ADDICTION, Issue 10 2003
Anders Romelsjö
ABSTRACT Aims, Very few studies indicating that low,moderate alcohol consumption protects from myocardial infarction (MI) controlled for social support and working conditions, which could confound the findings. Therefore, a first aim was to study the risk of non-fatal and total MI in relation to volume of alcohol consumption and measures of social support and working conditions. A second aim was to analyse the impact of the volume of earlier alcohol use in abstainers. Design, Data came from a case,control study, the Stockholm Heart Epidemiology Program (SHEEP), including first MI among Swedish citizens 45,70 years old. Setting, Stockholm County 1992,94. Participants, There were 1095 cases of MI in men and 471 in women (928 and 372 were non-fatal), and 2339 living controls from the general population. Measurement, Information about alcohol use at different periods in life and job strain, social anchorage and life control besides pre-existing health problems, smoking, physical activity, socio-economic status and marital status was obtained by a questionnaire from the cases and the controls. Findings, In multivariate logistic regression analyses, the relative risk for MI (especially non-fatal) was reduced among alcohol consumers. RR for non-fatal MI was 0.52 (95% confidence intervals 0.32, 0.85) in men with a consumption of 50,69.9 g 100% ethanol/day and 0.21 (95% confidence interval 0.06, 0.77) in women with a consumption of 30 g or more per day (reference category 0.1,5 g 100% ethanol/day). Men who were abstainers during the previous 1,10 years and with an earlier average consumption of 5,30 g 100% ethanol/day had a significantly lower relative risk compared to such abstainers with an earlier higher consumption. Earlier consumption among abstainers may also have an impact on gender differences in MI. Analyses showed positive interaction between abstention and low life-control in women, but only 4% of the female cases were due to this interaction. There were no other interactions between measures of alcohol use and social anchorage, life control and working situations. Conclusion, Alcohol use had a protective impact on MI, with little impact of job strain, social anchorage and life control, giving increased support for a protective impact of low-moderate alcohol use. The level of previous alcohol consumption among male 1,10-year-long abstainers influenced the risk of MI. [source]

Association of boiled and filtered coffee with incidence of first nonfatal myocardial infarction: the SHEEP and the VHEEP study

JOURNAL OF INTERNAL MEDICINE, Issue 6 2003
N. Hammar
Abstract., Hammar N, Andersson T, Alfredsson L, Reuterwall C, Nilsson T, Hallqvist J, Knutsson A, Ahlbom A (Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Stockholm Center of Public Health, Stockholm, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Västernorrland County Council, Sundsvall, Division of Social Medicine, Karolinska Institutet, Stockholm, Norrland University Hospital, Umeå, Sweden) Association of boiled and filtered coffee with incidence of first nonfatal myocardial infarction: the SHEEP and the VHEEP study. J Intern Med 2003; 253: 653,659. Objectives., To evaluate the influence of consumption of filtered and boiled coffee, on the incidence of first nonfatal myocardial infarction. Design., Population-based case,control study. Setting and subjects., The study base consisted of the population 45,65/70 years-old in two Swedish counties, Stockholm and Västernorrland, 1992/93,94. In all, 1943 cases of first nonfatal myocardial infarction were identified. For each case one control was selected from the study base concurrently with disease incidence by matching the sex, age and place of residence of the case. Information about coffee consumption and other factors was obtained by mailed questionnaire and a medical examination. The participation rate was 85% amongst cases and 74% amongst controls. Results., Men with a reported consumption of 7,9 dL filtered coffee per day showed an increased incidence of first myocardial infarction compared with consumers of 3 dL day,1 or less (RR: 1.32; 95% CI: 1.03,1.70). A consumption of at least 10 dL day,1 was associated with an RR of 1.93 (95% CI: 1.42,2.63) for filtered and 2.20 (95% CI: 1.17,4.15) for boiled coffee. Amongst women, no clear association was seen between consumption of filtered coffee and myocardial infarction but consumption of boiled coffee tended to be related to an increased incidence. Comparing subjects drinking boiled coffee with those drinking filtered coffee and adjusting for the amount consumed gave an increased incidence for boiled coffee amongst both men (RR: 1.41; 95% CI: 1.07,1.80) and women (RR: 1.63; 95% CI: 1.04,2.56). Conclusions., Consumption of boiled coffee appears to increase the incidence of first nonfatal myocardial infarction. This increased incidence is consistent with randomized trials showing an adverse impact of boiled coffee on blood lipids. [source]

,YOU MIGHT AS WELL BE HUNG FOR A SHEEP AS A LAMB': THE LOSS FUNCTION OF AN AGENT,

THE MANCHESTER SCHOOL, Issue 3 2008
MARGARET BRAY
Most of those who take macro and monetary policy decisions are agents. The worst penalty which can be applied to these agents is to sack them. Agents thus have loss functions which are bounded above. We work with a bell loss function which has this property. With additive uncertainty the certainty equivalence which holds for a quadratic loss function breaks down with a bell loss function when there are two or more targets. With multiplicative (Brainard) uncertainty policy is more conservative than in the absence of multiplicative uncertainty, but less so with the bell than the quadratic loss function. [source]

After the Sheep are Gone, Restoring an Invaded Ecosystem

CONSERVATION, Issue 4 2001
Jason Van Driesche
[source]

Sheep have the last word: kappa and delta opioid receptors initiate haemorrhagic hypotension

ACTA PHYSIOLOGICA, Issue 1 2007
William R. MillingtonArticle first published online: 3 AUG 200
No abstract is available for this article. [source]

Effects of Endotoxin Exposure on Cationic Amino Acid Transporter Function in Ovine Peripheral Blood Mononuclear Cells

EXPERIMENTAL PHYSIOLOGY, Issue 2 2003
Megan F. Clark
Rodent models of sepsis differ from clinical human disease in that humans make substantially less whole-body nitric oxide and have different cellular responses to endotoxin. Sheep, when exposed to endotoxin, behave in a manner more similar to humans. Many studies of rodent peripheral blood mononuclear cells (PBMCs) exposed to endotoxin demonstrate increased cationic amino acid transporter function (particularly through the y+ transporter) to supply arginine substrate to upregulated nitric oxide synthase. Whether this is true in sheep is not known. We have studied cationic amino acid transport in sheep PBMCs stimulated with endotoxin, using labelled lysine. PBMCs stimulated both in vitro and in vivo show an initial reduction in total and y+ lysine transport (after 1-2 h exposure to endotoxin): a previously undescribed effect of endotoxin. In in vitro activated cells, the reduction in y+ transport was prevented by the lipoxygenase inhibitor, nordihydroguaretic acid (NDGA), and the phospholipase inhibitor 4-bromophenacyl bromide (4-BPAB), but not cyclohexamide or a number of other inhibitors of intracellular second-messenger pathways. In contrast after 14 h incubation, the expected increase in total and y+ lysine transport was seen. The increase in y+ transport could be prevented by cyclohexamide, dexamethasone, ibuprofen, the protein kinase C inhibitor sphingosine, NDGA and 4-BPAB. These results suggest that in response to endotoxin exposure there is an initial decrease in y+ activity mediated by a lipoxygenase product, followed by a substantial increase in y+ activity mediated by the products of either cyclo-oxygenase or lipoxygenase. Cyclo-oxygenase and/or lipoxygenase inhibition might be useful in reducing arginine transport, and hence nitric oxide production, in these cells. [source]

Effect of Maternal Nutrient Restriction in Early Gestation on Responses of the Hypothalamic-Pituitary-Adrenal Axis to Acute Isocapnic Hypoxaemia in Late Gestation Fetal Sheep

EXPERIMENTAL PHYSIOLOGY, Issue 1 2000
Paul Hawkins
Epidemiological and experimental evidence suggests that maternal undernutrition during pregnancy may alter development of fetal organ systems. We have demonstrated previously that fetal hypothalamic-pituitary-adrenal (HPA) axis responses to exogenous corticotropin-releasing hormone (CRH) + arginine vasopressin (AVP), or adrenocorticotrophin hormone (ACTH), are reduced in fetuses of mildly undernourished ewes. To examine these effects further we tested HPA axis responses to acute isocapnic hypoxaemia in fetal sheep at 114-129 days gestation (dGA), following 15% reduction in maternal nutritional intake between 0 and 70 dGA. Fetuses from control (C) and nutrient-restricted (R) ewes were chronically catheterised and plasma ACTH and cortisol responses were determined at 114-115, 120-123 and 126-129 dGA during hypoxaemia (1 h) induced by lowering the maternal inspired O2 fraction (FI,O2). Basal plasma cortisol concentrations and HPA axis responses at 114-115 and 120-123 dGA did not differ between C and R fetuses. At 126-129 dGA, both plasma ACTH (P < 0.01) and cortisol (P < 0.05) responses were smaller in R fetuses compared to C fetuses. Fetal blood gas status, fetal body weight, body proportions and organ weights did not differ between the groups. We conclude that mild maternal undernutrition alters development of the fetal HPA axis producing a reduction in pituitary and adrenal responsiveness to endogenous stimuli. [source]

Selective defoliation by sheep according to slope and plant species in the hill country of New Zealand

GRASS & FORAGE SCIENCE, Issue 4 2003
I. F. López
Abstract The objective of the study was to evaluate the grazing behaviour by sheep in hill country paddocks in New Zealand which had received two long-term fertilization and stocking rate treatments [high fertility,high stocking rate (HH); low fertility,low stocking rate (LL)]. Herbage accumulation and selective grazing were evaluated within low slope (LS), medium slope (MS) and high slope (HS) categories. Transects lines were placed and tillers of Agrostis capillaris and Lolium perenne in the LS category; A. capillaris, Anthoxanthum odoratum and L. perenne in the MS category; and A. capillaris and A. odoratum in the HS category were marked. The leaf length of each marked tiller was measured and used to determine selective grazing over 3 weeks during each season. The highest herbage accumulation rates were during spring and the lowest in summer and winter. The LS category showed the highest herbage accumulation rates and HS the lowest. Except for autumn, the marked tillers were more frequently grazed in the HH than in the LL paddock. During summer, autumn and spring, grazing frequency in the slope categories was in the order LS > MS > HS. During winter sheep did not discriminate between slope category. During summer, autumn and spring, sheep did not selectively graze the species studied but this was not the case during winter. Overall, sheep selectively grazed L. perenne. In all the seasons L. perenne consistently had the longest leaves but within species there was no consistent relationship between leaf length and probability of being grazed. Selective grazing changed through the year according to herbage accumulation rate. Sheep concentrated grazing in the category LS when herbage accumulation rate was high, but they did not discriminate between slope categories in winter when herbage accumulation rate was low. [source]

The effects of methylene blue on ovine post-pneumonectomy pulmonary oedema

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2010
E. V. SUBOROV
Background: We recently reported that post-pneumonectomy pulmonary oedema (PPO) occurs after ventilating the remaining lung with excessive tidal volumes. Studies in small animals have indicated that nitric oxide (NO) release increases in hyper-inflated lungs, but confirmatory evidence from larger animals is still lacking. We hypothesized that PPO could be prevented by methylene blue (MB), an inhibitor of NO synthase. Methods: Sheep were subjected to a right-sided pneumonectomy (PE) and randomly assigned to a protectively ventilated group ((PROTV group, n=7) with tidal volumes of 6 ml/kg at 20 inflations/min and a positive end-expiratory pressure (PEEP) of 2 cmH2O, and two groups undergoing ,injurious ventilation' (INJV) with tidal volumes of 12 ml/kg and zero end-expiratory pressure (ZEEP), a control group (INJV group, n=7) and a treatment group subjected to MB 1 h after PE (INJV+MB group, n=7). Haemodynamic variables, lung mechanics, blood gases and plasma nitrites and nitrates (NOx) were determined. Results: PE reduced pulmonary blood volume, extravascular lung water (EVLWI) and quasistatic lung compliance in all groups, in parallel with a rise in peak airway pressure (P<0.05). In the INJV group, pulmonary arterial pressure, EVLWI and pulmonary vascular permeability index increased and arterial oxygenation decreased towards cessation of the experiments. These changes were not antagonized by MB. Plasma NOx increased in all the groups compared with baseline, but with no intergroup difference. Conclusion: MB did not reduce PPO and accumulation of NOx in sheep subjected to ventilation with excessive tidal volumes and ZEEP. [source]

Interlaboratory Collaborative Study on the Kjeldahl Reference Method for Nitrogen Determination in Sheep and Goat Milk according to ISO 8968-1/2,IDF 20-1/2

INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2010
Anna Polychroniadou
No abstract is available for this article. [source]

Mechanisms linking plant species richness to foraging of a large herbivore

JOURNAL OF APPLIED ECOLOGY, Issue 4 2010
Ling Wang
Summary 1.,There is general concern that local loss of plant diversity will adversely impact net primary productivity and other ecosystem properties. However, mechanisms linking plant diversity with other trophic levels, especially for large herbivores, are poorly understood. 2.,We examine the responses of foraging sheep to changes in plant species richness in an indoor cafeteria experiment involving six plant species richness levels (1, 2, 4, 6, 8 and 11 species) and three plant functional group compositions within each level, and in a field experiment involving three plant species richness levels (1, 4,6 or >8 species). 3.,Sheep preferred a diverse diet over a single diet even when palatable species were in the diet. Voluntary daily intake steadily rose with increases in plant species richness in both cafeteria and field experiments. The overall nutrient intake (i.e. daily energy and protein intakes) of sheep in the cafeteria also rose significantly with increased plant species richness until it reached a plateau at eight species. The quality of the diet selected by sheep was also significantly affected by plant species richness, but the variation of dietary quality was small and variable. 4.,High nutrient acquisition by the sheep depended on selecting those palatable species with high nutrient content from the plant forage on offer together with the complementary effects of plant species richness, especially for plant functional group richness. 5.,Synthesis and applications. Our experiments demonstrate an asymptotic relationship between plant species richness and voluntary intake by sheep. Increases in plant species richness from a low level led to increased daily nutrient intake, and presumably performance of the sheep. Natural grasslands are generally low in nutritional quality and so plant species richness will critically influence herbivore food intake and nutrition. The asymptotic relationship indicates that the maintenance of plant species richness in rangelands will benefit both domestic herbivore production and the conservation of biodiversity. [source]

Neurokinin 3 Receptor Immunoreactivity in the Septal Region, Preoptic Area and Hypothalamus of the Female Sheep: Colocalisation in Neurokinin B Cells of the Arcuate Nucleus but not in Gonadotrophin-Releasing Hormone Neurones

JOURNAL OF NEUROENDOCRINOLOGY, Issue 1 2010
M. Amstalden
Recent evidence has implicated neurokinin B (NKB) in the complex neuronal network mediating the effects of gonadal steroids on the regulation of gonadotrophin-releasing hormone (GnRH) secretion. Because the neurokinin 3 receptor (NK3R) is considered to mediate the effects of NKB at the cellular level, we determined the distribution of immunoreactive NK3R in the septal region, preoptic area (POA) and hypothalamus of the ewe. NK3R cells and/or fibres were found in areas including the bed nucleus of the stria terminalis, POA, anterior hypothalamic and perifornical areas, dopaminergic A15 region, dorsomedial and lateral hypothalamus, arcuate nucleus (ARC) and the ventral premammillary nucleus. We also used dual-label immunocytochemistry to determine whether a neuroanatomical basis for direct modulation of GnRH neurones by NKB was evident. No GnRH neurones at any rostral-caudal level were observed to contain NK3R immunoreactivity, although GnRH neurones and fibres were in proximity to NK3R-containing fibres. Because NKB fibres formed close contacts with NKB neurones in the ARC, we determined whether these NKB neurones also contained immunoreactive NK3R. In luteal-phase ewes, 64% ± 11 of NKB neurones colocalised NK3R. In summary, NK3R is distributed in areas of the sheep POA and hypothalamus known to be involved in the control of reproductive neuroendocrine function. Colocalisation of NK3R in NKB neurones of the ARC suggests a potential mechanism for the autoregulation of this subpopulation; however, the lack of NK3R in GnRH neurones suggests that the actions of NKB on GnRH neurosecretory activity in the ewe are mediated indirectly via other neurones and/or neuropeptides. [source]

Noradrenergic Regulation of Hypothalamic Cells that Produce Growth Hormone-Releasing Hormone and Somatostatin and the Effect of Altered Adiposity in Sheep

JOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2005
J. Iqbal
Abstract The growth hormone (GH) axis is sensitive to alteration in body weight and there is evidence that central noradrenergic systems regulate neurones that produce growth hormone-releasing hormone (GHRH) and somatostatin (SRIF). This study reports semiquantitative estimates of the noradrenergic input to neuroendocrine GHRH and SRIF neurones in the sheep of different body weights. We also studied the effects of altered body weight on expression of dopamine ,-hydroxylase (DBH), the enzyme that produces noradrenalin from dopamine. Ovariectomised ewes were made Lean (39.6 ± 2.6 kg; Mean ± SEM) by dietary restriction, whereas Normally Fed animals (61.2 ± 0.8 kg) were maintained on a regular diet. Brains were perfused for immunohistochemistry and in situ hybridisation. The Mean ± SEM number of GHRH-immunoreactive (-IR) cells was lower in Normally Fed (65 ± 7) than in Lean (115 ± 14) animals, whereas the number of SRIF-IR cells was similar in the two groups (Normally Fed, 196 ± 17; Lean 230 ± 21). Confocal microscopic analysis revealed that the percentage of GHRH-IR cells (Normally Fed 36 ± 1.5% versus Lean 32 ± 4.6%) and percentage of SRIF-IR cells (Normally Fed 30 ± 40.4% versus Lean 32 ± 2.3%) contacted by noradrenergic fibres did not change with body weight. FluoroGold retrograde tracer injections confirmed that noradrenergic projections to the arcuate nucleus are from ventrolateral medulla and noradrenergic projections to periventricular nucleus arise from the ventrolateral medulla, nucleus of solitary tract, locus coeruleus (LC) and the parabrachial nucleus (PBN). DBH expressing cells were identified using immunohistochemistry and in situ hybridisation and the level of expression (silver grains/cell) quantified by image analysis. The number of DBH cells was similar in Normally Fed and Lean animals, but the level of expression/cell was lower (P < 0.02) in the PBN and LC of Lean animals. These results provide an anatomical basis for the noradrenergic regulation of GHRH and SRIF cells and GH secretion. Altered activity or noradrenergic neurones in the PBN and LC that occur with reduced body weight may be relevant to the control of GH axis. [source]

Long-Term Undernutrition Followed by Short-Term Refeeding Effects on the Corticotropin-Releasing Hormone Containing Neurones in the Paraventricular Nucleus: An Immunohistochemical Study in Sheep

JOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2002
E. Chaillou
Abstract The effect of nutritional level on the immunoreactivity of corticotropin-releasing hormone (CRH) in neurones of the hypothalamic paraventricular nucleus was described in sheep, a ruminant, whose feeding strategy differs from that of monogastric species. Two groups of ewes were underfed (40%), or fed at maintenance (100%) for 167 days, after which one-half of each group was killed or ad libitum refed (at least 150% of maintenance) for 4 days before killing. The presence of CRH in the paraventricular nucleus was examined by immunohistochemistry. The number of CRH immunoreactive neurones was increased in underfed ewes, but without modification of the plasma concentration of cortisol, indicating that the rise of CRH was not released in the portal blood nor linked to the pituitary-adrenal axis. Refeeding did not modify significantly the number of CRH immunoreactive neurones in the nucleus although these neurones were increased, only in refed ewes that were previously underfed. These data differ from those for rats and mice where CRH expression is decreased or not modified by underfeeding which could reflect different effects of undernutrition on CRH immunoreactive neurones in monogastric compared to ruminants species. [source]

Effect of chitosan on the intranasal absorption of salmon calcitonin in sheep

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 6 2005
Michael Hinchcliffe
The effects of a chitosan-based delivery system on the pharmacokinetics of intranasally administered salmon calcitonin (sCT) were investigated in a sheep model. In particular, the feasibility of producing a formulation with a comparable or improved bioavailability and/or less variability than the currently marketed nasal product (Miacalcin nasal spray, Novartis Pharmaceuticals) was assessed. A comparator (control) formulation comprising sCT solution was also tested. Sheep (n = 6) were dosed intranasally according to a randomized crossover design. The intranasal sCT dose was 1100 IU (equivalent to approximately 17 IU kg,1). After completion of the nasal dosing legs, five of the sheep received 300 IU sCT (equivalent to approximately 5 IU kg,1) by subcutaneous injection to estimate relative bioavailability. After intranasal or subcutaneous dosing, serial blood samples were taken and plasma separated by centrifugation before measuring sCT concentrations by ELISA. Pharmacokinetic (non-compartmental) and statistical (analysis of variance or non-parametric alternative) analyses were performed. No systemic or local adverse effects were observed following intranasal or subcutaneous administration of sCT. The mean relative bioavailability of sCT from the chitosan solution was improved twofold compared with Miacalcin nasal spray and threefold compared with sCT control solution. Inter-animal variability in sCT absorption appeared to be lower with use of the chitosan-based solution compared with the control solution or commercial product. Based on the reported sheep data, a chitosan delivery system could offer the potential to significantly improve the intranasal absorption of sCT and reduce the variability in absorption. In the clinical setting, this may allow relatively lower doses of the drug to be given intranasally and/or lead to improvements in the efficacy or quality of intranasal therapy. [source]

West Nile Virus Encephalomyelitis in a Sheep

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 2 2003
Jeff W. Tyler
No abstract is available for this article. [source]

The behaviour of doramectin in the gastrointestinal tract, its secretion in bile and pharmacokinetic disposition in the peripheral circulation after oral and intravenous administration to sheep

JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 4 2000
D. R. HENNESSY
Sheep were ,compartmentalized' by surgically implanting cannulae in the rumen, abomasum and terminal ileum with a re-entrant cannula inserted between the cystic duct and the duodenum to monitor bile secretion. Doramectin, containing a trace of [3H]-doramectin, was administered both intravenously (i.v.) and intraruminally (i.r.) at a dosage of 150 ,g/kg. The pharmacokinetic behaviour of [3H]-labelled products was determined in these pools, and also in peripheral plasma, urine and faeces. Parent doramectin was also determined in plasma, abomasal digesta fluid and bile. Following i.r. administration, [3H] compounds were almost entirely associated with particulate digesta. A 14.5-h half-life in the rumen prolonged the presence of [3H] in the abomasum. Doramectin appeared to be degraded in abomasal digesta because only 24% of abomasal [3H] was attributed to the parent drug. Absorption of doramectin resulted in a systemic availability of 35%, of which 1.6 and 23.6% of the dose was contained in urine and biliary secretions, respectively. Following i.v. administration, almost negligible quantities of [3H] were secreted into the rumen or abomasum and only 2.7% of the dose was excreted in urine, whereas 132% was secreted in bile. This indicated that approximately one-third of biliary metabolites were enterohepatically recycled with biliary metabolites, elevating the proportion of [3H] in fluid digesta in the small intestine. Passage of the IR-administered drug through the gastrointestinal tract (GIT) resulted in virtually complete faecal excretion of [3H] within 5 days, whereas the continued secretion of i.v.-administered [3H] in bile prolonged the presence of [3H] in the GIT, with faecal clearance not being complete for at least 10 days. This multi-compartmental study has provided more information on the behaviour of doramectin than can be obtained from examining drug disposition in the peripheral circulation alone. With this knowledge, it is anticipated that opportunities for improving drug performance will be identified. [source]

Pathogenetical significance of porencephalic lesions associated with intracerebral inoculation of sheep with the bovine spongiform encephalopathy (BSE) agent

NEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 3 2009
S. Sisó
Decreased rates of transmission of transmissible spongiform encephalopathies (TSEs) to sheep have been attributed to some polymorphisms of the prion protein (PrP) and to a ,species barrier' on interspecies experiments. In addition, the blood,brain barrier may be a further impediment to TSE neuroinvasion. The intracerebral (I/C) route is generally considered the most efficient for TSE transmission, as it may help to bypass those factors. Therefore, susceptibility of particular species to specific TSE agents is conducted by this route. Aims: This study characterizes the traumatic brain lesions associated with the I/C injection of the bovine spongiform encephalopathy agent in sheep, assesses the relevance of such lesions in the outcome of clinical disease and provides insight into the mechanisms of PrPd conversion and amplification following I/C challenge. Methods: A total of 27 hemibrains have been macroscopically and immunohistochemically examined to investigate the presence of lesions compatible with the needle track and the PrPd distribution, respectively. Results: No residual inoculum was found and the extension and severity of the traumatic brain lesions were unrelated to the clinical outcome. Sheep with PrPd accumulation in the brain also showed conspicuous focal aggregates in the porencephalic lesions and in the circumventricular organs. In contrast, sheep without PrPd deposits in the brain were also negative in the traumatic lesions. Conclusion: Overall, these findings suggest that the efficiency of the I/C route is due to effective absorption and blood recirculation of infection, rather than to primary amplification at the site of injection. [source]

Spatial distributions of multiple plant species affect herbivore foraging selectivity

OIKOS, Issue 2 2010
Ling Wang
Spatial distribution of food resources is an important factor determining herbivore foraging. Previous studies have demonstrated that clumped distribution of preferred species increases its consumption by herbivores in single- or two-species systems. However, the potential impact of distribution pattern of less preferred species on foraging was ignored. In natural grasslands with high species diversity and complexity, the spatial distribution of preferred species impacts on herbivore foraging may be strongly correlated with the distribution of less preferred species. Our aims were to determine the effect of distribution of both preferred and other plant species on herbivore foraging under conditions close to a native, multi-species foraging environment, and conceptualize the relationships between spatial distribution of food resources and herbivore consumption. We hypothesized that random distribution of non-preferred species reduces herbivore consumption of preferred species because the dispersion of less preferred species likely disturbs herbivore foraging. We conducted an experiment using three species with five combinations of clumped and random distribution patterns. Three species Lathyrus quinquenervius, Phragmites australis and Leymus chinensis, were of high, intermediate and low preferences by sheep, respectively. Results showed that distribution of low preferred species, but not that of high preferred one, affected the consumption of preferred species. Sheep obtained higher consumption of high preferred species when low preferred species followed a clumped distribution than a random distribution. Distance between aggregations of high and low preferred species did not affect sheep foraging. It was concluded that the effects of spatial distribution of preferred species on its consumption are dependent on herbivore foraging strategy, and sheep can consume more preferred species when there is a consistent spatial pattern between preferred species and the entire food resource, and that the random dispersion of low preferred species in grassland may reduce herbivore consumption of high preferred species, thus minimizing selective grazing. [source]

Antibodies to surface epitopes of the carbohydrate larval antigen CarLA are associated with passive protection in strongylid nematode challenge infections

PARASITE IMMUNOLOGY, Issue 11-12 2008
G. B. L. HARRISON
SUMMARY Sheep were immunized by multiple truncated infections with the gastrointestinal nematodes Trichostrongylus colubriformis, Haemonchus contortus and Teladorsagia circumcincta. Three infections with T. colubriformis of 14 days plus five booster doses of L3 stimulated highly effective protection against challenge (99%). Three infections of 14 days plus three booster doses with H. contortus also resulted in significant protection against challenge infection (87%), but the same procedure was not effective for T. circumcincta. Antibodies derived from gastrointestinal mucus of these immunized sheep were tested for their ability to reduce worm burden following injection of antibody-coated exsheathed larvae into the abomasum (H. contortus and T. circumcincta) or duodenum (T. colubriformis) of nematode-naïve sheep in a passive immunity test. The IgG fraction from the mucus of immunized sheep reduced worm burdens by 62%, 76% and 91% in three tests with T. colubriformis but was not effective for either of the abomasal dwelling nematodes H. contortus and T. circumcincta. Antibodies in immune mucus predominantly recognized two larval surface antigens on immunoblots of L3 extract, a high MW surface glycoprotein and the carbohydrate larval antigen (CarLA). Antibodies raised against purified T. colubriformis glycoprotein Tc-120 and CarLA were tested in the passive immunity model and it was found that only the antibody against CarLA resulted in a significant reduction of infection (87%). The protective anti-CarLA antibodies strongly recognized the surface of living T. colubriformis L3. Antibodies from abomasal mucus of sheep immunized by H. contortus and T. circumcincta infections reacted weakly with CarLA and the larval surface and did not reduce worm counts in a passive immunity test. The results provide further evidence that the larval surface carbohydrate antigen CarLA has potential as a mucosal immunogen for a strongylid nematode vaccine. [source]

A previous infection with Toxoplasma gondii does not protect against a challenge with Neospora caninum in pregnant sheep

PARASITE IMMUNOLOGY, Issue 3 2001
E.A. Innes
Sheep immunized with Toxoplasma gondii (Toxovax®) prior to pregnancy were tested for their ability to withstand a challenge at 90 days gestation with 107 Neospora caninum (NC1) tachyzoites. The antibody responses in sheep following immunization with T. gondi were specific for T. gondii whereas peripheral blood mononuclear cells responded to both T. gondii and caninum antigen in vitro. This suggested that there was induction of crossreactive immune recognition in the sheep, at least at the cellular level. Following challenge of sheep at mid-gestation with N caninum, no febrile responses were recorded in the group of sheep which had previously received Toxovax® while significant febrile responses were recorded in the group of sheep which received N challenge alone. Antibody responses to N developed in all sheep following challenge and antibody responses to T,gondii were boosted in the group of sheep which had previously been immunized with Toxovax®. No antibodies to were observed in the sheep which received the challenge alone. Peripheral blood mononuclear cells from both groups of sheep responded to T.gondii N.caninum antigen invitro and interferon gamma was present in the cell-free supernatant from activated cells. However despite evidence of the induction of crossreactive immunity between T.gondii N.caninum this was not sufficient to prevent foetal death. The group of sheep which had received Toxovax® prior to pregnancy and the group of sheep which only received the N.caninum challenge experienced 100% foetal death compared with 0% in the unchallenged control group. Vaccination prior to pregnancy with Toxovax® did protect against foetal death following oral challenge at 90 days with 2000 oocysts which caused 100% foetal death in a control challenge group. [source]

Effect of Ram Age on Structural and Functional Competence of Frozen,Thawed Spermatozoa in Dairy Sheep

REPRODUCTION IN DOMESTIC ANIMALS, Issue 4 2010
AG Lymberopoulos
Contents The objectives of this study were to investigate the influence of ram age on structural and functional competence of frozen,thawed spermatozoa and to test the hypothesis that increasing number of sperm bound to the zona pellucida in vitro was associated with decreasing in vivo fertility of frozen semen. Rams were allocated into two groups. Each group consisted of five rams aged either 1,2 years (young) or 4,5 years (mature). Three successive ejaculates were collected from each ram using an artificial vagina. Only ejaculates of , 2.5 × 109 sperm/ml and 80% sperm progressive motility were pooled per ram, diluted with Bioxcell® medium and frozen in 0.25 ml straws. The end points of post-thawing semen evaluation were computer-assisted cell motility analysis, sperm capacitation (chlortetracycline assay), simultaneous assessment of plasma membrane integrity, mitochondrial membrane potential and condensation status of nucleus, per-cell analysis of lipid peroxidation using C11-BODIPY581/591, sperm-hemizona binding (HZB) ability and sperm fertility after laparoscopic insemination of ewes (n = 114) in the progestagen-synchronized oestrus. The results showed that mature rams had significantly lower values of sperm hyperactivated motility and peroxidized sperm, higher percentages of live non-capacitated sperm and sperm cells with intact plasma membrane, functional mitochondria and condensed chromatin, as well as, greater lambing rate and ewe prolificacy. Sperm HZB binding ability was higher (p < 0.05) for young than for mature rams. Significant correlations were found between number of spermatozoa bound to the zona pellucida and semen fertility (r = ,0.63 to ,0.71). In conclusion, mature rams have better semen quality and in vivo fertility than young rams. Cryocapacitation can be involved in decreasing ram semen fertility as evidenced by the high number of spermatozoa bound to the zona pellucida in vitro. [source]

Molecular Cloning and Characterization of CD9 cDNA from Sheep and Cashmere Goat

REPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2010
WJ Xing
Contents CD9 is a glycoprotein of the transmembrane 4 superfamily (TM4SF) and is involved in various cellular processes. Some CD9 cDNA have been cloned in mammals and certain fish genera in recent years, but goat and sheep counterparts of cattle, human and mouse have not been identified. To facilitate the studies, we cloned the cDNA encoding for CD9 of cashmere goat (Capra hircus) and sheep (Ovis aries), and expressed sheep CD9 in Escherichia coli cells. Structural analysis indicated for both goat and sheep that a 1123 bp cDNA spanned an open reading frame of 681 bp which predicted a protein of 226 amino acids with a typical TM4SF structure, including four highly conserved transmembrane domains, two extracellular domains and a CCG motif, which is a hallmark of the TM4SF. The predicted amino acid sequences were highly homologous to those of cattle, mouse and human CD9. Molecular phylogenetic analysis based on CD9 cDNA sequences indicated that goat and sheep CD9 were closely related to CD9 of cattle, which is in agreement with their morphological taxonomy. [source]

Ultrasonographic and Endocrine Evaluation of Three Regimes for Oestrus and Ovulation Synchronization for Sheep in the Subtropics

REPRODUCTION IN DOMESTIC ANIMALS, Issue 6 2009
A Ali
Contents This study aimed to evaluate three regimes for oestrus and ovulation synchronization in Farafra ewes in the subtropics. During autumn, 43 ewes were assigned to (i) controlled internal drug releasing (CIDR)-eCG group, treated with CIDR for 12 days and eCG at insert withdrawal, n = 13; (ii) PGF2,-PGF2, group, treated with two PGF2, injections at 11 days interval, n = 14; and (iii) GnRH-PGF2,-GnRH group, treated with GnRH, followed 5 days later with PGF2, and 24 h later with a second GnRH, n = 16. Oestrus-mating detection was carried out at 4 h intervals starting on day 0 [the day of CIDR withdrawal (CIDR-eCG group), the day of second PGF2, treatment (PGF2,-PGF2, group) and the day of PGF2, treatment (GnRH-PGF2,-GnRH group)]. Ovarian dynamics was monitored by ultrasound every 12 h beginning on day 0 and continued for 4 days. Blood samples were obtained daily for progesterone (P4) and oestradiol 17, (E2) estimation starting on day 0 and continued for 4 days. The obtained results showed that, oestrus expression, ovulation and conception were greater (p < 0.05) in CIDR-eCG and PGF2,-PGF2, groups than in GnRH-PGF2,-GnRH group. All ewes of PGF2,-PGF2, group presented, on day of second PGF2, injection with mature CL (P4 > 2.0 ng/ml), compared to 42.9% in GnRH-PGF2,-GnRH group (p = 0.01). The peak of oestrus occurred 32,52, 48,60 and 28,96 h after the end of treatment in CIDR-eCG, PGF2,-PGF2, and GnRH-PGF2,-GnRH groups, respectively. Ovulation started 48 h after treatment in all groups and extended for 24, 36 and 48 h for CIDR-eCG, PGF2,-PGF2, and GnRH-PGF2,-GnRH groups, respectively. Results demonstrated that oestrus and ovulation synchronization could be efficiently achieved in Farafra ewes using either CIDR-eCG or PGF2,-PGF2, regimes; however, the GnRH-PGF2,-GnRH treatment induced a more spread oestrus and ovulation that may make the protocol inadequate for timed artificial insemination. [source]

Seasonal Variation of Reproductive Performance, Foetal Development and Progesterone Concentrations of Sheep in the Subtropics

REPRODUCTION IN DOMESTIC ANIMALS, Issue 6 2008
A Ali
Contents The aim of the present study was to investigate the effect of breeding season [late spring (LSP) vs winter (WIN)] on reproductive performances, foetal development and progesterone (P4) concentrations of sheep in the subtropics. Ewes of Farafra breed were exposed for mating in LSP (n = 79) and WIN (n = 45). Ultrasonographic examinations were performed at days 25, 45 and 75 of mating to estimate the pregnancy rate, incidence of twinning and percentage of foetal losses. Foetal growth rate was determined at 10-day interval, and blood samples were taken on days 0 (oestrus), 8, 18 of oestrous cycle and on days 30, 45, 60 and 90 of pregnancy for P4 analysis. The results showed that pregnancy and lambing rates were greater (p < 0.01) for ewes mated in LSP (93.7% and 92.4%) than for those mated in WIN (75.6% and 71.1%), respectively. There was no effect of season on the incidence of twinning (overall 19.1%) or the frequency of foetal losses (overall 7.3%). Transient reduction of placental size, foetal growth and P4 concentration was observed following LSP matings. In conclusion, pregnancy and lambing rates were higher following LSP matings. Summer heat stress of the late spring mated ewes transiently interferes with foetal growth and P4 concentrations. [source]

Inhibitory Effect of Selenium Supplementation on the Reproductive Performance in Synchronized Merino Sheep at Range Conditions in a Selenium-deficient Area

REPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2008
J Sánchez
Contents The effect of selenium (Se) supplementation on the reproductive performance of Merino ewes mated out of the normal breeding season was studied in a 2 (no Se supplementation vs Se supplementation) × 2 (ewes mated at natural oestrus vs synchronized oestrus) factorial design with 50 ewes per treatment combination. Synchronization of oestrus was achieved by intravaginal insertion of 40 mg cronolone sponges for 14 days and administration of 440 IU PMSG at sponge withdrawal. Se supplementation was by the addition to the concentrate with 0.5 mg/kg of Se in the form of selenomethionin, for the 3 months prior to the mating and during gestation. Ewes were kept under range conditions in south-west Spain, and exposed to Merino rams at a female: male ratio of 4 : 1 from 2 days following sponge withdrawal, or the equivalent time, for 21 days. Se supplementation alone did not improve significantly ewe fertility or lamb birth weight, but there was a positive effect of synchronizing ewes mated out of the breeding season as more of these ewes lambed and produced more lambs than those not synchronized. However, a strong interaction was found between synchronization and Se supplementation, causing a deleterious effect on the reproductive performance of ewes. This negative effect, presumably related to high embrionary mortality caused by Se toxicity, should be taken into account for oestrus synchronizing in Se-deficient areas. The supplementation with Se, for the prevention of nutritional myodystrophy degeneration in lambs, should be conducted in a fashion which does not generate high levels of Se in the ewes around the mating period. [source]

Timing of Preovulatory LH Surge and Ovulation in Superovulated Sheep are Affected by Follicular Status at Start of the FSH Treatment

REPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2008
A Veiga-Lopez
Contents The aims of this study were to evaluate the chronology of periovulatory events (oestrus behaviour, LH surge and ovulation) in 16 superovulated Manchega sheep and to determine whether follicular status at start of the FSH supply might affect their occurrence. Mean timing for onset of oestrus behaviour was detected at 28.1 ± 0.7 h after sponge withdrawal; the preovulatory LH surge and ovulation started at 37.2 ± 0.7 h and 65.4 ± 0.7 h after progestagen withdrawal, respectively. The intervals between oestrus, LH surge and ovulation were affected by a high individual variability, which might be the cause for reported decreased efficiency in embryo production. Current results also addressed the role of follicular status at start of the superovulatory treatment on the preovulatory LH surge and the ovulation. The interval LH surge-ovulation was increased in ewes with a growing dominant follicle at starting the FSH treatment (32.3 ± 0.9 vs 28.6 ± 0.5 h, p < 0.05). The developmental stage of the largest follicle at starting the superovulatory treatment also affected occurrence of LH surge and ovulation; follicles in growing phase advanced the occurrence of the LH surge and ovulation when compared to decreasing follicles (33.0 ± 1.0 vs 43.5 ± 1.1 h, p < 0.05, for LH peak and 60.7 ± 1.1 vs 72.8 ± 1.2 h, p < 0.05, for ovulation). Thus, only ewes with growing follicles ovulated prior to 55 h after sponge withdrawal; conversely, no sheep with decreasing follicles ovulated earlier than 67 h, when an 85.7% of the ewes bearing growing follicles has ovulated at 63 h. [source]

Effects of Body Condition and Protein Supplementation on LH Secretion and Luteal Function in Sheep

REPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2007
CA Meza-Herrera
Contents In ruminants, nutrition is one of the exogenous inputs affecting reproductive function at different levels of the hypothalamic,hypophyseal,gonadal axis. However, the exact mechanisms or even the identification of the signalling metabolic compounds by which nutrition affects reproductive function still need further clarification. The role of static body condition (BC) and its interaction with a short-term protein supplementation (PL), on secretion of metabolic hormones [growth hormone (GH), insulin and insulin-like growth factor-1 (IGF-1)], as well as on secretion of LH and progesterone (P4) was evaluated in sheep. Twenty-four Rambouillet ewes divided into two groups, with lower (LBC) and higher body condition (HBC), were randomly assigned within BC to one of two PL levels: low (LPL, 24% of crude protein; 14 g/animal/day), and high (HPL, 44% of crude protein; 30 g/animal/day). The secretion of GH, insulin, IGF-1 and LH was evaluated on day 10 of the oestrous cycle; appearance and timing of oestrous behaviour were previously detected using rams. Progesterone secretion was evaluated on day 13 of the same cycle. No differences were found (p > 0.05) between PL groups on serum GH concentrations during the sampling period (overall mean of 4.0 ± 0.3 ng/ml), but a trend for lower values in HBC sheep was found (3.6 ± 0.4 vs 4.4 ± 0.4 ng/ml, p = 0.06). A BC effect was observed (p < 0.05) on serum IGF-1 level, with higher values in HBC sheep (p < 0.05). Neither BC nor PL affected (p > 0.05) secretion of LH and the number of corpora lutea, nor serum P4 and insulin concentrations. Results indicate a predominance of the static component of nutrition on sheep metabolic hormone responses, GH and IGF-1, with no effect of short-term PL on secretion of pituitary and ovarian hormones as well as luteal number and activity. [source]

Ovum Pick-up in Sheep: a Comparison between Different Aspiration Devices for Optimal Oocyte Retrieval

REPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2006
C Rodríguez
Contents In vivo ovum pick-up (OPU) in sheep may be improved with a proper choice of aspiration elements (needle and tubing) and aspiration vacuum pressure. In the present study, two experiments were carried out. In Expt 1, visible follicles in ovaries of slaughtered ewes (treated separately according to their diameters: small <3 mm, medium 3,5 mm and large >5 mm) were aspirated using different combinations of the three studied factors such as aspiration flow rate (10, 20, 30, 40 and 50 ml water/min), needle gauge (18 and 20 G) and tubing inner diameter (1, 2 or 3 mm internal diameter). In Expt 2, a study with two 18 G needles of different lengths (18 G: 82 mm; 18 GL: 600 mm) was carried out, using ovaries obtained post-mortem, and performing in vivo laparoscopic follicular aspiration on ewes. We considered good quality oocytes as those with both complete compact cumulus and a homogeneous cytoplasm. Recovery rate, proportion of good quality oocytes (good quality oocytes/100 oocytes recovered) and overall efficiency (good quality oocytes/100 follicles aspirated) were noted. In Expt 1, aspiration flow rate affect remarkable proportion of good quality oocytes (69.5%, 50.5%, 44.8%, 36.5% and 28.3% for flows from 10 to 50 ml/min respectively, p < 0.05). Needle gauge did not affect aspiration device efficiency. Thin and intermediate tubings were more effective (overall efficiency rates: 34.9%, 32.3% and 28.1% for 1, 2 and 3 mm respectively, p < 0.05). Follicle size did not affect recovery rate, but proportion of good quality oocytes was higher for large (77.9%) and medium (64.4%) follicles (p < 0.05). Finally, some combinations of the aspiration device showed greater effectiveness. In Expt 2, needle length did not influence recovery rate, but good quality oocytes rate was significantly modified both post-mortem and in vivo (good quality rate for 18 G vs 18 GL needles: 69.5% vs 47.7% and 58.1% vs 25.4%, post-mortem and in vivo respectively, p < 0.05). We conclude that low-aspiration flow rates (10 and 20 ml/min) with thin or intermediate tubings (1 and 2 mm), and any short needle (18 G or 20 G) are the most adequate aspiration factors for OPU in sheep. [source]

Assessment of Progesterone Concentration Using Enzymeimmunoassay, for Early Pregnancy Diagnosis in Sheep and Goats

REPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2003
CM Boscos
Contents The objective of this study was to determine a value of serum progesterone (P4) concentration, assessed using an enzymeimmunoassay (EIA), for the early distinction between pregnant and non-pregnant ewes and goats. Adult, non-lactating ewes of Chios (n=53), Berrichon (n=30) and Sfakia (n=45) breeds were synchronized during the breeding season with progestagens and gonadotrophins and mated to fertile rams (Experiment I). Adult, lactating goats of Swiss breeds (Alpine and Saanen, n=104) and indigenous Greek breed (n=45) were synchronized during the transitional season with progestagens, PGF2, and gonadotrophins. Cervical artificial insemination (AI) with fresh semen was applied once, 42,44 h after sponge removal (Experiment II). Jugular blood samples were collected on day 19 after sponge removal (ewes) or on day 21 after AI (goats) and serum P4 concentration was determined by EIA. Progesterone concentrations ,1.0, ,1.5, ,2.5 and ,4.0 ng/ml were tested as indicative of pregnancy. Pregnancy diagnosis was verified on birth. In the case of sheep, using a discriminatory level of 2.5 ng/ml, overall accuracy of pregnancy diagnosis was 91.4% and predictive value of negative and positive diagnoses were 98.3 and 85.3%, respectively. In the case of goats, predictive value of negative diagnosis was 95.8 and 94.0% and predictive value of positive diagnosis 71.3 and 71.7%, for 1.5 and 2.5 ng/ml, respectively; overall accuracy was 79.2% using either level. The other discriminatory levels tested did not improve these results. A significant positive correlation was observed between P4 concentration and the number of lambs or kids born, and further analysis indicated that this relationship is not a simple linear function. Based on the results of this study, P4 concentrations of 2.5 ng/ml in the case of ewes and 1.5,2.5 ng/ml in the case of goats, determined with EIA, are proposed as discriminatory levels between pregnant and non-pregnant animals, at an interval of one oestrous cycle after service. [source]