PMID(sorted ascending)
occurrence of gastrointestinal parasites in georgia cattle.a survey of gastrointestinal nematodes in georgia cattle was conducted from 1968 through 1973 from actual worm counts from viscera of 145 slaughtered beef cattle or from egg counts made from fecal samples from 3,273 beef and 100 dairy cattle. beef cattle were grouped as calves, yearlings, and cows. dairy cattle were grouped as calves, replacement heifers, and cows. results of fecal examinations positive; 99.5, 99.3, 99.6, and 41.2% of the calves, yearlings, drylot calves, and cows, respectively, ...1975123711
the control of adult parasitic nematodes of cattle with morantel tartrate.the anthelmintic efficacy of morantel tartrate at 5mg/kg bodymass was investigated in three separate controlled trials comprising 68 calves. high anthelmintic activity was established against adult haemonchus placei, ostertagia ostertagi, cooperia spp. (c.pertinata and c. punctata), bunostomum phlebotomum and oesophagostomum radiatum.1975131197
levamisole: anthelmintic activity in calves following dermal application.a series of seven experiments designed to evaluate the anthelmintic efficacy of levamisole (1-tetramisole) by dermal application is described. this work involved use of 181 artificially infested calves. the drug was formulated at a concentration of 10% m/v levamisole base in a solvent system promoting dermal absorption and was applied to both sides of the spine in the lumber region at a dose rate of 10 mg levamisole base per kg livemass. a consistent performance was achieved in these investigati ...1977144190
trials with rafoxanide. 8. efficacy of an injectable solution against trematodes and nematodes in cattle.four experiments are described in which the efficacy of an experimental 5% injectable solution of rafoxanide was evaluated against various adult and immature helminths in cattle. subcutaneous injection at a dosage of 3 mg/kg live mass resulted in the following reductions in mean worm burdens: adult fasciola hepatica, 82,6%; adult fasciola gigantica, 99,8% immature paramphistomum microbothrium, 10,1% adult haemonchus placei, 99,6%, third stage h. placei, 73,7%; adult bunostomum phlebotomum, 99,8% ...1977144191
occurrence and seasonal behavior of gastrointestinal nematodes infecting maine dairy cattle.gastrointestinal tracts of 48 yearling maine dairy cattle were examined (8 animals every 2 months) for 1 year. adult and immature nematodes were identified and counted. species recovered were bunostomum phlebotomum, cooperia mcmasteri, cooperia oncophora, cooperia pectinata, cooperia punctata, haemonchus placei, nematodirus helvetianus, oesophagostomum radiatum, ostertagia circumcincta, ostertagia lyrata, ostertagia ostertagi, trichostongylus axei, and trichuris ovis. strongyle parasitism was ob ...1977145192
effect of albendazole on gastrointestinal parasites of cattle.the efficacy of albendazole in removing gastrointestinal nematodes and tapeworms was studied in 16 treated and 16 untreated (control) beef calves. the anthelmintic was administered as an oral drench at a dose level of 5 ml/45.5 kg of body weight (5 mg/kg). percentage of efficacy against the various genera was: trichostrongylus axei, oesophagostomum radiatum, and moniezia-100.0; haemonchus placei, cooperia spp, and trichostrongylus colubriformis - greater than 99.0; ostertagia ostertagi -98.3; an ...1977145816
the efficacy of fenbendazole at a dosage rate of 7,5 mg/kg against nematode infestations in cattle.fenbedazole, dosed to artificially infested cattle at 7,5 mg/kg live mass, was more than 80% effective in more than 80% of the treated animals against immature and adult haemonchus placei, ostertagia ostertagi; cooperia spp., bunostomum phlebotum and oesophagostomum radiatum.1979162147
parasites of domestic and wild animals in south africa. xii. artificial transmission of nematodes from blesbok and impala to sheep, goats and cattle.sheep were successfully infested artificially with the larvae of haemonchus contortus, trichostrongylus axei, trichostrongylus falculatus and impalaja nudicollis, cultured from the faeces of blesbok naturally infested with these nematodes. haemonchus placei, longistrongylus sabie, trichostrongylus colubrifomis, t. falculatus, impalaia tuberculata and cooperia hungi likewise became established in sheep, goats and calves dosed with larvae cultured from the faeces of infested impala. sheep and goat ...1979460820
avermectins, new family of potent anthelmintic agents: efficacy of the b1a component.when given to sheep as a single oral dose at 0.1 mg/kg, the b(1a) component of the avermectins caused a reduction of >95% in the numbers of haemonchus contortus, ostertagia circumcincta (including inhibited l(4) larvae), trichostrongylus axei, trichostrongylus colubriformis, cooperia oncophora, and oesophagostomum columbianum. when given to cattle as a single oral dose at 0.1 mg/kg, avermectin b(1a) was >95% effective in reducing the numbers of haemonchus placei, ostertagia ostertagi (including ...1979464563
seasonal transmission of bovine gastrointestinal nematodes in the texas gulf coast.sentinel calves were placed in pastures for 1 month in two environmentally dissimilar areas of the texas gulf coast to determine the seasonal transmission of various gastrointestinal nematodes. transmission was determined for cooperia spp, haemonchus placei, ostertagia ostertagi, and trichostrongylus axei. large numbers of cooperia spp were acquired from may through november, with the peak of transmission occurring in july and august. haemonchus placei was encountered on both field sites but was ...1979500427
thiophanate in the treatment of cooperia punctata, c pectinata and haemonchus placei in cattle. 1979532046
the seasonal incidence of helminth parasites of cattle in the northern transvaal bushveld.during a period of 14 months two tracer calves per month were slaughtered after one month's exposure to natural helminth infestation on a farm in the northern transvaal bushveld. total parasitic helminth burdens, which were never large, were determined in order to define their seasonal incidence. the gastro-intestinal parasites that were recovered were bunostomum phlebotomum, cooperia pectinata, cooperia punctata, haemonchus placei, oesophagostomum radiatum and trichostongylus spp. of these coop ...1979551181
studies on haemonchus contortus. ii. the effect of abomasal nematodes on subsequent challenge with h. contortus.fifty-thousand infective larvae of trichostrongylus axei dosed to 7-9-month-old merinos protected them against a subsequent challenge with 50 000 infective larvae of haemonchus contortus. protection varied with the period between an initial dosage of t. axei and challenge with h. contortus as follows: after 90 days it was more than 80% effective in more than 80% of sheep; at 119 and 180 days there was still a significant reduction in the numbers of h. contortus recovered (p < 0,05 and p < 0,001, ...1979551369
cryopreservation of the infective larvae of the common nematodes of ruminants.exsheathed infective larvae (l 3) of 19 species of nematodes were tested for infectivity in either sheep or cattle after they had been frozen in 0,9% nacl solution, stored for a relatively short time in the gas phase of liquid nitrogen and subsequently thawed. in addition, 13 of these species were tested after similar storage for up to 18 months. in sheep, haemonchus contortus, ostertagia circumcincta, trichostrongylus axei, trichostrongylus colubriformis, nematodirus spathiger and oesophagostom ...1977566412
nitroxynil. anthelmintic activity in cattle following subcutaneous injection.nitroxynil injected subcutaneously at 10 mg/kg live mass achieved class a efficacy when evaluated by the non parametric method against adult fasciola gigantica. haemonchus placei, bonustomum phlebotomum and oesophagostomum radiatum in cattle. the compound was not effective against adult cooperia spp. at the same dosage.1978569707
parasites of domestic and wild animals in south africa. x. helminths in impala.two to four impala in the nylsvley nature reserve were culled each month from february 1975-february 1976. two trematode species, 1 cestode species and 13 species of nematodes were recovered from these antelope. of these, fasciola gigantica, gongylonema pulchrum, haemonchus placei and trichostrongylus falculatus are new records for impala. in general, h. placei, longistrongylus sabie and impalaia tuberculata exhibited a similar pattern of seasonal occurrence. adult worms were present during nove ...1978572950
the effect of dermally applied levamisole against the parasitic nematodes of cattle.a series of trials to establish the anthelmintic efficiency of levamisole, when applied dermally to calves, is described. the levamisole base was formulated in a suitable solvent system at 100 g/l and applied dermally at a dose rate of 8 mg base/kg. this gave efficiencies of 97.1-100%, 88.5-100%, 100%, 98.7-100% and 89.2-100% against adult haemonchus placei, ostertagia spp, cooperia spp, oesophagostomum radiatum and trichostrongylus axei, respectively. activity against the immature stages of h. ...1977588176
studies on nematode infections of beef cattle in new south wales.the occurrence and seasonal trends of nematode parasite infections in beef cattle on the tablelands and north coast regions of new south wales are described, based on worm counts from 627 spring-born steers slaughtered at 2-monthly intervals from 6 to 24 months of age. the predominant parasites were ostertagia ostertagi, trichostrongylus axei and cooperia spp. large burdens of adult ostertagia were seen in 12-month-old animals in late winter and early spring, and later in 18- to 20-month-old cat ...1977614021
helminth parasites of beef cattle in the east kimberley and victoria river districts of northern investigation into the helminth species present in cattle in the east kimberley and victoria river districts of northern australia was conducted over a 2-year period based on bi-monthly total and differential worm counts in weaner cattle as well as on a post mortem survey of adult cattle sent for slaughter. the most important species found in young cattle were haemonchus placei and cooperia spp. only small numbers of bunostomum phlebotomum, nematodirus spathiger, oesophagostomum radiatum and ...1978664015
parasites of domestic and wild animals in south africa. xi. helminths in cattle on natural pastures in the northern transvaal.after being exposed to infestation for 4 to 6 weeks, pairs of tracer calves were slaughtered to determine the seasonal incidence of helminth infestation in cattle on natural pasture. haemonchus placei was recovered from march-july and from november-february, and peak burdens were recorded during december and january. there was marked inhibition in larval development from april-july. trichostrongylus spp. were recovered from march-june and from november-february, the greatest number of worms bein ...1978754122
evaluation of less than recommended dosages of levamisole phosphate for the treatment of gastrointestinal nematodes of cattle.the anthelmintic activity of 3 dosages of injectable levamisole phosphate was evaluated in 84- to 145-kg calves from a herd of cattle with a history of heavy gastrointestinal nematode infections. trichostrongylid egg counts in the calves varied from 450 to 700/g of feces. the anthelmintic was administered subcutaneously to 3 groups of 10 calves each, at the rate of 8 mg/kg of body weight (current manufacturer's recommendation), 6 mg/kg, and 4 mg/kg. a 4th group of 10 calves was utilized as untre ...1977833031
the anthelmintic efficacy of fenbendazole against a mixed nematode infection in sheep.fenbendazole (methyl-5-(phenylthio)-2-benzimidazole carbamate) at dose rates of 5 mg/kg and above was 100 per cent effective in eliminating a naturally acquired dictyocaulus filaria infection in sheep. the drug was 100 per cent effective in eliminating concurrent infections of adult trichostrongylus axei, haemonchus contortus, haemonchus placei, ostertagia circumcincta, ostertagia ostertagii, cooperia oncophora, cooperia mcmasterii, nematodirus spathiger, neumatodirus filcollis, oesophagostomum ...19751153893
trials with rafoxanide. 7. efficacy against fasciola hepatica, haemonchus placei and bunostomum phlebotomum in cattle.anthelmintic efficacy studies involving 49 cattle either naturally or artificially infested with fasciola hepatica are described. some of the animals were also artificially infested with haemonchus placei and bunostomum phlebotomum. at dosage rates of 3,75 and 5,0 mg/kg live mass rafoxanide was 64,6 and 92,6 per cent effective respectively against adult naturally acquired infestations of f. hepatica. at 7,5 and 10,0 mg/kg it was 37,9 and 55,7 per cent effective against 42 day old liver fluke. at ...19751219107
anthelmintic activity of paraherquamide in calves.paraherquamide, an oxindole alkaloid metabolite of penicillium paraherquei and penicillium charlesii, was tested against the adult stages of nine common gastrointestinal and lung nematodes of calves at single, oral dosages of 0.5, 1.0, 2.0 or 4.0 mg kg-1. at dosages 1.0-4.0 mg kg-1 there was 95% or more removal of haemonchus placei, ostertagia ostertagi, trichostrongylus axei, trichostrongylus colubriformis, cooperia oncophora, nematodirus helvetianus, oesophagostomum radiatum, and dictyocaulus ...19921413457
efficacy of cydectin moxidectin 1% injectable against experimental infections of dictyocaulus viviparus and bunostomum phlebotomum superimposed on natural gastrointestinal infections in calves.twenty male holstein calves averaging 105 kg in weight and naturally infected with gastrointestinal nematodes and small numbers of lungworm and hookworm, were given experimental infections with the two latter species to provide adult and larval stages for anthelmintic evaluation. following random allotment, one group of 10 calves was injected subcutaneously with moxidectin at a dosage of 0.2 mg kg-1 of body weight. a second group of 10 was injected subcutaneously with unmedicated blank vehicle a ...19921413460
a preliminary study of the effect of microclimate on third-stage larvae of haemonchus contortus and haemonchus placei on irrigated pasture.assessments were made on the influence of several microclimatic variables on the availability of third-stage larvae of haemonchus contortus and haemonchus placei on four strata of irrigated kikuyu pasture. three replicates of these pasture samples were collected on 18 sample days over 12 months and the log10 mean counts of the larvae recovered were analysed by a step-wise regression model. predictors for the log counts of the four strata for the two nematode species included relative humidity, i ...19921428508
efficacy of moxidectin against gastrointestinal nematodes of cattle.three groups of 11 naturally infected crossbred beef calves were injected subcutaneously with moxidectin 1 per cent injectable at 0.2 or 0.3 mg moxidectin/kg bodyweight or with the unmedicated vehicle. nematode infections had been acquired during grazing from december to april. based on the faecal egg counts and total worm counts of the control calves at necropsy (11 to 13 days after treatment) most of the calves had heavy parasitic burdens. ostertagia ostertagi was predominant and the mean numb ...19921441146
efficacy of ivermectin delivered from a sustained-release bolus against inhibited early fourth-stage larvae of ostertagia ostertagi and other nematodes in cattle.the anthelmintic efficacy of ivermectin (ivm) delivered from a sustained-release (sr) bolus was evaluated against natural infections with gastrointestinal tract nematodes in 12 crossbred beef heifers in spring. the 12 calves were randomly allotted to 2 groups of 6 calves each. group-1 calves were treated with an sr bolus designed to deliver 8 mg of ivermectin/d. group-2 calves were nontreated controls. cattle groups were kept in separate concrete-floored pens (grass hay nutrition) and slaughter ...19921524310
efficacy of abamectin against natural infections of gastrointestinal nematodes and lungworm of cattle with special emphasis on inhibited, early fourth stage larvae of ostertagia ostertagi.the anthelmintic efficacy of abamectin (avermectin b1) was evaluated against gastrointestinal nematodes, including ostertagia ostertagi inhibited larvae and lungworm, in yearling crossbred beef heifers during late spring. the calves were grazed on contaminated pasture for 10 weeks and then held under conditions free of nematode infection for 3 weeks prior to allotment and treatment on 5 june. thirteen calves were randomly assigned to two groups of six by restricted randomization on body weights; ...19921532875
effects of low levels of lice and internal nematodes on weight gain and blood parameters in calves in central texas.the effects of low levels of both biting and sucking lice, a mixed population of nematodes, and a combination of all these parasites were evaluated in calves held in a barn with no environmental controls in central texas. observations at 122 sites on each animal for 16 wk consecutively in 1987 revealed that the largest numbers of all louse species [haematopinus eurysternus (nitzsch). linognathus vituli (l.), and bovicola bovis (l.)] occurred 3-7 wk after infestation. in 1988 l. vituli population ...19921607476
gastro-intestinal parasitism of cattle in native pasture grazing system in guadeloupe (french west indies).gastro-intestinal parasitism of creole cows and calves, limousin x creole cross calves and brahman x creole cross calves was recorded during seasons of calving in a native grazing system in guadeloupe, a wet tropical area. calvings were pooled during the dry season for two herds and during the rainy season for two other herds. for each calving season, calves of one herd were drenched monthly with anthelmintic. a marked periparturient rise in egg excretion was observed in cows. coccidial infectio ...19911763489
efficacy of albendazole, levamisole and fenbendazole against gastrointestinal nematodes of cattle, with emphasis on inhibited early fourth stage ostertagia ostertagi experiment was conducted to compare the anthelmintic efficacy of albendazole (abz), levamisole (lev) and fenbendazole (fbz) against inhibited early fourth stage larvae (el4) of ostertagia ostertagi during april in louisiana. forty cross-bred beef heifers (average weight 165 kg) were acquired during winter and grazed on pastures contaminated with o. ostertagi and other nematodes until early april. the cattle were weighed and randomly allotted into four groups of ten animals on 6 april and trea ...19911763491
effects of time of day, season and stratum on haemonchus contortus and haemonchus placei third-stage larvae on irrigated pasture.the effect of time of day, season and stratum of herbage and soil on the availability of haemonchus contortus and haemonchus placei third-stage larvae (l3) on pasture was assessed. feces from infected calves and lambs were placed on pasture plots and samples of upper herbage, lower herbage, mat and soil were collected at five intervals per day throughout the daylight hours on 18 sample days over 12 months. using recovery rate factors derived from a preliminary investigation on the efficacy of la ...19911763493
pathophysiology of haemonchus placei infection in calves.this study was conducted to investigate the pathophysiology of haemonchus placei infection in friesian calves. seven calves were divided into two groups, three uninfected calves (control group) and four infected animals. the latter group were infected orally with 500 h. placei larvae kg-1 body weight. five weeks after infection they were all housed in metabolic crates and injected with 125i-bovine albumin. 51cr-red cells and 59fe-transferrin, to study albumin metabolism, erythrokinetics and ferr ...19911858286
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 ...19902267727
the relationships among ecto- and endoparasite levels, class i antigens of the bovine major histocompatibility system, immunoglobulin e levels and weight gain.natural infestations of the cattle tick boophilus microplus, levels of the buffalo fly haematobia irritants exigua and faecal nematode egg concentrations (bunostomum phlebotomum, cooperia spp., haemonchus placei, oesophagostomum radiatum and trichostrongylus axei) were assessed in 221 belmont red calves during the post-weaning period, when the animals were between 9 and 18 months of age. in addition, the 98 males of this group were challenged with b. microplus larvae on two separate occasions. t ...19902316176
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 ...19902338992
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 ...19902353426
inhibited development of trichostrongylid worms in grazing cattle.inhibition of development of gastro-intestinal trichostrongylid worms was studied using successive groups of tracer calves and groups of continuously grazed calves over one year in the tully area of north queensland lowland wet tropics. the results, assessed by means of worms from these calves recovered at necropsy 3 weeks after their removal from pastures, showed inhibition in the development of haemonchus placei and cooperia punctata at the early fourth stage at the approach to and during the ...19892590137
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 ...19892723922
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 ...19892728298
factors affecting the survival and migration of the free-living stages of gastrointestinal nematode parasites of cattle in central queensland.faecal pats containing parasitic nematode eggs were deposited monthly on worm-free pasture, from mid-1975 to early in 1979, near rockhampton in central queensland. pasture samples were collected monthly from beside these pats and the number of infective larvae on the samples was counted. cooperia spp. were the most numerous larvae on pasture all year round and haemonchus placei were commonly present in low numbers. small numbers of oesophagostomum radiatum larvae were found, mostly during summer ...19892728322
the relation between the natural worm burden of steers and the faecal egg count differentiated to species.the relation between the faecal egg count and the worm burden was investigated in 104 steers of three breeds, 9-24 months of age, which were subjected to natural infection with nematode larvae from pasture at the national cattle breeding station near rockhampton in central queensland. the worm species found were cooperia spp., haemonchus placei, trichostrongylus axei, oesophagostomum radiatum and small numbers of bunostumum phlebotumum. the faecal egg count was found to be a reliable measure of ...19892728323
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 ...19883189987
abundance and survival of infective larvae of the cattle nematodes cooperia punctata, haemonchus placei and oesophagostomum radiatum from faecal pats in a wet tropical climate.observations were made on the abundance and survival of haemonchus placei, cooperia punctata and oesophagostomum radiatum infective larvae from cattle faecal pats exposed at various times of the year in north queensland wet tropics. pats exposed in the hot, wet season yielded abundant larvae on herbage. in the dry season, although low numbers of infective larvae were usual, considerable numbers were produced under conditions of heavy dews on dense herbage. irrespective of season of deposition of ...19883190586
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 ...19883361567
differential recoveries from faecal cultures of larvae of some gastro-intestinal nematodes of cattle.faecal cultures were established using bovine faeces containing known numbers of eggs from either oesophagostomum radiatum, haemonchus placei, cooperia pectinata or a mixture of all three. a substantially greater percentage of larvae was recovered from cultures of o. radiatum and c. pectinata than was recovered from cultures of h. placei. the same pattern was observed in mixed cultures although yields of larvae from all species in mixed cultures were significantly reduced (p less than 0.001). th ...19883397511
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 ...19883421523
prophylaxis of nematode infections in cattle with an indwelling rumino-reticular ivermectin sustained release bolus.ivermectin delivered continuously from a rumino-reticular sustained release device was prophylactically effective in preventing establishment of nine nematode parasite species in multiply-exposed cattle. ivermectin dosages which permitted less than or equal to 1% of infected control calf worm populations to establish ranged from less than 2.5 micrograms kg-1 day-1, which totally prevented infection with dictyocaulus viviparus and oesophagostomum radiatum, to approximately equal to 30 micrograms ...19863788027
efficacy of ivermectin in a topical formulation against induced gastrointestinal and pulmonary nematode infections, and naturally acquired grubs and lice in cattle.efficacy of ivermectin in a topical formulation was evaluated in cattle against adult gastrointestinal and pulmonary nematode infections (experiment 1, n = 24), the 2nd- and 3rd-stage larvae of hypoderma spp (experiment 2, n = 12), and the biting louse damalinia bovis (experiment 3, n = 12). nematode infections were induced and grubs and lice were naturally acquired. treatments consisted of a single dose of ivermectin in a topical formulation of 200, 500, or 1,000 micrograms/kg of body weight in ...19863789500
efficacy of ivermectin against gastrointestinal nematodes in cattle in south africa.the efficacy of ivermectin administered at 200 micrograms/kg was evaluated against induced infestations of 5 gastrointestinal nematode species in cattle. results were analysed by the modified non-parametric method and a "a" class (more than 80% effective in more than 80% of the treated animals) was achieved with an oral drench and subcutaneous injection against the third and fourth larval and adult stages of bunostomum phlebotomum, cooperia spp. (c. pectinata and c. punctata), haemonchus placei, ...19853839020
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 ...19863946069
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, ...19863946888
the anthelmintic activity of cambendazole in calves and lambs.tests were carried out on the efficacy of cambendazole (5-isopropoxy carbonylamino-2-(4-thiazolyl) benzimidazole) against lungworm and gastrointestinal parasites of calves and lambs. against dictyocaulus viviparus the compound was highly effective (80%) against mature worms at levels of 35 mg/kg and over and immature "arrested" worms at 60 mg/kg (71% efective). in the calves the compound was very effective (90 to 99%) against adult haemonchus placei, ostertagia spp., trichostrongylus axei and co ...19724259923
structural changes in the bovine nematode haemonchus placei, that may be associated with host immune response. 19734786829
the ultrastructure of the adult stage of trichostrongylus colubriformis and haemonchus placei. 19725018474
experimental haemonchus placei infection in calves. influence of anaemia and numbers of larvae on worm development. 19715090883
the fine structure of the alimentary tract of third-stage larvae of haemonchus placei and trichostrongylus colubriformis. 19715091364
electron-microscopical observations on the body wall of the third-stage larva of haemonchus placei. 19705445540
experimental haemonchus placei infection in calves. blood picture at three levels of infection. 19705449970
attempts, by blood transfusion, to replace blood loss due to haemonchus placei infection. 19695775380
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, ...19846377988
efficacy of avermectin b1a for treatment of experimentally induced nematode infections in cattle.two formulations of avermectin b1a, c-076 and mk-933, were examined for anthelmintic activity in two trials, each using 20 calves with experimentally produced nematode infections. in one trial, c-076 was given orally, and in the other trial, mk-933 was given by injection at dosages of 50, 100, and 200 micrograms/kg of body weight. treated calves were held for 7 to 8 days and then, together with nontreated controls, were euthanatized and were examined for nematodes in their gastrointestinal tract ...19806449894
efficacy of ivermectin in oral paste formulation against immature gastrointestinal and pulmonary nematodes in cattle.the anthelmintic efficacy of ivermectin in oral paste formulation was evaluated against the 4th-stage larvae of 8 gastrointestinal nematodes and the common lung-worm in 14 experimentally inoculated calves. two groups consisting of 7 calves each were formed by restricted randomization on body weight. the infective larvae were given orally to the animals on a staggered schedule so that the parasites were in the 4th larval stage when the animals were treated. one group was given vehicle paste, and ...19846547278
seasonal variation in anthelmintic response by cattle to dermally applied levamisole.four experiments in 1978-79, and 2 in 1982 designed to define the optimum dose rate of dermally applied formulations of levamisole are described. these experiments showed that the absorption of levamisole with resultant blood levels and anthelmintic activity is strongly influenced by temperature. in warm to hot conditions percutaneous absorption is rapid and high blood levels with high anthelmintic activity against haemonchus placei, ostertagi sp, trichostrongylus sp, cooperia sp, oesophagostomu ...19836615369
persistent anthelmintic effect of ivermectin in cattle.the persistent anthelmintic effect of ivermectin given subcutaneously at 200 mcg/kg was evaluated against induced infections of haemonchus placei, ostertagia ostertagi, cooperia spp. (c. pectinata and c. punctata), bunostomum phlebotomum and oesophagostomum radiatum in cattle. forty-four friesian bull calves raised under worm-free conditions were restrictively randomized to one untreated control group and 3 ivermectin treated groups of equal size according to mass. animals in the different treat ...19836689429
importance of gastro-intestinal helminths in calves in papua new guinea.gastro-intestinal nematodes caused poor growth rates and high mortality in undrenched calves when weaning preceded the wet season. cooperia punctata and haemonchus placei were the dominant species throughout the year with worm burdens and pasture contamination being highest during the wet season and lowest in the dry season. histotropic stages occurred throughout the year in weaner calves but with a clear peak during the wet season. the development of host resistance against the most important w ...19836868131
evaluation of albendazole in cattle naturally infected with nematodes.albendazole (7.5 mg/kg of body weight) was given to 10 calves naturally infected with gastrointestinal nematodes. ten similar calves served as controls. the compound provided 99% to 100% efficacy in removing haemonchus placei, ostertagia ostertagi, trichostrongylus axei, t colubriformis, nematodirus spathiger, n helvetianus, n filicollis, cooperia oncophora, c punctata, and oesophagostomum radiatum.19827073074
use of oxfendazole against natural infestations of haemonchus placei, cooperia punctata, cooperia pectinata and oesophagostomum radiatum in calves. 19827123665
anthelmintic efficacy of febantel against gastrointestinal helminths in calves.three dosage levels of febantel were tested for anthelmintic activities in calves under field conditions. a total of 20 feeder calves affected with naturally occurring gastrointestinal parasites were used in the controlled test. the calves were allotted to 4 groups of 5 each on the basis of degree of parasitism, body weight, age, and sex. calves in groups ii through iv were treated with febantel paste formulation at dosage levels of 5, 7.5, and 10 mg/kg of body weight; calves in group i were use ...19827165174
the seasonal incidence of helminth parasites of cattle in the eastern transvaal lowveld.two helminth-free tracer calves were exposed to natural helminth infestation of a farm in the eastern transvaal lowveld for one month. on a nearby farm calves grazed with the herd for at least 3 months before slaughter so that the cumulative worm burden could be determined. the gastro-intestinal parasites increased markedly after rain. the major species and order or prevalence were: cooperia pectinata, cooperia punctata, haemonchus placei and oesophagostomum radiatum; minor species were bunostom ...19827175905
oxfendazole: anthelmintic activity in calves artificially infected with six species of nematodes and in calves naturally infested with a series of 5 trials, in which 115 artificially infected calves were used, larval anthelmintic tests were done to assess the activity of oxfendazole at 4, 5 mg/kg against all 3 parasitic stages of 6 species of namatodes. an efficacy of over 98% was demonstrated against the 4th stage larvae (l4), 5th and adult stages of haemonchus placei, ostertagia ostertagi, cooperia pectinata, bunostomum phlebotomum and oesophagostomum radiatum and the 3rd larval stage (l3) of h. placei and c. pectinata. ag ...19827175907
the effect of predosing calves with trichostrongylus axei on subsequent challenge with haemonchus placei.twelve calves were dosed with 40 000 and a further 12 with 80 000 infective larvae of trichostrongylus axei respectively. these 2 groups and a control group were subsequently dosed with 50 000 infective larvae of haemonchus placei. predosing with t. axei had no effect on the establishment of h. placei. it is postulated that the numbers of t. axei worms present were below the 'threshold' value necessary to protect the calves against challenge with h. placei.19827177596
diseases of cattle in the solomon islands.between 1967 and 1977 a study was made of diseases of cattle in the solomon islands. tuberculosis was found in only 3 herds and was eradicated by 1975. brucellosis serology revealed very few reactors and by 1977 the herds involved were considered free of the disease. significant serological reactions were found to leptospira interrogans serovars pomona, hardjo, autumnalis and jez-bratislava. there was evidence that infectious bovine rhinotracheitis and mucosal disease were present. seventeen par ...19807247885
the efficacy of fenbendazole at a dosage rate of 5 mg/kg against nematode infestations in cattle.the anthelmintic efficacy of fenbendazole, dosed to artificially infested cattle at 5 mg/kg live mass was determined against immature and adult haemonchus placei. ostertagia ostertagi, cooperia spp., bunostomum phlebotomum and oesophagostomum radiatum. at this dosage rate, fenbendazole was more than 80% effective in more than 80% of the animals treated against the abovementioned nematodes. the only exception was against the third-stage larvae of b. phlebotomum when it fell to more than 60% effec ...19817265100
seasonal occurence of infective nematode larvae on irrigated pasture grazed by cattle in california.during the period extending from dec 1, 1975, to dec 22, 1976, 3 distinct peaks in the concentration of infective nematode larvae on pasture forage were detected by use of helminth-free tracer calves. two of these peaks, 1 occurring in the spring and 1 in the fall, consisted mainly of ostertagia ostertagi and cooperia sp. it is concluded that these 2 peaks can be anticipated annually and constitute unsafe periods of grazing. the 3rd peak was comprised largely of haemonchus placei and cooperia sp ...19817271041
hybridization of australian haemonchus placei (place, 1893), haemonchus contortus cayugensis (das & whitlock, 1960) and haemonchus contortus (rudolphi, 1803) from louisiana. 19817287298
survival and development of larvae of the common nematodes of ruminants after long-term cryopreservation and investigation of different routes of infestation.exsheathed infective larvae (l3) of 16 species of nematodes were tested for infectivity in either sheep or cattle after they had been frozen and stored in 0,09% nacl solution in the gas phase of liquid nitrogen for periods of up to 59 months. a mean of greater than 90% of the l3 of haemonchus contortus, ostertagia circumcincta, trichostrongylus axei, trichostrongylus colubriformis, nematodirus spathiger, oesophagostomum columbianum and chabertia ovina of sheep and haemonchus placei, ostertagia o ...19807465164
haemonchus placei in calves: effects of dietary protein and multiple experimental infection on worm establishment and experiment was conducted to examine the influence of dietary protein and immunisation on parasite establishment and pathogenesis of haemonchus placei in calves. four groups of 4-6-month-old worm-free calves (n = 4) were given a low protein diet (lp) containing 213 g crude protein (cp) per head per day or a high-protein diet (hp) containing 469 g per head per day cp. five weeks later, calves in one of the two groups of each dietary treatment were given 50,000 h. placei infective larvae (l3). t ...19957483235
persistent anthelmintic activity of ivermectin against gastrointestinal nematodes of cattle.two experiments were conducted to determine persistence of ivermectin (ivm) anthelmintic activity. in the first experiment, the injectable (inj) formulation at a dosage of 200 micrograms/kg of body weight and pour-on (po) formulation at a dosage of 500 micrograms/kg were compared in 5 groups of calves (n = 6/group). calves were treated at 14 and 7 days prior to experimentally induced infection. experimental groups were: 1--untreated, infected controls; 2--ivm po, day -14; 3--ivm po, day -7; 4--i ...19957486394
bilateral, perivulval cuticular pores in trichostrongylid nematodes.a new hypodermal gland was discovered in female nematodes of the family trichostrongylidae. because the new structure appears to be associated with the vulva, it was named the perivulval pore. it is similar, based on light and scanning electron microscopy, to phasmids that are located laterally on the tails of nematodes of the class secernentea. like phasmids, perivulval pores are paired and bilateral, with cuticular ducts to the surface in the areas of the lateral chords. they are located sligh ...19957623208
differentiation of haemonchus placei from h. contortus (nematoda: trichostrongylidae) by the ribosomal dna second internal transcribed spacer.there has been much debate as to whether h. placei is a separate species to h. contortus. the aim of this study is to provide molecular information to assess the species status of h. placei. using the polymerase chain reaction, the second internal transcribed spacer (its-2) of ribosomal dna was amplified and sequenced. comparison of the 231 base pair its-2 sequences showed no intraspecific variation in h. contortus, among one isolate from each of the united kingdom. switzerland and china and 5 i ...19957635624
effect of treatment with an ivermectin sustained-release bolus on productivity of stocker beef calves.three groups of 30 crossbred beef steers, 8-10 months of age and ranging in weight from 158 to 320 kg, were used to compare effects of treatment with an ivermectin sustained-release bolus or two ivermectin injectable treatments on parasite control and productivity in relation to untreated controls during a 168 day winter-spring grazing period. each group of 30 consisted of five cattle on each of six separate 1.6 ha pastures. treatments on day 0 (12 december) were: group 1: untreated controls; gr ...19957676602
comparative efficacy of levamisole, thiabendazole and fenbendazole against cattle gastrointestinal nematodes.efficacy of two older anthelmintics, levamisole and thiabendazole, was compared with a newer benzimidazole, fenbendazole, against naturally acquired gastrointestinal nematode infections in cattle superimposed with experimental infections of bunostomum phlebotomum and dictyocaulus viviparus. twenty-four crossbred beef heifers of 7-9 months of age and 152 kg in average weight were randomly allocated to four groups of six calves. the cattle grazed on pastures contaminated with larvae of gastrointes ...19957676603
effectiveness of doramectin for treatment of experimentally induced gastrointestinal tract larval nematode infections in calves.anthelmintic efficacy of doramectin, a macrocyclic lactone of the avermectin family, was evaluated against larval parasitic nematodes in calves. the investigational product was given sc at a dosage of 0.2 mg/kg of body weight to 10 calves infected 6 days previously with third-stage larvae of the genera haemonchus, ostertagia, cooperia, and nematodirus. ten additional calves with identical larval exposure were given saline solution sc also at 6 days after inoculation, and served as the nonmedicat ...19947944021
characterization of a tandemly repetitive dna sequence from haemonchus contortus.genomic dna from the sheep parasitic nematode haemonchus contortus was shotgun cloned in the plasmid vector puc18. recombinants which gave the strongest hybridization signals to 32p-radiolabelled genomic dna were selected as representatives of the repetitive component of the parasite dna. one repetitive sequence which hybridized only with dna from h. contortus and not with dna from two other sheep nematodes (trichostrongylus colubriformis and ostertagia circumcincta) was further characterized by ...19948021102
efficacy of injectable abamectin against gastrointestinal tract nematodes and lungworms of cattle.efficacy of abamectin against gastrointestinal tract nematodes and lungworms of cattle was determined in 4 experiments. the first 2 experiments were controlled trials in which efficacy was determined at necropsy in calves with either experimentally induced (n = 14) or naturally acquired (n = 16) infections. half the calves in each experiment were treated with abamectin (200 micrograms/kg of body weight, sc), and half were left untreated as controls. efficacy was > 99% against adult stages of dic ...19948192257
activity of doramectin against nematode endoparasites of cattle.a series of 28 controlled anthelmintic studies, involving 634 cattle, was conducted throughout north america and europe to evaluate the efficacy of doramectin against a broad range of gastrointestinal parasitic nematode species and lungworms in naturally and experimentally infected animals. within each study, one or two groups were treated with doramectin at 200 micrograms kg-1 and another group received no drug treatment. worm burdens were estimated by standardised techniques, and efficacy asse ...19938236735
efficacy of doramectin against field nematode infections of cattle in latin america.two studies were conducted, one in argentina and one in brazil, to evaluate the therapeutic efficacy of doramectin administered subcutaneously at a dose rate of 200 micrograms kg-1 (1 ml per 50 kg) to cattle harboring mixed field infections of gastrointestinal nematodes. in each trial, 20 heifers were randomly allocated to a control or treated group of ten animals each, on the basis of fecal egg counts. animals in the treated and control groups received an injection of doramectin or saline in th ...19938236736
cloning and characterization of ribosomal rna genes from three species of haemonchus (nematoda: trichostrongyloidea) and identification of pcr primers for rapid differentiation.genomic dnas prepared from adult worms of haemonchus contortus, haemonchus placei, and haemonchus similis were used to clone and map complete ribosomal rna gene repeats from each species. the lengths of the repeating units were estimated at 7.2, 7.2, and 7.4 kb, respectively, with a second and distinct repeat 6.9 kb in length identified from h. contortus only. restriction enzyme recognition sites within all ribosomal rna genes were fully conserved except for the loss of a sali site within the la ...19948299758
ostertagia, haemonchus, cooperia, and oesophagostomum: construction and characterization of genus-specific dna probes to differentiate important parasites of cattle.partial genomic dna libraries for four common cattle parasites, ostertagia ostertagi (oo), haemonchus placei (hp), cooperia oncophora (co), and oesophagostomum radiatum (or), were generated and differentially screened with radiolabeled homologous and heterologous genomic dna. clones were identified from each parasite species which did not cross react with dna from the heterologous genera by southern blot or slot-blot analyses. four clones, poo2, php2.1, pco2, and por14 were chosen for further ex ...19948299764
new morphological characters for identifying individual specimens of haemonchus spp. (nematoda: trichostrongyloidea) and a key to species in ruminants of north america.the large stomach worms haemonchus contortus, haemonchus placei, and haemonchus similis are important pathogens of cattle and sheep. this paper describes characteristics of surface cuticular ridges (synlophe), which for the first time provide morphological criteria for identifying individual adult specimens of either sex. the diagnostic patterns of the synlophe on the anterior half of specimens can be observed at 400x in temporary mounts on glass slides. the synlophe can be studied in cleared pr ...19948308643
antagonistic effect of predacious arthrobotrys fungi on infective haemonchus placei larvae.laboratory experiments were performed to investigate the ability of isolates from the predacious fungus species arthrobotrys conoides (one isolate) and al. robusta (four isolates) to trap and kill infective haemonchus placei larvae. three groups for each isolate were formed: group 1, fungi and infective larvae; group 2, fungi; group 3, infective larvae. there were statistically significant differences (p < 0.05) between the antagonistic effects of three isolates of a. robusta, but there was no s ...19938354858
epizootiology of ostertagia ostertagi in cow-calf production systems in the american midwest.the most common gastrointestinal nematodes found in cattle in the midwest are ostertagia ostertagi and cooperia oncophora. other parasites include haemonchus placei, bunostomum phlebotomum and nematodirus helvetianus. parasite numbers are generally low in this region, as indicated by fecal egg counts and tracer calf worm recoveries, and the numbers of parasites decrease as one travels farther north. this decrease in parasite numbers also corresponds to a similar reduction in the prevalence of cl ...19938484220
influence of host genetics upon antibody responses against gastrointestinal nematode infections in cattle.previous studies have shown that the number of gastrointestinal nematode eggs released per gram of feces (epg) of calves is strongly influenced by host genetics. the purpose of this study was to determine if host genetics also influenced immune recognition of parasite antigens in these same calves. serum samples were taken at monthly intervals from calves during their first grazing season, from approximately 4 months after the onset of calving and were continued until weaning. serum samples were ...19938484226
host movement and the genetic structure of populations of parasitic nematodes.mitochondrial dna (mtdna) sequence data were used to compare the population genetic structures of five species of parasitic nematodes from three different hosts: ostertagia ostertagi and haemonchus placei from cattle, h. contortus and teladorsagia circumcincta from sheep, and mazamastrongylus odocoilei from white-tailed deer. the parasites of sheep and cattle showed a pattern consistent with high gene flow among populations. the parasite of deer showed a pattern of substantial population subdivi ...19958582607
microclimatic effect on vertical migration of haemonchus contortus and haemonchus placei third-stage larvae on irrigated kikuyu pasture.the influence of microclimate on numbers of third-state larvae of haemonchus contortus and haemonchus placei in four strata of irrigated kikuyu pasture was assessed. on 36 different, interspersed days three replicates of pasture samples were collected on three occasions per day from 1990-1992 for larval recovery and the log10 mean counts of the larvae recovered were analysed by use of anova models. because the ground-surface area from which herbage was collected was standardized, estimated larva ...19958600435
efficacy of moxidectin pour-on against gastrointestinal nematodes and dictyocaulus viviparus in cattle.twenty crossbred beef heifer calves were used for an efficacy evaluation of 0.5% moxidectin pour-on against gastrointestinal nematodes and dictyocaulus viviparus. the latter parasite and bunostomum phlebotomum were the target species. the calves were exposed to natural infection on pasture from late september to december 22. additionally, all calves were experimentally infected with b. phlebotomum at 71 and 29 days before treatment and with d. viviparus at 29 days before treatment. the 20 calves ...19968893482
prevalence and epidemiology of trichostrongylids in wyoming cattle with consideration of the inhibited development of ostertagia ostertagi.during 1988, monthly collections of abomasa and the cranial portion of the small intestine of 208 native wyoming cattle were examined for adult and larval helminth parasites. egg counts were performed on colonic faecal specimens. the animals ranged from 7 months to 8 years of age and were sampled at slaughter houses or diagnostic laboratories from five different counties in the state. most of the cattle had ranged for a long time on non-irrigated, high altitude grass plains from about 1250 to 25 ...19968893483
efficacy of moxidectin 0.5% pour-on against naturally acquired nematode infections in cattle.the efficacy of 0.5% moxidectin pour-on at two dosages was evaluated in 30 cattle with naturally acquired gastrointestinal nematode infections. the cattle were ranked according to pretreatment fecal egg counts and body weights, and were randomly assigned from replicates to three treatment groups. the mean number of trichostrongyle eggs in pretreatment fecal samples did not differ among the groups. groups i and ii received 0.5% moxidectin pour-on at dosages of 0.25 mg moxidectin per kg body weigh ...19968916402
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