Availability to grazing sheep of gastrointestinal nematode infection arising from summer contamination of pastures

1978 ◽  
Vol 29 (1) ◽  
pp. 189 ◽  
Author(s):  
AD Donald ◽  
FHW Morley ◽  
PJ Waller ◽  
A Axelsen ◽  
JR Donnelly
Keyword(s):  
Haemonchus Contortus ◽  
Subterranean Clover ◽  
Summer Rainfall ◽  
Gastrointestinal Nematode ◽  
Infected Sheep ◽  
Grazing Management ◽  
Late Winter ◽  
Nematode Eggs ◽  
Autumn And Winter ◽  
Clover Pasture

In two successive years, separate phalaris-subterranean clover pasture plots near Canberra were contaminated with nematode eggs by grazing with naturally infected sheep in each of the summer months (December, January, February) and the first month of autumn (March). At intervals until mid- to late winter, the availability of infection on pasture was estimated by grazing with worm-free 'tracer' lambs which were subsequently slaughtered for worm counts. Summer rainfall in both years was above average. Tracer counts of Haemonchus contortus and Ostertagia, Trichostrongylus and Nematodirus spp. per l08 eggs per hectare remained high during summer, with evidence that migration of larvae to the herbage could continue for at least 2 months after contamination. Rates of decline in tracer worm counts over the autumn and winter did not differ between years, and from an assumed maximum 2 months after contamination in each of the summer months, were fastest from December and slowest from February contamination. These rates were similar for all genera on December-contaminated plots, but on January and February plots, Ostertagia spp. declined more slowly. H. contortus numbers fell sharply in early autumn to be low by the end of May. By mid July there would be few larvae of all genera available on pastures contaminated in December and January, but this is less certain on February-contaminated pastures, especially for Ostertagia spp. Implications for the control of nematode infections in sheep by anthelmintic treatment and grazing management are considered.

Voluntary intake of a medicated feed block by grazing sheep is increased by gastrointestinal nematode infection

2012 ◽  
Vol 52 (12) ◽  
pp. 1136
Author(s):  
F. J. Fishpool ◽  
L. P. Kahn ◽  
D. J. Tucker ◽  
J. V. Nolan ◽  
R. A. Leng
Keyword(s):  
Haemonchus Contortus ◽  
Gastrointestinal Nematode ◽  
Gastrointestinal Nematodes ◽  
Infected Sheep ◽  
Self Medication ◽  
Blood Samples ◽  
Voluntary Intake ◽  
Grazing Sheep ◽  
Long Acting ◽  
To Receive

The aim of this study was to determine the rate, variability and repeatability of intake by grazing sheep of a medicated feed block (MFB) containing fenbendazole and investigate if infection with gastrointestinal nematodes altered consumption patterns of the MFB in the same grazing mob. In Experiment 1, 30 Merino wethers were given access to an MFB for two separate 1-week periods, with blood sampling at Days 2, 4 and 6 of each period to determine MFB intake. In Experiment 2, the wethers were selected based on previous MFB intake and allocated to receive an oral dose of 10 000 Trichostrongylus colubriformis and 3000 Haemonchus contortus (anthelmintic susceptible) or a long acting anthelmintic. After 5 weeks, sheep were given access to an MFB (1.5 mg fenbendazole/g) and eight blood samples were taken over 2 weeks to determine intake. In Experiment 1, individual MFB intake in Week 1 and Week 2 was positively correlated (P = 0.002, R2 = 0.287). Mean individual MFB intake in Experiment 1 and Experiment 2 was positively correlated (P = 0.008, R2 = 0.047). In Experiment 2, more infected wethers (95%) consumed the MFB than did uninfected wethers (79%) (P < 0.001) and infected wethers ate significantly more MFB over the first 4 days (P = 0.041) of access. All infected sheep consumed sufficient MFB to receive a therapeutic dose and worm egg counts in infected sheep declined from 2165 epg to 120 epg in the first week of access to MFB. The decline in differences in MFB intake between infected and uninfected sheep corresponded to the decline in worm egg count, suggesting the existence of self-medication with parasitism accounting for intake differences.

Nitrogen fertiliser use on rain-fed pasture in the Mt Lofty Ranges, SouthAustralia. 2. Responses of perennial grasses, Tama ryegrass, andsod-sown oats to nitrogen fertiliser and cutting frequency

2003 ◽  
Vol 43 (6) ◽  
pp. 579 ◽  
Author(s):  
D. E. Elliott ◽  
R. J. Abbott
Keyword(s):  
Perennial Ryegrass ◽  
South Australia ◽  
Subterranean Clover ◽  
Perennial Grasses ◽  
Late Winter ◽  
Nitrogen Fertiliser ◽  
Cutting Frequency ◽  
Series Of Experiments ◽  
Fertiliser Application ◽  
Autumn And Winter

Two series of experiments were conducted in the Mt Lofty Ranges, South Australia, to examine, in a grass–subterranean clover pasture, the contribution of the companion grass to herbage mass and the responsiveness to the application of nitrogen (N) fertiliser. The first study examined the responsiveness, to a single rate of N, of grass–clover pastures containing either Tama ryegrass, sod-sown oats or 1 of 4 perennial grasses, viz. Victorian perennial ryegrass, Demeter fescue, Currie cocksfoot or Australian phalaris. These were compared in 2 experiments, under 3��different cutting frequencies at 3 periods during the growing season. In the other study, consisting of 12�experiments, the response to increasing rate of N fertiliser application of sod-sown oats or the existing pasture were compared over a 3-month period following N fertiliser application in autumn.In autumn and winter, all pastures responded significantly to N fertiliser, whereas in spring, the proportion of clover in each pasture and its growth determined whether or not there was a response to N fertiliser. Clover composition of pastures declined with N application, but clover was not eliminated from swards by application of 210 kg N/ha a year. In both series of experiments, pastures that established well with a high density of sod-sown oats out-yielded all other pastures in autumn and winter, whether the swards were unfertilised or received regular N fertiliser applications. In late winter, pastures sod-sown with Tama ryegrass yielded as well as the pasture sod-sown with oats, and enhanced spring growth significantly compared with perennial ryegrass. However, spring production of Tama ryegrass was poorer than that of perennial ryegrass, and overall no increase in annual production occurred. Of the perennial grasses, the highest yielding when N fertiliser was applied were Currie cocksfoot and perennial ryegrass (yielding in autumn), phalaris (winter), and perennial ryegrass and Demeter fescue (spring). Increased cutting frequency depressed the herbage mass response to N fertiliser following the initial application, but increased herbage N concentration of all pastures and also increased the final clover composition of N-fertilised pasture of 4�pasture types.

Effects of irrigation timing in autumn and spring on seed production of subterranean clover, and the change in permeability and rate of germination of seed

1987 ◽  
Vol 27 (6) ◽  
pp. 799 ◽  
Author(s):  
KB Kelly ◽  
WK Mason
Keyword(s):  
Seed Production ◽  
Subterranean Clover ◽  
Late Summer ◽  
Summer Rainfall ◽  
Late Winter ◽  
Germination Test ◽  
Seed Burial ◽  
Feed Production ◽  
Large Influence ◽  
Number Of Seeds

The effects of time of initial irrigation in late summer-autumn and final irrigation in spring on the amount of seed present, seed burial, relative proportions of each cultivar and changes in seed permeability with time were studied in mixed cultivar swards (cvv. Clare, Woogenellup and Trikkala) of subterranean clover. Irrigation treatments were 3 times of initial irrigation (1 February, 1 March and 1 April) combined with 2 times of final irrigation (mid October and mid November) from 1982 to the autumn of 1985. Seed was sampled 3 times per year; in mid December, prior to initial irrigation and in late winter. The timing of the first irrigation in autumn had no effect on the number of seed present in December which averaged 55,57 and 78 seeds/dm2 in 1982, 1983 and 1984 respectively. Time of final irrigation in spring had a large influence on the number of seeds present in mid December, with a 3-year average of 42 seeds/dm2 for the mid October treatment and 85 seeds/dm2 for the mid November treatment. Rainfall in summer and early autumn reduced the number of seed present between December and the initial irrigation. Residual seed measured in late winter accounted for 18% of the seed present in the previous December and was mostly located below the ground. Without summer rainfall, the proportion of permeable seed averaged over all cultivars increased from approximately 20% in mid December to 40, 60 and 70% in February, March and April respectively. The rate of germination of permeable seed was influenced by time of sampling, temperature of germination test (15 and 30�C), the incidence of rainfall, and the type of cultivar. The limitations of current subterranean clover cultivars under irrigated conditions are discussed and an outline of the characteristics required by cultivars to be used under irrigation is presented, with particular reference to autumn feed production.

Factors affecting the productivity of irrigated annual pastures. 1. Time of first irrigation in late summer-early autumn

1986 ◽  
Vol 26 (3) ◽  
pp. 297 ◽  
Author(s):  
CR Stockdale
Keyword(s):  
Nitrogen Content ◽  
Irrigation Treatment ◽  
Subterranean Clover ◽  
Late Summer ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Factors Affecting ◽  
Autumn And Winter ◽  
Clover Content

The influence of time of first irrigation (mid-February, early March, or late March) on the productivity of an annual pasture was studied for 3 years in northern Victoria. Beginning the irrigation of annual pastures in late summer instead of at the normal time of late March- April provided additional herbage in autumn and winter and did not adversely affect herbage production in late winter-early spring; up to 2.3 t/ha DM of additional herbage was obtained by mid June and 4.3 t/ha DM over the whole season. Earlier irrigation also increased the subterranean clover content of the pasture, resulting in herbage that was lower in digestibility and higher in nitrogen content than that in the other treatments. The benefit of early irrigation in increasing clover content may be offset by invasion by weeds. In this experiment, a potential weed problem in the earliest irrigation treatment appeared at the beginning of year 3.

Barley grass control with herbicides in subterranean clover pasture. 1. Effect on pasture in the year of spraying

1993 ◽  
Vol 33 (6) ◽  
pp. 737 ◽  
Author(s):  
DW Stephenson ◽  
GJ Mitchell
Keyword(s):  
Dry Matter ◽  
Subterranean Clover ◽  
Ground Cover ◽  
Dry Matter Production ◽  
Late Winter ◽  
Pasture Production ◽  
Leaf Stage ◽  
Early Removal ◽  
Matter Production ◽  
Clover Pasture

Barley grass (Hordeum spp.) in a subterranean clover pasture was controlled with herbicides in the time between the 2-3 leaf stage and flowering. The effects on subsequent pasture production and composition were measured and the interaction between grazing and herbicides was also assessed. Early removal of barley grass reduced dry matter production in winter by an average of 41%. It also allowed an incursion of Indian hedge mustard (Sisymbrium orientale L.). which was suppressed by grazing but comprised an average of 23% ground cover in ungrazed pasture. Loss of total pasture production decreased as the date of herbicide application was delayed from June to September. Broadleaf species compensated for the early removal of barley grass, so that total dry matter production in spring in herbicide-treated areas was higher than in the unsprayed pasture. Fluazifop-p at 32, 53, and 106 g a.i/ha gave, respectively, 94, 91, and 94% reduction in barley grass seedhead density when applied at the 2-3 leaf stage, and 64, 88, and 98% reduction when applied at mid jointing. Application of this herbicide at 53 or 106 g a.i/ha for barley grass control can be delayed until late winter, thereby maintaining winter feed production but avoiding declining palatability and awned barley grass seeds.

scholarly journals Ovine CD14- an Immune Response Gene Has a Role Against Gastrointestinal Nematode Haemonchus contortus—A Novel Report

2021 ◽  
Vol 12 ◽  
Author(s):  
Kavita Rawat ◽  
Aruna Pal ◽  
Samiddha Banerjee ◽  
Abantika Pal ◽  
Subhas Chandra Mandal ◽  
...  
Keyword(s):  
Immune Response ◽  
Haemonchus Contortus ◽  
Evolutionary Relationship ◽  
Gastrointestinal Nematode ◽  
Infected Sheep ◽  
Model Organisms ◽  
Immune Response Gene ◽  
Response Gene ◽  
Amino Terminal

CD14 (also known as the monocyte differentiation antigen) is an important immune response gene known to be primarily responsible for innate immunity against bacterial pathogens, and as a pattern recognition receptor (PRR), binds with LPS (endotoxin), lipoproteins, and lipotechoic acid of bacteria. So far very limited work has been conducted in parasitic immunology. In the current study, we reported the role of CD14 in parasitic immunology in livestock species (sheep) for the first time. Ovine CD14 is characterized as a horse-shoe shaped bent solenoid with a hydrophobic amino-terminal pocket for CD14 along with domains. High mutation frequency was observed, out of total 41 mutations identified, 23 mutations were observed to be thermodynamically unstable and 11 mutations were deleterious in nature, causing major functional alteration of important domains of CD14, an indication of variations in individual susceptibility for sheep against Haemonchus contortus infestations. In silico studies with molecular docking reveal a role of immune response against Haemonchus contortus in sheep, which is later confirmed with experimental evidence through differential mRNA expression analysis for sheep, which revealed better expression of CD14 in Haemonchus contortus infected sheep compared to that of non-infected sheep. We confirmed the above findings with supportive evidence through haematological and biochemical analyses. Phylogenetic analysis was conducted to assess the evolutionary relationship with respect to humans and it was observed that sheep may well be used as model organisms due to better genetic closeness compared to that of mice.

scholarly journals Gastrointestinal nematode infections in sheep raised in Botucatu, state of São Paulo, Brazil

2014 ◽  
Vol 23 (3) ◽  
pp. 348-354 ◽  
Author(s):  
Maurício Orlando Wilmsen ◽  
Bruna Fernanda Silva ◽  
César Cristiano Bassetto ◽  
Alessandro Francisco Talamini do Amarante
Keyword(s):  
Haemonchus Contortus ◽  
Natural Infection ◽  
Gastrointestinal Nematode ◽  
Gastrointestinal Nematodes ◽  
Sao Paulo ◽  
São Paulo ◽  
Mean Intensity ◽  
Oesophagostomum Columbianum ◽  
The Mean ◽  
In Parenthesis

Gastrointestinal nematode infections were evaluated in sheep raised in Botucatu, state of São Paulo, Brazil between April 2008 and March 2011. Every month, two tracer lambs grazing with a flock of sheep were exposed to natural infection with gastrointestinal nematodes for 28 consecutive days. At the end of this period, the lambs were sacrificed for worm counts. Haemonchus contortus presented 100% of prevalence. The seasons exerted no significant influence on the mean intensity of H. contortus, which ranged from 315 worms in November 2010 to 2,5205 worms in January 2011. The prevalence of Trichostrongylus colubriformis was also 100%, with the lowest mean intensity (15 worms) recorded in February 2011 and the highest (9,760 worms) in October 2009. In the case of T. colubriformis, a significant correlation coefficient was found between worm counts vs. rainfall (r = −0.32; P <0.05). Three other nematodes species were found in tracer lambs, albeit in small numbers. Their prevalence and mean intensity (in parenthesis) were as follows: Oesophagostomum columbianum 28% (25.2), Cooperia curticei 7% (4.5) and Trichuris spp. 2% (1). In conclusion, the environmental conditions of the area proved to be highly favorable for the year-round transmission of H. contortus and T. colubriformis.

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