| 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 |
| 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 |
| 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 |
| 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 |
| dermal responses to ostertagia ostertagi in ostertagia ostertagi- and cooperia punctata-inoculated calves. | calves harboring patent ostertagia ostertagi or cooperia punctata were given intradermal injections of o ostertagi 3rd-stage larval antigen. the initial injections were followed 30 days later by a 2nd series of injections. skin thickness was measured at injection sites for 72 hours after injection. selected injection sites including saline solution control sites were biopsied at 30 minutes, at 3, 24, 48, and 72 hours, and at 30 days after injection. after the 1st series of injections, there was ... | 1985 | 2409852 |
| acute phase response in calves following infection with pasteurella haemolytica, ostertagia ostertagi and endotoxin administration. | the concentrations of bovine acute phase proteins were monitored in plasma following experimental infection with pasteurella haemolytica and ostertagia ostertagi and after endotoxin administration. raised levels of haptoglobin, alpha 1 proteinase inhibitor and seromucoid were detected after pasteurella infection and endotoxin administration. ceruloplasmin levels increased after endotoxin administration but not during pasteurella infection. raised levels of the four acute phase proteins were foun ... | 1989 | 2477881 |
| epidemiology of ostertagia ostertagi in dairy cow from different breeding systems. | the epidemiology of trichostrongylidae infections in three dairy cow groups reared under different conditions and in different habitats was studied with particular emphasis on ostertagia ostertagi. in cows bred intensively in swampy lowlands (po river valley) the prevalence of infection was 43% and the mean intensity 567. in cows bred traditionally (friuli, northern-eastern italy), the prevalence in permanently housed cows was 24% (mean intensity: 13). in grazing cows, it was 68% (mean intensity ... | 1989 | 2486992 |
| 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 |
| the residual effect of treatment with ivermectin after experimental reinfection with nematodes in calves. | the residual effect of treatment with ivermectin after experimental reinfection in calves was tested. twenty-four calves were divided into 6 groups of 4 calves each. all calves received a primary infection of 50,000 larvae of both ostertagia ostertagi and cooperia oncophora and 1000 dictyocaulus viviparus larvae. calves of group 1 remained untreated, and all other calves were treated 21 days after primary infection (0.2 mg/kg injected subcutaneously). calves of groups 1 and 2 were slaughtered 7 ... | 1986 | 2941914 |
| interactions between chemoprophylaxis and immunity to bovine parasitic gastroenteritis and bronchitis: pilot studies using an oxfendazole pulse release bolus. | in separate experiments, the immune status of six matched pairs of yearling heifers from a field trial in which both parasitic gastroenteritis and husk had occurred in control animals, was tested with a single massive challenge of either dictyocaulus viviparus or ostertagia ostertagi. the clinical responses of untreated controls and animals that had carried an oxfendazole pulse release intraruminal device (oprb) were in all cases similar (with the exception of one lung-worm-challenged control th ... | 1987 | 2961034 |
| interactions between lungworms and gastrointestinal worms in calves. | interactions between gastrointestinal worms (ostertagia ostertagi, cooperia oncophora) and lungworms (dictyocaulus viviparus) in calves were studied by assessing the effect of primary infections with either group of worms on the development of homologous or heterologous challenge infections. primary infections with lungworms resulted in some degree of resistance to challenge with gastrointestinal worms, but this resistance was lower than that found after homologous infection. primary infections ... | 1988 | 2964752 |
| efficacy of febantel against abomasal nematodes and lungworms in cattle. | the efficacy of febantel at a dosage of 5 mg/kg (45.5% paste formulation) against inhibited early 4th-stage larvae (el4) of ostertagia ostertagi, other nematodes of the abomasum, and dictyocaulus viviparus was investigated in 4- to 6-month-old holstein calves that grazed on pasture heavily contaminated with parasites from february 24 to april 1, 1986 (36 days). in louisiana, this is the first month of a 3-month period in which increasing numbers of inhibition-prone o ostertagi larvae are acquire ... | 1988 | 2977070 |
| preparation and evaluation of the specificity of parafilaria bovicola antigen for detection of specific antibodies by elisa. | an enzyme-linked immunosorbent assay (elisa) for the detection of antibodies in bovine sera against parafilaria bovicola nematodes was developed and its sensitivity was compared with the immunodiffusion (id) method. an exoantigen of p. bovicola which was shown to contain four major polypeptides was used in these procedures. the serological reactivity of the antigen polypeptides was defined by using the enzyme-linked immunoelectrotransfer blot technique (eitb) and whole-worm extract proteins. it ... | 1988 | 3133870 |
| persistent anthelmintic activity of ivermectin in cattle. | two studies are described which demonstrate the persistent activity of ivermectin injected subcutaneously into cattle at 200 micrograms/kg in preventing the establishment of induced infections with the gastrointestinal parasites ostertagia ostertagi and cooperia oncophora and the lungworm dictyocaulus viviparus. these results indicated a reduction in mean worm count compared with the control group for o ostertagi of more than 99, 45 and 94 per cent with a seven, 14 or 21 day interval between tre ... | 1985 | 3157261 |
| prophylactic efficacy of an ivermectin sustained-release bolus against challenge exposure with gastrointestinal and pulmonary nematode infective larvae in calves. | twelve holstein calves were used to determine the prophylactic efficacy of ivermectin against challenge exposure with gastrointestinal and pulmonary nematodes. two groups of 6 calves (mean body weight, 205 kg) each were formed by restricted randomization according to body weight. group-1 calves served as nonmedicated controls. each calf of group 2 was orally given one prototype sustained-release bolus designed to deliver ivermectin at a continuous daily dose of 8 mg. third-stage nematode infecti ... | 1988 | 3189987 |
| blood gastrin and pepsinogen responses to subclinical infection with ostertagia ostertagi in adult dairy cattle. | blood gastrin and pepsinogen responses to a single infection with 100,000 ostertagia ostertagi infective larvae in lactating dairy cows were investigated. none of the infected cows showed signs of clinical ostertagiasis, nor was there any difference in live weight gain, milk yield or faecal egg count between groups. pepsinogen levels of the infected group were significantly elevated between days 3 and 24 after infection (peak 1041 mu tyrosine; day 14). in contrast, there was no significant diffe ... | 1988 | 3222546 |
| effect of strategic anthelmintic treatment and pasture management on productivity and control of nematode parasites in weaner-yearling beef cattle. | three groups of 17 beef calves were used to evaluate effects of strategic anthelmintic treatment on safe (group 1) and contaminated (group 2) pasture in comparison with minimal treatment at weaning and contaminated pasture (group 3). the investigation extended from weaning in november 1982 to the following august. results of faecal egg counts, herbage larval counts, plasma pepsinogen and tracer calf worm counts in autumn and spring indicated minimal levels of infection on safe pastures provided ... | 1988 | 3222550 |
| the capability of the predacious fungus arthrobotrys oligospora (hyphomycetales) to reduce numbers of infective larvae of ostertagia ostertagi (trichostrongylidae) in cow pats and herbage during the grazing season in denmark. | artificially prepared cow pats containing ostertagia ostertagi eggs were deposited on two pasture plots in may, june and july 1986. half of the cow pats, placed on one plot, were inoculated with 2000 conidia per gram faeces of the predacious fungus arthrobotrys oligospora. on the other plot fungus-free control cow pats were placed at the same time. in the faeces generally fewer infective o. ostertagi larvae developed in the inoculated than in the control cow pats. on the herbage around the contr ... | 1988 | 3235796 |
| high concentration of serum gastrin immunoreactivity and abomasal mucosal hyperplasia in calves infected with ostertagia ostertagi and/or trichostrongylus axei. | parasite-free, 4-month-old-calves were inoculated with ostertagia ostertagi and/or trichostrongylus axei, followed 6 weeks later by inoculation with increasing doses of o ostertagi for 8 weeks in the 2 groups (n = 4) of calves that had been given o ostertagi. gastrin immunoreactivity concentration in serum was measured before and after infection and was correlated with changes in mucosal thickness. gastrin immunoreactivity concentration in preinoculation control sera ranged from 95.2 to 287.1 pg ... | 1988 | 3239847 |
| aspects of the biology of ostertagia ostertagi in relation to the genesis of ostertagiasis. | adaptations such as the capacity of free-living stages to survive environmental stress, inhibition and density-dependent effects on population size and fecundity show o. ostertagi to be a consummate parasite of cattle in temperate environments. knowledge of these adaptations, within an animal management context, provides the key to understanding the occurrence of disease and a basis for control of parasite numbers. substantial infections do arise from low egg contamination rates of pastures. dis ... | 1988 | 3284162 |
| immunity to ostertagia ostertagi. | control of ostertagiasis is a major economic problem in the temperate areas of the world. an immunological control scheme for cattle is an important aspect of integrated control and its achievement is dependent on our understanding of how immunity is acquired. also, host mechanisms regulated by ostertagia need to be understood in order to address immunological questions. little is known about acquired immunity to ostertagia infection in cattle. the degree of immunity is incomplete and its develo ... | 1988 | 3284164 |
| epidemiology of ostertagia ostertagi in warm temperate regions of the united states. | for many years our general knowledge on the epidemiology of ostertagia ostertagi in the u.s.a. was based on research conducted in scotland and england. during the last 10 years, epidemiologic investigations on o. ostertagi and other gastrointestinal nematodes of cattle have been conducted in various sections of the u.s.a. and canada. definite seasonal patterns of o. ostertagi larval inhibition have been demonstrated, but occurrences of the type i and type ii clinical entities have not been adequ ... | 1988 | 3284165 |
| the epidemiology of bovine ostertagiasis in the north temperate regions of north america. | ostertagia ostertagi is widely distributed and is the most pathogenic of the parasitic nematodes affecting cattle in this region. clinical ostertagiasis is seen mainly in calves and yearlings but outbreaks tend to be sporadic; the subclinical disease is of greater importance. studies on the population dynamics of the free-living stages have shown that infective larvae can survive on pasture over the relatively severe winter conditions encountered in this region but that such pasture contaminatio ... | 1988 | 3284167 |
| control of ostertagia ostertagi infections in australia. | the control of ostertagia ostertagi infections in australia is aimed specifically at young cattle in their first and second year of grazing after weaning. mature breeding stock are not routinely treated. the recommended strategy is preventive, using an integrated approach of timed anthelmintic treatments in relation to the epidemiology of ostertagiasis in different environments. best results are obtained when treatments, given at weaning and 6 months later, are combined with a move to 'safe' pas ... | 1988 | 3284168 |
| epidemiology and control of bovine ostertagiasis in south america. | gastrointestinal parasitism has been recognized by practitioners as the most common disease in beef cattle, mainly in weaning calves and fattening steers. among the different genera, ostertagia ostertagi is the predominant parasite in the temperate climate, in which the major beef and dairy cattle area of south america is situated. outbreaks of type i ostertagiasis are usually seen after weaning time (autumn-winter) when larvae counts are high and food availability is low. the development of the ... | 1988 | 3284169 |
| mathematical models of the population biology of ostertagia ostertagi and teladorsagia circumcincta, and the economic evaluation of disease control strategies. | the construction and use of mathematical models of the population biology of ostertagia ostertagi and teladorsagia circumcincta is discussed. simulated field trials implemented by deterministic mathematical models currently share with actual field trials the disadvantage that they convey no information concerning the risk associated with the net return demonstrated by the trial. this has important implications when it is necessary to rank disease control strategies in order of usefulness. | 1988 | 3284170 |
| anthelmintics and control. | anthelmintic control of ostertagia ostertagi in cattle presents some special problems because the arrested larval stage (hypobiotic el4) tolerates all of the older anthelmintics. the only anthelmintics on the north american market that are effective against this stage as well as the adult and developing stages are ivermectin and fenbendazole. in addition to these, the newer broad-spectrum benzimidazoles and probenzimidazoles, albendazole, febantel, netobimin and oxfendazole, are effective and av ... | 1988 | 3284172 |
| endocrine effects of a single infection with ostertagia ostertagi in the calf. | | 1987 | 3308726 |
| interactions between the predacious fungus arthrobotrys oligospora and third-stage larvae of a series of animal-parasitic nematodes. | interactions between the predacious hyphomycete arthrobotrys oligospora and third-stage larvae of nine animal-parasitic nematodes were tested in vitro. the trap-inducing capabilities of the ruminant trichostrongylus cooperia oncophora, c. curticei, haemonchus contortus and ostertagia ostertagi and of equine cyathostomes were almost comparable to those of free-living soil nematodes, and significantly higher than those of the porcine oesophagostomum dentatum and oe. quadrispinulatum and of the mur ... | 1988 | 3347992 |
| larvicidal properties against ostertagia ostertagi of the faeces of calves treated with a sustained release formulation of morantel tartrate. | an experiment was carried out to assess the effect of morantel tartrate in the faeces of calves treated with a bolus on the survival and development of ostertagia ostertagi eggs. since the drug delivered from the bolus greatly reduces the nematode population in an infected animal and thus the number of eggs excreted it was necessary to mix o ostertagi eggs into the faeces of calves to which boluses had been administered. in three preliminary experiments it was shown that the methods used to extr ... | 1988 | 3354163 |
| prophylactic efficacy of sustained-release ivermectin against induced nematode infestations in cattle. | the efficacy of sustained-release ivermectin was evaluated against challenge infestations of gastro-intestinal nematodes in a laboratory study involving 12 treated and 12 untreated control cattle. a weighted, orally administered osmotically activated device designed to lodge in the rumeno-reticulum and to deliver ivermectin at a dosage rate of approximately 8 mg/day for a 120-day period, was administered to treated cattle. animals were challenged with infective larvae of bunostomum phlebotomum a ... | 1988 | 3361567 |
| immunity of ivermectin treated cattle to challenge from helminth parasites in the following season. | two groups of yearling cattle which had been treated with ivermectin either three and eight, or three, eight and 13 weeks after turn out to trichostrongyle contaminated pasture in their first grazing season were exposed in the following season to natural challenge with helminth parasites. to assess their immunity to this challenge each group shared a pasture with parasite naive first season calves. no anthelmintic treatments were administered at any time during the year. throughout the grazing p ... | 1988 | 3363811 |
| preliminary report: immunodiagnosis of pre-type ii ostertagiasis. | ostertagia ostertagi soluble antigens were prepared by gel electrophoresis and electrophoretic transfer onto nitrocellulose for enzyme-linked immunosorbent assays with serum probes. serologic responses to l3-derived antigen of approximately 32 kda may be unique and diagnostic for cattle harboring inhibited larvae, or pre-type ii ostertagiasis. specificity was evaluated by comparing sera from pre-type ii cattle to sera from type i, uninfected, fascioloides magna infected, fasciola hepatica infect ... | 1988 | 3363842 |
| sequential histopathologic changes of type i, pre-type ii and type ii ostertagiasis in cattle. | yearling cattle in louisiana were examined at monthly intervals for abomasal nematode burdens and histological lesions over a year. tracer calves were grazed for 3 to 4 weeks and removed from pasture for 2 to 3 weeks, then slaughtered; a few animals were killed in extremis shortly after removal from pasture. histological changes were correlated with worm burdens and characterized according to the type of ostertagia ostertagi infection present. in cattle with acute type i ostertagiasis, changes v ... | 1988 | 3363843 |
| experimental infections of ostertagia ostertagi in goats. | in order to determine the usefulness of the goat as a model host for ostertagia ostertagi, a series of experiments was conducted in which young goats and calves were experimentally infected with l3 of calf-source and goat-source isolates. the goat-source isolate was derived from a continuous passage of the bovine parasite in goats. patent infections resulted in 73 out of 86 inoculated goats (85%). the largest number of patent infections was observed when inoculation consisted of a single dose of ... | 1988 | 3363845 |
| grazing pressure and acquisition of ostertagia ostertagi in calves. | the effect of stocking rate on the acquisition of ostertagia ostertagi infection and performance of yearling calves grazing a marshland area in the southwest of jutland (denmark) was examined. during the early part of the grazing season, when grass growth was high and pasture infectivity low, there was little stocking rate effect on performance. however, during the late part of the grazing season (characterized by poorer grass growth and high pasture infectivity) gains were significantly lower a ... | 1988 | 3369080 |
| additional investigations on hypobiosis of ostertagia ostertagi after transfer between northern and southern u.s.a. | | 1988 | 3372123 |
| forms of bovine pepsinogen in plasma from cattle with three different 'syndromes' of ostertagia ostertagi infection. | calves infected orally with third stage larvae of ostertagia ostertagi or infected with adult o ostertagi by direct transplantation into the abomasum had raised plasma pepsinogen activity, as did four-year-old dairy cattle challenged with o ostertagi third stage larvae on five occasions. using fast protein liquid chromatography two forms of pepsinogen; pepsinogen 1 (pg1) and pepsinogen 2 (pg2) were identified in each of the parasitic infection regimes. | 1988 | 3375583 |
| seasonal prevalence of gastrointestinal nematodes of beef calves grazed on irrigated pastures in the lower sacramento valley of california. | two worm-free calves were allowed to graze on irrigated pasture with a naturally infected herd for each of 34 one-month periods from november 1979 to august 1982. after each grazing period, the calves were transferred to a cement-floored pen for 3 weeks and then were euthanatized and necropsied. ostertagia ostertagi and cooperia oncophora were the most prevalent species of nematodes recovered. adults and larvae of ostertagia spp and cooperia spp were most numerous in winter and spring and least ... | 1988 | 3377319 |
| the difference between two strains of ostertagia ostertagi in resistance to morantel tartrate. | | 1988 | 3417377 |
| effect of diet on gastrin response to ostertagia ostertagi infection in the calf. | | 1988 | 3417383 |
| efficacy of oxfendazole against inhibited larvae of ostertagia ostertagi acquired by calves in the spring. | during the spring of 1985, 40 calves grazed pastures known to have high numbers of spring inhibition-prone, infective ostertagia ostertagi larvae. calves were removed from pasture and placed in outdoor pens with concrete floors from 10 days prior to treatment until necropsy 14 days after treatment. ten calves were allocated to each of 4 treatment groups, and oxfendazole was administered to each group by intraruminal injection at dosages of 0, 2.25, 4.5, and 6.75 mg/kg of body weight. efficacies ... | 1988 | 3421523 |
| anthelmintic efficacy of netobimin against naturally acquired gastrointestinal nematodes in yearling heifers. | the efficacy of netobimin (coded sch 32481, schering corporation) in removing naturally acquired gastrointestinal nematode infections was evaluated in 10 treated and 10 untreated (control) yearling beef heifers. the anthelmintic was administered as an oral drench at a dose level of 7.5 mg kg-1 body weight. fecal egg per gram (epg) counts were reduced with netobimin by 98% (p less than or equal to 0.01) at both 1 and 2 weeks post-treatment (pt). the compound was highly effective in removing oesop ... | 1987 | 3439007 |
| multiple forms of bovine pepsinogen: isolation and identification in serum from calves with ostertagiasis. | by using fast protein liquid chromatography (fplc) a new form of bovine pepsinogen has been identified. compared with the previously isolated pepsinogen (pg i) the new pepsinogen (pg ii) is less mobile on agarose electrophoresis, is eluted earlier from an anion-exchange column and is 30 times less abundant. agarose electrophoresis identified pg i in the serum of calves given third stage ostertagia ostertagi larvae, while fplc identified both pg i and pg ii in such serum. | 1987 | 3444973 |
| a field experiment on rain splash dispersal of infective larvae of ostertagia ostertagi (trichostrongylidae) from cow pats to surrounding grass. | | 1987 | 3454559 |
| limiting dilution analyses for the quantification of cellular immune responses in bovine ostertagiasis. | a sensitive limiting dilution analysis (lda) was used to quantitate the local and systemic cellular immune response of cattle after immunization with keyhole limpet hemocyanin (klh) and infection with ostertagia ostertagi. the assay measures the proliferative response of bovine t-cells after in vitro stimulation with antigen. interleukin 2 activity was supplied by supernates from mitogen-stimulated bovine peripheral blood lymphocytes (pbl) and accessory cell function was in the form of irradiate ... | 1986 | 3486522 |
| abomasal parasitism in dairy cows in belgium. | over a period of one year, from march 1984 to april 1985, the abomasa of 157 dairy cows in east flanders (belgium) were collected and examined for the presence of nematodes. faeces and blood were also collected from the animals. no worms were recovered from 18 cows (11.5%), 118 cows (75%) had a low to moderate worm burden (10-10,000) and 21 cows (13.5%) a high worm burden (greater than 10,000). the geometric mean total number was 2171. ostertagia ostertagi and trichostrongylus axei were the main ... | 1986 | 3564332 |
| infection with ostertagia ostertagi in goats and calves. | in order to determine the usefulness of the goat as a model host for ostertagia ostertagi, a series of experiments was conducted in which young goats and calves were experimentally infected with l3 of calf-source and goat-source isolates. the goat-source isolate was derived from a continuous passage of the bovine parasite in goats. patent infections resulted in 73 out of 86 inoculated goats (85%). the largest number of patent infections was observed when inoculation consisted of a single dose of ... | 1987 | 3564343 |
| suspected resistance of ostertagia ostertagi in cattle to levamisole. | observations on a beef cattle farm in flanders led to the suspicion of resistance to levamisole in a strain of ostertagia ostertagi. after treating a group of six animals with levamisole (5 mg kg-1 l.w., i.m.) the reduction in the number of trichostrongylid eggs per gram of faeces varied between 0 and 66.6%, whereas a similar group treated with fenbendazole (7.5 mg kg-1 l.w., p.o.) showed a reduction in worm burdens of 100%. coproculture showed that the remaining eggs in the first treatment grou ... | 1987 | 3564345 |
| efficacy of morantel sustained release bolus against gastrointestinal nematodes in first season grazing holstein calves. | the efficacy of the morantel sustained release bolus (msrb) in reducing gastrointestinal parasitism in first season grazing calves was evaluated during the summer--autumn grazing seasons of 1982 and 1983 in western oregon. each of 38 calves (1982) and 40 calves (1983) were randomly assigned to either control or treatment groups which were given msrb on the day of turnout onto pasture. mean worm burdens from tracer calves grazed with treated animals in 1982 and 1983 showed overall reductions of 8 ... | 1987 | 3564351 |
| monthly and seasonal fluctuations in abomasal nematode worm burden of naturally infected cattle in austria. | from october 1980 until september 1981, 191 abomasa of naturally infected cattle were obtained from the slaughter-houses of mürzhofen and graz in the province of styria, and of wiener neustadt in the province of lower austria and examined to study the monthly and seasonal occurrence of hypobiosis in ostertagia ostertagi and trichostrongylus axei. infections in pastured animals (cows, steers and heifers) were compared with those in stabled animals (bulls fed on green forage and silage). except fo ... | 1987 | 3564352 |
| dermal cellular responses of helminth-free and ostertagia ostertagi-infected calves to intradermal injections of soluble extracts from o. ostertagi l3 larvae. | twelve calves were raised helminth-free until 9 weeks of age when six were orally inoculated with 100,000 ostertagia ostertagi infective stage larvae (l3). three uninfected and three experimentally infected calves received intradermal injections of sterile saline and soluble larval extract (sle) from o. ostertagi l3 with a protein concentration ranging from 1 to 200 micrograms ml-1. biopsies were performed 48 h post-injection. a kinetic study was performed on the remaining six calves, three infe ... | 1987 | 3564354 |