Populations of free-living stages of Ostertagia ostertagi and O. circumcincta in a winter rainfall region

1983 ◽  
Vol 34 (5) ◽  
pp. 569 ◽  
Author(s):  
RR Young
Keyword(s):  
Population Dynamics ◽  
Survival Rate ◽  
Larval Survival ◽  
Moisture Loss ◽  
Free Living ◽  
Winter Rainfall ◽  
Faecal Pellets ◽  
Infective Larvae ◽  
Cattle Faeces ◽  
Rainfall Region

Pats of cattle faeces containing eggs of the trichostrongylid Osferfagia ostertagi and deposits of sheep faecal pellets containing eggs of O. circumcincta were placed on dry and irrigated pasture plots at four times during the period October 1977 to February 1978. Faecal pellets lost moisture far more rapidly than did dung pats. The rate of moisture loss from both faecal deposits was greater on dry plots than on irrigated plots. Despite large differences between irrigated and dry plots in soil temperature and soil and pasture moisture status, the temperatures recorded in both dung pats and faecal pellets were similar on all plots at each time of deposition. A significantly greater proportion of O . circumcincta eggs was recovered as infective larvae in faeces, on herbage and in soil compared with that of O. osterfagi eggs. Irrigation did not result in either substantially more eggs developing to infective larvae in faeces or higher recoveries of larvae from herbage and soil. No significant differences were detected in temperature or moisture measurements or in parameters of free-living development and larval survival between plots with long or short pasture herbage. There were marked differences between the population dynamics of the infective larvae of Ostertagia spp. and between the numbers of larvae on irrigated and dry plots. On dry plots, O . circumcincta migrated in abundance from faecal deposits after smaller falls of rain than were required for migration of O . ostertagi larvae. Larvae of both species persisted in abundance on the herbage of most dry plots until late spring. On irrigated plots, migration of both species of larvae occurred immediately and was independent of rainfall, but survival rate of larvae was lower than on the corresponding dry plots.

The ecology of the free-living stages of Ostertagia ostertagi in a winter rainfall region

1981 ◽  
Vol 32 (2) ◽  
pp. 371 ◽  
Author(s):  
RR Young ◽  
N Anderson
Keyword(s):  
Developmental Stages ◽  
Mortality Rates ◽  
Wide Distribution ◽  
Early Spring ◽  
Initial Population ◽  
Free Living ◽  
Infective Larvae ◽  
Cattle Faeces ◽  
Eggs And Larvae ◽  
Rainfall Region

On a series of pasture plots, 500 g pats of cattle faeces containing eggs of the trichostrongylid Ostevtagia ostertagi were deposited at intervals of about 6 weeks from June 1976 to June 1977. The development and survival of eggs and larvae in dung pats and the survival of larvae on surrounding herbage and soil were measured and expressed as a percentage of the initial population of eggs. During summer months comparisons were made between the pats on irrigated and those on non-irrigated plots. Minimum temperatures within dung pats were always greater than those required for development, and infective larvae were recovered from all plots. The onset of development was delayed from 3 to 12 days in summer and from 34 to 68 days in winter, which led to a wide distribution of developmental stages. Rates of development were closely related to the temperatures in soil and dung pats, and mortality rates of pre-infective stages increased very rapidly with increasing temperatures and decreasing moisture levels. Infective larvae were present in abundance on herbage and in soil between 6 and 10 weeks after deposition, provided that the moisture content of these was high. Mortality of these larvae was low during winter and early spring but increased rapidly in mid- to late spring, irrespective of the time of deposition of dung pats. Mortality rates of infective larvae in dung pats deposited in either spring or summer were low and a large proportion of these larvae were capable of moving into herbage and soil after autumn rains. Irrigation during summer did not provide ideal conditions for the development of infective larvae from eggs, but hastened larval migration from dung pats.

scholarly journals Recovery of Trichostrongylus colubriformis infective larvae from three grass species contaminated in the autumn

2012 ◽  
Vol 21 (4) ◽  
pp. 372-378 ◽  
Author(s):  
Raquel Abdallah da Rocha ◽  
Patrizia Ana Bricarello ◽  
Gilberto Pedroso da Rocha ◽  
Alessandro Francisco Talamini do Amarante
Keyword(s):  
Dry Matter ◽  
Cynodon Dactylon ◽  
Larval Survival ◽  
Grass Species ◽  
Panicum Maximum ◽  
Free Living ◽  
Trichostrongylus Colubriformis ◽  
Brachiaria Decumbens ◽  
Infective Larvae ◽  
Experimental Plots

This experiment aimed to assess the recovery of infective larvae (L3) of Trichostrongylus colubriformis from Brachiaria decumbens cv. Australiana, Cynodon dactylon cv. Coast-cross and Panicum maximum cv. Aruana. The experimental module comprised six plots, with two plots per herbage species. Larval survival was assessed from autumn to winter, under the effect of two herbage-paring heights (5 and 30 cm). TThe paring was carried out immediately before contamination with faces containing T. colubriformis eggs. The feces and herbage were collected at one, two, four, eight, 12 and 16 weeks after feces had been deposited in the experimental plots. In general, larvae were recovered from both herbage and feces until the 16th week. The longer persistence of these larvae in the environment was probably due to warmer temperatures. The number of L3 recovered from the pasture was not influenced by the height of plants, except for Brachiaria and Aruana herbage in the fourth week. Regarding the concentrations of larvae per kg of dry matter (L3/kg DM), recovery was higher from low pasture in all three herbage species. During the autumn, the development and survival of the T. colubriformis free-living stages were not affected by the different herbage species.

Observations on the bionomics of the free-living stages of Trichostrongylus vitrinus

1984 ◽  
Vol 58 (1) ◽  
pp. 49-58 ◽  
Author(s):  
J. H. Rose ◽  
A. J. Small
Keyword(s):  
Tap Water ◽  
Climatic Conditions ◽  
Cold Weather ◽  
Free Living ◽  
Faecal Pellets ◽  
Infective Larvae ◽  
Laboratory Development ◽  
The Relationship ◽  
Very High ◽  
Continuous Freezing

AbstractEggs of Trichostrongylus vitrinus in faecal pellets deposited on grass plots each month from April 1981 to March 1982 developed into infective larvae. From October to March development was slow and mortality of the pre-infective stages was very high. From April to September development was more rapid. The weather was generally dry and mortality of the pre-infective stages was high on plots with short herbage but was lower on most of the plots with long herbage, especially in July and August. In the laboratory, development of eggs into infective larvae was completed at temperatures ranging from 4°C to 27°C in faecal pellets which were either kept moist or dried out slowly, but not in faecal pellets which dried out rapidly. The rate of development increased as the temperature rose. Infective larvae survived for up to 16 months on the herbage of grass plots; some survived during very cold weather in the winter of 1981/82. In the laboratory, infective larvae suspended in tap water survived even longer at 4°C and 10°C but not at higher temperatures. They were rapidly killed by continuous freezing. They Survived for up to 8 weeks when subjected to desiccation, The relationship between climatic conditions and the development and survival of the free-living stages is discussed

Trichostrongylid infections of sheep in a winter rainfall region. II. Epizootiological studies in the western district of Victoria, 1967-68

1973 ◽  
Vol 24 (4) ◽  
pp. 599 ◽  
Author(s):  
N Anderson
Keyword(s):  
Weather Conditions ◽  
Mucosal Damage ◽  
Anthelmintic Treatment ◽  
Free Living ◽  
Winter Rainfall ◽  
Wool Production ◽  
Adult Sheep ◽  
The Relationship ◽  
Region Ii ◽  
Rainfall Region

Mean counts of O. circumcincta and Trichostrongylus spp. from groups of 'tracer' sheep ranged between 220 and 2150 per fortnight between June and October and were less than 100 per fortnight from November to February inclusive. O. circumcincta was more numerous than Trichostrongylus spp. The relatively low numbers of available larvae were attributed to the dry weather conditions in autumn which did not favour development and survival of the free-living stages. Between May and December 1967, worm numbers increased linearly in weaner sheep to reach mean levels of 14,000 without any detectable resistance to reinfection or significant decrease in liveweight gain or wool production. Correlations between mean plasma pepsinogen concentrations from weaner and adult sheep and 'tracer' worm burdens were significantly different; r = 0.37 and 0.47 for weaners and r = 0.8 for adult sheep. Thus the relationship between larval intake and abomasal damage as reflected by plasma pepsinogen concentrations is not a simple one. Mucosal damage is probably preceded by a hypersensitive state. Anthelmintic treatment, given in October and January, reduced the worm egg output of treated sheep to one-tenth that of untreated sheep for a period of 18 weeks between October and March.

STUDIES ON STRONGYLOIDES OF PRIMATES: IV. EFFECT OF TEMPERATURE ON THE MORPHOLOGY OF THE FREE-LIVING STAGES OF STRONGYLOIDES FULLEBORNI

1958 ◽  
Vol 36 (4) ◽  
pp. 623-628 ◽  
Author(s):  
Premvati
Keyword(s):  
Morphological Changes ◽  
Effect Of Temperature ◽  
Optimum Temperature ◽  
Free Living ◽  
Infective Larvae ◽  
Complete Development

The optimum temperature for the complete development of the free-living and the infective larvae of Strongyloides fülleborni is 25 °C. Morphological changes are seen at higher or lower temperatures.

Occurrence of putatively resistant plantago in the winter rainfall region of South Africa: a survey

2021 ◽  
Vol 38 (5) ◽  
pp. 411-415
Author(s):  
Vhuthu Ndou ◽  
Ethel E Phiri ◽  
Frederik H Eksteen ◽  
Petrus J Pieterse
Keyword(s):  
South Africa ◽  
Winter Rainfall ◽  
Rainfall Region

The ecology of immature phases of Trichostrongyle nematodes: II. The effect of climatic factors on the availability of the infective larvae of Trichostrongylus retortaeformis to the host

Parasitology ◽  
1948 ◽  
Vol 39 (1-2) ◽  
pp. 26-38 ◽  
Author(s):  
H. D. Crofton
Keyword(s):  
Climatic Factors ◽  
Faecal Pellet ◽  
Cold Weather ◽  
Maximum Temperature ◽  
Infective Stage ◽  
Faecal Pellets ◽  
Infective Larvae ◽  
High Death ◽  
Maximum Temperatures ◽  
Rate Of Evaporation

1. Eggs and larvae of Trichostrongylus retortaeformis were used.2. The rate of hatching of eggs was shown to be mainly related to temperature. From November to March, when maximum temperatures were below 50° F., there was no hatching. When maximum temperatures of 50–55° F. occurred eggs hatched on or before the fifteenth day, but never during the first 8 days. Eggs hatched in 8 days or less when maximum temperatures of 60–80° F. occurred.3. When the rate of evaporation in the air was high, eggs still hatched and reached the infective stage, the grass blades reducing the rate of loss of moisture from the faecal pellet. Laboratory experiments show that eggs may not develop to the infective stage if the faecal pellets are on a grassless portion of the pasture. This is most likely to occur when the rate of evaporation is high and the temperature low.4. Hatching may be delayed by cold conditions, but some eggs remain viable for long periods and they hatch when the temperature rises. Eggs passed by the host in the autumn can survive a cold winter and hatch in the spring, but eggs passed during the coldest period die.5. During periods when the maximum temperature never exceeded 55° F., little or no migration of larvae occurred. When temperatures rose above 55° F. the number of larvae migrating increased; but rise of temperature was associated with increase in the rate of evaporation. High rates of evaporation reduced the number of larvae migrating on the grass blades.6. Some infective larvae died soon after exposure on grass plots, but a small number survived long periods. In cold weather some larvae were still alive after 20 weeks. A high death-rate occurred in warm weather. A large proportion of the larvae died during periods in which the rate of evaporation was high; in one of these periods 95% of the larvae were dead at the end of 4 weeks' exposure.7. The number of larvae on grass blades of a pasture was shown to be dependent, at any time, upon the climate at that time, and upon past conditions which had influenced hatching and survival:

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