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Adult Sheep (adult + sheep)
Selected AbstractsPrevalence and Preliminary Genetic Analysis of Giardia Isolated from Adult Sheep in Galicia (Northwest Spain)THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2006JOSÉ A. CASTRO-HERMIDA [source] A preliminary study of possible genetic influences on the susceptibility of sheep to Johne's diseaseAUSTRALIAN VETERINARY JOURNAL, Issue 7 2005LA REDDACLIFF Objective To investigate possible genetic influences on susceptibility or resistance of sheep to Johne's disease. Design A field and laboratory study of two fine-wool Merino flocks with a high prevalence of disease due to Mycobacterium avium subsp paratuberculosis infection. Procedure Adult sheep were phenotypically classified as having severe, mild or no disease on the basis of clinical, pathological and cultural tests for paratuberculosis, and as positive or negative in tests for humoral immunity (agar gel immunodiffusion test) or cell mediated immunity (skin test for delayed type hyper-sensitivity). Correlations with phenotype were sought for polymorphisms at loci within selected immune function genes (NRAMP, MHC complex, IFN-,, lysozyme, leukaemia inhibiting factor). Results Possible associations of particular NRAMP and MHC alleles with susceptibility or resistance to Johne's disease were detected. Conclusion If the results of this preliminary study are confirmed in further work, then the use of rams with "resistant" genotypes may assist in the control of Johne's disease in infected flocks. [source] Effect of fetal anaemia on myocardial ischaemia-reperfusion injury and coronary vasoreactivity in adult sheepACTA PHYSIOLOGICA, Issue 4 2008Bohuslav OstadalArticle first published online: 11 NOV 200 No abstract is available for this article. [source] Responses of weaned lambs to fear-eliciting situations: Origin of individual differencesDEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2003Manon Viérin Abstract The aims of this study were 1) to develop methods of objectively measuring fear in weaned lambs, and 2) to evaluate the effects of age, sex, breed, and rearing conditions on fear reactions. Four hundred forty-one lambs, aged 3 to 6 months, were submitted to three fear-eliciting situations (isolation, surprise effect, and human presence). Factor analysis revealed a first factor, interpreted in terms of fear, that accounted for 40% of total variance in the three tests. As in adult sheep, the main signs of fear were inhibition of feeding, long distance from the frightening stimulus, frequent immobilizations, and numerous high-pitch bleats. Behavior was also influenced by differences in general locomotor activity and exploratory motivation. Fear reactions were influenced by age (3- to 4-month-old lambs more fearful than 5- to 6-month-old), sex (females more fearful than males), breed (Romanov more fearful than Ile-de-France), and rearing conditions (artificial vs. maternal: almost no influence in males and influence in females depending on age). These results with sheep provide interesting theoretical and practical perspectives to the study of fearfulness. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 42: 131,147, 2003 [source] A Sheep Model for the Study of Focal Epilepsy with Concurrent Intracranial EEG and Functional MRIEPILEPSIA, Issue 8 2002Helen I. Opdam Summary: ,Purpose: We describe a sheep model of penicillin-induced seizure activity using electroencephalography (EEG) and functional MRI (fMRI). Methods: Ten adult sheep were used. Spikes and seizures were generated by instillation of 8,000,10,000 IU of penicillin into the right prefrontal cortex via a specially designed port. Bilateral intracranial EEG was acquired by using carbon fiber electrodes. Animals had behavioral characterization of their seizures and were then anesthetized for fMRI studies. Functional MRI was performed at 1.5 and 3 Tesla by measuring blood oxygen level,dependent (BOLD) weighted signal intensity at different times during the evolution of seizures. Results: Behavioral seizures were associated with electrographic seizures. Intracranial EEG obtained in the MR scanner was of high quality. Focal spiking and seizures were seen in all animals and developed 11.3 ± 11.2 s and 17.3 ± 12.1 min after penicillin administration, respectively. An average of 13 ± 4.8 seizures were seen per animal, each lasting 27.3 ± 12.3 s. Functional MR images with little parenchymal artefact were obtained. Regional BOLD signal-intensity changes were observed during seizures at the seizure focus and ipsilateral amygdala. Conclusions: We have developed an animal model of partial epilepsy in which seizures can be reliably elicited with concurrent fMRI and intracranial EEG. During unilateral electrographic seizures, focal BOLD signal changes occurred at the seizure focus and ipsilateral amygdala, suggesting the presence of a cortico,subcortical loop. This observation illustrates the potential of the model for understanding seizure generation, spread, and possibly the consequences of repeated seizures on the brain. [source] Life history correlates of oxidative damage in a free-living mammal populationFUNCTIONAL ECOLOGY, Issue 4 2009Daniel H. Nussey Summary 1Reactive oxygen species, produced as a by-product of normal metabolism, can cause intracellular damage and negatively impact on cell function. Such oxidative damage has been proposed as an evolutionarily important cost of growth and reproduction and as a mechanistic explanation for organismal senescence, although few tests of these ideas have occurred outside the laboratory. 2Here, we examined correlations between a measure of phospholipid oxidative damage in plasma samples and age, growth rates, parasite burden and investment in reproduction in a population of wild Soay sheep on St. Kilda, Scotland. 3We found that, amongst females of different ages, lambs had significantly elevated levels of oxidative damage compared to all other age classes and there was no evidence of increasing damage with age amongst adult sheep. 4Amongst lambs, levels of oxidative damage increased significantly with increasing growth rates over the first 4 months of life. Neither mean damage nor the effect of growth rate on damage differed between male and female lambs. 5Amongst adult female sheep, there was no evidence that body mass, current parasite burden or metrics of recent and past reproductive effort significantly predicted oxidative damage levels. 6This study is the first to examine age variation in an assay of oxidative damage and correlations between oxidative damage, growth and reproduction in a wild mammal. Our results suggest strong links between early conditions and oxidative damage in lambs, but also serve to highlight the limitations of cross-sectional data for studies examining associations between oxidative stress, ageing and life history in free-living populations. [source] Age-associated plasticity in the intrinsic innervation of the ovine rumenJOURNAL OF ANATOMY, Issue 3 2003Helga Pfannkuche Abstract The rumen of adult sheep functions as a large fermentation chamber. In the newborn suckling ruminant, the rumen is bypassed and milk enters the abomasum directly. It was the aim of our study to investigate whether the transmitter content of intrinsic nerves changes with the developmental stage. The neurochemical code of myenteric neurons in the rumen from suckling lambs, fattened lambs and adult sheep was determined by using quadruple immunohistochemistry against choline-acetyltransferase (ChAT), nitric oxide synthase (NOS), substance P (SP) and vasoactive intestinal peptide (VIP). Three neurochemically distinct subpopulations were identified within the rumen. They expressed the code ChAT/,, ChAT/SP and NOS/VIP. The number of ChAT/SP neurons did not change during development. It was 62% in the newborn lamb and remained stable in fattened lambs (63%) and adult sheep (63%). By contrast, the number of ChAT/, neurons decreased significantly from 20% in suckling lambs to 11% and 7% in fattened lambs and adult sheep, respectively. Simultaneously, the proportion of NOS/VIP neurons increased from 16% in suckling lambs to 29% in adult sheep. The increase in the proportion of NOS/VIP immunoreactive neurons indicates an adaptation to large volumes of ingesta at the beginning of roughage intake and rumination. We conclude that the age-associated changes in neurochemical code of myenteric neurons in the forestomach are related to the adaption of the rumen to different functional properties during development. [source] A biomechanical and histological analysis of standard versus hydroxyapatite-coated pins for external fixationJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Antonio Moroni Abstract This sheep study was designed to make a comparative evaluation of two external fixation pin types each with and without hydroxyapatite (HA) coating. The two pins had different taper, pitch, and self drilling capabilities. Twenty Orthofix standard, self-tapping pins (group A), 20 Orthofix HA-coated, self-tapping pins (group B), 20 X-caliber, self-drilling, self-tapping pins (group C), and 20 X-caliber HA-coated, self-drilling, self-tapping pins (group D) were selected. Four pins were implanted in the right femurs of 20 adult sheep that were euthanized at 6 weeks. Mean pin insertion torque was 2745 ± 822 Nmm in group A, 2726 ± 784 Nmm in group B, 2818 ± 552 Nmm in group C, and 2657 ± 732 Nmm in group D (ns). Mean pin extraction torque was 1567 ± 541 Nmm in group A, 2524 ± 838 Nmm in group B, 1650 ± 650 Nmm in group C, and 2517 ± 726 Nmm in group D. HA-coated pins (group B and D) had a significantly greater mean pin extraction torque compared to similar uncoated pins (group A and C) (p < 0.0005). Histological analysis showed good osteointegration of the two coated pin types. This study shows that HA-coating is more important for optimal pin fixation than the particular combination of design parameters used in each pin type. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Pharmacokinetics of flubendazole and its metabolites in lambs and adult sheep (Ovis aries)JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2009Flubendazole (FLU) is indicated for control of helminthoses in pig and avian species (monogastric animals) and its corresponding pharmacokinetics are well known. The information on FLU's pharmacokinetic behavior in animal species with forestomach (ruminants) has been limited although the use of FLU in these species could be beneficial. The aim of this study was to investigate the pharmacokinetics of FLU and its main metabolites in sheep. The effects of animal age (sexually immature and mature ones) and gender were also studied. FLU was orally administered in a single experimental dose (30 mg/kg of body weight) in the form of oral suspension. Treated immature animals (aged 3 months) and 5 months later the same mature individuals (aged 8 months) were kept under the same conditions (food, water and management) and treated with FLU. Within 72 h after FLU administration, plasmatic samples were collected and FLU and its Phase I metabolites were quantified using high-performance liquid chromatography. FLU was detected in very low concentrations only, reduced FLU (FLU-R) was identified as the main metabolite, and hydrolyzed FLU (FLU-H) as the minor one. Formation of FLU-R was stereospecific with (+)-FLU-R domination. The plasmatic concentrations of (+)-FLU-R reached 10,15 times higher values than those of FLU, (,)-FLU-R and FLU-H. A significant gender effect on pharmacokinetics of FLU or (+)-FLU-R metabolite in the mature animals was found and a wide significant difference between lambs and adult sheep in FLU including both metabolites has been proved. [source] Moxidectin and ivermectin metabolic stability in sheep ruminal and abomasal contentsJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2005A. LIFSCHITZ The oral administration of macrocyclic lactones to sheep leads to poorer efficacy and shorter persistence of the antiparasitic activity compared to the subcutaneous treatment. Gastrointestinal biotransformation occurring after oral treatment to ruminant species has been considered as a possible cause of the differences observed between routes of administration. The current work was addressed to evaluate on a comparative basis the in vitro metabolism of moxidectin (MXD) and ivermectin (IVM) in sheep ruminal and abomasal contents. Both compounds were incubated under anaerobic conditions during 2, 6 and 24 h in ruminal and abomasal contents collected from untreated adult sheep. Drug concentrations were measured by high-performance liquid chromatography with fluorescence detection after sample clean up and solid phase extraction. Neither MXD nor IVM suffered metabolic conversion and/or chemical degradation after 24-h incubation in ruminal and abomasal contents collected from adult sheep. Unchanged MXD and IVM parent compounds represented between 95.5 and 100% of the total drug recovered in the ruminal and abomasal incubation mixtures compared with those measured in inactive control incubations. The partition of both molecules between the solid and fluid phases of both sheep digestive contents was assessed. MXD and IVM were extensively bound (>90%) to the solid material of both ruminal and abomasal contents collected from sheep fed on lucerne hay. The results reported here confirm the extensive degree of association to the solid digestive material and demonstrates a high chemical stability without evident metabolism and/or degradation for both MXD and IVM in ruminal and abomasal contents. [source] Cloning Adult Farm Animals: A Review of the Possibilities and Problems Associated with Somatic Cell Nuclear TransferAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 2 2003J. L. Edwards In 1997, Wilmut et al. announced the birth of Dolly, the first ever clone of an adult animal. To date, adult sheep, goats, cattle, mice, pigs, cats and rabbits have been cloned using somatic cell nuclear transfer. The ultimate challenge of cloning procedures is to reprogram the somatic cell nucleus for development of the early embryo. The cell type of choice for reprogramming the somatic nucleus is an enucleated oocyte. Given that somatic cells are easily obtained from adult animals, cultured in the laboratory and then genetically modified, cloning procedures are ideal for introducing specific genetic modifications in farm animals. Genetic modification of farm animals provides a means of studying genes involved in a variety of biological systems and disease processes. Moreover, genetically modified farm animals have created a new form of ,pharming' whereby farm animals serve as bioreactors for production of pharmaceuticals or organ donors. A major limitation of cloning procedures is the extreme inefficiency for producing live offspring. Dolly was the only live offspring produced after 277 attempts. Similar inefficiencies for cloning adult animals of other species have been described by others. Many factors related to cloning procedures and culture environment contribute to the death of clones, both in the embryonic and fetal periods as well as during neonatal life. Extreme inefficiencies of this magnitude, along with the fact that death of the surrogate may occur, continue to raise great concerns with cloning humans. [source] | |||||||||||||