Publications

increased establishment of lungworms (dictyocaulus viviparus) in calves after previous infections with gastrointestinal nematodes (ostertagia ostertagi and cooperia oncophora).	the influence of a priming infection with gastrointestinal nematodes on the subsequent establishment of lungworms was studied. repeated inoculations of calves with ostertagia ostertagi and cooperia oncophora during 3, 5 or 7 weeks resulted in an establishment of lungworms that was 191% of the establishment found in naïve controls. the higher take was associated with a higher faecal output of lungworm larvae and with lower weight gains of calves. the effect was not significantly influenced by the ...	1989	2529698
ostertagia ostertagi infection in the calf: effects of a trickle challenge on appetite, digestibility, rate of passage of digesta and liveweight gain.	the effects of a trickle challenge with the equivalent of 10,000 infective ostertagia ostertagi larvae per day on appetite, digestibility, rate of passage of digesta and liveweight gain were investigated in 12 calves assigned to infected, pair-fed control and ad libitum-fed control groups. digestibility of cellulose, nitrogen, organic matter and dry matter was determined using insoluble acid detergent fibre as a marker on two occasions during the study: (i) between days 31 and 38, when abomasal ...	1989	2595086
ostertagia ostertagi infection in the calf: effects of a trickle challenge on the hormonal control of digestive and metabolic function.	metabolic effects of a trickle challenge with the equivalent of 10,000 infective ostertagia ostertagi larvae per day were investigated in 12 calves allocated to infected, pair-fed control or ad libitum-fed control groups. changes in hormone levels reflecting abomasal, pituitary and pancreatic function were monitored using radioimmunoassay techniques previously validated for use in cattle. a range of metabolic profile parameters and blood metabolites was also measured. feed intake of the infected ...	1989	2595087
[the helminth fauna of the gastrointestinal tract of young cattle in northwest germany].	ten unmedicated animals of a controlled anthelmintic trial were used to analyse the present gastrointestinal helminth fauna of young cattle from the northwest of germany. this survey done in august revealed ostertagia ostertagi to represent the most prevalent and abundant species followed by cooperia oncophora and nematodirus helvetianus. o. lyrata, o. leptospicularis, c. zurnabada, c. punctata, trichostrongylus axei, haemonchus contortus, bunostomum phlebotomum, capillaria bovis and trichuris d ...	1989	2598802
visualization of eosinophil chemotactic factor in abomasal tissue of cattle by immunoperoxidase staining during ostertagia ostertagi infection.	eosinophil chemotactic factor (ecf) was localized predominantly in the intestinal cells and lateral hypodermal cords of developing fifth stage larvae (l5) of ostertagia ostertagi within abomasal tissue cross-sections by peroxidase in an antibody sandwich technique using monoclonal antibody to ecf. cooperia oncophora larvae in tissue cross-sections did not stain using this technique. these experiments demonstrate that ecf is localized in ostertagia ostertagi organelles and is probably released by ...	1989	2658300
pathophysiological and parasitological studies on ostertagia ostertagi infections in calves.	friesian calves given a low level infection of the abomasal parasite ostertagia ostertagi over a six week period displayed a mild diarrhoea with high faecal egg counts and elevated plasma pepsinogen values. at necropsy on day 23 abomasal lesions characteristic of ostertagiasis were widespread. at 42 and 84 days oedema and congestion were also prominent. total worm burdens on days 23 and 42 were similar but a marked decrease had occurred by day 84. feed digestibility and nitrogen economy were not ...	1989	2704887
reliability and reproducibility of the larval paralysis test as an in vitro method for the detection of anthelmintic resistance of nematodes against levamisole and morantel tartrate.	in order to study the reliability of the larval paralysis test as an in vitro assay for the detection of resistance of nematodes to levamisole and morantel tartrate, the influence of different parameters was evaluated using resistant and susceptible ostertagia ostertagi strains. the operator, the sample (10% of the larvae present in the suspension), the incubation time (24, 48 or 72 h), the incubation temperature (20 or 25 degrees c) and the observation period of the larvae (5 or 15 s) had no st ...	1989	2705288
soluble extracts from larval ostertagia ostertagi modulating immune function.	balb/c mice were immunized with ostertagia ostertagi antigens and keyhole limpet hemocyanin (klh) or sheep erythrocytes (sr) for evaluation of antibody production by enzyme linked immunosorbent assay (elisa) or modified jerne plaque assay. one semi-purified larval antigen caused both decreased anti-klh serum antibody levels and fewer anti-sr igm-secreting b cells. this antigen was shown to depress lymphocyte blastogenesis to concanavalin a when added to cultured balb/c splenic lymphocytes.	1989	2707963
comparison of egg excretion and serum pepsinogen levels as measures of nematode worm burdens in calves with limited pasture exposure.	four- to 6-mo-old calves raised on clean pastures were allowed to graze for about 30 days on pastures naturally contaminated with ostertagia ostertagi, cooperia spp., haemonchus placei, and nematodirus helvetianus. the calves were then housed on concrete for 3 wk before slaughter. at necropsy the eggs per gram of feces (epg) and the total worm burdens from the abomasum and small intestine were determined. blood samples were also obtained for serum pepsinogen (pep) assays. a total of 44 calves wa ...	1989	2723922
efficacy of oxfendazole against inhibited larvae of ostertagia ostertagi in naturally infected calves in the southern usa.	forty yearling calves were assigned to four equal groups; three of the groups were treated with oxfendazole at dose rates of 6.75 mg/kg, 4.50 mg/kg, or 2.25 mg/kg bodyweight while the fourth group served as an untreated control. the calves were native to north-east mississippi, usa, and harboured natural infections of gastrointestinal nematodes. the study was conducted during july when inhibited early fourth-stage larvae may be found in large numbers after their acquisition in the spring. the ca ...	1989	2728298
factors influencing rain splash dispersal of infective larvae of ostertagia ostertagi (trichostrongylidae) from cow pats to the surroundings.	laboratory experiments were conducted to investigate rain splash dispersal of infective ostertagia ostertagi larvae (l3) from cow pats to the surroundings during simulated rainfall. simulated rainfall on dry cow pats resulted in dispersal of only very few l3. when cow pats were watered prior to the experiments, many infective larvae were stimulated to migrate up onto the surface of the pats, where they might be hit by water drops. when pre-watered pats were hit by falling drops, a considerable p ...	1989	2728328
attempts to control infection with ostertagia ostertagi (trichostrongylidae) in grazing calves by adding mycelium of the nematode-trapping fungus arthrobotrys oligospora (hyphomycetales) to cow pats.	artificially prepared cow pats containing ostertagia ostertagi eggs were deposited on two comparable grazing plots at weekly intervals during june and july 1987. before deposition the cow pats, on the one plot, were inoculated with 0.250 g mycelial fragments per kg of faeces of the predacious fungus arthrobotrys oligospora. on the other control plot comparable numbers of non-inoculated cow pats were placed at the same time. subsequently, in july, two equal groups of calves were turned out one on ...	1989	2738380
a comparison of two methods and two additives for faecal cultivation of bovine trichostrongyle larvae.	the larval recovery rates of ostertagia ostertagi and cooperia oncophora from monospecific copro-cultures were determined by the methods of corticelli and lai, and henriksen and korsholm using vermiculite or polystyrene pellets as inert additives. the addition of either vermiculite or polystyrene pellets in the two culture methods significantly (p less than 0.05) improved larval recoveries of both parasite species. recovery rates with the henriksen and korsholm method were higher (p less than 0. ...	1989	2763446
induction of nematode-trapping organs in the predacious fungus arthrobotrys oligospora (hyphomycetales) by infective larvae of ostertagia ostertagi (trichostrongylidae).	laboratory experiments were designed to study the influence of temperature, concentrations of nematodes, oxygen tension, light, and nutrient levels, on the induction of nematode-trapping hyphal nets in the predacious fungus arthrobotrys oligospora. when induced by infective ostertagia ostertagi larvae, a maximum number of nets was produced at 20 degrees c, at which temperature nets in surplus were produced at larval concentrations up to 1,000 larvae per cm2. a. oligospora did not produce nets in ...	1989	2782235
studies of the immunomodulatory effects of low-level infection with ostertagia ostertagi in calves.	possible immunomodulation by low-level infection with ostertagia ostertagi was studied in 4-month-old calves. six groups of 4 calves each were subjected to the following regimens: group 1--nonparasitized controls; group 2--nonparasitized, but challenge exposed at day 64 with brucella abortus strain 19 vaccine (ba) and at day 78 with iv administration of a soluble third-stage larval (l3) antigen preparation of o ostertagi (oag); group 3--nonparasitized, but challenge exposed at day 78 with 75 x 1 ...	1989	2802311
characterization and purification of parafilaria bovicola antigens by chromatofocusing to enhance specificity in serodiagnosis.	a study was conducted to determine if the purification of parafilaria bovicola antigens can increase the specificity of serodiagnosis of parafilariasis in enzyme-linked immunosorbent assay. antigens released from adult worms of p. bovicola were separated by chromatofocusing on a polybuffer exchanger of the ph range 7.3-4.0 polypeptide analysis by sodium dodecyl sulphate polyacrylamide gel electrophoresis showed the presence of four major polypeptides with mws of 41, 36, 24 and 20 kda. additional ...	1989	2815540
interpretation of abomasal worm burdens in cattle.	the significance of the worm burden in the diagnosis of parasitic gastroenteritis is examined. it is emphasised that the worm population is in a dynamic state with the calf constantly losing part of its worm burden while picking up new infective larvae. the numbers and proportion of late fourth stage ostertagia ostertagi larvae gives an indication of the success of the animal in controlling its worm burden. during an examination of the worm population it is also necessary to look at the conditio ...	1989	2929084
persistent anthelmintic activity of topically administered ivermectin in cattle.	the persistent anthelmintic effect of ivermectin as a topical treatment at 500 microg/kg was evaluated against induced infections of ostertagia ostertagi, trichostrongylus axei and dictyocaulus vivparus in calves. the results showed a highly significant (p<0.001) anthelmintic activity for at least 14 days against o. ostertagi and t.axei (>99 per cent efficacies) and for at least 28 days (98 per cent efficacy) against d. viviparus.	1989	16031549
the surface lipid of parasitic nematodes: organization, and modifications during transition to the mammalian host environment.	the biophysical properties of the surface lipid of a range of nematode species and their developmental stages were examined, using fluorescent lipid probes and fluorescence recovery after photobleaching (frap). these methods can be applied to living, intact parasites, and the analysis confined to lipid on the outermost surface. in all cases, surface lipid was unusual in its selectivity for the insertion of the lipid probes. in addition, a polar lipid probe was generally not free to diffuse in th ...	1990	1978532
stage-specific cuticular proteins of ostertagia circumcincta and ostertagia ostertagi.	in this study we have shown that nhs-biotin and i125-streptavidin can detect cuticular polypeptides of ostertagia spp. the labelled polypeptide profile of intact nematodes is simple compared to the profile obtained by labelling homogenates. none of the major internal polypeptides are labelled and the subset of proteins labelled in intact nematodes appears to be mainly surface associated. the results presented here demonstrate that nhs-biotin may be used as a reagent for the analysis of surface p ...	1990	2074129
ostertagia ostertagi: isolation and partial characterization of somatic and metabolic antigens.	one metabolic (es) and two somatic extracts (as and ms) were prepared from ostertagia ostertagi. partial characterization of the three preparations was accomplished by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and immunoblot techniques. in immunoblots, as showed a low number of bands that reacted weakly with sera collected from infected calves. ms reacted strongly with the homologous sera, and a sharp group of bands appeared from 12 to 14 kda, increasing in intensity a ...	1990	2074130
effects of ivermectin and fenbendazole in strategic treatment of gastrointestinal nematode infections in cattle.	four groups of 18 beef calves each were used to evaluate effects of different treatments on parasite control and weight gains. the investigation extended from november 1986 (weaning) to october 1987. group-1 calves were treated with ivermectin (200 micrograms/kg of body weight, sc) at approximately 6-week intervals for a total of 8 treatments; group-2 calves were given the same dosage of ivermectin by the same route of administration as group-1 calves in november, march, and july; group-3 calves ...	1990	2085231
increased establishment of lungworms after exposure to a combined infection of ostertagia ostertagi and cooperia oncophora.	three-month-old calves were infected three times weekly during a 5-week period with cooperia oncophora, ostertagia ostertagi or a combination of these two species. for each type of infection two dose levels were applied. in addition one group of calves was kept uninfected. after removal of the primary infection by anthelmintic treatment all calves were challenged with lungworm larvae and slaughtered 5 weeks later. the groups receiving either c. oncophora or o. ostertagi as a monospecific infecti ...	1990	2143329
effect of ostertagia ostertagi secretions and various putative secretagogues and inhibitors on aminopyrine accumulation in dispersed bovine abomasal gland cells.	aminopyrine accumulation in suspensions of isolated gastric glands was used to determine the effect of ostertagia ostertagi secretions and putative secretagogues and inhibitors on abomasal parietal cells. parasite secretions did not affect acid production nor did histamine. dibutyryl cyclic adenosine monophosphate (camp) and pentagastrin significantly increased aminopyrine accumulation by gastric glands and cimetidine, omeprazole and thiocyanate significantly decreased aminopyrine accumulation c ...	1990	2176337
effects of microclimatic variables on the availability and movement of third-stage larvae of ostertagia ostertagi on herbage.	assessments were made of the influence of several microclimatic variables on the availability of third-stage larvae of ostertagia ostertagi, on pasture herbage. variables most closely related to recovery of larvae from the lower herbage samples were: maximum air, mat and dung temperatures. recovery of larvae from the upper portion of the herbage was closely correlated with dung temperature, sampling-time air temperature and maximum air temperature. bearing in mind that the moisture threshold was ...	1990	2216346
effects of tactical late-season treatments with ivermectin on calves naturally exposed to trichostrongyles.	this study was conducted to evaluate the effects of tactical treatments with ivermectin against trichostrongyles in first-season grazing heifer calves in the danish marshland. a group of black-pied friesian calves was turned out in early may on a permanent pasture naturally infected with trichostrongyle larvae. in late july, when high herbage infectivity started to appear, the pasture was divided into two plots of equal size, which from then and until housing in late october were each grazed by ...	1990	2251746
[dominant characteristics of helminth parasitism in cattle in ituri (haut-zaire). i. the helminth fauna].	the identification of cattle helminths in ituri was carried out by post mortem examinations in slaughterhouses and tracer calves. the thirty diagnosed species were typical of wet tropical areas of africa. the presence of dictyocaulus viviparus, ostertagia ostertagi and haemonchus similis and the absence of echinococcus granulosus constituted the original features of this inventory.	1990	2263748
genetic control of immunity to gastrointestinal nematodes of cattle.	previous studies have indicated that host genetics significantly affects the number of gastrointestinal nematode eggs per gram (epg) in the feces of calves during their first grazing season. an entire calf crop of approximately 190 animals was monitored monthly until weaning to verify these earlier results, and to begin to discern the basis for this phenomenon. a significant genetic effect on fecal epg values was not observed until calves had been on pasture for 2-3 months, and was demonstrable ...	1990	2267727
the influence of a low cobalt intake on the neutrophil function and severity of ostertagia infection in cattle.	two trials involving housed cattle examined the effect of co depletion and supplementation on immune status as assessed by the neutrophil function test which measures the ability of isolated neutrophils to kill the yeast candida albicans. a third trial investigated the extent to which co status influenced the severity of ostertagia ostertagi infection. in the first two trials liveweight gains were unaffected until some 40-60 weeks on the low dietary co intake despite very low serum vitamin b12 v ...	1990	2271909
stimulated pepsinogen secretion from dispersed abomasal glands exposed to ostertagia species secretion.	carbachol and secretions from ostertagia species parasites significantly (p less than 0.001) stimulated isolated preparations of dispersed gastric glands from bovine and ovine abomasal mucosa to secrete pepsinogen. atropine reduced the response to both secretagogues. live adult and larval stages of ostertagia ostertagi and o circumcincta and homogenates of these parasites did not significantly (p greater than 0.05) increase pepsinogen production from bovine or ovine gland preparations.	1990	2300718
efficacy of concomitant early summer treatment with fenbendazole and clorsulon against fasciola hepatica and gastrointestinal nematodes in calves in louisiana.	the efficacy, safety, and compatibility of fenbendazole (fbz) and clorsulon (cln) were tested after oral administration of label recommended and of higher (5x) dosage rates to calves naturally infected with gastrointestinal nematodes and fasciola hepatica. results for 42 calves allotted to 4 treatment groups indicated a similar efficacy against mature f hepatica by fbz (5 mg/kg of body weight) and cln (7 mg/kg) in a combined oral suspension, compared with cln (7 mg/kg) alone (100 vs 99% reductio ...	1990	2301813
pathophysiological and parasitological studies on a concurrent infection of ostertagia ostertagi and cooperia oncophora in calves.	calves which had received daily concurrent infections of 2000 ostertagia ostertagi and 10,000 cooperia oncophora infective larvae over a 42-day period displayed a range of clinical signs typical of acute parasitic gastroenteritis including inappetence, weight loss, hypoalbuminaemia and diarrhoea. there were consistent and significant depressions in both digestive efficiency and nitrogen retention. radioisotopic studies revealed marked disturbances in protein metabolism which were associated with ...	1990	2333427
adverse immune reactions and the pathogenesis of ostertagia ostertagi infections in calves.	the possible development of type-1 hypersensitivity reactions in the abomasal mucosa caused by soluble l3 products of ostertagia ostertagi was studied in 4-month-old calves sensitized by repeated exposure to l3 over a 50-day period followed by anthelmintic treatment. four groups each of 4 calves were used. group 1 served as nonsensitized controls and group 2 as sensitized controls, group 3 was challenge exposed at 2-week intervals beginning at week 10 with a soluble l3 product (oag), and group 4 ...	1990	2337287
cryopreservation of some common nematodes of ruminants for up to 11,3 years.	infective larvae of selected batched of the following nematode species from sheep and cattle were examined for survival and infectivity (by injection into either the abomasum, the duodenum, or the jugular vein) after having been stored in liquid nitrogen for 103-136 months: haemonchus contortus, haemonchus placei, ostertagia circumcincta, ostertagia ostertagi, marshallagia marshalli, cooperia spp., trichostrongylus axei, trichostrongylus colubriformis, trichostrongylus falculatus, nematodirus sp ...	1990	2338992
bovine immune recognition of ostertagia ostertagi larval antigens.	analysis of a detergent-solubilized somatic antigen of ostertagia ostertagi 3rd stage larvae by sds-page and western blotting has revealed two specific antigens with apparent molecular weights of 17 and 43 kd under reducing conditions. probing of the ostertagia ostertagi preparation with preinfection control sera has shown two cross-reacting antigens with apparent molecular weights of 67 and 81 kd. both the 17 and the 43 kd antigens were recognised by igg1 which was the predominant reactive subc ...	1990	2339503
the identification of females within the subfamily ostertagiinae lopez-neyra 1947.	as a result of the examination of many thousands of female nematodes classified as belonging to the sub-family ostertagiinae lopez-neyra 1947, it became possible to compile descriptions of different female types, each of which corresponds to a polymorphic species as determined by male morphology. the female types have been designated as follows: ostertagia ostertagi (males o. ostertagi and o. lyrata), ostertagia circumcincta (males o. circumcincta, o. trifurcata and teladorsagia davtiani), oster ...	1990	2343529
epidemiology of abomasal nematodes of dairy cattle in hokkaido, northern japan.	the prevalence and intensity of infection with abomasal nematodiasis was studied in dairy cattle of hokkaido, northern japan, for successive two years. during the period of march in 1985 to september in 1987, a total number of 393 abomasa of holstein-friesian cows was examined for nematode parasites. nematodes were detected from 75% of the cows. the prevalence of nematode species detected was ostertagia ostertagi 250 (63.6%), mecistocirrus digitatus 181 (46.1%), trichostrongylus axei 85 (21.6%) ...	1990	2348599
anthelmintic efficacy of febantel paste in naturally infected calves.	the purpose of the present study was to verify results of the lowest dose (5 mg kg-1) of febantel evaluated in an earlier trial in which there were no differences in efficacies of three dose rates (5, 7.5 and 10 mg kg-1 body weight) against natural gastrointestinal nematode infections of cattle. fourteen angus calves (mean weight and age of 155 kg and 525 days, respectively), from the same farm, with relatively heavy (mean of 448 eggs g-1 feces (epg] parasite burdens were selected. after an adju ...	1990	2353426
cloning and characterization of the ribosomal rna gene repeat from ostertagia ostertagi.	clones of the rrna genes of ostertagia ostertagi were selected from a library prepared from the genomic dna of adult worms of strain la-2. a 13.4-kb insert in a clone, lambda oor78, is comprised of one complete 7.5-kb rdna unit and portions of two adjacent units. the rdna unit is directly repeated in a head-to-tail fashion and represents approximately 0.9% of the total genomic dna. this repeating unit appears to be the only long tandemly repeated sequence in the genome. restriction enzyme recogn ...	1991	1674820
continued susceptibility of ostertagia ostertagi infective larvae to morantel tartrate.		1991	1763471
efficacy of albendazole, levamisole and fenbendazole against gastrointestinal nematodes of cattle, with emphasis on inhibited early fourth stage ostertagia ostertagi larvae.	an experiment was conducted to compare the anthelmintic efficacy of albendazole (abz), levamisole (lev) and fenbendazole (fbz) against inhibited early fourth stage larvae (el4) of ostertagia ostertagi during april in louisiana. forty cross-bred beef heifers (average weight 165 kg) were acquired during winter and grazed on pastures contaminated with o. ostertagi and other nematodes until early april. the cattle were weighed and randomly allotted into four groups of ten animals on 6 april and trea ...	1991	1763491
efficacy of levamisole against ostertagia ostertagi in louisiana cattle during maturation of inhibited larvae (september) and during minimal inhibition (december/january).	levamisole (lev) was tested in four experiments to compare efficacy values against ostertagia ostertagi when larval maturation was occurring (september), following inhibition and also when populations were expected to be largely adult (winter). a primary objective was to determine the importance of developing fourth-stage larvae (dl4) and inhibited, early fourth-stage larvae (el4) in replacing adult worms lost through treatment and the effect of this on reduced efficacy against adult worms. youn ...	1991	1763492
pathophysiologic effects of ostertagia ostertagi in calves and their prevention by strategic anthelmintic treatments.	pathophysiologic effects of ostertagia ostertagi infection and their prevention by strategic anthelmintic treatments were studied in 3 groups each of 6 steer calves. group-1 calves were noninfected controls. group-2 calves were inoculated with 100,000 third-stage larvae on the 1st and 28th days of the experiment and grazed on pasture initially free of contamination. group-3 calves were on a similar regimen as those in group 2, but were also treated with ivermectin 9 days after each larval inocul ...	1991	1767994
epizootiology of helminth parasitism in a beef cow/calf herd in minnesota.	to test the effect of a parasite control program for cattle, 2 groups of similar composition were grazed on separate, but equivalent, improved pastures. cattle in 1 group were treated with fenbendazole at 5.0 mg/kg of body weight at the time they were turned out on pasture in the spring and again at midsummer, when the cattle were moved to a new pasture. the control group was not treated. parasite egg counts were significantly (p less than 0.04) lower in the treated group. trichostrongyle-type e ...	1991	1767995
further studies with a strain of ostertagia ostertagi resistant to morantel tartrate.	two experiments with a morantel resistant strain of ostertagia ostertagi were carried out. in the first experiment five groups of five calves were infected with 60,000 larvae of this resistant strain. calves of one group remained untreated, calves of the other groups were treated with morantel tartrate, oxfendazole, levamisole or ivermectin in the recommended doses. it was demonstrated that there was side resistance to levamisole, but not to oxfendazole or ivermectin. compared with the untreated ...	1991	1774123
ability of the fungus pleurotus pulmonarius to immobilise preparasitic nematode larvae.	in vitro experiments showed that the oyster mushroom pleurotus pulmonarius exerts a strong immobilising effect on preinfective larvae of the animal parasitic nematodes ostertagia ostertagi, cooperia oncophora, oesophagostomum quadrispinulatum and cyathostoma species. infective stages of the same species seemed less vulnerable to fungal attack, possibly because they are protected by their outer cuticle.	1991	1780575
ostertagia ostertagi in neonatal calves: establishment of infection in ruminating and non-ruminating calves.	an experiment was carried out to study the role of the ruminal function in the establishment of ostertagia ostertagi in neonatal calves. three groups of calves were fed either milk only (groups a and c), or hay and concentrate in addition to milk (group b) from birth. at the time of infection, ruminal function was negligible in groups a and c, whereas it was well developed in group b. calves of groups a and b were each given 25,000 normal ensheathed infective larvae of o ostertagi and those of g ...	1991	1780595
effect of sustained release and pulse release anthelmintic intraruminal devices on development of pathophysiological changes and parasite populations in calves infected with ostertagia ostertagi and cooperia oncophora.	an experiment was conducted in calves to investigate the effect of sustained release and pulse release anthelmintic intraruminal boli on the development of pathophysiological changes following daily infection with ostertagia ostertagi and cooperia oncophora for six weeks. after infection various pathophysiological changes were detected including increases in serum pepsinogen concentration, enteric plasma protein losses and in the catabolic rate of albumin. such changes developed rapidly in the u ...	1991	1788487
identification and isolation of a specific antigen with diagnostic potential from dictyocaulus viviparus.	the purpose of the investigation was to isolate and identify a specific antigen of dictyocaulus viviparus that can be used to diagnose lungworm infections in cattle. somatic, excretion and secretion antigens of adult d. viviparus and somatic antigens of l3 larvae were examined in an indirect enzyme-linked immunosorbent assay (elisa) to determine whether they cross-reacted with sera collected from calves with mono-infections of fasciola hepatica. ostertagia ostertagi, ascaris suum, or cooperia on ...	1991	1832795
celiac trunk cannulation for obtaining abomasal lymph from cattle.	cannulation of the celiac trunk was surgically performed in 26 holstein steers. the procedure was successful in 23 (88.5%) of the steers. twenty-two of the steers were infected either naturally or experimentally with the abomasal nematode, ostertagia ostertagi and/or other gastrointestinal parasites. the remaining 4 steers were not infected. lymph obtained after surgery was used in various immunologic and biochemical assays. daily lymph flow rate and total and differential wbc counts were determ ...	1991	1892266
age resistance in calves to ostertagia ostertagi and cooperia oncophora.	calves were infected repeatedly during a period of 6 weeks with ostertagia ostertagi and cooperia oncophora, at an age of 3, 6 or 9 months. the inoculations were performed during three periods, february-march, may-june and august-september, to account for possible seasonal effects or effects of larval batches. observations were done on faecal egg output, antibody titres and weight gains. calves were slaughtered for post mortem examinations 9 weeks after the start of infections. the influence of ...	1991	1897112
parasites of south african wildlife. ix. helminths of kudu, tragelaphus strepsiceros, in the eastern cape province.	the helminths of 25 kudu, tragelaphus strepsiceros, from 3 localities in the eastern cape province were collected, counted and identified. the majority of kudu harboured no worms, and the burdens of those infected were small. a race of cooperia rotundispiculum, a dictyocaulus sp., a haemonchus sp., nematodirus helvetianus and ostertagia ostertagi were recovered. two parasites, nematodirus helvetianus and ostertagia ostertagi can be added to the list of helminth parasites of kudu in south africa.	1991	1923383
protective immunity to a blood-feeding nematode (haemonchus contortus) induced by parasite gut antigens.	to determine the ability of gut antigens to induce a protective immune response against blood-feeding nematodes, isolated gut antigens were used to immunize goats against haemonchus contortus. immunization-induced antibody responses recognized parasite gut antigens which were associated predominantly with the microvillous membrane region of the parasite gut. antibody from immune serum also recognized seven predominant gut proteins on a western blot (immunoblot). several of these proteins appeare ...	1991	1937800
in vitro stress selection of nematophagous fungi for biocontrol of parasitic nematodes in ruminants.	laboratory experiments were designed to select nematophagous fungi that were able to survive in vitro conditions simulating passage through the gastro-intestinal tract of cattle. all of the tests were conducted at 39 degrees c. in a primary stress selection step in diluted rumen fluid, 21 isolates were obtained. each of the primary stress selected isolates was tested in synthetic saliva, rumen fluid simulating the activity in the rumen, rumen fluid followed by pepsin-hydrochloric acid treatment ...	1991	1940249
immune modulation by ostertagia ostertagi and the effects of diet.	igg1 antibody responses to ostertagia ostertagi third stage larvae (l3) and the third party antigen, keyhole limpet haemocyanin (klh), and faecal egg counts were determined in calves infected with a single dose of o. ostertagi and in uninfected, pair-fed calves. the infected and uninfected calves were given diets either high (h) or low (l) in protein and energy. the diets were within the normal range of husbandry practice in the uk. igg1 antibody responses to l3 antigen were significantly greate ...	1991	1957492
efficacy of ivermectin administered via sustained-release bolus against gastrointestinal nematodes in cattle.	twelve calves (mean weight, 175.5 kg) were used to confirm efficacy of ivermectin delivered from a prototype sustained-release bolus against naturally acquired gastrointestinal nematodes including early fourth-stage (inhibited) larvae of ostertagia ostertagi. the calves were allocated by restricted randomization on weight to 1 of 2 groups: controls, to which a placebo bolus was given orally, and treated calves, to which a sustained-release bolus designed to deliver 8 mg of ivermectin/day at a st ...	1991	2021255
gastrin and pepsinogen changes during an ostertagia ostertagi challenge infection in calves.	daily changes in serum gastrin and pepsinogen concentration have been studied during two types of infection with ostertagia ostertagi in calves. in a first experiment two calves were trickle infected (10 times 10,000 l3 ostertagia) and two animals received a single infection of 100,000 l3 ostertagia. gastrin and pepsinogen changes are discussed in relation to adult wormburdens. the second experiment involved 8 calves and was designed to investigate pepsinogen and gastrin changes following a chal ...	1991	2063640
the relationship between appetite and plasma non-esterified fatty acid levels in housed calves.	non-esterified fatty acid (nefa) levels in housed, 3-month-old calves were monitored in two experiments designed to establish (i) the effect of diet and time of sampling in relation to feeding on blood levels; and (ii) the relationship between appetite and plasma nefa in animals on chopped hay. in the first experiment, a significant drop in nefa levels was recorded after feeding. furthermore, the nefa levels of calves maintained on concentrate were significantly lower than those on hay throughou ...	1991	2068796
inoculation of conventionally and specific-pathogen-free reared rabbits with ostertagia ostertagi isolated from cattle.	eleven trials were conducted to collect helminthologic and pathologic data from 27 conventionally reared (cr) and 53 specific-pathogen-free (spf) 6- to 13-week-old male new zealand white rabbits. these rabbits were given 50,000 to 100,000 ensheathed third-stage infective ostertagia ostertagi larvae (l3) orally. the l3 had been isolated from the feces of cattle. fecal egg counts were conducted and worm populations were determined after euthanasia 3 to 56 days after inoculation. at necropsy, nodul ...	1992	1385683
anthelmintic activity of paraherquamide in calves.	paraherquamide, an oxindole alkaloid metabolite of penicillium paraherquei and penicillium charlesii, was tested against the adult stages of nine common gastrointestinal and lung nematodes of calves at single, oral dosages of 0.5, 1.0, 2.0 or 4.0 mg kg-1. at dosages 1.0-4.0 mg kg-1 there was 95% or more removal of haemonchus placei, ostertagia ostertagi, trichostrongylus axei, trichostrongylus colubriformis, cooperia oncophora, nematodirus helvetianus, oesophagostomum radiatum, and dictyocaulus ...	1992	1413457
efficacy of cydectin moxidectin 1% injectable against experimental infections of dictyocaulus viviparus and bunostomum phlebotomum superimposed on natural gastrointestinal infections in calves.	twenty male holstein calves averaging 105 kg in weight and naturally infected with gastrointestinal nematodes and small numbers of lungworm and hookworm, were given experimental infections with the two latter species to provide adult and larval stages for anthelmintic evaluation. following random allotment, one group of 10 calves was injected subcutaneously with moxidectin at a dosage of 0.2 mg kg-1 of body weight. a second group of 10 was injected subcutaneously with unmedicated blank vehicle a ...	1992	1413460
efficacy of moxidectin against gastrointestinal nematodes of cattle.	three groups of 11 naturally infected crossbred beef calves were injected subcutaneously with moxidectin 1 per cent injectable at 0.2 or 0.3 mg moxidectin/kg bodyweight or with the unmedicated vehicle. nematode infections had been acquired during grazing from december to april. based on the faecal egg counts and total worm counts of the control calves at necropsy (11 to 13 days after treatment) most of the calves had heavy parasitic burdens. ostertagia ostertagi was predominant and the mean numb ...	1992	1441146
efficacy of the morantel sustained release trilaminate bolus against gastrointestinal nematodes and its influence on immunity in calves.	an experiment was conducted in calves to investigate the efficacy of a morantel sustained release trilaminate bolus (msrt) to control gastrointestinal parasitism and to assess the development of immunity during the use of msrt. two groups (m and u) of four calves each were infected three times a week with a mixed ostertagia ostertagi and cooperia oncophora infection for 12 weeks. calves of group m received an msrt at the start of the experiment. twenty weeks after the start of the experiment, al ...	1992	1441195
antigenic differences between the life cycle stages of cooperia oncophora.	the antigenic differences among the life cycle stages of cooperia oncophora were studied by sds-gel electrophoresis and western blotting. sodium dodecylsulphate polyacrylamide gel electrophoresis of the different life cycle stages of c oncophora revealed a complex protein pattern with a decreasing number of protein bands towards the adult stages. several bands of the fourth stage larvae were in common with both the third stage and the adult nematode. western blotting with sera from c oncophora m ...	1992	1465515
seasonal patterns of total and ostertagia-specific ige in grazing cattle.	serum samples, collected monthly from january through december 1988 from 10 cows, their calves, and 10 yearling heifers, were used to determine total and ostertagia-specific ige levels. in addition, serum pepsinogen concentration, fecal egg counts, and body weights were measured. the following observations were made. (1) total and ostertagia-specific ige levels followed similar seasonal patterns, being generally highest in the spring. (2) breed and/or sire effects on total ige levels were observ ...	1992	1466130
attempts to immunize cattle against ostertagia ostertagi infections employing 'normal' and 'chilled' (hypobiosis-prone) third stage larvae.	immunity to ostertagia ostertagi infections in calves develops slowly and only becomes manifest towards the end of a grazing season in which they have been exposed to the parasite. in an attempt to hasten the onset of immune reactions, three immunization protocols were set up. twenty four heifers were allocated into four groups. beginning in january, animals in two of the groups were inoculated with four 1-monthly increasing dosages of either 'normal' or 'chilled' (hypobiosis-prone) larvae, thos ...	1992	1466132
effects of clinically apparent and subclinical ostertagia ostertagi infections on nitrogen and water metabolism in calves.	four balance trials were conducted in 3 groups of 5 calves each at 0, 4, 8, and 14 weeks after initial inoculation with ostertagia ostertagi. group-1 calves were inoculated with 100,000 third-stage larvae (l3) of o ostertagi/wk for 14 weeks. group-2 calves were inoculated with 10,000 l3/wk for 14 weeks, and group-3 calves were not inoculated. effects of infection on apparent digestibilities of dry matter and nitrogen, and balances of nitrogen and water were evaluated. neither clinically apparent ...	1992	1466493
nutritional and pathophysiologic effects of clinically apparent and subclinical infections of ostertagia ostertagi in calves.	nutritional and physiologic effects of clinically apparent and subclinical ostertagia ostertagi infections were studied in 3 groups of 5 calves each. group-1 calves were inoculated with 100,000 ostertagia ostertagi third-stage larvae (l3)/calf/wk for 14 weeks. group-2 calves were inoculated with 10,000 l3/calf/wk for 14 weeks, and group-3 calves were no inoculated. calves in group 1 had decreased dry matter intake and feed utilization from 4 weeks after initial inoculation. group-2 calves had no ...	1992	1466494
effects of ostertagia ostertagi infection on secretion of metabolic hormones in calves.	effects of ostertagia ostertagi infection on secretion of insulin, pancreatic glucagon, cortisol, gastrin, and pepsinogen were studied in calves inoculated with 100,000 (group 1) or 10,000 (group 2) o ostertagi infective larvae weekly for 14 weeks. plasma insulin concentrations in both inoculated groups were lower than those in a non-infected (group 3) control group. the differences between group 1 and group 3 were significant (p < 0.05) at 2 and 12 weeks after initial inoculation. plasma pancre ...	1992	1466495
isolation of putative cysteine protease genes of ostertagia ostertagi.	recombinant phage containing putative ostertagia ostertagi cysteine protease genes have been isolated from a lambda embl-3:genomic dna library using a haemonchus contortus cathepsin b-like cysteine protease cdna as hybridization probe. restriction enzyme maps of the phages suggest that they identify at least 3 genes, 2 of which appear to be linked in tandem. the complete nucleotide sequence of one gene, cp-1, was determined. the cp-1 gene appears to be organized into 12 exons than span 4.5 kb of ...	1992	1475000
development of immunity to ostertagia ostertagi (trichostrongylidae: nematoda) in pastured young cattle.	this experiment comprised 3 groups of calves, (+p2), (-p2) and (-p1), which all started their first grazing season as parasite-free calves. the (+p2)- and (-p2)-group grazed 2 seasons. in the first season the (-p2)-group of calves was grazing a pasture with no detectable trichostrongyles and treated with anthelmintics every second week. the untreated (+p2)-group grazed an ostertagia ostertagi contaminated pasture. during the second grazing season these 2 original groups grazed together with a ne ...	1992	1488946
efficacy of moxidectin against naturally acquired nematode infections in cattle.	the efficacy of moxidectin, a new endectocide against natural nematode infections, was evaluated. twenty-five calves were divided into two groups of eight calves each and a third group of nine calves. moxidectin was administered s.c. to two groups (i, 0.2 mg kg-1 body weight (bw); ii, 0.3 mg kg-1 bw) and the third group (iii) received the vehicle (placebo) s.c. two pre-treatment and one post-treatment faecal nematode egg count determinations were made from all calves, and they were necropsied 2 ...	1992	1502785
modulation of calf immune responses by ostertagia ostertagi: the effect of diet during trickle infection.	the effects of ostertagia ostertagi infection and diet on antibody responses to o. ostertagi third stage larval (l3) antigen and to an unrelated antigen, keyhole limpet haemocyanin (klh) were determined in calves experimentally infected with 3000 l3 on alternate days for 6 weeks. calves were given one of two diets, and were either infected or not infected with o. ostertagi l3. the diets were either high (h) or low (l) in protein/energy and were within the range of normal husbandry practice in th ...	1992	1514241
efficacy of ivermectin delivered from a sustained-release bolus against inhibited early fourth-stage larvae of ostertagia ostertagi and other nematodes in cattle.	the anthelmintic efficacy of ivermectin (ivm) delivered from a sustained-release (sr) bolus was evaluated against natural infections with gastrointestinal tract nematodes in 12 crossbred beef heifers in spring. the 12 calves were randomly allotted to 2 groups of 6 calves each. group-1 calves were treated with an sr bolus designed to deliver 8 mg of ivermectin/d. group-2 calves were nontreated controls. cattle groups were kept in separate concrete-floored pens (grass hay nutrition) and slaughter ...	1992	1524310
efficacy of abamectin against natural infections of gastrointestinal nematodes and lungworm of cattle with special emphasis on inhibited, early fourth stage larvae of ostertagia ostertagi.	the anthelmintic efficacy of abamectin (avermectin b1) was evaluated against gastrointestinal nematodes, including ostertagia ostertagi inhibited larvae and lungworm, in yearling crossbred beef heifers during late spring. the calves were grazed on contaminated pasture for 10 weeks and then held under conditions free of nematode infection for 3 weeks prior to allotment and treatment on 5 june. thirteen calves were randomly assigned to two groups of six by restricted randomization on body weights; ...	1992	1532875
establishment and pathogenicity of two strains of ostertagia ostertagi and cooperia oncophora in calves in different locations.	an experiment was carried out simultaneously in glasgow and in wageningen to investigate possible differences between the local strains of ostertagia ostertagi and cooperia oncophora. in each location calves of the local friesian breed were infected with 100,000 larvae of either the glasgow or wageningen strain of o ostertagi or c oncophora. at both locations the calves received the same diet. the glasgow strain of o ostertagi was more pathogenic than the wageningen strain and a larger proportio ...	1992	1553434
a natural infection of sheep with ostertagia ostertagi.		1992	1554339
suitability of mitochondrial dna for assaying interindividual genetic variation in small helminths.	the current paucity of data on the genetic structure of parasitic helminth populations results partly from the lack of a suitable molecular technique for assigning genotypes to small individuals. this report describes the cloning of the mitochondrial dna (mtdna) from a small parasitic nematode, ostertagia ostertagi, and the potential use of this cloned mtdna as a hybridization probe to detect genetic variation among individuals. by using cloned, homologous mtdna, labeled to high specific activit ...	1992	1556654
studies on an ostertagia ostertagi strain suspected to be resistant to benzimidazoles.	four calves were infected with a susceptible (laboratory) strain of ostertagia ostertagi and four with a field strain suspected to be resistant to benzimidazoles. after 25 days two calves from each group were treated with 3.5 mg kg-1 fenbendazole. egg output fell to zero in all treated calves. treated calves did not harbour worms at slaughter 35 days after infection. significant differences between the strains were shown for ed50 values for thiabendazole in the egg hatch assay, but not in the tu ...	1992	1561765
interbreeding in the subfamily ostertagiinae (nematoda: trichostrongylidae) of ruminants.	the interbreeding of 6 species of ostertagiines was studied in a sheep model. virgin young females of selected nonpolymorphic strains of ostertagia ostertagi, ostertagia leptospicularis, and teladorsagia circumcincta were mated with various male ostertagiines. interbreeding was successful between o. ostertagi and ostertagia lyrata, o. leptospicularis and ostertagia kolchida, and t. circumcincta and teladorsagia trifurcata, respectively. their offspring were fertile and resembled one parent or th ...	1992	1597780
in vivo passage through calves of nematophagous fungi selected for biocontrol of parasitic nematodes.	the experiment was designed to test the survival and performance of stress selected nematophagous fungi after passage through the gastro-intestinal tract of cattle. ruminating calves were fed daily with a fixed amount of fungal material grown on barley grains. the excreted dung was collected on days four and five after the start of the feeding experiment. barley grains were washed out of the excreted dung and incoculated on water-agar plates. after incubation for one week, nine of ten fungal iso ...	1992	1640088
persistent anthelmintic activity of abamectin injection in cattle.	the duration of the anthelmintic activity of abamectin administered by subcutaneous injection at 200 microg/kg was determined using induced infections of haemonchus placei, ostertagia ostertagi, cooperia spp., and oesophagostomum radiatum in cattle. twenty-four friesian calves, raised under worm-free conditions, were assigned to four groups of six animals using a randomised block design based on bodyweight. one group acted as untreated controls and the other three were treated with abamectin 14, ...	1992	16031652
unusual population genetics of a parasitic nematode: mtdna variation within and among populations.	very little is known about the distribution of genetic variance within and among populations of parasitic helminths. in this study we used mitochondrial dna (mtdna) restriction fragment analysis to describe the population genetic structure of ostertagia ostertagi, a nematode parasite of cattle, in the united states. estimates of within-population mtdna diversity are 5 to 10 times greater than typical estimates reported for species in other taxa. although populations are genetically differentiate ...	1992	28564029
migration, selection and population size in ostertagia ostertagi.		1993	15463699
migration, selection and population size in ostertagia ostertagi: reply.		1993	15463705
immunoglobulin e and type i hypersensitivity in bovine ostertagiosis.	a series of experiments were performed to determine whether immunoglobulin e (ige) and type i hypersensitivity reactions might be involved in the immune response of cattle to infection with ostertagia ostertagi. the following observations were made. (1) when calves were lightly infected, serum ige levels paralleled worm burdens. however, in heavy infections, both serum and lymph ige levels were inversely related to burdens of o. ostertagi. (2) increases in mediators, especially histamine and leu ...	1993	7683445
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