Parasitism and production in weaner sheep grazing alternately with cattle

1978 ◽  
Vol 18 (92) ◽  
pp. 340 ◽  
Author(s):  
IA Barger ◽  
WH Southcott
Keyword(s):  
Haemonchus Contortus ◽  
Cattle Grazing ◽  
Sheep Grazing ◽  
Trichostrongylus Colubriformis ◽  
The Third ◽  
Cooperia Oncophora ◽  
Faecal Egg Counts

Three systems for the post-weaning management of Merino wethers were compared over two years. In all systems, the sheep were given two anthelmintic treatments with levamisole per year; at weaning in January, and in July. In the first system (SC) the same paddock was used as a weaning paddock each year in succession. In the second system (SC 6) sheep and cattle grazed the paddock alternately for 6- month periods from January and July; the third system (SC 12) comprised sheep and cattle grazing alternately for 12-month periods from July of each year. Compared with the SC treatment, weaners from the SC 6 treatment had significantly lower faecal egg counts and lower burdens of Haemonchus contortus, Trichostrongylm axei, Trichostrongylus colubriformis and Nematodirus spp. They had significantly higher numbers of Cooperia oncophora and similar numbers of Ostertagia circumcincta. SC 6 sheep made greater liveweight gains, produced heavier fleeces, and suffered lower mortalities than their SC counterparts. Results for the SC 12 system were usually intermediate. In a third year, the SC 12 system was modified to include a monthly treatment with levamisole. The liveweight gains, egg counts and mortalities of the monthly treatment sheep did not differ significantly from those of the SC 6 sheep. Both systems were superior to the SC treatment in controlling nematode infections in weaner sheep. There were no significant effects of any treatment on liveweight gains of cattle, although outbreaks of ostertagiosis occurred in the third year in two of the four replicates of the SC system.

The comparative efficacy of oxfendazole administered as bolus and suspension to naturally infected sheep in Greece

1986 ◽  
Vol 60 (3) ◽  
pp. 245-249
Author(s):  
C. A. Himonas ◽  
J. Theodorides
Keyword(s):  
Body Weight ◽  
Dose Rate ◽  
Active Ingredient ◽  
Haemonchus Contortus ◽  
Infected Sheep ◽  
Comparative Efficacy ◽  
Cooperia Oncophora ◽  
Oesophagostomum Columbianum ◽  
Faecal Egg Counts ◽  
Moniezia Expansa

AbstractIn a flock of 20 ewes naturally infected with those parasites of sheep most common in Greece, and kept indoors during the whole trial, oxfendazole at the dose rate of approximately 2–9 and 2–8 mg/kg body-weight was tested as a 4 g bolus containing 112 mg active ingredient and a 2–265% suspension. The evaluation of its efficacy was based on the necropsy findings which were also supported by faecal egg counts. No differences in efficacy were noticed between the two formulations of the drug. Both bolus and suspension proved to be 100% effective against Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus axei, T. colubriformis and Chabertia ovina. The efficacy against Cooperia oncophora, Nematodirus spathiger, Bunostomum trigonocephalum, Oesophagostomum columbianum and Moniezia expansa could not be evaluated, because these species, though not found in any of the treated animals, were found in fewer than three controls.

The use of irradiated larvae as immunizing agents in Haemonchus contortus and Trichostrongylus colubriformis infections in sheep

1961 ◽  
Vol 12 (6) ◽  
pp. 1175 ◽  
Author(s):  
W Mulligan ◽  
HMcL Gordon ◽  
DF Stewart ◽  
BM Wagland
Keyword(s):  
Haemonchus Contortus ◽  
Significant Proportion ◽  
X Rays ◽  
Fourth Stage ◽  
Trichostrongylus Colubriformis ◽  
The Third ◽  
Moderately Resistant ◽  
Experimental Challenge

Six of 10 lambs previously given two doses of irradiated (60 kr) Haemonchus contortus larvae showed solid resistance to an experimental challenge with 10,000 larvae. The remaining four lambs in the group developed moderate infections. Nine of 10 lambs previously given two doses of irradiated (80 kr) Trichostrongylus colubriformis larvae showed solid resistance to an experimental challenge with 30,000 larvae. The 10th lamb was moderately resistant. Doses of X-rays within the range 40–100 kr had no effect on the exsheathment of H. contortus in the rumen, but few male worms developed as far as the fourth stage. It seems likely that the irradiated males and possibly a significant proportion of the irradiated females are unable to complete the ecdysis from the third to the fourth stage.

scholarly journals Epidemiologia das helmintoses gastrintestinais de ovinos no Planalto Catarinense

2004 ◽  
Vol 34 (6) ◽  
pp. 1889-1895 ◽  
Author(s):  
César Itaqui Ramos ◽  
Valdomiro Bellato ◽  
Antonio Pereira de Souza ◽  
Volney Silveira de Avila ◽  
Guilherme Caldeira Coutinho ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Santa Catarina ◽  
Trichostrongylus Colubriformis ◽  
Ostertagia Ostertagi ◽  
Cooperia Oncophora ◽  
Teladorsagia Circumcincta ◽  
Intestino Delgado

Este trabalho foi desenvolvido em três propriedades rurais nos municípios de Lages, São Joaquim e Campos Novos, estado de Santa Catarina, com os objetivos de determinar a prevalência, a intensidade e a variação sazonal de helmintos gastrintestinais e pulmonares em ovinos no Planalto Catarinense. Com base nos resultados aintenção é propor um esquema estratégico de controle. Para isso, foram utilizados mensalmente três cordeiros traçadores por propriedade, os quais, antes de serem conduzidos às mesmas, foram estabulados por 30 dias e executados tratamentos supressivos com anti-helmínticos de diferentes princípios ativos, com exames parasitológicos semanais para verificar a total eliminação de infecção parasitária. A seguir, foram encaminhados às três propriedades onde permaneceram em pastejo por 28 dias, sendo posteriormente recolhidos ao estábulo por mais 20 dias. Após foram sacrificados e realizada a coleta de alíquotas de 10% dos conteúdos do abomaso e intestino delgado, todos os helmintos do intestino grosso e pulmão. As maiores infecções por Haemonchus contortus ocorreram durante o período de outubro a março. O parasitismo por Trichostrongylus axei e Trichostrongylus colubriformis teve índices crescentes ao longo dos anos experimentais, apresentando maior pico de maio a outubro de 1999. Predominaram as espécies, no abomaso: Haemonchus contortus (100%); Trichostrongylus axei (98,7%); Trichostrongylus colubriformis (1,3%); Teladorsagia circumcincta (100%); Ostertagia ostertagi (100%). No intestino delgado: Trichostrongylus colubriformis (100%); Cooperia punctata (69,1%); Cooperia pectinata (18,4%); Cooperia curticei (6,9%); Cooperia oncophora (4,8%); Cooperia spatulata (0,8%) e Nematodirus spathiger (100%). No intestino grosso: Oesophagostomum venulosum (100%) e Trichuris ovis (100%). No pulmão, não foram encontrados parasitos.

Nematode ligand-gated chloride channels: an appraisal of their involvement in macrocyclic lactone resistance and prospects for developing molecular markers

Parasitology ◽  
2007 ◽  
Vol 134 (8) ◽  
pp. 1111-1121 ◽  
Author(s):  
S. McCAVERA ◽  
T. K. WALSH ◽  
A. J. WOLSTENHOLME
Keyword(s):  
Haemonchus Contortus ◽  
Chloride Channels ◽  
Macrocyclic Lactone ◽  
Parasitic Nematodes ◽  
C Elegans ◽  
Molecular Tests ◽  
Cooperia Oncophora ◽  
Macrocyclic Lactone Resistance ◽  
High Level ◽  
Laboratory Models

SUMMARYLigand-gated chloride channels, including the glutamate-(GluCl) and GABA-gated channels, are the targets of the macrocyclic lactone (ML) family of anthelmintics. Changes in the sequence and expression of these channels can cause resistance to the ML in laboratory models, such as Caenorhabditis elegans and Drosophila melanogaster. Mutations in multiple GluCl subunit genes are required for high-level ML resistance in C. elegans, and this can be influenced by additional mutations in gap junction and amphid genes. Parasitic nematodes have a different complement of channel subunit genes from C. elegans, but a few genes, including avr-14, are widely present. A polymorphism in an avr-14 orthologue, which makes the subunit less sensitive to ivermectin and glutamate, has been identified in Cooperia oncophora, and polymorphisms in several subunits have been reported from resistant isolates of Haemonchus contortus. This has led to suggestions that ML resistance may be polygenic. Possible reasons for this, and its consequences for the development of molecular tests for resistance, are explored.

Tedera proves its value as a summer and autumn feed for sheep in Mediterranean-like climates

2018 ◽  
Vol 58 (12) ◽  
pp. 2269 ◽  
Author(s):  
D. Real ◽  
C. M. Oldham ◽  
A. van Burgel ◽  
E. Dobbe ◽  
J. Hardy
Keyword(s):  
Western Australia ◽  
Farming Systems ◽  
Early Summer ◽  
Grazing Management ◽  
Sheep Grazing ◽  
Rotational Grazing ◽  
The Third ◽  
Continuous Grazing ◽  
Condition Score ◽  
Sheep Production

Tedera (Bituminaria bituminosa C.H Stirt. vars. albomarginata and crassiuscula) is a traditional forage species for goats in the Canary Islands, Spain. It has agronomic characteristics ideally suited to Mediterranean-like climates that allows it to provide high quality green forage for grazing animals during summer and autumn. It can be used to extend the growing season into late spring and early summer and/or to reduce or eliminate the need for expensive hand feeding of grain and hay to sheep to fill the ‘feed gap’ during the dry season in southern Australian farming systems. Three sheep grazing experiments were carried out with the objective to evaluate sheep production during summer and autumn with tedera as the sole diet. A 3-ha site at Dandaragan, Western Australia was grazed during the summer and autumn of 2014–2015 and 2016 and a 2.4-ha site was grazed at Kojonup, Western Australia during the same period in 2016. At each site, two grazing treatments were evaluated, continuous grazing and rotational grazing with six plots (14 days of grazing and 70 days of recovery). The first hypothesis tested was that tedera plants would not survive continuous grazing during summer and autumn. The second hypothesis tested was that without hand feeding, 10 dry sheep equivalents/ha would be able to at least maintain weight and condition score during summer and autumn. The third hypothesis tested was that rotational grazing would improve the production of the sheep (liveweight and condition score) compared with continuous grazing. The first hypothesis was rejected, the population of tedera plants did not significantly decline due to being continuously grazed during summer and autumn. The second hypothesis was confirmed, at the three experimental sites, 10 dry sheep equivalents/ha were able to at least maintain weight and condition score without any hand feeding. The third hypothesis was partially rejected; continuous grazing had a better performance of the sheep than rotational grazing. However, the rotational grazing plots had more tedera on offer in the remaining grazing plots in the rotation with the potential for a longer grazing time. These three experiments clearly demonstrate that tedera can be used to reduce or eliminate expensive hand feeding during summer and autumn using the simplest and least expensive grazing management; continuous grazing.

Studies on resistance of sheep to infestation with Haemonchus contortus and Trichostrongylus spp. and on the immunological reactions of sheep exposed to infestation. VI. The influence of age and nutrition on resistance to Trichostrongylus colubriformis.

1953 ◽  
Vol 4 (3) ◽  
pp. 340 ◽  
Author(s):  
DF Stewart ◽  
HMcL Gordon
Keyword(s):  
Haemonchus Contortus ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Previous Exposure ◽  
Trichostrongylus Colubriformis ◽  
The Poor ◽  
Experimental Infestation ◽  
Immunological Reactions ◽  
Striking Contrast

Of 10 sheep aged 3-4 years which had been born and maintained under worm-free conditions, 7 died from an initial experimental infestation with Trichostrongylus colubriformis. This mortality was in striking contrast to the results with nine-months-old sheep which had had previous experience of infestation. It demonstrated that resistance to T. colubriformis could not be ascribed to increasing age. In a group fed on a low plane of nutrition and given 40,000 or 100,000 T. colubriformis larvae, more sheep developed infestations than did similar sheep in groups given an adequate or a high-protein diet. in lambs which had been kept worm-free since birth and then dosed with 20,000 T. colubriformis larvae, infestation developed almost equally in those fed on the poor diet and those fed on the high-protein diet. The groups fed on the low plane of nutrition successfully withstood subsequent challenge doses of up to 300,000 T. colubriformis larvae. In these experiments, previous exposure to infestation apparently exercised more influence on resistance than did diet.

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