Parasite-induced anorexia in a free-ranging mammalian herbivore: an experimental test using Soay sheep

2006 ◽  
Vol 84 (5) ◽  
pp. 685-692 ◽  
Author(s):  
O.R. Jones ◽  
R.M. Anderson ◽  
J.G. Pilkington
Keyword(s):  
Parasite Burden ◽  
Gastrointestinal Parasites ◽  
Ovis Aries ◽  
Domestic Sheep ◽  
Intake Rate ◽  
Soay Sheep ◽  
Day Range ◽  
Behavioural Effects ◽  
Host Mortality ◽  
Free Ranging

Theory suggests that gastrointestinal parasites can influence herbivore population dynamics by increasing host mortality rates. In addition, parasites may have a non-lethal range of both physiological and behavioural effects on their hosts. Two potential behavioural effects are parasite-induced anorexia and the alteration of diet selection patterns — both of which may influence plant communities without necessarily causing herbivore mortality. We report here the results of an experiment carried out in August–September 2001 to examine herbivore response to parasitism using feral Soay sheep ( Ovis aries L., 1758) living on Hirta, St. Kilda (Scotland, UK), as a model system. The aim of the experiment was to determine whether the sheep exhibit significant parasite-induced anorexia and whether diet selectivity was also altered in response to parasitism. The n-alkane technique was used to estimate forage intake rates and diet composition. Overall, intake rate increased with body mass and the mean (±SE) over both sexes was 737 ± 40 g DM / day (range 458–1241 g DM / day). However, we found no effect of parasite burden upon intake rate or selection patterns. The results of a power analysis imply that any reduction in intake rate was less than 30%, which is less than the 30%–60% reduction in intake rate recorded for domestic sheep under moderate parasite burdens. This suggests that Soay sheep are more resilient to parasitism than domestic breeds. Despite evidence to the contrary from simple farm-based studies, the lack of any effect on selection patterns in this case suggests that parasites do not cause significant alterations to the selection patterns of herbivores in complex non-agricultural environments.

Sex Differences in Feeding Behaviour at Feeding Station Scale in Soay Sheep (Ovis Aries)

Behaviour ◽  
2004 ◽  
Vol 141 (8) ◽  
pp. 999-1020 ◽  
Author(s):  
◽  
◽  
Keyword(s):  
Feeding Behaviour ◽  
Ovis Aries ◽  
Intake Rate ◽  
Same Sex ◽  
Soay Sheep ◽  
Food Items ◽  
Feeding Station ◽  
Foraging Decisions ◽  
Mouth Size ◽  
Mechanistic Response

AbstractHerbivorous ungulates live in a spatially heterogeneous environment making foraging decisions at a range of hierarchical scales, from bite size to landscape. We investigated the factors that control intake rate in Soay sheep (Ovis aries) when discrete items of food were sparsely distributed at the feeding station scale. Within the feeding station we varied the difficulty of accessing food, distance between items of food, difficulty of finding the food and complexity of the feeding station and recorded how intake rate responded in relation to body size, mouth size and the sex of the animal. Our findings demonstrated how increasing difficulty of accessing food, and increasing complexity of the feeding station negatively affected intake rate. The expected mechanistic response that smaller animals or animals with smaller mouth size were better at handling discrete small items of food, was overridden by individual and sexual differences in behaviour. We also considered that intake rate within a feeding station could be maximised by optimising the spatial pattern of offtake, and the results clearly indicated that both sexes tended to show clustered patterns of offtake. Animals of the same sex responded in a similar way to the difficulty in handling food items; males persevered more than females and consequently were less handicaped by having larger mouths. We discussed these results in relation to behavioural and body mass differences between the sexes and animals.

Mortality of lambs in free-ranging domestic sheep (Ovis aries) in northern Norway

2001 ◽  
Vol 254 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Jerry T. Warren ◽  
Ivar Mysterud ◽  
Torun Lynnebakken
Keyword(s):  
Ovis Aries ◽  
Domestic Sheep ◽  
Northern Norway ◽  
Free Ranging

scholarly journals Gastrointestinal nematode species burdens and host mortality in a feral sheep population

Parasitology ◽  
2006 ◽  
Vol 133 (4) ◽  
pp. 485-496 ◽  
Author(s):  
B. H. CRAIG ◽  
J. G. PILKINGTON ◽  
J. M. PEMBERTON
Keyword(s):  
Gastrointestinal Nematode ◽  
Nematode Species ◽  
Gastrointestinal Nematodes ◽  
Domestic Sheep ◽  
Host Age ◽  
Age Classes ◽  
Sheep Population ◽  
Soay Sheep ◽  
New Findings ◽  
Host Mortality

Every few years a large proportion of the feral sheep on Hirta, St Kilda die due to food shortage. The effects of malnutrition are exacerbated by gastrointestinal nematodes. As found in sheep flocks in mainland Britain,Teladorsagia circumcinctahas long been considered the predominant and most pathogenic nematode species in all age classes of Soay sheep. Previous research indicated that intensity of this species showed a negative association with host age and comprised 75% of the entire gastrointestinal burden. Here we present new data that showTrichostrongylus axeiandTrichostrongylus vitrinusto be the predominant worm pathogens in young Soay sheep. In the present study,Trichostrongylusspp. burdens declined with host age whereasT. circumcinctaactually increased in burden over the first few age classes. Also, male hosts had significantly higher burdens ofTrichostrongylusspp. than females, with this genus making up a higher proportion of the strongyle egg producing community in male hosts than female hosts. These new findings raise questions concerning our previous interpretation of the main nematode species contributing to strongyle egg count in the population, and the contrasting infection patterns of these nematode species in unmanaged St Kilda Soay sheep compared with domestic sheep in mainland Britain.

Energetics of free-ranging large herbivores: when should costs affect foraging behaviour?

2000 ◽  
Vol 78 (9) ◽  
pp. 1604-1615 ◽  
Author(s):  
Helen M Armstrong ◽  
Antony Robertson
Keyword(s):  
Energy Balance ◽  
Foraging Behaviour ◽  
Ovis Aries ◽  
Energetic Cost ◽  
Domestic Sheep ◽  
Net Energy ◽  
Large Herbivores ◽  
Wind Speeds ◽  
Free Ranging ◽  
The Impact

Published relationships were used to build a mathematical model that predicts the daily net energy balance of free-ranging domestic sheep (Ovis aries L.) grazing in the U.K. hills. Net energy balance was predicted for a plausible range of environmental conditions. The behaviour of the model suggested the following predictions. Locomotion will be a relatively unimportant energetic cost. Ambient temperature and rainfall alone will rarely affect energy expenditure, whereas wind will greatly increase energetic costs in winter. These are further increased, but to a relatively small extent, by any concurrent rainfall. Predictions of foraging behaviour based on maximisation of energy intake alone are likely to significantly overestimate dry matter intake from climatically exposed vegetation in winter. Where shelter is available, such models will also overestimate total intake in winter by not taking account of sheltering behaviour. This effect will be most pronounced when forage is of low digestibility or availability, wind speeds are high, or the level of coat insulation is low. Foraging models based instead on maximisation of net energy balance are likely to greatly improve predictions of the impact of large herbivores on vegetation and the mechanisms driving their population dynamics.

The diet of brown bears Ursus arctos in central Scandinavia: effect of access to free-ranging domestic sheep Ovis aries

1998 ◽  
Vol 4 (1) ◽  
pp. 147-158 ◽  
Author(s):  
Bjørn Dahle ◽  
Ole J. Sørensen ◽  
Egil H. Wedul ◽  
Jon E. Swenson ◽  
Finn Sandegren
Keyword(s):  
Ursus Arctos ◽  
Ovis Aries ◽  
Domestic Sheep ◽  
Brown Bears ◽  
Free Ranging

scholarly journals A microsatellite polymorphism in the gamma interferon gene is associated with resistance to gastrointestinal nematodes in a naturally-parasitized population of Soay sheep

Parasitology ◽  
2001 ◽  
Vol 122 (5) ◽  
pp. 571-582 ◽  
Author(s):  
D. W. COLTMAN ◽  
K. WILSON ◽  
J. G. PILKINGTON ◽  
M. J. STEAR ◽  
J. M. PEMBERTON
Keyword(s):  
Interferon Gamma ◽  
Cell Subset ◽  
Gastrointestinal Nematode ◽  
Gastrointestinal Nematodes ◽  
Ovis Aries ◽  
Domestic Sheep ◽  
Soay Sheep ◽  
Nematode Parasites ◽  
Ifn Γ ◽  
Trait Locus

Free-living Soay sheep (Ovis aries) on the island of Hirta, St Kilda, Scotland, are naturally parasitized by gastrointestinal nematodes, predominantlyTeladorsagia circumcincta. In this paper we show that reduced faecal egg counts (FEC) are associated with an allele at a microsatellite locus located in the first intron of the interferon gamma gene (o(IFN)-γ) in Soay sheep lambs and yearlings, measured at approximately 4 and 16 months of age, respectively. The same allele was also associated with increasedT. circumcincta-specific antibody (IgA) in lambs, but not associated significantly in yearlings. Flanking control markers failed to show a significant association with either FEC or IgA. These results suggest that a polymorphic gene conferring increased resistance to gastrointestinal nematode parasites is located at or near the interferon gamma gene, and support previous reports which have mapped a quantitative trait locus (QTL) for resistance to this region in domestic sheep. Our data are consistent with the idea that a functional polymorphism leading to reduced expression or efficacy of (IFN)-γ could enhance the immune response to gastrointestinal nematodes by favouring the activity of the Th2cell subset and antibody associated immune mechanisms.

Modalités d’élevage et parasites gastrointestinaux des ovins au centre de la Côte d’Ivoire

2020 ◽  
Vol 45 (2) ◽  
pp. 7931-7943
Author(s):  
Alain Gérard Ambroise APALA ◽  
Amoin Marie Amélie Clarisse KOMOIN-OKA ◽  
Kouassi Rufin ASSARÉ ◽  
Aboukary TOURE ◽  
Kouakou Eliezer N’GORAN
Keyword(s):  
Cote D'ivoire ◽  
Questionnaire Survey ◽  
Côte D’Ivoire ◽  
Parasite Burden ◽  
Gastrointestinal Parasites ◽  
Cote D’Ivoire ◽  
Traditional System ◽  
Côte D'ivoire ◽  
Hygiene Measures ◽  
Intensive System

Une étude portant sur les modalités d’élevage et le parasitisme digestif des ovins a été réalisée dans 3 régions du centre de la Côte d’Ivoire, d’Août 2017 à Avril 2018. Elle a comporté une enquête par questionnaire menée dans 25 élevages, et une enquête coprologique effectuée sur 550 ovins dans 12 de ces élevages. Les résultats de l’enquête par questionnaire montrent que le système de production le plus répandu demeure le système traditionnel (68% des élevages), suivi du système amélioré semi-intensif (20%) et enfin du système moderne intensif (12%). Les 3 élevages modernes de l’étude se sont révélés d’un niveau élevé de technicité et de productivité ; cependant les mesures d’hygiène peuvent encore y être améliorées. Les élevages traditionnels sont d’un niveau sanitaire médiocre, qui se traduit par un niveau d’infestation parasitaire des ovins plus élevé. En effet, la charge parasitaire moyenne des ovins des élevages traditionnels était de 428,0 œufs par gramme (opg) de fèces avec 81,7% des animaux excrétant moins de 500 opg ; pour les élevages semiintensifs, la moyenne était de 198,7 opg avec 84,1% des ovins excrétant moins de 500 opg ; et pour les élevages modernes intensifs, la moyenne était de 193,0 opg avec 99,2% des ovins excrétant moins de 500 opg. Ces différences étaient statistiquement significatives. L’identification des œufs par les examens coprologiques a permis de mettre en évidence la présence de strongles digestifs, de Trichuris sp, de Strongyloides papillosus, de Moniezia sp et des ookystes de coccidies du genre Eimeria. L’identification des espèces parasitaires après la coproculture a révélé que 75% des larves appartiennent au genre Haemonchus, 8,6% au genre Trichostrongylus, 8,2% au genre Strongyloides, 8% au genre Cooperia et 0,2% au genre Oesophagostomum. Apala et al., 2020 Journal of Animal & Plant Sciences (J.Anim.Plant Sci. ISSN 2071-7024) Vol.45 (2): 7931-7943 https://doi.org/10.35759/JAnmPlSci.v45-2.5 7932 Breeding modalities and the challenge of gastrointestinal parasites of sheep in central Côte d'Ivoire SUMMARY A study on rearing and ovine digestive parasitism was conducted in 3 regions of central Côte d'Ivoire, from August 2017 to April 2018. It included a questionnaire survey conducted on 25 farms and a coprological study- carried out on 550 sheep in 12 of these farms. The results of the questionnaire survey showed that the most widespread production system remains the traditional system (68% of the farms), followed by the improved semi-intensive system (20%) and finally the modern intensive system (12%). The three modern farming methods in the study proved to be of high-level technicality and productivity, however, hygiene measures can still be improved. Traditional herds are of a poor health level, which results in a higher level of parasitic infestation of sheep. In fact, the average parasite burden of sheep in traditional farms was 428.0 eggs per gram (epg) of faeces with 81.7% of animals excreting less than 500 epg; for semi-intensive farms. The average was 198.7 epg with 84.1% of sheep excreting less than 500 epg; and for intensive modern breeding, the average was 193.0 epg with 99.2% of sheep excreting less than 500 epg. The identification of the eggs by the coprological examinations revealed the presence of digestive strongles, Trichuris sp, Strongyloides papillosus, Moniezia sp and coccidia oocysts of the genus Eimeria. Identification of parasite species after stool culture revealed that 75% of the larvae belong to the genus Haemonchus, 8.6% to the genus Trichostrongylus, 8.2% to the genus Strongyloides, 8% to the genus Cooperia and 0.2% to the genus Oesophagostomum.

​Re-sequencing of Whole Genome Jordanian Awassi Ewes using Hiseq Sequencing Technology: Major Step Towards Sheep Genomic Selection

2021 ◽  
Author(s):  
Hussein Migdadi ◽  
Nizar Haddad ◽  
Ruba AlOmari ◽  
Mohammad Brake ◽  
Mustafa AlShdaifat ◽  
...  
Keyword(s):  
Production Systems ◽  
Ovis Aries ◽  
Domestic Sheep ◽  
Major Step ◽  
Illumina Hiseq ◽  
Structure Variation ◽  
Awassi Sheep ◽  
Wide Range ◽  
Number Variation ◽  
Paired End Sequencing

Background: Jordanian Awassi sheep (Ovis aries) is the dominant fat tail sheep breed that appeals to customers because of its various production systems, including fiber, meat and milk. This report is the first whole ewe genome sequence (WGS) of O. aries submitted in the NCBI database from Jordan. Methods: 64 Paired-end sequencing libraries were constructed and subjected to Illumina Hiseq 2500 sequencing system. High-quality reads were aligned against the reference sheep genome and detecting comprehensive sources (SNPs, InDels, SV, CNVs) of genetic variations. We have deposited data sequences at the NCBI under SRA (sequence reads archives) under the accession numbers SRR11128863, PRJNA574879. Result: Genome resequencing of Jordanian Awassi ewe was carried out with approximately 93.88 Gb with a mapping rate and effective mapping depths were 99.28% and 36.32. Around 19 million SNPs, 3,6 million InDels, 35,180 Structure variation and 13,524 copy number variation among the Jordanian ewe genome were detected. This wide range of genetic variation provides a framework for further genetic studies that will help understand the molecular basis underlying phenotypic variation of economically important traits in sheep and improve intrinsic defects in domestic sheep breeds.

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