| distribution of ostertagia ostertagi infective larvae on pasture herbage. | | 1973 | 4748245 |
| effect of gastrointestinal nematode and liver fluke infections on weight gain and reproductive performance of beef heifers. | spring born, crossbred beef heifers (n=372) were utilized over four years to measure reductions in body weights, reproductive performance and calf weights caused by gastrointestinal nematodes (primarily ostertagia ostertagi) and the bovine liver fluke (fasciola hepatica) and to differentiate losses attributable to each type of parasitism. each year, weaned heifers were allotted to one of the four treatment regimens: group 1, untreated controls; group 2, treated for nematodes; group 3, treated fo ... | 2002 | 12127252 |
| seasonal changes of gastrointestinal nematode populations in yearling beef cattle in louisiana with emphasis on prevalence of inhibition in ostertagia ostertagi. | | 1983 | 6853015 |
| comparative efficacy of ivermectin pour-on, albendazole, oxfendazole and fenbendazole against ostertagia ostertagi inhibited larvae, other gastrointestinal nematodes and lungworm of cattle. | an experiment was conducted to evaluate the current efficacy of albendazole (abz), oxfendazole (oxf) and fenbendazole (fbz) compared with ivermectin pour-on (ivm-po) against inhibited early fourth-stage larvae (iel4) of ostertagia ostertagi, other gastrointestinal nematodes and lungworm of cattle during spring in louisiana. twenty-five crossbred beef heifer calves of 235 kg average weight and 10-12 months of age were acquired in late winter and grazed for 9 weeks on pasture contaminated with o. ... | 1997 | 9477494 |
| additional investigations on hypobiosis of ostertagia ostertagi after transfer between northern and southern u.s.a. | | 1988 | 3372123 |
| efficacy of levamisole against ostertagia ostertagi in louisiana cattle during maturation of inhibited larvae (september) and during minimal inhibition (december/january). | levamisole (lev) was tested in four experiments to compare efficacy values against ostertagia ostertagi when larval maturation was occurring (september), following inhibition and also when populations were expected to be largely adult (winter). a primary objective was to determine the importance of developing fourth-stage larvae (dl4) and inhibited, early fourth-stage larvae (el4) in replacing adult worms lost through treatment and the effect of this on reduced efficacy against adult worms. youn ... | 1991 | 1763492 |
| sequential histopathologic changes of type i, pre-type ii and type ii ostertagiasis in cattle. | yearling cattle in louisiana were examined at monthly intervals for abomasal nematode burdens and histological lesions over a year. tracer calves were grazed for 3 to 4 weeks and removed from pasture for 2 to 3 weeks, then slaughtered; a few animals were killed in extremis shortly after removal from pasture. histological changes were correlated with worm burdens and characterized according to the type of ostertagia ostertagi infection present. in cattle with acute type i ostertagiasis, changes v ... | 1988 | 3363843 |
| 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 |
| develpoment and survival of infective larvae of the cattle nematode, ostertagia ostertagi. | | 1971 | 5102817 |
| 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 |