Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| species and morphs in the ostertagiinae: an allozyme study of seven species. | five enzymes, malate dehydrogenase, lactate dehydrogenase, mannose-phosphate isomerase, glucose-phosphate isomerase and phosphoglucomutase from seven putative species of ostertagiinae were compared using starch-gel electrophoresis. the nei distances were not much affected by origin of specimens or host species. six of the putative species could form polymorphic pairs: ostertagia ostertagi and ostertagia lyrata, ostertagia leptospicularis and ostertagia kolchida, teladorsagia circumcincta and tel ... | 1993 | 8300286 |
| characterization of excretory-secretory products of adult dictyocaulus viviparus and the antibody response to them in infection and vaccination. | in vitro released products of the adult stage of the bovine lungworm. dictyocaulus viviparus, were characterized according to their sds-page profile, glycosylation pattern, in vitro synthesis and antigenicity in the context of infection and vaccination with irradiated larvae. biosynthetic labelling experiments with 35s-methionine indicated active synthesis of es throughout this time. there was, however, little incorporation of 3h-glucosamine into es products, and lectin affinity chromatography a ... | 1993 | 8316410 |
| the presence of an early l4 larvae population in relation to the immune response of calves against ostertagia ostertagi. | the influence of different levels of infection with ostertagia ostertagi on the development of a protective immune response in calves was investigated. four groups of calves were infected with either 5000 (group a), 10,000 (group b), 20,000 (group c) or 40,000 (group d) infective larvae (o. ostertagi l3) weekly until treatment began. group e functioned as controls. all animals were treated with oxfendazole (9 mg ml-1) at week 17 (groups a, b and e) or week 18 (groups c and d). sixteen days post- ... | 1993 | 8333131 |
| serum anti-trichostrongyle antibody responses fo first and second season grazing calves. | serum anti-ostertagia ostertagi and anti-cooperia oncophora antibody responses were assessed in first season and second season calves grazing permanent paddocks. calves without previous exposure to trichostrongyles were found to mount significant parasite-specific igg1 antibody responses within two months of introduction to the pastures. a significant serum iga response to o ostertagi and igg2 responses to both o ostertagi and c oncophora antigens were also observed, but these responses were wea ... | 1993 | 8337481 |
| gastrin and gastrin-related responses to infection with ostertagia ostertagi in the calf. | the effects of a single challenge with 60,000 infective ostertagia ostertagi larvae on blood and gastrointestinal mucosal gastrin concentrations, gastrin-producing g-cell numbers in the pyloric mucosa and growth of different parts of the gut were investigated in 16, two-and-a-half-month-old calves. infected calves exhibited a rise in abomasal ph which was accompanied by a 145 per cent increase in wet weight of the fundic mucosa (p < 0.05) and a significant rise in blood total gastrin concentrati ... | 1993 | 8337488 |
| [the serological diagnosis of gastrointestinal nematode infections in cattle]. | ostertagia ostertagi and cooperia oncophora are widely distributed and are the most important parasites affecting young bovine livestock. therefore, there is a substantial need for sensitive and specific parameters in support of their diagnosis, especially for sub-clinical disease correlated to production loss. in this review, the value and the application as a diagnostic tool of pepsinogen, gastrin and antibody response are discussed. an increase in pepsinogen or gastrin reflects mucosal damage ... | 1993 | 8342328 |
| rapid changes in the surface of parasitic nematodes during transition from pre- to post-parasitic forms. | all mammalian-parasitic stages of a range of nematode species investigated (brugia pahangi, acanthocheilonema viteae, strongyloides ratti, nippostrongylus brasiliensis, trichinella spiralis and ostertagia ostertagi) labelled in a surface-restricted manner with the fluorescent lipid analogues 5-n-(octadecanoyl)aminofluorescein (af18) or nitrobenzoxadiazole-cholesterol (nbd-chol), but failed to bind other similar probes. in contrast, the surfaces of the 'pre-parasitic' infective stages of these sp ... | 1993 | 8355993 |
| cellular and chemical mediators of type 1 hypersensitivity in calves infected with ostertagia ostertagi: mast cells and eosinophils. | abomasal mucosal mast cell and eosinophil accumulation was morphometrically evaluated in 26 holstein steers after natural or experimental infection with ostertagia ostertagi. results showed that following infection, accumulation of mast cells and eosinophils in abomasal tissue was dependent on infection pattern. eosinophilia was greater in steers with type 1 ostertagiosis, while mastocytes was more pronounced in steers with type 2 ostertagiosis. | 1993 | 8359982 |
| cellular and chemical mediators of type 1 hypersensitivity in calves infected with ostertagia ostertagi: histamine, prostaglandin d2, prostaglandin e2 and leukotriene c4. | plasma histamine, prostaglandin e2 (pg) d2, pge2, and leukotriene (lt) c4 levels were determined in 26 holstein steers before and after natural or experimental infection with ostertagia ostertagi. post-infection abomasal lymph was also assayed for pgd2, pge2, and ltc4. histamine determinations were performed on abomasal tissue from three locations. results showed that: (1) tissue histamine levels increased in steers with type 2 ostertagiosis, (2) lymphatic pgd2 and pge2 levels were increased, pr ... | 1993 | 8359983 |
| immunologic changes in ostertagia ostertagi-infected calves treated strategically with an anthelmintic. | immunomodulation by ostertagia ostertagi and the effects of strategic anthelmintic treatments were studied in 3 groups of 6 calves each: an infected group, inoculated with 100,000 third-stage larvae (l3)/calf at 1 and 28 days; an infected-treated group, similarly inoculated, but treated with ivermectin 9 days after each inoculation; and a noninfected control group. calves were grazed on 2 previously clean pastures, with the infected and infected-treated calves sharing 1 pasture. all calves were ... | 1993 | 8368602 |
| experimental concurrent infections with ostertagia ostertagi and cooperia oncophora in the calf. | an experiment was conducted to investigate the effects of experimental concurrent infection with ostertagia ostertagia and cooperia oncophora compared with the effects of monospecific infections with o ostertagi under conditions designed to mimic natural conditions on pasture during a grazing season. the present experiment was not able to demonstrate any significant effect of c oncophora on the course of an o ostertagi infection. neither did c oncophora influence the build up of immunity to o os ... | 1993 | 8378618 |
| efficacy of abamectin against nematodes in cattle. | eight controlled trials were conducted, using 96 cattle of european breeds, to evaluate the efficacy of abamectin against natural and artificially acquired infections of adult and fourth-stage larvae of all the economically important gastrointestinal nematodes and lungworms in germany and the united kingdom. half the animals were treated on one occasion with abamectin at a dose of 200 micrograms/kg bodyweight given subcutaneously while the other half remained untreated. worms were counted 14 or ... | 1993 | 8442334 |
| pharmacodynamics, pharmacokinetics and faecal persistence of morantel in cattle and goats. | morantel could not be detected (< 0.05 microgram/ml) in the plasma of cattle or goats following the oral administration of morantel tartrate at a dose rate of 10 mg/kg bodyweight. no morantel was detected in the milk of lactating goats except in one animal where a concentration of 0.092 microgram/ml was detected at 8 h after drug administration. morantel was highly effective against cooperia oncophora infections in calves treated 6, 9 or 18 days after infection; however, was highly effective aga ... | 1993 | 8479005 |
| anthelmintics. | anthelmintics remain the principal means for the prevention and control of subclinical and clinical ostertagiasis. the selection of an appropriate anthelmintic depends on whether one is controlling or preventing type i ostertagiasis (caused by the establishment of adult worms derived from recently acquired infective larvae), preventing type ii (treating pre-type ii or inhibited larvae) or controlling type ii ostertagiasis (caused by the development of inhibited larvae to adults), or using the an ... | 1993 | 8484204 |
| anthelmintic resistance. | in populations of livestock in which anthelmintics have become the only means of control, individual worms in some species of helminths evade the effects of specific anthelmintics. if these resistant individuals are selected (by removing the susceptible individuals in the population) then the resistant worm population on individual farms becomes dominant in both numbers and effect. this selection of anthelmintic resistant populations is most often reported in equids and small ruminants (the host ... | 1993 | 8484205 |
| pathophysiology of infection with ostertagia ostertagi in cattle. | infection with the abomasal nematode, ostertagia ostertagi, is an important cause of impaired productivity in young cattle in temperate parts of the world. such losses have been associated with marked changes in feed intake, gastrointestinal function, protein, energy and mineral metabolism, and in body composition. the reduction in feed intake is an important factor in the pathogenesis of infection and may account for a large part of the difference in weight gain between ad libitum fed control a ... | 1993 | 8484207 |
| evaluation of pepsinogen, gastrin and antibody response in diagnosing ostertagiasis. | ostertagia ostertagi is widely distributed and is one of the most important parasites affecting young bovine livestock. there is, therefore, a substantial need for sensitive and specific parameters in support of diagnosis of ostertagiasis, especially for subclinical disease related to production losses. in this review, the value and application of pepsinogen, gastrin and antibody response as diagnostic tools are discussed. these three parameters are useful and comparable for confirming clinical ... | 1993 | 8484209 |
| gastrointestinal nematode infections and weight gain in dairy replacement stock: first-year calves. | for the evaluation of control strategies against, and economic impact of gastrointestinal nematode infection, the quantitative relationship between level of exposure to infection and growth performance is important. available data in the literature are summarised. based on questions derived from earlier work concerning the relationships between infection, growth performance and acquired immunity during the entire rearing period, two experiments were set up. in these experiments, groups of calves ... | 1993 | 8484213 |
| mathematical models for the population biology of ostertagia ostertagi and the significance of aggregated parasite distributions. | parasite frequency distributions are frequently aggregated. such distributions are conveniently described using the negative binomial frequency distribution. this distribution is completely characterized by two parameters: the mean of the distribution and an exponent, k. the degree of aggregation is inversely proportional to the value of k. aggregated parasite distributions enhance the ability of regulatory processes to maintain parasite populations at or near their equilibrium level but incorpo ... | 1993 | 8484215 |
| ostertagiasis in the cow and weaned calf in the northeastern usa. | most gastrointestinal nematode infections of cattle in the northeast usa are combinations of ostertagia ostertagi and cooperia oncophora. these infections are usually of little consequence in adult cattle because of immunity and consequent low levels of infection. some work has been done on the effects of infection on milk production but the results are equivocal. clinical ostertagiasis in calves can lead to mortality. such outbreaks are often associated with situations where calves are pastured ... | 1993 | 8484217 |
| epidemiology of ostertagia ostertagi in cow-calf herds in the southeastern usa. | ostertagia ostertagi is commonly found in the brood cow and nursing calf in the southeastern usa, this information being derived from fecal egg counts, coproculture and necropsy results; however, clinical disease and large burdens of this parasite are rarely reported. fecal egg counts in brood cows are routinely low and are generally reported to be 10 eggs per gram of feces (epg) or less. nematode egg counts in spring-born calves are also generally low prior to weaning; they increase steadily du ... | 1993 | 8484218 |
| epizootiology of ostertagia ostertagi in cow-calf production systems in the american midwest. | the most common gastrointestinal nematodes found in cattle in the midwest are ostertagia ostertagi and cooperia oncophora. other parasites include haemonchus placei, bunostomum phlebotomum and nematodirus helvetianus. parasite numbers are generally low in this region, as indicated by fecal egg counts and tracer calf worm recoveries, and the numbers of parasites decrease as one travels farther north. this decrease in parasite numbers also corresponds to a similar reduction in the prevalence of cl ... | 1993 | 8484220 |
| current and future prospects for control of ostertagiasis in northern europe--examples from denmark. | this review primarily discusses the status and prospects for control of bovine ostertagiasis in northern europe, with examples from denmark. there are different ongoing developments in agricultural systems and practices, and methods and possibilities for practical control depend on the intensity and specialisation of these; the modern dairy farm remains at highest risk of parasitism, owing to increasing stocking densities and limited natural control elements at hand. epidemiology and course of i ... | 1993 | 8484221 |
| epidemiology of ostertagia ostertagi in weaner-yearling cattle. | epidemiologic events in the life cycle of ostertagia ostertagi are best known in the weaner-yearling phase of cattle development throughout the concentrated cattle-rising areas of the world. animal and pasture management demands placed on this age class are greater than for suckling calves and adult stock in either beef or dairy breeds. this fact alone would likely account for a higher prevalence of clinical and subclinical disease in weaner-yearlings. additionally, the developing immune respons ... | 1993 | 8484223 |
| the systematics of nematodes that cause ostertagiasis in domestic and wild ruminants in north america: an update and a key to species. | studies of medium stomach worms (subfamily ostertagiinae) of domestic and wild ruminants in north america have refined our understanding of the systematics, host distribution and biogeography of these nematodes. strong support for recognition of monophyly for the ostertagiinae has resulted from preliminary phylogenetic analyses of morphological characters among these and other trichostrongylids. evaluation of morphological and biochemical characters in our laboratory and elsewhere has not refute ... | 1993 | 8484224 |
| regulation of immunity to ostertagia ostertagi. | knowledge of bovine immune response to ostertagiasis is important to understanding the mechanisms of innate and acquired immunity to this economically important helminth parasite that infects cattle worldwide. infection causes both antibody and cellular immune responses. evidence shows that ostertagia possesses excretory-secretory (es) molecules that may regulate immune cell responses that affect acquired immunity and pathophysiological changes to infection. ostertagia can down-regulate antibody ... | 1993 | 8484225 |
| influence of host genetics upon antibody responses against gastrointestinal nematode infections in cattle. | previous studies have shown that the number of gastrointestinal nematode eggs released per gram of feces (epg) of calves is strongly influenced by host genetics. the purpose of this study was to determine if host genetics also influenced immune recognition of parasite antigens in these same calves. serum samples were taken at monthly intervals from calves during their first grazing season, from approximately 4 months after the onset of calving and were continued until weaning. serum samples were ... | 1993 | 8484226 |
| inverse relationship between ige and worm burdens in cattle infected with ostertagia ostertagi. | changes in serum total and ostertagia-specific ige levels, and pepsinogen concentrations were evaluated in 28 holstein calves naturally or experimentally infected with ostertagia ostertagi. in addition, ige and pepsinogen concentrations were determined in abomasal lymph. results showed that (1) lymph ige responses were inversely correlated with worm burdens, and (2) serum ige levels were unreliable for predicting worm burdens. | 1993 | 8493771 |
| biological control of ostertagia ostertagi by feeding selected nematode-trapping fungi to calves. | three nematode-trapping fungi, one arthrobotrys oligospora and two duddingtonia flagrans isolates, were fed to ostertagia ostertagi-infected calves to test their ability to destroy larvae of this parasite in faeces and consequently to reduce the transmission of infective larvae to herbage. the fungi had previously been selected for their capability to pass the alimentary tract of cattle without losing growth and nematode-trapping potentials. dung was collected from three calves each fed one of t ... | 1993 | 8509616 |
| amplification and characterization of cysteine proteinase genes from nematodes. | in order to isolate proteinase genes from parasitic nematodes by polymerase chain reaction (pcr) techniques, we employed a pair of consensus oligonucleotide primers designed to anneal to the active site cysteine (primer ncpc) and asparagine (primer ncpn) coding regions of cysteine proteinases. the primers were biased toward the nucleotide and codon usages of cysteine proteinase genes of nematodes and were based on the consensus nucleotide sequences flanking the active site residues of genes from ... | 1995 | 8525283 |
| cloning and sequencing of an excretory/secretory antigen from ostertagia ostertagi fourth-stage larvae containing multiple tandem repeats. | 1995 | 8538694 | |
| immunodiagnosis of taenia saginata in cattle using hydrophobic antigens from t. hydatigena metacestode cyst fluid. | hydrophobic fractions isolated from cyst fluid of taenia hydatigena metacestodes, obtained from naturally infected goats from tanzania, were used in an indirect elisa and in immunoblot (western or dot blot) procedures. the use of the most hydrophobic fractions of the cyst fluid proved to result in a better diagnostic discrimination in elisa than the more hydrophilic fractions. best diagnostic ratio between responses from t. saginata infected and non-infected cattle was achieved when using horse- ... | 1995 | 8541896 |
| host movement and the genetic structure of populations of parasitic nematodes. | mitochondrial dna (mtdna) sequence data were used to compare the population genetic structures of five species of parasitic nematodes from three different hosts: ostertagia ostertagi and haemonchus placei from cattle, h. contortus and teladorsagia circumcincta from sheep, and mazamastrongylus odocoilei from white-tailed deer. the parasites of sheep and cattle showed a pattern consistent with high gene flow among populations. the parasite of deer showed a pattern of substantial population subdivi ... | 1995 | 8582607 |
| viability of infective larvae of haemonchus contortus, ostertagia ostertagi, and trichostrongylus colubriformis following exsheathment by various techniques. | various techniques were examined to determine optimum conditions for exsheathing infective larvae of 3 important ruminant parasites (haemonchus contortus, ostertagia ostertagi, and trichostrongylus colubriformis). in repeated experiments, aliquots of 10(5)-10(6) infective larvae, 1-2 mo old, of each parasite were incubated in each of 4 exsheathing media (distilled water, earle's balanced salt solution + carbon dioxide, nematode washing buffer + carbon dioxide, or sodium hypochlorite) for 1 or 18 ... | 1996 | 8627476 |
| the synlophe and other structural characteristics of sarwaria bubalis (nematoda: trichostrongyloidea) from cattle in guyana. | the synlophe (longitudinal, surface cuticular ridges) of sarwaria bubalis is described for the first time. it is a tapering lateral synlophe of about 40 ridges. the synlophe of s. bubalis is similar to that of ostertagia ostertagi but markedly different from that of species of spiculopteragia and mazamastrongylus. new information is provided also on the structure of the esophagus and perivulval pores. the esophageal valve is more than twice as long as wide. the bilateral perivulval pores were lo ... | 1996 | 8627485 |
| persistent activity of ivermectin topical and moxidectin injection against ostertagia ostertagi and dictyocaulus viviparus in calves. | 1995 | 8693675 | |
| the effects of early-season treatments with doramectin on set-stocked calves naturally exposed to trichostrongyles. | a study was carried out to evaluate the effects of strategic early-season treatments with doramectin on first-season grazing calves exposed to trichostrongylid infection on a naturally contaminated pasture. two groups of cross-bred limousine/red danish calves were turned out in early may on two plots that were similar with respect to size and herbage infectivity. they grazed separately until housing in early october. one of these groups was given doramectin at turnout and 10 weeks later, while t ... | 1996 | 8693699 |
| isolation, characterization and immunolocalization of a globin-like antigen from ostertagia ostertagi adults. | western blot analysis using an anti-globin rabbit serum rb94 revealed a major band of 17 kda in extracts of ostertagia ostertagi adults and 4th-stage larvae. the adult stage globin-like antigen (ooadglb) was purified from total worm extracts by liquid chromatography. the protein has an estimated molecular mass of 36 kda under non-reducing conditions, suggesting a dimeric structure containing 2 non-covalently linked 17 kda monomers. tryptic peptides were sequenced and showed strong similarities w ... | 1996 | 8710416 |
| influence of chemoprophylaxis on protective immunity to nematodes in cattle: a two-year study comparing four control strategies. | a two-year study was conducted in three sequential phases. initially, four matched groups of nine calves grazing similar pastures were subjected to different chemoprophylactic control programmes while a fifth group acted as unprotected controls. after being housed in the autumn, three calves from each group and two parasite-naive controls were challenged experimentally with ostertagia ostertagi, cooperia oncophora and dictyocaulus viviparus. post mortem worm counts revealed gradations of protect ... | 1995 | 8748170 |
| the effects of first-season strategic and tactical ivermectin treatments on trichostrongylosis in the first- and second-season grazing. | a 2 year study was conducted to evaluate the effects of first-season strategic or tactical treatments with ivermectin on trichostrongylosis in heifer calves in the first and second-season grazing. three groups of each eight holstein-friesian calves were turned out in early may onto a permanent pasture naturally contaminated with trichostrongyle larvae. two of these groups were given ivermectin either as strategic treatments (weeks 3, 8 and 13 after turnout) or as tactical treatments (weeks 14, 1 ... | 1996 | 8888555 |
| a tandemly repetitive dna sequence is present at diverse locations in the genome of ostertagia circumcincta. | a novel repetitive dna sequence in the sheep parasitic nematode ostertagia circumcincta was cloned and sequenced. this 1.2-kb sequence (oc1b) was not found in the closely related cattle parasite ostertagia ostertagi, nor in the more distantly related sheep parasites haemonchus contortus or trichostronylus colubriformis. sequences similar to oc1b were found at various genomic locations and contained a pair of 33-bp direct repeats. oc1b also contained a single copy of a 218-bp sequence (designated ... | 1996 | 8890746 |
| efficacy of moxidectin pour-on against gastrointestinal nematodes and dictyocaulus viviparus in cattle. | twenty crossbred beef heifer calves were used for an efficacy evaluation of 0.5% moxidectin pour-on against gastrointestinal nematodes and dictyocaulus viviparus. the latter parasite and bunostomum phlebotomum were the target species. the calves were exposed to natural infection on pasture from late september to december 22. additionally, all calves were experimentally infected with b. phlebotomum at 71 and 29 days before treatment and with d. viviparus at 29 days before treatment. the 20 calves ... | 1996 | 8893482 |
| prevalence and epidemiology of trichostrongylids in wyoming cattle with consideration of the inhibited development of ostertagia ostertagi. | during 1988, monthly collections of abomasa and the cranial portion of the small intestine of 208 native wyoming cattle were examined for adult and larval helminth parasites. egg counts were performed on colonic faecal specimens. the animals ranged from 7 months to 8 years of age and were sampled at slaughter houses or diagnostic laboratories from five different counties in the state. most of the cattle had ranged for a long time on non-irrigated, high altitude grass plains from about 1250 to 25 ... | 1996 | 8893483 |
| efficacy of moxidectin 0.5% pour-on against naturally acquired nematode infections in cattle. | the efficacy of 0.5% moxidectin pour-on at two dosages was evaluated in 30 cattle with naturally acquired gastrointestinal nematode infections. the cattle were ranked according to pretreatment fecal egg counts and body weights, and were randomly assigned from replicates to three treatment groups. the mean number of trichostrongyle eggs in pretreatment fecal samples did not differ among the groups. groups i and ii received 0.5% moxidectin pour-on at dosages of 0.25 mg moxidectin per kg body weigh ... | 1996 | 8916402 |
| digital image analysis and identification of eggs from bovine parasitic nematodes. | computer-assisted microscopy and multivariate statistics were used to establish and evaluate a procedure for identification of bovine strongylid eggs. ostertagia ostertagi, cooperia oncophora, haemonchus placei, trichostrongylus axei, and oesophagostomum radiatum eggs were obtained from faeces voided by monospecifically infected calves. images of single eggs (400 x magnification) were recorded by a ccd camera fitted onto a microscope and digitized on a pc. after separation of eggs from the image ... | 1996 | 8960211 |
| induction of traps by ostertagia ostertagi larvae, chlamydospore production and growth rate in the nematode-trapping fungus duddingtonia flagrans. | biological control of parasitic nematodes of domestic animals can be achieved by feeding host animals chlamydospores of the nematode-trapping fungus duddingtonia flagrans. in the host faeces, d. flagrans develop traps that may catch nematode larvae. in experiments on agar, d. flagrans had a growth rate between 15 and 60 mm/week at temperatures between 20 and 30 degrees c. the presence of nematodes induces the fungus to produce traps. the rate of trap formation in d. flagrans has an optimum at 30 ... | 1996 | 8960226 |
| seasonal pattern of inhibition of ostertagia ostertagi in calves in northeast mississippi. | the composition of, and seasonal changes in, populations of gastrointestinal parasites of calves in northeast mississippi were determined for 10 months post-weaning. after weaning on 15 october, 20 mixed breed beef steers were grazed together on a 4 ha fescue/bermudagrass pasture. from november through august of the following year, two of the calves were removed each month for necropsy and counting of gastrointestinal nematodes. eight species of worms were found: haemonchus placei, ostertagia os ... | 1996 | 8983154 |
| the epidemiology of gastrointestinal nematode infections in communal cattle and commercial beef cattle on the highveld of zimbabwe. | an epidemiological study of gastrointestinal nematode infections of cattle was conducted on the highveld of zimbabwe from june 1993 to may 1995. the study was carried out in two communal areas, two conventional beef farms and two commercial beef farms with irrigated pastures. on all farms/areas, faecal egg counts were low (< 500 eggs per g faeces) during the dry season. during the rainy season faecal egg counts were highest in communal areas and lowest in conventional beef farms. those of irriga ... | 1996 | 9011020 |
| monthly fluctuations of worm burdens and hypobiosis of gastrointestinal nematodes of calves in extensive management systems in the pyrenees (spain). | monthly fluctuations of worm burdens and arrested development of gastrointestinal nematodes in cattle from a mountainous region of spain were studied. fourteen previously helminth-naive calves grazed together with a herd of 120 cattle from may to november following the traditional extensive grazing system used in mountainous regions of spain (permanent calves). each month, throughout the grazing season, two helminth-naive calves (tracer calves) were added to the herd and allowed to graze for 4 w ... | 1996 | 9017870 |
| the effect of truncated infections with ostertagia ostertagi on the development of acquired resistance in calves. | the relative contribution of the third (l3), fourth (l4) and adult stages of ostertagia ostertagi to the development of immunity was assessed in calves which were either continuously infected during 21 weeks or subjected to infections truncated by anthelmintic treatment at the l3 or l4 stage. a fourth group remained uninfected (control group). faecal samples and blood samples were collected weekly for faecal egg counts and determination of pepsinogen and antibody levels. only the continuously in ... | 1996 | 9017885 |
| 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 |
| eprinomectin: a novel avermectin for use as a topical endectocide for cattle. | eprinomectin (mk-397 or 4"-epi-acetylamino-4"-deoxy-avermectin b1) is a novel avermectin selected for development as a topical endectocide for all cattle, including lactating dairy cows. herein, we show its anthelmintic, insecticidal and miticidal activity. to determine its anthelmintic capabilities, eprinomectin was tested topically on jersey calves at 0.08, 0.2, or 0.5 mg kg-1 in a probe formulation against experimental infections of adult haemonchus placei, ostertagia ostertagi, trichostrongy ... | 1996 | 9024867 |
| persistent efficacy of abamectin and doramectin against gastrointestinal nematodes of cattle. | to assess the persistent activity of injectable formulations of abamectin and doramectin against gastrointestinal nematodes of cattle. | 1997 | 9034496 |
| effects of ostertagia ostertagi on gastrin gene expression and gastrin-related responses in the calf. | 1. 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 on gastrin mrna expression, blood and tissue gastrin concentrations, the different molecular forms of gastrin in each, and pyloric mucosal chromogranin a-derived peptides were investigated in the calf. 2. an increase in blood gastrin concentrations in the infected group reached a peak by day 28 postinfection ... | 1997 | 9051591 |
| efficacy of doramectin for treatment of experimentally induced infection with gastrointestinal nematodes in calves. | to determine the efficacy of injectable doramectin against experimentally induced infections with adult and larval (l4) stages of gastrointestinal nematodes in calves. | 1997 | 9055975 |
| persistent efficacy of topical moxidectin against dictyocaulus viviparus and ostertagia ostertagi. | the persistent activity of moxidectin topically administered at the dose rate of 0.5 mg kg-1 bodyweight was evaluated against experimental nematode infection in 30 calves randomly allocated to six groups. five groups were treated on days -42, -35, -28, -21 and -14. the 6th group remained untreated as a control. on day 0, the calves were infected experimentally with 1000 dictyocaulus viviparus and 50,000 ostertagia ostertagi larvae and killed 3 weeks later. the formulation of moxidectin showed ex ... | 1997 | 9066064 |
| evaluation of the persistence of the effect of ivermectin and abamectin against gastrointestinal and pulmonary nematodes in cattle. | the persistence of the effect of ivermectin and abamectin against gastrointestinal nematodes and lungworm in cattle was evaluated in two trials, each involving 28 animals. groups of seven cattle either remained untreated, or were treated topically with ivermectin at 500 micrograms/kg bodyweight or subcutaneously with either ivermectin or abamectin at 200 micrograms/kg bodyweight. starting on the day of treatment the cattle were given daily trickle infections with various infective nematode larva ... | 1997 | 9090034 |
| the presence of an early l4 population in relation to the acquired resistance of calves naturally infected with ostertagia ostertagi. | the aim of the present study was to determine if the presence of inhibited l4 ostertagia ostertagi populations during the housing period influenced the level of acquired immunity in calves at the start of the second grazing season. four groups (a-d) of first season grazing calves were turned out onto a heavily infected pasture for five months, while the fifth group (e) was kept as uninfected controls. at housing all group a calves were necropsied for worm counts. a mean total of 78915 ostertagia ... | 1997 | 9106955 |
| nematocidal efficacy of eprinomectin, delivered topically, in naturally infected cattle. | to assess the nematocidal efficacy of eprinomectin in naturally infected cattle. | 1997 | 9185967 |
| epidemiological observations on gastrointestinal nematode infections in grazing cow-calf pairs in belgium. | the epidemiology of gastrointestinal helminth infections in beef cows and calves on pasture was studied in belgium during the 1990 and 1992 grazing seasons. weight gain, faecal egg counts, generic differentiation of infective larvae, serum pepsinogen levels, herbage larval counts and worm burdens of tracer calves were used as parameters. in study 1 two groups of ten cows with their spring-born calves grazing on separate pastures (a and b) were monitored during the 1990 grazing season. ostertagia ... | 1997 | 9187031 |
| effect of simulated rain, coat length and exposure to natural climatic conditions on the efficacy of a topical formulation of eprinomectin against endoparasites of cattle. | a series of five controlled studies involving 114 cattle were conducted in australia, north america and the united kingdom to examine the effect of simulated rain, coat length and exposure to natural climatic conditions, on the efficacy of a topical formulation of eprinomectin against nematode parasites of cattle. in all trials infections were induced with a range of bovine nematode species and treatment was applied when the majority of nematodes were mature. in one study, simulated rain was app ... | 1997 | 9187034 |
| the influence of a cooperia oncophora priming on a concurrent challenge with ostertagia ostertagi and c. oncophora in calves. | the development of immunity to ostertagia ostertagi and cooperia oncophora and interactions between these species were investigated in experimentally infected calves. parasitological, serological and histological parameters were used for assessing immune responses. no conclusive evidence of an effect of c. oncophora on the course of an o. ostertagi infection in calves could be shown. following a challenge with c. oncophora and o. ostertagi of c. oncophora primed calves, no significant reductions ... | 1997 | 9195718 |
| evaluation of an elisa for the routine diagnosis of dictyocaulus viviparus infections in cattle. | an enzyme-linked immunosorbent assay (elisa) that detects antibodies against dictyocaulus viviparus in experimentally and naturally infected cattle was evaluated for its sensitivity, specificity, the moment of seroconversion and persistence of the anti-d. viviparus response and precision. the first three parameters were compared with those of an indirect haemagglutination assay (iha). specificity and sensitivity of both assays were assessed in sera collected from calves experimentally infected w ... | 1997 | 9195719 |
| use of cloned excretory/secretory low-molecular-weight proteins of cooperia oncophora in a serological assay. | the potential of cooperia oncophora excretory/secretory (es) proteins as antigens in a serological assay which aims to establish exposure levels in cattle was assessed. es proteins were analyzed by one- and two-dimensional polyacrylamide gel electrophoresis and immunoblotting. the n-terminal domains of two es proteins were sequenced, and the corresponding cdnas were cloned. two cdnas, designated coes14.0 and coes14.2, were expressed in escherichia coli. the recombinant proteins were tested in an ... | 1997 | 9196182 |
| induction and suppression of lymphocyte proliferation by antigen extracts of ostertagia ostertagi. | to obtain an insight into the responses of t-cells of cattle to ostertagia ostertagi, the responses of peripheral blood and lymph node lymphocytes to o. ostertagi antigen extracts were determined in both exposed and naive calves. the lymphocyte responses induced by o. ostertagi antigen extracts of the third (l3) and fourth (l4) larval stages, as well as adult worms, were analysed. although peripheral blood lymphocyte responses were very low or absent, abomasal lymph node lymphocytes of exposed a ... | 1997 | 9239839 |
| isolation and phenotypic characterization of abomasal mucosal lymphocytes in the course of a primary ostertagia ostertagi infection in calves. | isolation and characterization of surface marker phenotypes of abomasal intraepithelial (iel), lamina propria (lpl) and abomasal lymph node lymphocytes (abln) from uninfected calves were conducted, and the dynamics of change in these populations during the course of a primary ostertagia ostertagi infection were defined. to obtain viable iel and lpl from the abomasal mucosa of cattle, a modified isolation method was developed. the phenotypic characterization of abomasal lymphocytes was accomplish ... | 1997 | 9239841 |
| therapeutic and prophylactic efficacy of the ivomec sr bolus against nematodes and psoroptes ovis in cattle weighing more than 300 kg at the time of treatment. | three trials using 50 european breed cattle were conducted to evaluate the therapeutic and prophylactic efficacy of the ivomec sr bolus against nematodes (2 trials) and psoroptes ovis (1 trial) in cattle weighing more than 300 kg at the time of treatment. the ivomec sr bolus proved to be highly effective against economically important gastrointestinal and pulmonary nematodes (ostertagia ostertagi, trichostrongylus axei, cooperia punctata, oesophagostomum radiatum, dictyocaulus viviparus) and imp ... | 1997 | 9272566 |
| cytokine profile induced by a primary infection with ostertagia ostertagi in cattle. | changes that occur in the local draining lymph nodes including, changes in cell surface markers and cytokine gene expression were studied over the first 4 weeks of a primary, ostertagia ostertagi infection of the abomasum. cells recovered from the abomasal lymph nodes (abln) after infection showed a decrease in the percentage of cd3+ cells, and an increase in the percentage of igm+ cells and cells bearing the tcr1 marker. these changes were coincident with an increase in the proportion of activa ... | 1997 | 9343340 |
| persistent efficacy of doramectin against experimental challenge with ostertagia ostertagi in cattle. | two studies were conducted in north america to evaluate the persistent efficacy of doramectin injectable solution against experimental challenge with infective larvae of ostertagia ostertagi. in both studies, four groups of 10 randomly-assigned calves, negative for trichostrongyle-type eggs on fecal examination, were treated subcutaneously in the midline of the neck with saline (1 ml 50 kg-1) on day 0 or doramectin (200 micrograms kg-1 = 1 ml 50 kg-1) on day 0, 7, or 14. two additional calves fr ... | 1997 | 9403972 |
| comparative persistent efficacy of doramectin, ivermectin and fenbendazole against natural nematode infections in cattle. | a study was conducted in argentina, to investigate the period of protection of a single injection of doramectin administered subcutaneously (s.c.) at 200 micrograms kg-1 (1 ml/50 kg) compared with single treatments of ivermectin (200 micrograms kg-1 s.c.) and fenbendazole (5 mg kg-1 p.o.), against field infections of gastrointestinal parasites of cattle. eighty-three animals were selected and ranked on the basis of serial fecal egg counts (e.p.g.'s). from this group, three animals were slaughter ... | 1997 | 9403975 |
| quantification of cytokine gene expression in lamina propria lymphocytes of cattle following infection with ostertagia ostertagi. | changes in cell surface markers and cytokine transcription were analyzed in lamina propria lymphocytes from control animals (noninfected calves) and calves after a single high but nonprotective primary infection with ostertagia ostertagi. flow cytometry of cells recovered from the lamina propria showed an increase in the percentages of igm+, wc1+, and il-2r+-bearing cells 10 days after infection; however, 2 mo after infection, cell staining was comparable to preinfection levels. transcription le ... | 1997 | 9406777 |
| environmental factors influencing transmission. | the free-living stages of gastro-intestinal nematodes on pasture (i.e. eggs, developing and infective larvae) are often overlooked and not considered by producers. the factors that influence the development, survival, distribution, or migratory behavior of the free-living larvae seen on pasture are primarily weather related. the deposition of helminth eggs in feces is the starting point for the contamination of the pasture and the subsequent development of the parasites. the cumulative numbers o ... | 1997 | 9460201 |
| pathophysiology of infection with gastrointestinal nematodes in domestic ruminants: recent developments. | infection with gastrointestinal nematodes, particularly ostertagia species in domestic ruminants, continues to represent an important cause of impaired productivity in temperate parts of the world. the mechanisms responsible for such losses include changes in feed intake, gastrointestinal function, protein, energy and mineral metabolism, and body composition, and were described in detail at the last ostertagia workshop (fox, m.t. 1993. pathophysiology of infection with ostertagia ostertagi in ca ... | 1997 | 9460203 |
| immunity development against ostertagia ostertagi and other gastrointestinal nematodes in cattle. | the immunological response to gastrointestinal nematodes is complex and it will take time and financial support to dissect the different components of protective immunity in ruminants. the present review briefly summarises different aspects and manifestations of protective immunity in cattle against gastrointestinal nematodes, especially ostertagia ostertagi, and the factors that may interact with the development of this immunity. | 1997 | 9460204 |
| effects of gastrointestinal nematode infection on the ruminant immune system. | gastrointestinal (gi) nematodes of ruminants evoke a wide variety of immune responses in their hosts. in terms of specific immune responses directed against parasite antigens, the resulting immune responses may vary from those that give strong protection from reinfection after a relatively light exposure (e.g. oesophagostomum radiatum) to responses that are very weak and delayed in their onset (e.g. ostertagia ostertagi). the nature of these protective immune responses has been covered in anothe ... | 1997 | 9460205 |
| 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 |
| 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 |
| 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 |