichostrongylus vitrinus, trichostrong ... | 2004 | 15373337 |
| effect of eprinomectin treatment at calving on milk production in dairy herds with limited outdoor exposure. | the objective of this study was to determine the effect of anthelmintic treatment at calving in herds that were totally or semiconfined during the summer. in totally confined herds, lactating and dry cows were housed throughout the summer and had no access to pasture. in semiconfined herds, lactating and dry cows had limited outdoor exposure to a small pasture or paddock but were still fed a ration that met all their nutritional requirements. the study was carried out between february 2002 and f ... | 2005 | 15738227 |
| protection studies with a globin-enriched protein fraction of ostertagia ostertagi. | the protective capacity of an adult stage ostertagia ostertagi globin antigen was tested in four vaccination experiments in cattle. in a preliminary experiment, calves were vaccinated three times intraperitoneally with 250 microg globin in freund's adjuvant and challenged with a trickled infection of 25,000 infective larvae. in three subsequent field studies, calves were vaccinated twice or three times intramuscularly with 80-100 microg globin in quil a and challenged with a natural gastrointest ... | 2005 | 15740867 |
| an aspartyl protease inhibitor of ostertagia ostertagi: molecular cloning, analysis of stage and tissue specific expression and vaccine trial. | protease inhibitors are thought to protect intestinal parasitic nematodes from their hostile proteolytic environment. in a previous study, screening of ostertagia ostertagi cdna libraries with local antibody probes of the abomasal lymph nodes and mucus revealed a (28 kda) aspartyl protease inhibitor (api), which was exclusively recognised by antibodies from immune calves. here we report the molecular characterization of oo-api (sequence analysis, developmental expression and localization) and a ... | 2005 | 15811529 |
| a survey to determine relationships between bulk tank milk antibodies against ostertagia ostertagi and milk production parameters. | in temperate climate regions, gastrointestinal nematodes are still widespread in adult dairy cows, but until now there exists no reliable diagnostic tool that can identify herds where the infection interferes with productivity. the objective of this study was to investigate the relationships between levels of antibodies against ostertagia ostertagi in bulk tank milk and milk production. bulk tank milk samples of 2553 dairy herds were obtained in spring and 2104 of these herds were sampled a seco ... | 2005 | 15817205 |
| exsheathment of ostertagia ostertagi infective larvae following exposure to bovine rumen contents derived from low and high roughage diets. | the objective of this study was to characterize the exsheathment kinetics of ostertagia ostertagi infective larvae (l3) following in vivo exposure to bovine rumen contents derived from low and high roughage diets. o. ostertagi l3 were placed in disposable dialysis bags and incubated for various time points between 0 and 360 min in the rumen of a fistulated steer maintained on a 71% grain diet or a 100% grass diet. the maximum percentage of exsheathed l3 was observed 120 min post-exposure to gras ... | 2005 | 15817206 |
| assessment of the repeatability of a milk ostertagia ostertagi elisa and effects of sample preparation. | an indirect ostertagia ostertagi elisa on milk is a promising diagnostic tool in bovine parasitology. interpretation of the test results requires a good knowledge of the test characteristics. in this study, border effects, the repeatability of the elisa and the effect of different factors such as storage, skimming and freeze-thaw cycles of the milk samples were investigated. the border effects trial showed that significant border effects can occur. the repeatability trial was conducted over 3 da ... | 2005 | 15820120 |
| the effect of dietary polyunsaturated fatty acids (pufa) on infection with the nematodes ostertagia ostertagi and cooperia oncophora in calves. | diet-induced changes in the polyunsaturated fatty acid (pufa) content of immune cells influences the immune phenotype that develops following infection. the aim of this study was to examine the effect of manipulating dietary pufa supply on tissue fatty acids composition and immunity to a mixed infection with an abomasal and an intestinal nematode parasite in calves. calves (n=24) were allocated into two treatment groups and fed 25 g/day of either fish oil (n-3 group) or a binary mixture of palm/ ... | 2005 | 15845283 |
| the use of an indirect ostertagia ostertagi elisa to predict milk production response after anthelmintic treatment in confined and semi-confined dairy herds. | an indirect ostertagia ostertagi elisa was used in late lactation milk samples from cows in confined and semi-confined dairy herds to determine if it could predict milk production response after endectocide treatment at calving. holstein cows from 9 dairy farms from prince edward island (pei), 5 from central nova scotia and 16 from southern ontario that were participating in a clinical trial of endectocide treatment around calving were used in this study. the cows were randomly treated with eith ... | 2005 | 15893078 |
| sewage sludge or cattle slurry as pasture fertilisers: comparative cysticercosis and trichostrongylosis risk for grazing cattle. | sewage sludge and slurry are used as fertilisers on pastures grazed by ruminants. the former may be a source of taenia saginata, which causes cysticercosis in cattle and taeniosis in man. the latter is a source of digestive tract-strongyles, a major helminth infection in cattle. the interest of application on pastures of these two biowastes is environmental (optimal recycling of biowastes) and agronomic (fertilisation). the parasitic risk and the fertilisation value of such applications on pastu ... | 2005 | 15948008 |
| associations between dairy herd management factors and bulk tank milk antibody levels against ostertagia ostertagi. | a cross-sectional questionnaire survey was performed on dairy herds in flanders (belgium) to detect management factors that are associated with an increased gastrointestinal parasite infection level of adult dairy cows. at the end of the grazing season, information concerning general herd factors, pasture management and anthelmintic treatment strategy was obtained from 956 herds. a bulk tank milk sample was obtained from 779 out of the 956 herds and the antibody levels (odr) against ostertagia o ... | 2005 | 15964688 |
| evaluation of the stability of ostertagia ostertagi elisa microtitre plates over time using cow milk samples. | the objective of this study was to assess the stability of elisa plates prepared with one of three blocking agents and used with one of two conjugates at various time intervals after preparation of the plates. two of the blocking agents used were commercially available: one termed stabilgaurd (stab) and one manufactured by svanova biotek ab inc. (svan). the third blocking agent used was bovine serum albumin (bsa). a polyclonal rabbit anti-bovine igg (poly) and an anti-bovine igg monoclonal (mono ... | 2005 | 16029930 |
| assessing the agreement between ostertagia ostertagi elisa tests performed using the crude adult antigen and the adult and larval stage 4 excretory/secretory antigens. | the objective of this study was to determine the agreement between elisa tests conducted using three o. ostertagia antigens: crude adult worm, larval stage 4 (l4) excretory/secretory (es) and adult es. this study was carried out on 289 holstein cows from five herds in prince edward island and one herd in nova scotia. composite milk samples of these cows were collected (between may and september 2002) from the respective provincial laboratories and sent to the atlantic veterinary college where ea ... | 2005 | 16039779 |
| cytokine responses in immunized and non-immunized calves after ostertagia ostertagi infection. | the objective of this study was to evaluate abomasal cytokine responses in helminth-naive calves and calves vaccinated with protective antigen fractions from ostertagia ostertagi after an experimental challenge infection with infective third stage (l3) larvae. abomasal lymph nodes and/or abomasal mucosa were collected and messenger rna for the th1 cytokines (ifn-gamma, il-2, il-12 p40 subunit), the th2 cytokines (il-4, il-5, il-6, il-10, il-13, il-15) and the th3/tr cytokine tgf-beta was quantif ... | 2005 | 16149990 |
| putative g protein-coupled receptors in parasitic nematodes--potential targets for the new anthelmintic class cyclooctadepsipeptides? | parasitic nematodes cause major problems in livestock animals. resistances to the most commonly used drugs are arising. the cyclooctadepsipeptide emodepside belongs to a new class of anthelmintics. a receptor for emodepside, hc110-r, was previously identified in haemonchus contortus. we have identified the complete coding sequences of putative orthologues in cooperia oncophora and ostertagia ostertagi, tri-chostrongyles in cattle. the putative receptors were named depsiphilins. the deduced amino ... | 2005 | 16228272 |
| molecular analysis of astacin-like metalloproteases of ostertagia ostertagi. | in this study, we describe the molecular analysis of zinc-metalloproteases from the abomasal nematode ostertagia ostertagi which were exclusively recognized by local antibodies of immune cattle. full-length or partial coding sequences of 4 different zinc-metalloprotease cdnas of ostertagia (met-1, -2, -3 and -4) were amplified using gene-specific primers using the 3'- and 5'-rapid amplification of cdna ends (race) technique. sequence analysis identified the cdnas as encoding zinc-metalloprotease ... | 2005 | 15700760 |
| arrested development of ostertagia ostertagi: effect of the exposure of infective larvae to natural spring conditions of the humid pampa (argentina). | the aim of this study was to determine the effect of environmental conditions and the time of exposure to the conditions required for ostertagia ostertagi to become inhibited in development at the early fourth larval stage in the host. two comparable experiments were conducted from september to january, experiment i in 1997-1998 and experiment ii in 1999-2000. twenty-thousand third-stage larvae (l3), freshly obtained from coprocultures, were spread in different parasite-free grass plots at the b ... | 2005 | 15710526 |
| the effect of an experimentally induced acute mastitis on the test results of an ostertagia ostertagi milk elisa. | antibody levels against ostertagia ostertagi in the milk are a promising parameter to identify dairy cows or herds with production losses due to gastrointestinal nematodes. however, milk antibody levels can be influenced by udder-related factors. in this study, the effect of an experimentally induced mastitis on the test results (odr) of a milk o. ostertagi elisa was investigated. twenty-five cows that were naturally infected with gastrointestinal nematodes, were inoculated in their left udder q ... | 2006 | 16300898 |
| improved methods for isolating dna from ostertagia ostertagi eggs in cattle feces. | a multiplex pcr assay for differentiating strongyle eggs from cattle has recently been described; however, the egg disruption and dna extraction procedures, though effective, are inadequate for large studies or clinical application. the purpose of this research was to evaluate methods for disrupting trichostrongyle eggs, then assess commercial kits for extracting egg dna using ostertagia ostertagi as a model species. egg disruption procedures tested included probe sonication, bath sonication, be ... | 2006 | 16303253 |
| reindeer as hosts for nematode parasites of sheep and cattle. | the reindeer husbandry range of scandinavia overlaps with sheep, goat, and cattle pastures. the aim of this study was to determine whether reindeer are suitable hosts for ovine or bovine nematode parasites, and thus may spread these parasites into the reindeer husbandry regions. to render worm-free, twelve 4-month-old male reindeer calves, six lambs, and six bovine calves were given ivermectin at 200 microg/kg body weight. five weeks post-treatment, six reindeer calves were each artificially dos ... | 2006 | 16386848 |
| an immunogenic cathepsin f secreted by the parasitic stages of teladorsagia circumcincta. | teladorsagia circumcincta is a common, pathogenic abomasal nematode of sheep. in order to improve disease control in parasite isolates resistant to several anthelmintics, alternative methods must be sought. sheep develop acquired immunity to t. circumcincta so vaccination is a valid option for control. for this reason, we are investigating parasite excretory/secretory products for molecules, which have potential to invoke protective immunity against t. circumcincta. here, we describe experiments ... | 2006 | 16387304 |
| effects of single or concurrent infections with eimeria alabamensis and gastrointestinal nematodes on the performance of calves on pasture. | twenty-four calves unexposed to pasture were allocated to four groups and inoculated with either two doses of 5 million eimeria alabamensis oocysts at turn-out (e), 90,000 l3 of ostertagia ostertagi and cooperia oncophora divided on six occasions (n) or both oocysts and larvae as above (e + n). a control group was left uninoculated (c). for 10 weeks, the groups grazed in separate uniform paddocks not previously grazed by cattle. by day 5, most calves in groups e and e + n developed clinical cocc ... | 2006 | 16496174 |
| mathematical models to assess strategies for the control of gastrointestinal roundworms in cattle 1. construction. | mathematical models were constructed to simulate the effect of ostertagia ostertagi infections on the growth of young cattle. the equations are based on system dynamics using the dysmap 2 software package in their construction. a pasture and animal growth model simulates the growth of pasture and the influences of management and climate on it; cattle feed intake and conversion into energy for maintenance and liveweight gain; the effect of the parasite burden on feed intake and utilization of ene ... | 2006 | 16517076 |