| 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 |
| 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 |
| 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 |
| the effect of experimental ostertagia ostertagi infections in stabled milking cows on egg output, serum pepsinogen levels, antibody titres and milk production. | two trials with stabled milking cows were carried out. in the first trial, cows were either experimentally infected with ostertagia ostertagi larvae or served as naturally-infected controls. in the second trial, cows were treated the same as in the first trial, but in addition half of the number of cows of each group were treated with oxfendazole before the trial started. the results showed that experimental infection influenced ostertagia egg output, host serum pepsinogen levels and anti-ostert ... | 1985 | 4002600 |
| effects of season and physical condition on the gastrointestinal helminth community of white-tailed deer from the texas edwards plateau. | eighty-six adult female white-tailed deer, odocoileus virginianus (zimmermann), collected over a 12-mo period in the texas edwards plateau, harbored six species of nematodes (haemonchus contortus, gongylonema pulchrum, oesophagostomum venulosum, ostertagia ostertagi, cooperia sp., and apteragia odocoilei), and two cestodes (moniezia sp. and taenia hydatigena). the patterns of distribution of the three common species of gastrointestinal helminths (h. contortus, o. venulosum, and g. pulchrum) were ... | 1985 | 4032624 |
| trichostrongyle larval populations on herbage from grazed and ungrazed cattle pastures in south west scotland. | in the course of studies on the control of bovine parasitic gastroenteritis in south west scotland using a morantel sustained release bolus the populations of trichostrongyle infective larvae on herbage were monitored over a two-year period. from the results of the herbage analysis and the worm burdens in parasite naive tracer calves introduced at the end of 18 months, it was clear that considerable numbers of infective larvae of ostertagia ostertagi and cooperia oncophora survived for at least ... | 1985 | 4035086 |
| 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 |
| experimentally induced ostertagiosis in rabbits inoculated with ostertagia ostertagi of bovine origin. | weanling specific-pathogen-free rabbits were orally inoculated with 50,000 ostertagia ostertagi 3rd-stage infective larvae cultured from bovine feces and were killed 42 days after inoculation. two preliminary trials were done, using conventionally reared weanling rabbits inoculated with 2,500, 5,000, and 50,000 o ostertagi 3rd-stage larvae and dexamathasone in 1 of the trials; the rabbits were killed 14 and 28 days after inoculation. fecal egg counts were monitored, and worm burdens were determi ... | 1985 | 4062028 |
| chemotactic factors for eosinophils in soluble extracts of l3 stages of ostertagia ostertagi. | | 1985 | 4066145 |
| 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 |
| serological studies of parasitized cattle. i. complement--fixing activity of serial serum samples. | complement-fixation (cf) tests with sonicated aqueous extracts of adult forms of five species of gastrointestinal nematodes as antigens have been made on serial biweekly bleedings from two groups of parasitized calves grazing on infected pastures during the 1963 or 1964 seasons. three of these nematode species, cooperia oncophora, ostertagia ostertagi and nematodirus helvetianus, were found in large numbers in most of these animals. the calves were negative serologically before being placed on p ... | 1966 | 4226342 |
| the effects of age and previous infection on the development of gastrointestinal parasitism in cattle. | an age resistance in cattle to establishment of infection with cooperia oncophora was not demonstrated. cattle exposed to a heavy infection for the first time at approximately 15 months of age were as susceptible to establishment of infection as 3 to 4 month old calves, but stunting of worms and inhibition of ovulation did occur in the older animals, possibly due to a rapid development of resistance as a result of sensitization by a previous extremely light infection. an age resistance in cattle ... | 1968 | 4234780 |
| on the survival of overwintering bovine gastrointestinal nematode larvae during the subsequent grazing season. | large numbers of overwintering nematodirus helvetianus were shown to survive on maritime marshland pastures throughout the ensuing grazing season, while the numbers of ostertagia ostertagi and cooperia oncophora declined rapidly after the first few weeks. it was concluded that pastures carrying heavy overwintering residual infections, particularly of n. helvetianus, may be unsafe for susceptible cattle at any time during the following grazing season. | 1969 | 4237295 |
| the epidemiology of ostertagia ostertagi and other gastrointestinal nematodes of cattle in louisiana. | the epidemiology of ostertagia ostertagi and other gastrointestinal nematodes in yearling beef cattle was examined in each of 2 successive years. during each year 50 head of newly weaned beef calves were given a single dose of thiabendazole and then placed on experimental pastures. twenty-four of the animals were designated for monthly slaughter (n = 2) and analysis of worm population characteristics and 25 were designated for blood and faecal collection and for weighing. parasite-free tracer ca ... | 1987 | 3670895 |
| the development, clinical signs and economic losses of gastrointestinal parasitism in feeder cattle on irrigated and non-irrigated dikeland and upland pastures. | investigations were carried out over three grazing seasons with parasitized and treated (control) steers on irrigated and non-irrigated upland and dikeland pastures. the stocking rate in each paddock was adjusted by either adding or removing animals so as to maintain as uniform a sward and rate of grazing as possible. animals were weighed on and off the pastures and fortnightly during the grazing seasons. during the first grazing season clinically normal steers shedding low numbers of gastrointe ... | 1972 | 4263919 |
| on the immunological response of young calves to light nematodirus helvetianus infection. | infecting parasite-free eight week old calves with 8,000 infective nematodirus helvetianus larvae did not modify appreciably their response to a later heavy field challenge with n. helvetianus, ostertagia ostertagi and cooperia oncophora, although two of six animals did have smaller nematodirus burdens. | 1973 | 4270440 |
| abomasal nematodes in cattle in ontario. | during 1970, 93 abomasa from cattle in ontario were examined, and from 63 of these abomasa nematode species of the genera ostertagia, haemonchus and/or trichostrongylus axei were recovered. the abomasa were from cattle six months to two years of age and were collected either from the postmortem room at the ontario veterinary college or from two abattoirs near guelph. the numbers of worms per abomasum were estimated and their genera were identified from a one-twentieth volume of the washings and ... | 1974 | 4272952 |
| overwintering of bovine gastrointestinal nematodes in southwestern ontario. | several steers, reared in isolation until approximately six months of age, were placed on a small isolated enclosed pasture from late spring to late fall of 1970, 1971 and 1972. the pasture was left vacant and unused during the winters and early springs. the pasture had been used in previous years by cattle, and in the late spring of 1970 was grazed by cattle know to be passing gastrointestinal nematode eggs in their feces. the steers were slaughtered periodically, and the prevalence of nematode ... | 1974 | 4272963 |
| the effects of anthelmintic treatments on the development of gastrointestinal parasitism in calves. | fortnightly treatment of susceptible calves with 1-tetramisole during the first two months of continuous exposure to pastures residually heavily-infected with ostertagia ostertagi, cooperia oncophora and nematodirus helvetianus did not prevent the development of clinical parasitic gastroenteritis, although the infections were not as severe as in nontreated calves. development of resistance in treated calves was manifested by significantly smaller numbers of cooperia eggs in utero (which were ref ... | 1974 | 4274819 |
| on the natural seeding of marshland pastures with bovine gastrointestinal parasites. | by placing parasite-free calves in paddocks grazed by infected animals for 18 day periods at various times during the previous season it was shown that eggs of ostertagia ostertagi, cooperia oncophora and nematodirus helvetianus deposited on pastures from early july to october of one year were able to survive in the maritime area of canada over winter either as eggs and/or larvae and contribute to residual infections on these pastures the following spring. the greatest deposition and/or survival ... | 1974 | 4274825 |
| the regulation of ostertagia ostertagi populations in calves: the effect of past and current experience of infection on proportional establishment and parasite survival. | a mathematical model of the parasitic phase of the life-cycle of ostertagia ostertagi in calves is described. the model is used in the re-analysis of previously published data from a long-term trickle infection experiment in which groups of calves were infected daily with graded doses of 3rd-stage (l3) larvae. the results of the analysis are consistent with the hypothesis that the observed changes in the intensity of infection in the calves were the result of a decline in the proportional establ ... | 1987 | 3696770 |
| the survival of infective larvae of ostertagia ostertagi and cooperia oncophora in hayloft-dried grass. | | 1974 | 4432682 |
| trichostrongylus askivali dunn, 1964, and ostertagia ostertagi (stiles, 1892) in white-tailed deer (odocoileus virginianus) of the southeastern united states. | | 1974 | 4436752 |
| studies on the survival of eggs and infective larvae of ostertagia ostertagi and cooperia oncophora in herbage. | | 1974 | 4475530 |
| studies on arrested development of ostertagia ostertagi and cooperia oncophora. | | 1974 | 4478097 |
| the survival of eggs and infective larvae of ostertagia ostertagi and cooperia oncophora in solid cattle manure and urine. | | 1974 | 4478790 |
| effect of temperature on development of the free-living stages of ostertagia ostertagi. | | 1972 | 4641869 |
| the development and symmetry of the vulval flap of ostertagia ostertagi. | | 1972 | 4661361 |
| host induced effects on the vulval flap of ostertagia ostertagi. | | 1972 | 4661362 |
| effect of temperature on survival of the free-living stages of ostertagia ostertagi. | | 1972 | 4674485 |
| ostertagia ostertagi: protective immunity in calves. the development in calves of a protective immunity to infection with ostertagia ostertagi. | | 1973 | 4691928 |
| inhibition of development: variation within a population of ostertagia ostertagi. | | 1973 | 4727894 |
| predatory activity of nematode trapping fungi against the larvae of trichostrongylus axei and ostertagia ostertagi: a possible method of biological control. | | 1973 | 4735716 |
| distribution of ostertagia ostertagi infective larvae on pasture herbage. | | 1973 | 4748245 |
| first report of human infection with haemonchus contortus, ostertagia ostertagi, and marshallagia marshalli (family trichostrongylidae) in iran. | | 1973 | 4760647 |
| studies on the influence of lime, formalin, formic acid, and ammonium persulphate on the eggs and larvae of ostertagia ostertagi and cooperia oncophora in liquid cattle manure. | | 1973 | 4798421 |
| ostertagia ostertagi: establishment of patent infections in calves by intravenous inoculation. | | 1974 | 4813202 |
| nonenzymic histochemistry of bovine abomasal tissue infected with ostertagia ostertagi. | | 1974 | 4821117 |
| the effect of corticosteroid treatment on the development of inhibited ostertagia ostertagi larvae. | | 1974 | 4830990 |
| inhibited development of ostertagia ostertagi, cooperia oncophora, and nematodirus helvetianus in parasite-free calves grazing fall pastures. | | 1974 | 4842852 |
| studies on the survival of infective larvae of ostertagia ostertagi and cooperia oncophora in silage grass containing formic acid. | | 1974 | 4844325 |
| studies on the survival of eggs and infective larvae of ostertagia ostertagi and cooperia oncophora in liquid cattle manure. | | 1974 | 4858506 |
| studies on the bionomics of eggs and infective larvae of ostertagia ostertagi and cooperia oncophora in soil. | | 1974 | 4858507 |
| develpoment and survival of infective larvae of the cattle nematode, ostertagia ostertagi. | | 1971 | 5102817 |
| functional morphology and histochemistry of structural proteins of the genital cone of ostertagia ostertagi, with a comparison of the genital cones of other ostertagia common in cattle in the united states. | | 1971 | 5105969 |
| on experimental transmission of ostertagia ostertagi (stiles, 1892) ransom, 1907, to sheep. | | 1971 | 5145205 |
| host-induced effects on the size and body proportions of ostertagia ostertagi (stiles, 1892) ransom, 1907, a nematode parasite of cattle. | | 1971 | 5157152 |
| adult worms as a factor in the inhibition of development of ostertagia ostertagi in the host. | | 1971 | 5161202 |
| inhibition of ostertagia ostertagi at the early fourth larval stage. i. the seasonal incidence. | | 1969 | 5348694 |
| inhibition of ostertagia ostertagi at the early fourth larval stage. ii. the influence of environment on host or parasite. | | 1969 | 5348695 |
| the development of the parasitic stages of ostertagia ostertagi. | | 1969 | 5381123 |
| the effect of cortisone on populations of ostertagia ostertagi of uniform age. | | 1969 | 5386283 |
| the regulation of egg output by ostertagia ostertagi in calves infected once only. | | 1969 | 5390574 |
| the regulation of ostertagia ostertagi populations in calves: density-dependent control of fecundity. | the decline in faecal egg counts, characteristic of calves which have been experimentally infected with ostertagia ostertagi, is analysed using a mathematical model in which parasite fecundity is assumed to be an inverse function of both the duration and intensity of infection. the model incorporates a description of the frequency distribution of mature parasites between hosts (which is less over-dispersed than is usual for many other helminth infections). the model provides a good overall descr ... | 1987 | 3696771 |
| a mathematical model of the population biology of ostertagia ostertagi in calves and yearlings. | a mathematical model of the population biology of ostertagia ostertagi is described. the model assumes that the natural control and regulation of parasite numbers is mediated by four processes: the effect of climate on the development and survival of the free-living stages; changes in the rate of establishment of the infective larvae, and density-dependent variations in parasite survival and fecundity. the model is used to compare the course of the infection in two groups of calves. one group is ... | 1987 | 3696772 |
| population biology of ostertagia ostertagi and anthelmintic strategies against ostertagiasis in calves. | five chemoprophylactic or chemotherapeutic strategies against bovine ostertagiasis are compared using a mathematical model of the population biology of ostertagia ostertagi. the model offers a means of screening novel strategies prior to their further investigation in the field. under conditions of climate and management typical of many regions in northern temperate europe, the model indicates that all of the tested prophylactic strategies will result in a profound reduction in the intensity of ... | 1987 | 3696773 |
| the development and mortality of the non-infective free-living stages of ostertagia ostertagi in the field and in laboratory culture. | a deterministic model of the population biology of the non-infective free-living phase of ostertagia ostertagi is described and tested. a comparison of field and laboratory studies indicates that the pre-infective larvae of o. ostertagi spend about twice as long in this phase in the field as in laboratory culture (13 days and 7 days respectively at 15 degrees c), and that the subsequent transition (i.e. second moult) to the infective phase also proceeds at a much slower rate (about 10 times less ... | 1986 | 3714308 |
| maximum-likelihood estimates of the mortality and migration rates of the infective larvae of ostertagia ostertagi and cooperia oncophora. | we present an analysis of the survival and migration rates of the infective (l3) stages of ostertagia ostertagi and cooperia oncophora. although the majority of laboratory studies show that the survival of the l3 stage depends upon temperature, moisture and the age of the larvae, a simple mathematical model of larval demography, in which their mortality and migration rates are held constant, provides as good agreement between observed and predicted larval counts as models in which these rate pro ... | 1986 | 3737245 |
| strategic deworming for spring-calving beef cow/calf herds. | strategic application of an anthelmintic was tested during the 1982 grazing season as part of the continued study of the epidemiology of beef cattle parasitism in central missouri. forty hereford and hereford x simmental cow/calf pairs were assigned to 2 treatment groups. the 20 cow/calf pairs in group 1 were nonmedicated controls. after calving in mid-march, the 20 cows in group 2 were drenched with a 10% suspension of the anthelmintic fenbendazole (10 mg/kg of body weight). ten cow/calf pairs ... | 1986 | 3759614 |
| further studies on the response to transplanted adult ostertagia ostertagi in calves. | calves infected by surgical transplantation of adult ostertagia ostertagi had raised levels of plasma pepsinogen and those in which the largest number of worms established also had elevated plasma gastrin concentrations. despite the elevated plasma pepsinogen values, the abomasal ph of the animals did not change significantly, and there was no significant difference in the percentage establishment of adult parasites in calves previously infected with o ostertagi third stage larvae and those whic ... | 1987 | 3823628 |
| pathogenesis of simulated natural infections with ostertagia ostertagi in calves. | the possibility of a mucosal hypersensitivity reaction and its relationship to the pathogenesis of simulated natural infections with ostertagia ostertagi were studied in calves. four groups of 4 calves each were used. one group was used as noninfected control; a 2nd group was given increasing doses of infective larvae; a 3rd group was given increasing doses of larvae and these were removed by succeeding treatment with an anthelmintic; and a 4th group was given an initial dose of larvae which was ... | 1987 | 3826866 |
| 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 |
| efficacy of the tris-salt of 2 [(methoxycarbonylamino)-[2-nitro-5-(n-propylthio) phenylimimo] methylamino] ethane sulfonic acid against inhibited larvae of ostertagia ostertagi. | the tris-salt of 2-[(methoxy-carbonylamino) - [2-nitro-5-(n-propylthio) phenylimimo] methylamino] ethane sulfonic acid (mca) was evaluated against naturally acquired gastrointestinal parasitism in cattle during spring in louisiana to determine efficacy of the compound against inhibited early 4th-stage larvae (el4) of ostertagia ostertagi. forty-three crossbred yearling beef heifers were grazed together on contaminated pastures between mar 1 and apr 18, 1984. on april 17, 3 of the 43 heifers were ... | 1985 | 3917240 |
| seasonal comparisons of anthelmintic activity of levamisole pour-on in cattle in the usa. | anthelmintic activity of a pour-on formulation of levamisole, applied during warm weather (16 degrees to 36 degrees c) at 10 mg/kg bodyweight, was evaluated in groups of naturally parasitised calves. this activity was compared to that obtained in similar groups of calves treated in the winter (-4 degrees to +7 degrees c). controlled efficacy of the pour-on formulation was determined for each season by comparing mean worm burdens in treated calves sacrificed seven to nine days after treatment to ... | 1986 | 3946069 |
| efficacy of an albendazole feed formulation against bovine gastrointestinal nematodes including arrested larvae of ostertagia ostertagi. | the efficacy of an albendazole feed premix formulation was compared with that of an albendazole drench suspension for control of gastrointestinal nematodes in 31 beef cattle. the premix (11 cattle) and drench suspension (9 cattle) were found to have similar efficacies at a dosage of 7.5 mg/kg of body weight. when compared with controls (11 cattle), both formulations caused significant (p less than 0.05) reductions in worm counts with an efficacy of 98% or greater against adult haemonchus placei, ... | 1986 | 3946888 |
| 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 |
| 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 |
| 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 |
| immunosuppression of lymphocyte blastogenesis in cattle infected with ostertagia ostertagi and/or trichostrongylus axei. | twenty 4-month-old calves were infected with o ostertagi and/or t axei and the responses to phytolectins were evaluated. whole blood cultures were incubated with phytohemagglutinin (pha), concanavalin a (con a) and pokeweed mitogen (pwm). the blastogenic response was determined by tritiated thymidine uptake with results presented as counts per minute (cpm), stimulation indices (si) and a mononuclear cell responsive index determined by dividing the phytomitogen induced cpm by the absolute mononuc ... | 1986 | 3962170 |
| 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 |
| 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 |
| synergistic influence of ostertagia ostertagi and trichostrongylus axei on ostertagia ostertagi larval inhibition and abomasal lesions in cattle. | parasite-free 4-month-old calves were inoculated with ostertagia ostertagi and/or trichostrongylus axei followed 6 weeks later by increasing doses of o ostertagi for 8 weeks. clinical signs of parasitism, fecal egg counts, and plasma pepsinogen concentrations were monitored, and gross lesions and parasite burdens were determined postmortem. clinical signs of parasitism were not observed and weight gains were not affected in experimentally infected calves. in calves infected with o ostertagi, mea ... | 1985 | 4037502 |
| on the persistence of infective ostertagia ostertagi, cooperia oncophora and nematodirus helvetianus on pastures. | by grazing parasite-free susceptible calves on naturally infected paddocks for eighteen day periods, nematodirus helvetianus was shown to survive over two winters on marshland pastures under maritime climatic conditions in three successive years although the numbers surviving the second winter in two of the three years were low. climatic conditions of below normal temperatures and little snowfall would appear to have a detrimental effect on the survival of nematodirus over a second winter althou ... | 1972 | 4263911 |
| inhibited development in ostertagia ostertagi infections--a diapause phenomenon in a nematode. | | 1974 | 4418146 |
| effect of ostertagia ostertagi on lamb performance and cross resistance to o circumcincta. | fifteen worm-free lambs (two-and-a-half to three months or four to four-and-a-half months old) were infected with 3500 or 4000 ostertagia ostertagi larvae on five days each week for six weeks, and their performance compared to that of controls. eleven lambs were killed after eight weeks and four were challenged with o circumcincta to determine whether any cross resistance had developed. a feature of the o ostertagi infection was the considerable variation in response. overall liveweight gain was ... | 1985 | 4070787 |
| observations on the faecal egg count of calves naturally infected with ostertagia ostertagi. | | 1969 | 5390577 |
| some observations on the worm burdens of calves infected daily with ostertagia ostertagi. | | 1969 | 5393715 |
| the effect of cortisone on the worm burdens of calves infected daily with ostertagia ostertagi. | | 1969 | 5393716 |
| the regulation of egg output by ostertagia ostertagi in calves infected once only. | | 1969 | 5393717 |
| observations on the faecal egg count of calves naturally infected with ostertagia ostertagi. | | 1969 | 5393718 |
| the effect of oral parbendazole against ostertagia ostertagi and cooperia punctata in experimentally infected calves. | | 1970 | 5411561 |
| the regulation of population of ostertagia ostertagi in calves. | | 1970 | 5534089 |
| the effect of host resistance on the development of the vulval flap in ostertagia ostertagi. | | 1967 | 5625912 |
| [biology and ecology of pre-parasitic development stages of ostertagia ostertagi and cooperia oncophora (nematoda, trichostrongylidae) in view of the epidemiology of trichostrongyloidiasis of cattle]. | | 1967 | 5631855 |
| [biology and ecology of the preparasitic development stages of ostertagia ostertagi and cooperia oncophora (nematoda, trichostrongyloidea) with reference to the epidemiology of cattle trichostrongyloidiasis]. | | 1967 | 5632511 |
| critical trials on the efficacy of thiabendazole against ostertagia ostertagi, cooperia oncophora, and nematodirus helvetianus. | | 1968 | 5650475 |
| [experimental vaccination of calves with irradiated larvae of ostertagia ostertagi and cooperia oncophora]. | | 1969 | 5796074 |
| experimental ostertagia ostertagi infections in calves: parasitology and pathogenesis of a single infection. | | 1966 | 5961410 |
| experimental infections of ostertagia ostertagi in calves: results of two regimens of multiple innoculations. | | 1967 | 6065936 |
| some aspects of resistance to animal and human helminths. acquired resistance and its effect on populations of ostertagia ostertagi. | | 1967 | 6066882 |
| regulation of egg output of populations of ostertagia ostertagi. | | 1967 | 6069727 |
| controlled test of the efficacy of the feed premix formulation of crufomate on the parasites of the gastrointestinal tract and lungs of dairy calves. | activity of the feed premix formulation (m-1839) of crufomate against helminths of the gastrointestinal tract and lungs of cattle was determined in a controlled test. eight calves were treated and 7 were nontreated. the dosage rate of crufomate was 17 mg of active drug/kg of body weight daily for 3 consecutive days. removal activity was high against mature cooperia oncophora (99%) and c punctata (96%) and immature cooperia spp (87%). removal of mature ostertagia ostertagi was 68%. the removal of ... | 1982 | 6213184 |
| therapeutic and prophylactic efficacy of morantel when administered directly into the rumen of cattle on a continuous basis. | the efficacy of morantel tartrate when administered on a continuous basis directly into the rumen/reticulum of cattle, either by a cannula or from a specially designed device, was evaluated against gastrointestinal parasites under laboratory conditions. in two experiments the continuous infusion of morantel at rates between 0.26 and 1.04 mg/kg body weight per day using a peristaltic pump was highly efficacious in both preventing the establishment of infections and removing established infections ... | 1983 | 6225238 |
| experimental and natural infection of calves with bunostomum phlebotomum. | an experiment was conducted to determine the efficiency of a method of experimental infection of weaner beef calves with bunostomum phlebotomum and to compare such infection with that established by natural infection. six calves, maintained on a concrete-floored pen, were inoculated with b. phlebotomum l3 by placing the larval inocuulum, in small volume, in the outer chamber of the ear while the animal was restrained for 18 min. inoculation doses of 20, 30, 40, 50, 60, and 80 thousand l3 were us ... | 1983 | 6229089 |
| enzyme-linked immunosorbent assay for the detection of antibodies to hypoderma bovis in cattle. | an adaptation of the enzyme-linked immunosorbent assay has been shown to detect antibodies in the circulation of cattle infected with hypoderma bovis. strong positive reactions were obtained from all infected cattle, even those which harboured only one larva. a strong cross reaction was observed in sera taken from cattle infected with h lineatum, but not in cattle infected with fasciola hepatica or ostertagia ostertagi. | 1983 | 6344168 |
| [efficacy of albendazole as a pellet formulation against ostertagia ostertagi and cooperia oncophora in experimentally infected calves]. | | 1984 | 6370654 |
| controlled and clinical evaluations of the anthelmintic activity of a levamisole pour-on formulation against gastrointestinal nematodes in cattle. | beef-type calves (n = 107) with naturally occurring helminth infections were used in a series of 3 controlled experiments to study the anthelmintic activity of a new pour-on formulation of levamisole. in the 1st experiment, the efficacy of a single treatment of levamisole pour-on at a rate of 10 mg/kg of body weight was determined, using a placebo pour-on in a similar volume as a control. in the 2nd experiment, calves were treated with levamisole pour-on at doses 0 (nontreated control), 7.5, 10, ... | 1984 | 6377988 |
| experimental studies on the interaction between infections of ostertagia leptospicularis and other bovine ostertagia species. | experimental infections of calves were carried out with either isolates of predominantly ostertagia ostertagi, pure o. leptospicularis or a mixed isolate of equal numbers of both these species. the total worms established on day 21 for the mixed species from a total inoculum of 100 000 infective larvae, was 1.2 times greater than from 100 000 larvae of the o. ostertagi isolate and 3.3 times that of the pure o. leptospicularis isolate. the increased establishment in the mixed inoculum referred to ... | 1984 | 6441374 |