Journal articles: 'Sheep stable'

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Friend, M. A., and G. E. Robards. "Wool production and quality of three strains of Merino in a semi-arid environment under different grazing strategies." Australian Journal of Experimental Agriculture 46, no. 1 (2006): 37. http://dx.doi.org/10.1071/ea04018.

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Three strains of Merino wethers (strong, medium and fine wool; n = 30 each; 3 years old) were grazed under 3 different management regimes (10 from each strain) in a semi-arid environment to test the hypothesis that attempting to keep liveweight stable at upper and lower levels would improve staple strength relative to sheep in which no attempt was made to limit liveweight fluctuations, and that strength and wool colour would not differ between strains. Sheep in the low grazing regime were managed in an attempt to keep liveweight stable at a level below that of sheep in the high grazing regime, which were managed in an attempt to keep liveweight stable at a level higher than sheep in the low grazing regime. For the control group, no attempt was made to limit liveweight fluctuations through grazing management. Sheep in the high grazing regime had greater liveweights throughout the experiment than sheep in the low grazing regime, while the liveweight of sheep in the control group was usually intermediate. Staple strength did not differ significantly between the strains, but was greater (P<0.05) for sheep in the high grazing regime (58.3 ± 2.2 N/ktex) than for sheep in the control (39.0 ± 2.3 N/ktex) and low (33.8 ± 2.3 N/ktex) grazing regimes, which did not differ significantly from each other. Wool yellowness was not affected by grazing regime, but was lower (P<0.05) in fine wool sheep (1.0 ± 0.1%) than medium wool sheep (1.4 ± 0.1%), which, in turn, was less (P<0.05) than in strong wool sheep (1.7 ± 0.1%). Staple strength was significantly (P<0.05) correlated with mean liveweight (0.27), mean fibre diameter (0.25), minimum fibre diameter (0.36), coefficient of variation of fibre diameter (–0.50), coefficient of variation of diameter along fibres (–0.48) and between fibres (–0.41). The results indicate staple strength was not adversely affected by the choice of strain in a semi-arid environment, and that nutritional management to limit fibre diameter variability can be an effective strategy to improve staple strength, regardless of strain.

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Vilarino, Marcela, Delia Alba Soto, Yanina Soledad Bogliotti, Leqian Yu, Yanli Zhang, Chunsheng Wang, Erika Paulson, et al. "Derivation of sheep embryonic stem cells under optimized conditions." Reproduction 160, no. 5 (November 2020): 761–72. http://dx.doi.org/10.1530/rep-19-0606.

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Until recently, it has been difficult to derive and maintain stable embryonic stem cells lines from livestock species. Sheep ESCs with characteristics similar to those described for rodents and primates have not been produced. We report the derivation of sheep ESCs under a chemically defined culture system containing fibroblast growth factor 2 (FGF2) and a tankyrase/Wnt inhibitor (IWR1). We also show that several culture conditions used for stabilizing naïve and intermediate pluripotency states in humans and mice were unsuitable to maintain ovine pluripotency in vitro. Sheep ESCs display a smooth dome-shaped colony morphology, and maintain an euploid karyotype and stable expression of pluripotency markers after more than 40 passages. We further demonstrate that IWR1 and FGF2 are essential for the maintenance of an undifferentiated state in de novo derived sheep ESCs. The derivation of stable pluripotent cell lines from sheep blastocysts represents a step forward toward understanding pluripotency regulation in livestock species and developing novel biomedical and agricultural applications.

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Tran, Nam D., Christopher D. Porada, Graça Almeida-Porada, Hudson A. Glimp, W. French Anderson, and Esmail D. Zanjani. "Induction of stable prenatal tolerance to β-galactosidase by in utero gene transfer into preimmune sheep fetuses." Blood 97, no. 11 (June 1, 2001): 3417–23. http://dx.doi.org/10.1182/blood.v97.11.3417.

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The successful transduction of hematopoietic stem cells and long-term (28 months) transgene expression within the hematopoietic system following the direct injection of high-titer retroviral vectors into preimmune fetal sheep was previously demonstrated. The present studies extended these analyses for 40 months postinjection and evaluated whether the longevity of transgene expression in this model system was the result of induction of prenatal tolerance to the transgene product. The intraperitoneal injection of retroviral vectors into preimmune sheep fetuses transduces thymic epithelial cells thought to present antigen and thus define self during immune system development. To directly demonstrate induction of tolerance, postnatal sheep were boosted with purified β-galactosidase and showed that the peripheral blood lymphocytes from in utero–transduced sheep exhibited significantly lower stimulation indices to transduced autologous cells than did control animals and that the in utero–transduced sheep had a reduced ability to mount an antibody response to the vector-encoded β-galactosidase protein compared with control sheep. Collectively, our results provide evidence that the direct injection of retroviral vectors into preimmune sheep fetuses induces cellular and humoral tolerance to the vector/transgene products and provide an explanation for the duration and stability of transgene expression seen in this model. These results also suggest that even relatively low levels of gene transfer in utero may render the recipient tolerant to the exogenous gene and thus potentially permit the successful postnatal treatment of the recipient.

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Piccione, Giuseppe, Claudia Giannetto, Stefania Casella, and Giovanni Caola. "Circadian Activity Rhythm in Sheep and Goats Housed in Stable Conditions." Folia Biologica 56, no. 3 (June 30, 2008): 133–37. http://dx.doi.org/10.3409/fb.56_3-4.133-137.

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Martins, M. B., C. Ducatti, C. L. Martins, J. C. Denadai, A. S. Natel, C. R. Souza-Kruliski, and M. M. P. Sartori. "Stable isotopes for determining carbon turnover in sheep feces and blood." Livestock Science 149, no. 1-2 (November 2012): 137–42. http://dx.doi.org/10.1016/j.livsci.2012.07.004.

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Lira, Kariny Cavalcante de, José Carlos Batista Dubeux, Mário de Andrade Lira, Francisco Fernando Ramos Carvalho, Mércia Virgínia Ferreira Santos, Márcio Vieira Cunha, Alexandre Carneiro Leão Mello, David M. Jaramillo, and José Diogenes Pereira Neto. "Tracing sheep binary C3–C4 diet using stable isotope ratio (δ13C)." Italian Journal of Animal Science 20, no. 1 (January 1, 2021): 288–94. http://dx.doi.org/10.1080/1828051x.2021.1881413.

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Birhan, Getachew Bitew, Justin Manango W. Munganga, and Adamu Shitu Hassan. "Mathematical Modeling of Echinococcosis in Humans, Dogs, and Sheep." Journal of Applied Mathematics 2020 (November 1, 2020): 1–18. http://dx.doi.org/10.1155/2020/8482696.

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In this paper, a model for the transmission dynamics of cystic echinococcosis in the dog, sheep, and human populations is developed and analyzed. We first model and analyze the predator-prey interaction model in these populations; then, we propose a mathematical model of the transmission dynamics of cystic echinococcosis. We calculate the basic reproduction number R 0 and prove that the disease-free equilibrium is globally asymptotically stable, and hence, the disease dies out if R 0 > 1 . We further show that the endemic equilibrium is globally asymptotically stable, and hence, the disease persists if R 0 < 1 . Numerical simulations are performed to illustrate our analytic results. We give sensitivity analysis of the key parameters and give strategies that are helpful to control the transmission of cystic echinococcosis, from which the most sensitive parameter is the transmission rate of Echinococcus’ eggs from the environment to sheep ( β es ). Thus, the effective controlling strategies are associated with this parameter.

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Kitching, R. P., P. P. Bhat, and D. N. Black. "The characterization of African strains of capripoxvirus." Epidemiology and Infection 102, no. 2 (April 1989): 335–43. http://dx.doi.org/10.1017/s0950268800030016.

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SUMMARYIsolates of capripoxvirus collected from sub-Saharan Africa were compared in sheep, goats and cattle and by restriction endonuclease digestion of their purified DNA. Biochemical techniques were used to precisely identify strains of capripoxvirus for epidemiological investigations. Strains of capripoxvirus infecting cattle have remained very stable over a 30-year period and are closely related to strains recovered from sheep in Africa.

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De LANGE, M. M. A., B. SCHIMMER, P. VELLEMA, J. L. A. HAUTVAST, P. M. SCHNEEBERGER, and Y. T. H. P. VAN DUIJNHOVEN. "Coxiella burnetii seroprevalence and risk factors in sheep farmers and farm residents in The Netherlands." Epidemiology and Infection 142, no. 6 (August 7, 2013): 1231–44. http://dx.doi.org/10.1017/s0950268813001726.

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SUMMARYIn this study, Coxiella burnetii seroprevalence was assessed for dairy and non-dairy sheep farm residents in The Netherlands for 2009–2010. Risk factors for seropositivity were identified for non-dairy sheep farm residents. Participants completed farm-based and individual questionnaires. In addition, participants were tested for IgG and IgM C. burnetii antibodies using immunofluorescent assay. Risk factors were identified by univariate, multivariate logistic regression, and multivariate multilevel analyses. In dairy and non-dairy sheep farm residents, seroprevalence was 66·7% and 51·3%, respectively. Significant risk factors were cattle contact, high goat density near the farm, sheep supplied from two provinces, high frequency of refreshing stable bedding, farm started before 1990 and presence of the Blessumer breed. Most risk factors indicate current or past goat and cattle exposure, with limited factors involving sheep. Subtyping human, cattle, goat, and sheep C. burnetii strains might elucidate their role in the infection risk of sheep farm residents.

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Hamzić Gregorčič, Staša, Doris Potočnik, Federica Camin, and Nives Ogrinc. "Milk Authentication: Stable Isotope Composition of Hydrogen and Oxygen in Milks and Their Constituents." Molecules 25, no. 17 (September 2, 2020): 4000. http://dx.doi.org/10.3390/molecules25174000.

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This paper summarises the isotopic characteristics, i.e., oxygen and hydrogen isotopes, of Slovenian milk and its major constituents: water, casein, and lactose. In parallel, the stable oxygen isotope ratios of cow, sheep, and goat’s milk were compared. Oxygen stable isotope ratios in milk water show seasonal variability and are also 18O enriched in relation to animal drinking water. The δ18Owater values were higher in sheep and goat’s milk when compared to cow milk, reflecting the isotopic composition of drinking water source and the effect of differences in the animal’s thermoregulatory physiologies. The relationship between δ18Omilk and δ18Olactose is an indication that even at lower amounts (>7%) of added water to milk can be determined. This procedure once validated on an international scale could become a reference method for the determination of milk adulteration with water.

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11

Balabanova, Tatyana Boryanova, and Mihaela Georgieva Ivanova. "Effect of stage of lactation on somatic cell count in sheep milk of Pleven Blackhead breed." Food Science and Applied Biotechnology 4, no. 1 (March 19, 2021): 14. http://dx.doi.org/10.30721/fsab2021.v4.i1.124.

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Milk secretion in small ruminants present some particularities for cytoplasmatic particles which are shed in the milk together with leukocytes and epithelial cells. Therefore, a parameter like a somatic cell count is worldwide used as a measurement indicator of subclinical mastitis. The aim of the present study was to establish the change of chemical and microbiological characteristics on the composition of sheep milk, obtained from Pleven Blackhead sheep breed during different stages of lactation. It was established that the chemical characteristics of sheep milk varied widely according to the way animals were raised and fed. The obtained results described a slight increase in the values of the total concentration of minerals (up to 1%) and titratable acidity from 19 to 25°T. A decrease in the values of total solids (19.2-16.6%), milk fat (8.0-6.2%), and protein content (5.8-4.9%) during the stages of lactation was established. The microbiological analysis showed that somatic cell count and total bacterial count during lactation progressively decreased, probably due to the account the hygienic conditions, nutrition, environment and health status of the animals. Moreover, changes in the composition of sheep milk were directly dependent on stable, stable/pasture and pasture feeding system during lactation period.

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Yu, Yibo, Yun Wang, Liang Zhong, Hongjuan Zhu, and Jiapeng Qu. "Variations in Behavioral and Physiological Traits in Yearling Tibetan Sheep (Ovis aries)." Animals 11, no. 6 (June 4, 2021): 1676. http://dx.doi.org/10.3390/ani11061676.

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Temperament is a consistent behavioral difference among individuals over time or in different contexts. A comprehensive understanding of temperament and complex behavioral interactions enhances knowledge on animal evolution, welfare, and productivity. However, reports on the development of behavioral consistency over ontogeny are vague. Here, we tested the ontogeny of the temperament and physiological traits of Tibetan sheep (Ovis aries) in three crucial age stages. The mean level of the risk-taking variable increased, while that of the vocalizations variable decreased. The exploration variable was stable over ontogeny. The novelty decreased and the heart rate increased from the juvenile to the adolescent stage but stabilized at the adult stage. The fecal cortisol concentration (CORT) variable was stable at the juvenile and adolescent stages but decreased at the adult stage. Stable correlations were reported for the juvenile and adolescent stages and for the behavioral variables and heart rate. However, some correlations emerged only after maturation, whereas others disappeared over ontogeny. Moreover, CORT was independent of temperament and heart rate at different ages. These results demonstrate that age affects temperament and physiology and their correlations. Hence, developmental aspects should be incorporated into future temperament studies.

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13

Archer, Fabienne, Corinne Bachelin, Olivier Andreoletti, Nathalie Besnard, Gregory Perrot, Christelle Langevin, Annick Le Dur, et al. "Cultured Peripheral Neuroglial Cells Are Highly Permissive to Sheep Prion Infection." Journal of Virology 78, no. 1 (January 1, 2004): 482–90. http://dx.doi.org/10.1128/jvi.78.1.482-490.2004.

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ABSTRACT Transmissible spongiform encephalopathies arise as a consequence of infection of the central nervous system (CNS) by prions. Spreading of the infectious agent through the peripheral nervous system (PNS) may represent a crucial step toward CNS neuroinvasion, but the modalities of this process have yet to be clarified. Here we provide further evidence that PNS glial cells are likely targets for infection by prions. Glial cell clones originating from dorsal root ganglia of transgenic mice expressing ovine PrP (tgOv) and simian virus 40 T antigen were found to be readily infectible by sheep scrapie agent. This led us to establish two stable cell lines that exhibited features of Schwann cells. These cells were shown to sustain an efficient and stable replication of sheep prion based on the high level of accumulation of abnormal PrP and infectivity in exposed cultures. We also provide evidence for abnormal PrP deposition in peripheral neuroglial cells from scrapie-infected tgOv mice and sheep. These findings have potential implications in terms of designing new cell systems permissive to prions and of peripheral pathobiology of prion infections.

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Witt, GB, EJ Moll, and RJS Beeton. "Sheep Faeces Under Shearing Sheds: a Documentary of Vegetation Change Using Stable Carbon Isotope Analysis." Rangeland Journal 19, no. 1 (1997): 109. http://dx.doi.org/10.1071/rj9970109.

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In this study we report on a new technique for reconstructing long-tgrm vegetation changes in the Australian rangelands. Sheep faeces, which accumulate annually beneath shearing sheds, provide an untapped and potentially continuous record of vegetation change at a property scale. From stable carbon isotope analysis, inferences about the available vegetation can be made. Our analysis revealed vegetation changes slnce the construction of two sheds, a period of approximately 40 years. Results indicated a significant reduction in the availability of C, grasses on Currawinya (south-west Queensland). However, for the same period there was no significant change in proportion of C, and C, species contributing to the diet of sheep on Talyealye (north-west New South Wales). Given the abundance, age and distribution of shearing sheds in the Australian rangelands, the potential exists to reconstruct a detailed picture of vegetation change at a national scale.

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Paterson, Adrienne C., Graham S. Baldwin, and Arthur Shulkes. "Metabolism of recombinant progastrin in sheep." American Journal of Physiology-Endocrinology and Metabolism 283, no. 3 (September 1, 2002): E449—E456. http://dx.doi.org/10.1152/ajpendo.00042.2002.

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Precursor forms of peptide hormones may be biologically active with effects distinct from the mature end product. Nonamidated progastrin-derived peptides stimulate growth of colonic epithelium and are elevated in the circulation of patients with colorectal carcinomas, whereas the amidated end product is the major regulator of gastric acidity. Using region-specific radioimmunoassays, we here compared the in vitro and in vivo metabolism of recombinant human progastrin-(6–80) and two other nonamidated gastrins, gastrin-17-Gly and Tyr70-progastrin-(71–80). Although progastrin-(6–80) was very stable in vitro, both progastrin-(6–80) and gastrin-17-Gly were degraded in vivo. The in vivo data were best fitted by a double-exponential decay curve, and the half-lives for progastrin-(6–80) ( t ½α = 5.1 ± 1.1, t ½β = 42 ± 11 min) were significantly ( P < 0.05) longer than for gastrin-17-Gly ( t ½α = 2.2 ± 0.6, t ½β = 13 ± 1 min). Tyr70-progastrin-(71–80) was degraded more rapidly. Comparison with amidated gastrins suggests that peptide length, rather than sequence, is the critical determinant of clearance. Progastrin has the clearance characteristics to be considered a circulating hormone.

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Sproston, Emma L., Iain D. Ogden, Marion MacRae, John F. Dallas, Samuel K. Sheppard, Alison J. Cody, Frances M. Colles, Michael J. Wilson, Ken J. Forbes, and Norval J. C. Strachan. "Temporal Variation and Host Association in the Campylobacter Population in a Longitudinal Ruminant Farm Study." Applied and Environmental Microbiology 77, no. 18 (July 22, 2011): 6579–86. http://dx.doi.org/10.1128/aem.00428-11.

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ABSTRACTCampylobacter jejuniandC. coliwere quantified and typed, using multilocus sequence typing (MLST), from fecal samples collected from a mixed cattle and sheep farm during summer. Cattle had a significantly higher prevalence than sheep (21.9% [74/338] and 14.0% [30/214], respectively), but both decreased over time. There were no differences in the averageCampylobacterconcentrations shed by cattle (600 CFU g−1) and sheep (820 CFU g−1), although sheep did show a significant temporal reduction in the number ofCampylobacterorganisms shed in their feces. A total of 21 different sequence types (STs) (97.7%C. jejuni, 2.3%C. coli) were isolated from cattle, and 9 different STs were isolated from sheep (40.6%C. jejuni, 59.4%C. coli). TheCampylobacterpopulation in cattle was relatively stable, and the frequencies of genotypes isolated showed little temporal variation. However, the composition of subtypes isolated from sheep did show significant temporal differences. The cattle and sheep consistently showed significant differences in their carriage ofCampylobacterspecies, STs, and CCs despite the fact that both were exposed to the same farming environment. This work has highlighted the patterns of aCampylobacterpopulation on a ruminant farm by identifying the existence of both temporal and between-host variations.

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Bazzy, A. R., and D. F. Donnelly. "Diaphragmatic failure during loaded breathing: role of neuromuscular transmission." Journal of Applied Physiology 74, no. 4 (April 1, 1993): 1679–83. http://dx.doi.org/10.1152/jappl.1993.74.4.1679.

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To determine whether central or peripheral mechanisms are responsible for diaphragmatic failure during loaded breathing, phrenic nerve activity (iENG), diaphragm muscle electromyogram (iEMG), and transdiaphragmatic pressure (Pdi) were measured in unanesthetized chronically instrumented sheep during inspiratory flow-resistive (IFR) loaded breathing. After placement of the IFR load, Pdi increased initially and remained relatively stable for 10–30 min [Pdi = 69.9 +/- 6.3 (SE) cmH2O, n = 6]; arterial PCO2 also increased from baseline (35.8 +/- 0.9 Torr) to 55.1 +/- 4.7 Torr. During IFR loading, iEMG and iENG also increased from baseline, but during the plateau phase of Pdi, iENG continued to increase at the same time while iEMG was stable, and the M wave, evoked by phrenic nerve stimulation, decreased during this period. After the plateau phase, Pdi decreased and arterial PCO2 increased, at which point the study was terminated (at 82.1 +/- 20.6 min). The observation that iENG increased while Pdi and iEMG were stable demonstrates a reduced efficiency of neuromuscular transmission and suggests that the neuromuscular junction is an important site of diaphragmatic failure in unanesthetized sheep during IFR loaded breathing.

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Scheidweiler, Karl B., Jalil Shojaie, Mark A. Plessinger, Ronald W. Wood, and Tai C. Kwong. "Stability of Methylecgonidine and Ecgonidine in Sheep Plasma in Vitro." Clinical Chemistry 46, no. 11 (November 1, 2000): 1787–95. http://dx.doi.org/10.1093/clinchem/46.11.1787.

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Abstract Background: Crack smokers are exposed to a pyrolysis product, methylecgonidine (MEG), which can be used as an analytical marker for crack smoking. Ecgonidine (EC), a hydrolytic product of MEG, has been identified in urine of crack smokers. MEG undergoes conversion to EC, complicating analysis and perhaps explaining a lack of forensic blood specimens containing MEG. Methods: We developed gas chromatography–mass spectrometry (GC-MS) assays for MEG and EC. Plasma was collected from sheep blood containing 0, 0.06, or 0.24 mol/L (0%, 0.25%, or 1%) NaF. MEG was added to these plasmas, and they were incubated at −80, 1, 21, or 37 °C to determine whether there were temporal, temperature, or storage effects on MEG stability over 48 h. Results: Decreased temperature and increased NaF concentrations limited MEG degradation and EC formation. MEG stored in plasma at −80 °C was stable up to 1 month, even in the absence of NaF. Conclusions: MEG is stable in sheep plasma collected in commercially available, evacuated blood-collection tubes containing NaF and stored at −80 °C. In vitro formation of EC can be minimized with appropriate sample handling, and its in vivo formation may provide a better marker of crack smoking than its parent pyrolysis product.

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Mandapati, Ravi, Allan Skanes, Jay Chen, Omer Berenfeld, and José Jalife. "Stable Microreentrant Sources as a Mechanism of Atrial Fibrillation in the Isolated Sheep Heart." Circulation 101, no. 2 (January 18, 2000): 194–99. http://dx.doi.org/10.1161/01.cir.101.2.194.

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Pearson, Jessica, and Matt Grove. "Counting sheep: sample size and statistical inference in stable isotope analysis and palaeodietary reconstruction." World Archaeology 45, no. 3 (July 29, 2013): 373–87. http://dx.doi.org/10.1080/00438243.2013.820646.

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Coil, David A., John H. Strickler, Sharath K. Rai, and A. Dusty Miller. "Jaagsiekte Sheep Retrovirus Env Protein Stabilizes Retrovirus Vectors against Inactivation by Lung Surfactant, Centrifugation, and Freeze-Thaw Cycling." Journal of Virology 75, no. 18 (September 15, 2001): 8864–67. http://dx.doi.org/10.1128/jvi.75.18.8864-8867.2001.

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ABSTRACT Jaagsiekte sheep retrovirus (JSRV) replicates in the lungs of sheep and causes the secretion of copious lung fluid containing the virus. Adaptation of JSRV to infection and replication in the lung and its apparent resistance to the denaturing activity of lung fluid suggest that vectors based on JSRV would be useful for gene therapy targeted to the lung. We show here that a retrovirus vector bearing the JSRV Env is stable during treatment with lung surfactant while an otherwise identical vector bearing an amphotropic Env is inactivated. Furthermore, the JSRV vector was stable during centrifugation, allowing facile vector concentration, and showed no loss of activity after six freeze-thaw cycles. However, the JSRV vector was inactivated by standard disinfectants, indicating that JSRV vectors pose no unusual safety risk related to their improved stability under other conditions.

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Topczewska, Jadwiga, and Anna Rogowska. "Assessment of housing conditions in selected horse stables." Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego 13, no. 4 (December 28, 2017): 67–75. http://dx.doi.org/10.5604/01.3001.0013.5204.

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The objective of the study was to assess housing conditions for horses. Both new and adapted stables were selected for the study. Measurements of the buildings were made, the area of the boxes was calculated, and the equipment was evaluated. The microclimate of the stables was evaluated by means of direct measurements in the boxes and in the corridors in six replications, at 7 am, 2 pm and 7 pm, taking into account the season of the year. The temperature, relative humidity and air speed were measured with a Kastrel 3000 anemometer, and light intensity with a TES-1335 light meter. The concentration of gaseous impurities (CO2, H2S and NH3) was measured with a GAS-HUNTER meter. The results obtained were statistically analysed using STATISTICA 10.0. Several of the boxes in the adapted sheep building did not have the recommended minimum area of 9 m2, and also had smallest the cubic area per head. The air temperature was within the recommended range, but in one of the stables a temperature of 4°C was recorded in winter. The air movement in the passageways exceeded the recommended levels due to aeration through open doors. The skylights in the stable located next to the riding halls improved the natural lighting. In contrast, the stable adapted from a sheep building, with its low ceiling and small windows, was dimly lit and required artificial lighting. Despite the significant differences in the construction of the buildings, when they were erected, and the size of the stud, the microclimatic conditions were not found to differ significantly from the recommended standards.

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Ling, W. D., D. P. Brooks, J. T. Crofton, L. Share, and D. F. Bohr. "Pressor responses to vasopressin in pigs and sheep with DOCA hypertension." American Journal of Physiology-Heart and Circulatory Physiology 256, no. 1 (January 1, 1989): H101—H104. http://dx.doi.org/10.1152/ajpheart.1989.256.1.h101.

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Pressor responses to vasopressin were determined in pigs and sheep during three experimental periods: 1) before deoxycorticosterone acetate (DOCA) treatment, 2) 21 days after DOCA implantation (100 mg/kg) when a stable hypertension had developed, and 3) after reversal of the hypertension by removing the implant in the sheep or by decreasing the dietary sodium intake in the pigs. The infusion of lysine (LVP) or arginine (AVP) vasopressin into pigs and sheep, respectively, resulted in dose-dependent increases in plasma vasopressin concentration. The levels of plasma LVP or AVP achieved by these infusions were not altered in any of the experimental periods. The administration of vasopressin resulted in dose-dependent increases in mean arterial blood pressure. However, pigs required five times more LVP than sheep required AVP to achieve similar pressor responses. The pressor responsiveness to vasopressin was attenuated when either species was made hypertensive. This effect was reversed when normal blood pressure was restored by reducing sodium intake in the pigs or by removing the DOCA implant from the sheep. These data establish that an increased pressor response to vasopressin does not contribute to DOCA hypertension in pigs or sheep.

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Sumer, Huseyin, Jun Liu, Luis Malaver Ortega, and Paul J. Verma. "INDUCING PLURIPOTENCY IN RUMINANTS." Reproduction, Fertility and Development 24, no. 1 (2012): 285. http://dx.doi.org/10.1071/rdv24n1ab245.

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The generation of ES cell lines in ruminants, including cattle and sheep, has been inefficient with putative ESCs undergoing rapid spontaneous differentiation. Recently direct reprogramming of rodent and primate somatic cells to induced Pluripotent Stem Cells (iPSC) is possible simply by forcing expression of a handful of transcription factors, typically OCT3/4, SOX2, KLF4 and cMYC (OSKM). Using a similar approach we have identified that addition of NANOG to the reprogramming cocktail was essential for the generation of stable bovine induced pluripotent stem cells (biPSC). Conversely, generation of reprogrammed sheep iPS (siPSC) cells was achieved by transduction of four factors (OSKM) alone. Significantly, at passage 17 the siPS cells showed silencing of the OSKM transgenes with concomitant reactivation of endogenous pluripotent genes, including OCT4, SOX2 and NANOG. The generation of stable ruminant pluripotent cell lines paves the way for the use of these cells for both biomedical research and agricultural outcomes.

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Hobson, Keith A., Mark L. Gloutney, and H. Lisle Gibbs. "Preservation of blood and tissue samples for stable-carbon and stable-nitrogen isotope analysis." Canadian Journal of Zoology 75, no. 10 (October 1, 1997): 1720–23. http://dx.doi.org/10.1139/z97-799.

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Researchers engaged in collecting animal material for stable-carbon and stable-nitrogen isotope analysis are frequently faced with the need to preserve tissues prior to transportation to the laboratory. In many cases, freezing is not possible in the field, so we investigated the potential of several techniques for preserving tissues for this purpose. We also included preservation techniques used for DNA analyses in order to evaluate how they might alter δ13C and δ15N values in tissues and, ultimately, whether archived DNA samples could be used for stable-isotope assay. Tissues included blood and pectoral muscle from quail (Coturnix coturnix japonica) and blood from sheep (Ovis aries). Preservation techniques for blood included freeze-drying (control), drying on precombusted glass-fibre filter paper, and storing in 70% ethanol, 10% buffered formalin, ABI lysis buffer, and Queen's lysis buffer. After 8 weeks, the use of both lysis buffers and formalin resulted in significant depletion of 13C and 15N in blood. Values for samples dried on glass-fibre filter paper or stored in 70% ethanol did not differ significantly from those for the control. Muscle tissue was freeze-dried (control) or stored in 70% ethanol, 10% buffered formalin, or DMSO solution. Both the DMSO and formalin treatments resulted in significant depletion of 13C and 15N compared with the control. Only the 70% ethanol treatment did not result in changes to either isotope ratio in muscle. Where freezing is not possible, we recommend that blood samples be dried or stored in 70% ethanol. Our study provides an estimate of isotopic correction factors that may be applied to tissues archived for DNA analysis or stored in formalin.

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González, Lorenzo, Francesca Chianini, Nora Hunter, Scott Hamilton, Louise Gibbard, Stuart Martin, Mark P. Dagleish, et al. "Stability of murine scrapie strain 87V after passage in sheep and comparison with the CH1641 ovine strain." Journal of General Virology 96, no. 12 (December 1, 2015): 3703–14. http://dx.doi.org/10.1099/jgv.0.000305.

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Breed- and prion protein (PRNP) genotype-related disease phenotype variability has been observed in sheep infected with the 87V murine scrapie strain. Therefore, the stability of this strain was tested by inoculating sheep-derived 87V brain material back into VM mice. As some sheep-adapted 87V disease phenotypes were reminiscent of CH1641 scrapie, transgenic mice (Tg338) expressing ovine prion protein (PrP) were inoculated with the same sheep-derived 87V sources and with CH1641. Although at first passage in VM mice the sheep-derived 87V sources showed some divergence from the murine 87V control, all the characteristics of murine 87V infection were recovered at second passage from all sheep sources. These included 100 % attack rates and indistinguishable survival times, lesion profiles, immunohistochemical features of disease-associated PrP accumulation in the brain and PrP biochemical properties. All sheep-derived 87V sources, as well as CH1641, were transmitted to Tg338 mice with identical clinical, pathological, immunohistochemical and biochemical features. While this might potentially indicate that sheep-adapted 87V and CH1641 are the same strain, profound divergences were evident, as murine 87V was unable to infect Tg338 mice but was lethal for VM mice, while the reverse was true for CH1641. These combined data suggest that: (i) murine 87V is stable and retains its properties after passage in sheep; (ii) it can be isolated from sheep showing a CH1641-like or a more conventional scrapie phenotype; and (iii) sheep-adapted 87V scrapie, with conventional or CH1641-like phenotype, is biologically distinct from experimental CH1641 scrapie, despite the fact that they behave identically in a single transgenic mouse line.

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Mason, J., M. Lamand, J. C. Tressol, and G. Mulryan. "Studies of the changes in systemic copper metabolism and excretion produced by the intravenous administration of trithiomolybdate in sheep." British Journal of Nutrition 59, no. 2 (March 1988): 289–300. http://dx.doi.org/10.1079/bjn19880036.

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1. The effects of intravenous trithiomolybdate administration on the fate of 64Cu and on stable Cu metabolism were examined in sheep held in metabolism cages and fed on a low-Cu diet supplying 2·95 mg Cu/animal per d.2. In Expt 1 the injection of trithiomolybdate, 30 mg molybdenum/sheep per d for 5 d, greatly increased plasma Cu levels and more than doubled the faecal Cu excretion. Urinary Cu excretion was unaffected. The disappearance from plasma of 64Cu injected during the trithiomolybdate administration was slowed although faecal 64Cu excretion was increased more than threefold.3. In Expt 2 trithiomolybdate, 10 and 30 mg Mo/sheep per d for 3 d, was administered 22 h after the injection of 64Cu. Radioactivity reappeared immediately in plasma and faecal 64Cu excretion was increased.4. In both experiments the 64Cu and the increased stable Cu in plasma were associated with albumin.5. The experiments explain the effectiveness of thiomolybdates as ‘decoppering’ agents and provide a model for some of the systemic effects seen in ruminants exposed to increased dietary Mo. The experiments support the view that the thiomolybdates, by causing the appearance of new ligands, alter the distribution of Cu in tissues and cause an overall depletion.

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Miao, Darryl C., Sithembiso C. Velaphi, Timothy Roy, Kevin DeSpain, and Charles R. Rosenfeld. "Metabolism and synthesis of arginine vasopressin in conscious newborn sheep." American Journal of Physiology-Endocrinology and Metabolism 295, no. 3 (September 2008): E672—E677. http://dx.doi.org/10.1152/ajpendo.90441.2008.

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Arginine vasopressin (AVP) is an important regulator of cardiovascular homeostasis in the fetus, but its role after birth is unclear. Although infused AVP increases mean arterial pressure (MAP) during the 1st mo after birth, pressor responses are unchanged, suggesting that vascular responsiveness is also unchanged. Alternatively, this could reflect increases in AVP metabolic clearance rate (MCRAVP). However, newborn AVP metabolism and synthesis are poorly studied. Therefore, we examined the pressor responses to infused AVP and the pattern of circulating AVP, AVP production rate (PRAVP), and MCRAVP in conscious newborn sheep ( n = 5) at 9–38 days after birth. Basal MAP rose and heart rate (HR) fell during the study period ( P ≤ 0.02), while circulating AVP was unchanged ( P > 0.1), averaging 3.01 ± 0.86 pg/ml. Infused AVP elicited steady-state responses at 10–40 min, increasing plasma AVP and MAP and decreasing HR ( P < 0.001). Although pressor responses were unchanged between 9 and 38 days, the rise in MAP correlated with increases in plasma AVP ( R = 0.47, P = 0.02, n = 24). MCRAVP was unchanged throughout the 1st mo ( P > 0.2), averaging 205 ± 17 ml·kg−1·min−1, and was associated with an elevated PRAVP, 973 ± 267 pg·kg−1·min−1, which also was unchanged ( P > 0.1). After birth, MCRAVP and PRAVP are elevated, probably accounting for the stable plasma AVP levels. The former is also likely to account for the stable pressor responses to infused AVP during the 1st mo. The reason for the elevated PRAVP is unclear but may relate to increases in vascular volume associated with postnatal growth.

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Zhang, Yufei, Jing Shi, and Shuying Liu. "Establishment and Characterization of a Telomerase-Immortalized Sheep Trophoblast Cell Line." BioMed Research International 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/5808575.

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The primary sheep trophoblast cells (STCs) have a finite lifespan in culture. This feature limits the scope for long-termin vitrostudies with STCs. This study was an attempt to establish and characterize a telomerase-immortalized sheep trophoblast cell line. STCs were isolated and purified by using Percoll and specific immunoaffinity purification, respectively. The purified STCs were transfected with a plasmid carrying sequences of human telomerase reverse transcriptase (hTERT) to create immortalized sheep trophoblast cell line (hTERT-STCs). hTERT-STCs showed a stable expression of hTERT gene, serially passaged for a year, and showed active proliferation without signs of senescence. Cytokeratin 7 (CK-7), secreted human chorionic gonadotrophin subunitβ(CG-β), placental lactogen (PL), and endogenous jaagsiekte sheep retrovirus (enJSRV) envelope genes were expressed in hTERT-STCs. Transwell cell invasion assay indicated that hTERT-STCs still possessed the same invasive characteristics as normal primary sheep trophoblast cells. hTERT-STCs could not grow in soft agar and did not develop into tumors in nude mice. In this study, we established a strain of immortalized sheep trophoblast cell line which could be gainfully employed in the future as an experimental model to study trophoblast cells with secretory function, invasive features, and probable biological function of enJSRV envelope genes.

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Strampe, Malte, Marcus Stoffel, Dieter Weichert, Richard Martin Sellei, and Hans-Christoph Pape. "Study of the biomechanical behaviour of structurally stable/unstable motion segments of the sheep spine." PAMM 12, no. 1 (December 2012): 97–98. http://dx.doi.org/10.1002/pamm.201210040.

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Keevallik, Leelo. "Sequence Initiation or Self-Talk? Commenting on the Surroundings While Mucking out a Sheep Stable." Research on Language and Social Interaction 51, no. 3 (July 3, 2018): 313–28. http://dx.doi.org/10.1080/08351813.2018.1485233.

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Couldrey, C., R. Brauning, H. V. Henderson, and J. C. McEwan. "Genome-wide DNA methylation analysis: no evidence for stable hemimethylation in the sheep muscle genome." Animal Genetics 46, no. 2 (February 6, 2015): 185–89. http://dx.doi.org/10.1111/age.12268.

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Balasse, Marie, and Stanley H. Ambrose. "Distinguishing sheep and goats using dental morphology and stable carbon isotopes in C4 grassland environments." Journal of Archaeological Science 32, no. 5 (May 2005): 691–702. http://dx.doi.org/10.1016/j.jas.2004.11.013.

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Huang, Yifei, Stephen N. Hunyor, Lele Jiang, Osamu Kawaguchi, Kazuaki Shirota, Yoshihiko Ikeda, Takeshi Yuasa, Gabrielle Gallagher, Biao Zeng, and Xing Zheng. "Remodeling of the chronic severely failing ischemic sheep heart after coronary microembolization: functional, energetic, structural, and cellular responses." American Journal of Physiology-Heart and Circulatory Physiology 286, no. 6 (June 2004): H2141—H2150. http://dx.doi.org/10.1152/ajpheart.00829.2003.

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The mandatory use of pharmacotherapy in human heart failure (HF) impedes further study of natural history and remodeling mechanisms. We created a sheep model of chronic, severe, ischemic HF [left ventricular (LV) ejection fraction (LVEF) <35% stable over 4 wk] by selective coronary microembolization under general anesthesia and followed hemodynamic, energetic, neurohumoral, structural, and cellular responses over 6 mo. Thirty-eight sheep were induced into HF (58% success), with 23 sheep followed for 6 mo (21 sheep with sufficient data for analysis) after the LVEF stabilized (median of 3 embolizations). Early doubling of LV end-diastolic pressure persisted, as did increases in LV end-diastolic volume, LV wall stress, and LV wall thinning. Contractile impairment (LV end-systolic elastance, LV preload recruitable stroke work, and dobutamine-responsive contractile reserve) and diastolic dysfunction also remained stable. Cardiac mechanical energy efficiency did not recover. Plasma atrial natriuretic peptide levels remained elevated, but rises in plasma aldosterone and renin activity were transient. Collagen content increased 170%, the type I-to-III phenotype ratio doubled in the LV, but right ventricular collagen remained unaltered. Fas ligand cytokine levels correlated with expression of both caspase-3 and -2, suggesting a link in the apoptotic “death cascade.” Caspase-3 activity also bore a close relationship to LV meridional wall stress calculated from echocardiographic and intraventricular pressure measurements. We concluded that the stability of chronic untreated severe ischemic HF depends on the recruitment of myocardial remodeling mechanisms that involve an interaction among hemodynamic load, contractile efficiency/energetics, neurohumoral activation, response of the extracellular matrix, wall stress, and the myocyte apoptotic pathway.

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Akens, M. K., D. Nadler, P. Bittmann, K. Zlinszky, S. B. R. Kästner, J. A. Auer, and B. von Rechenberg. "Mosaicplasty with photooxidized, mushroom shaped, bovine, osteochondral xenografts in experimental sheep." Veterinary and Comparative Orthopaedics and Traumatology 19, no. 03 (2006): 147–56. http://dx.doi.org/10.1055/s-0038-1632991.

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SummaryThe goal was to study the performance of mushroom shaped, photooxidized, osteochondral grafts in mosaicplasty focusing on graft stability and survival. Mushroom shaped, photooxidized grafts (6 mm for the cartilaginous head of the mushroom, 3 mm for the stem) were implanted in the medial femoral condyle of 10 sheep. Four transplants were inserted per condyle in an overlapping fashion using the pressfit technique (n=40 grafts in 10 condyles). The grafts were followed for 6 and 12 months. Semi-quantitative evaluation of graft performance was performed using a validated score system. All grafts were mechanically stable at 6 and 12 months with one exception, where the mushroom head broke off. The formation of cystic lesions in the subchondral bone area was minimal. Repopulation of the old photooxidized cartilage was noticed with cells invading the matrix from the subchondral bone area and also from the pannus on the surface. Fusion between host and graft cartilage was observed in some of the grafts at 12 months, while remodeling of the calcified cartilage zone and tidemark was noticed in all grafts. Results scored significantly better for the 6 months compared to the 12 months group if cartilage surface integrity was compared (p<0.05). In all other variables no significant differences were found between groups. Despite moderate graft recession in the 12 months group partial fusion of grafts and functional results were satisfactory. The photooxidized mushroom shaped osteochondral transplants may be a suitable type of graft for functional results in cartilage resurfacing if stable anchorage of the grafts can be achieved.

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Hoffman, Louwrens, and Sara Erasmus. "Provenance in Sheep: The Karoo Lamb Story." Proceedings 36, no. 1 (April 8, 2020): 188. http://dx.doi.org/10.3390/proceedings2019036188.

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Noted for its unique herbaceous flavour which is imbued from a diet of indigenous fragrant plants, Karoo lamb is marketed as one of South Africa’s finest meat products and enjoys Protected Geographical Indication (PGI) status in South Africa and the European Union. Its distinct quality is imparted through natural grazing of the sheep on the Karoo veld that has a significant influence on the sensory and chemical profile of the meat. Descriptive sensory analysis, fatty acid analysis, solid-phase microextraction, isotope ratio mass spectrometry, portable near-infrared reflectance spectroscopy and proton transfer reaction-mass spectrometry proved to be very successful analytical tools for the authentication of regionally unique lamb meat, distinguishing Karoo from Non-Karoo lamb. Characteristic volatiles, specifically terpenes, present in both the Karoo bushes and the Karoo lamb meat and fat were detected. The dominant terpenes were tentatively identified as α-pinene, β-pinene, limonene and trans-caryophyllene, and they were particularly prominent in the fat tissue. Within the Karoo, regional differences were apparent as Hantam Karoo lamb had the highest ratings for herbaceous aroma and flavour and contained the greatest concentration of terpenes. Herbaceous aroma and flavour attributes associated with a diet rich in fragrant Karoo plants were verified with stable isotope ratio analysis. The results confirm that Karoo bushes are responsible for the distinct aroma and flavour of Karoo lamb, thereby providing vital evidence for its certification and to justify the protection of its indicator status.

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Bazzy, A. R., L. M. Pang, S. R. Akabas, and G. G. Haddad. "O2 metabolism of the sheep diaphragm during flow resistive loaded breathing." Journal of Applied Physiology 66, no. 5 (May 1, 1989): 2305–11. http://dx.doi.org/10.1152/jappl.1989.66.5.2305.

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To determine whether O2 availability limited diaphragmatic performance, we subjected unanesthetized sheep to severe (n = 11) and moderate (n = 3) inspiratory flow resistive loads and studied the phrenic venous effluent. We measured transdiaphragmatic pressure (Pdi), systemic arterial and phrenic venous blood gas tensions, and lactate and pyruvate concentrations. In four sheep with severe loads, we measured O2 saturation (SO2), O2 content, and hemoglobin. We found that with severe loads Pdi increased to 74.7 +/- 6.0 cmH2O by 40 min of loading, remained stable for 20–30 more min, then slowly decreased. In every sheep, arterial PCO2 increased when Pdi decreased. With moderate loads Pdi increased to and maintained levels of 40–55 cmH2O. With both loads, venous PO2, SO2, and O2 content decreased initially and then increased, so that the arteriovenous difference in O2 content decreased as loading continued. Hemoglobin increased slowly in three of four sheep. There were no appreciable changes in arterial or venous lactate and pyruvate during loading or recovery. We conclude that the changes in venous PO2, SO2, and O2 content may be the result of changes in hemoglobin, blood flow to the diaphragm, or limitation of O2 diffusion. Our data do not support the hypothesis that in sheep subjected to inspiratory flow resistive loads O2 availability limits diaphragmatic performance.

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Jarmuji, Jarmuji. "Kurva Laktasi Induk Domba Jonggol (Domba Ekor Tipis) Berdasarkan Umur Induk yang Dipelihara dengan Sistem Penggembalaan Grazing System." Jurnal Sain Peternakan Indonesia 9, no. 1 (June 24, 2014): 51–59. http://dx.doi.org/10.31186/jspi.id.9.1.51-59.

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ABSTRACTThe objectives of this research were to know the effect of ewe’s age on curve of milk yield reared on grazing. This research was done in The Jonggol Animal Science Teaching, and Research Unit (JASTRU) located in Singasari Village, Jonggol, Bogor district. As many 100 local sheep comprises of pregnant and lactating ewes on average 1-4 years old were used in this research. The sheeps were grazed from 9 a.m. to 4 p.m. and housed on night. The result showed that ewe’s age different effect its of curve milk yield. Lactation peak is expected within 1-2 weeks of lambing, followed by a decreasing phase to the 16 weeks. Decreace of theewes 1 year age showed is not stable if comparation the ewes 3-4 year age.Key words : ewes, curve milk yield,grazing system.

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Oliva, Gabriel, Daniela Ferrante, Silvina Puig, and Marcos Williams. "Sustainable sheep management using continuous grazing and variable stocking rates in Patagonia: a case study." Rangeland Journal 34, no. 3 (2012): 285. http://dx.doi.org/10.1071/rj12016.

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Adaptive rangeland management based on continuous grazing by sheep was implemented at Los Pozos station, on the Magellan tussock steppes of southern Patagonia, between 1990 and 2010. The numbers of sheep were adjusted annually following a stocking strategy tracking the herbage mass. Herbage mass was assessed by harvesting short grass species at peak herbage mass and grazing capacity was estimated based on sheep requirements. Historic production records under a traditional continuous grazing management (1930–89) were contrasted with those of the adaptive management period (1990–2010). Stocking rates of 0.59 sheep ha–1 year–1 in the period from 1930 to 1989 dropped to 0.35 sheep ha–1 year–1 in the adaptive management period. Mean herbage mass of short grasses during this latter period was 194 ± 12 kg DM ha–1 and the stubble height of the key species, Poa spiciformis, was 24 ± 0.7 mm. Lamb marking rates and extraction rates increased from 72 to 87%, and from 28 to 48%, respectively, under adaptive management when compared with historic management, and historic levels of sheep sales were maintained: 4405 v. 4602 animals year–1. Wool production fell from 36 102 to 26 771 kg year–1. Annual sheep production under adaptive management was less variable, as the annual coefficient of variation fell by 41% for lambing rates, by 25.8% for wool production, and by 40% for sheep extraction rates, compared with historic records, even though the inter-annual rainfall coefficient of variation increased by 25% over the same period. It is concluded that, under adaptive management, herbage production, stubble height and sheep production remained stable over 20 years. The adaptive strategy allowed a stabilisation of production and is a potentially valuable management tool in view of the expected increase in variability of rainfall predicted by global climate models for Patagonia and other rangeland areas.

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DYUSEGALIYE, MUKHIT, UTENBERGEN BISENOV, AYMAN NURGALIYEVA, and ELMIRA ADIETOVA. "Index selection of Kazakh karakul sur-type sheep with platinum shades." Medycyna Weterynaryjna 77, no. 01 (2021): 6492–2021. http://dx.doi.org/10.21521/mw.6492.

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Aim of the study: Karakul sheep farming is one of the effective subsectors of animal breeding in the southwestern region of Kazakhstan. Sheep coloring is a result of genetic factors. Breeding can provide farmers with offspring of the desired color through the selection of parental couples. Materials: This research introduces an index method for breeding sur-type sheep with the proportion of underfur fibers under 25%. Such a proportion of underfur fibers provides a 15.25% deeper color within the breed at the 25.3% higher chance of getting platinum shades. Methods: Platinum coloring in sheep makes them less piebald. The inheritance index is quite stable and is within 55.66-65.66%. In the breeding flock, the initial proportion of sur-type lambs which could be used in coat making (elite class) was up to 8.72%. The analysis of platinum color heritability by Kazakh sur-type karakul sheep shows that this color is inherited as a dominant one in the line breeding. The share of sur-type sheep with platinum shades was between 85.85% and 87.27%. Results: The difference in the inherited trait between the groups of sheep selected according to the proportion of underfur fibers was insignificant, 0.99-1.42% (P > 0.05). The stabilizing selection introduced into the theory of line breeding of Kazakh sur-type sheep allowed optimizing the variability of selected features to the level of desired parameters. The authors have proposed the index selection method for sur-type sheep breeding that can be applied to improve the Atyrau sheep flock, to increase their genetic potential, and to apply various line breeding levels to accelerate the breeding process. Conclusions: The originally designed method for improving breeding indexes will be useful when setting optimal breeding goals (fur color and quality) and assessing genetic parameters of a certain sheep flock. The study was approved by the Ethics Committee attached to the Far Eastern State Agrarian University (Protocol No. 5 of 25 May 2010).

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Ioffe, S., A. H. Jansen, and V. Chernick. "Analysis of respiratory neuronal activity in fetal sheep." Journal of Applied Physiology 73, no. 5 (November 1, 1992): 1972–81. http://dx.doi.org/10.1152/jappl.1992.73.5.1972.

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We developed a new method to monitor fetal medullary respiratory neurons utilizing a two-stage approach. At 129–133 days of gestation, sheep were anesthetized, and a window was placed over the area of the fourth ventricle. After a recovery period of 3–5 days, the fetus was exteriorized into a saline bath under maternal spinal anesthesia, and the head was connected rigidly to a stereotaxic frame. Microelectrodes were inserted into the area of the nucleus tractus solitarius during rapid-eye-movement sleep, and extracellular recordings of 223 respiratory neurons were analyzed: 76% were inspiratory, 9% expiratory, and 15% phase spanning, as classified by visual and computer correlation to diaphragmatic activity. More detailed analysis of 100 neurons was done to assess the respiratory component (eta 2) by use of a modification of the method developed by Orem and Dick (J. Neurophysiol, 50: 1098–1107, 1983). With use of cohorts of 25 breaths, fetal respiratory neurons were found to frequently change their phase relationship to diaphragmatic activity. The eta 2 statistic of fetal respiratory neurons was not a stable characteristic but changed over time. This could be a reflection of an immature central respiratory system before birth or the lack of major sensory inputs.

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Balcaen, A., E. Claeys, V. Fievez, P. Boeckx, O. van Cleemput, and S. de Smet. "Stable carbon isotope analysis of faecal and blood samples of sheep in relation to the diet." Proceedings of the British Society of Animal Science 2003 (2003): 159. http://dx.doi.org/10.1017/s1752756200013181.

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Stable isotopes have been extraordinarily helpful in understanding animal migration, diet, food webs and nutrient flow (Hilderbrand et al., 1996), based on the property that C3 and C4 plants possess distinctly different 13C/12C ratios (δ13C value) due to isotopic fractionation during photosynthetic carbon fixation (Smith & Epstein, 1971). Most woody species and temperate graminoids assimilate carbon via the Calvin cycle (C3), which discriminates stronger against the heavier isotope (13C) than Hatch-Slack (C4) species (tropical and subtropical graminoids and some shrubs). C3 and C4 plant species have mean δ13C values of -27 ‰ and -13 ‰ respectively (O’Leary, 1981). DeNiro & Epstein (1978) were one of the first to show that the isotopic composition of the whole animal body is similar to that of its diet. Other authors have also found relationships between the isotopic composition of animal tissues and the diet (González-Martin et al., 1999; Jones et al., 1979). The aim of this study was to investigate stable carbon isotope composition in sheep fed diets consisting of either C3 or C3+C4 plants.

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Tomczyk, J., H. Wierzbowski, and M. Zalewska. "Stable Isotope Record of Human and Sheep Enamel Carbonate from the Ancient Middle Euphrates Valley (Syria)." International Journal of Osteoarchaeology 26, no. 4 (April 16, 2015): 599–609. http://dx.doi.org/10.1002/oa.2449.

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Carver, Andrew S., Michael A. Dalrymple, Gordon Wright, Denise S. Cottom, Dawn B. Reeves, Yvonne H. Gibson, Jayne L. Keenan, et al. "Transgenic Livestock as Bioreactors: Stable Expression of Human Alpha-1-Antitrypsin by a Flock of Sheep." Nature Biotechnology 11, no. 11 (November 1993): 1263–70. http://dx.doi.org/10.1038/nbt1193-1263.

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Meijer, D. W., and P. J. Klopper. "Construction of a stable nipple valve with processed dermal sheep collagen for continent ileostomy and urostomy." Urological Research 18, no. 5 (October 1990): 353–55. http://dx.doi.org/10.1007/bf00300787.

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Sano, H., T. Fujita, M. Murakami, and A. Shiga. "Stimulative effect of epinephrine on glucose production and utilization rates in sheep using a stable isotope." Domestic Animal Endocrinology 13, no. 5 (September 1996): 445–51. http://dx.doi.org/10.1016/0739-7240(96)00074-4.

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47

McGregor, B. A. "Influence of stocking rate and mixed grazing of Angora goats and Merino sheep on animal and pasture production in southern Australia. 1. Botanical composition, sward characteristics and availability of components of annual temperate pastures." Animal Production Science 50, no. 2 (2010): 138. http://dx.doi.org/10.1071/an09128.

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The effects of animal species (AS; Angora goats, Merino sheep or goats and sheep mixed grazed together at ratio 1 : 1) and stocking rate (SR; 7.5, 10 and 12.5 animals/ha) on the availability, botanical composition and sward characteristics of annual temperate pastures under continuous grazing were determined in a replicated experiment from 1981 to 1984. AS and SR had significant effects on pasture availability and composition and many AS × SR interactions were detected. The pastures grazed by sheep had significantly reduced content and proportion of subterranean clover and more undesirable grasses compared with those grazed by goats. There were no differences in dry matter availabilities between goat- and sheep-grazed pastures at 7.5/ha, but at 10 and 12.5/ha goat pastures had significantly increased availabilities of green grass, dead and green clover and less weeds compared with sheep pastures. There was a significant AS × SR interaction for the density of seedlings in May following pasture germination. Between July and January, the height of pastures was greater under goats than sheep but from January to March pasture height declined more on goat-grazed than on sheep-grazed pastures. There was an AS × SR interaction for incidence of bare ground. Increasing the SR increased bare ground in pastures grazed by sheep but no change occurred on pastures grazed by goats. Changes in pasture characteristics due to increased SR were minimised on pastures grazed by goats but the grazing of sheep caused larger and faster changes and the pastures were damaged at the highest SR. Goats did not always select the same herbage material as sheep, changed their selection between seasons and were not less selective than sheep. Angora goats were flexible grazers and continually adapted their grazing behaviour to changing herbage conditions. Goat grazing led to an increase in subterranean clover, an accumulation of dead herbage at the base of the sward, reduced bare ground, taller pastures in spring and a more stable botanical composition. Mixed-grazed pasture characteristics were altered with SR. With careful management Angora goats on sheep farms may be used to manipulate pasture composition, to speed up establishment of subterranean clover, to decrease soil erosion and to reduce weed invasion.

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Caola, Giovanni, Stefania Casella, Claudia Giannetto, and Giuseppe Piccione. "Daily locomotor activity in five domestic animals." Animal Biology 60, no. 1 (2010): 15–24. http://dx.doi.org/10.1163/157075610x12610595764057.

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AbstractThe aim of this study was to compare locomotor activity in five domestic animals. Five female Comisana sheep, five female Maltese goats, five female Bruna cows, and five female Thoroughbred horses were housed separately in a soundproof box equipped with an airflow system and five female Blue Vienna rabbits were individually housed in metallic cages. Animals were kept under a 12/12 Light/Dark cycle and indoor ambient temperature (16-20°C). To record activity, an Actiwatch-Mini® was placed on each animal by means of a collar. Analysis by the cosinor procedure indicated a daily rhythm of locomotor activity in each of the five species studied. The main activity was observed during the photophase in sheep, goats, cows and horses, and during the scotophase in rabbits. The comparison among the species studied underlined a stable daily rhythm of locomotor activity in cows and horses, while sheep, goats and rabbits showed a weak daily rhythm of locomotor activity.

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Ranilla, M. J., S. López, F. J. Giráldez, C. Valdés, and M. D. Carro. "Comparative digestibility and digesta flow kinetics in two breeds of sheep." Animal Science 66, no. 2 (April 1998): 389–96. http://dx.doi.org/10.1017/s1357729800009528.

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AbstractA study was conducted to compare apparent digestibility and digesta flow kinetics in the whole digestive tract in two breeds of sheep (Churra and Merino) offered alfalfa hay at about maintenance. Ten mature sheep (five Churra and five Merino) each fitted with a rumen cannula were used in the study. Apparent digestibility was determined by total faecal collection. Liquid (Co-EDTA) and solid (Cr-mordanted fibre) markers were used to estimate rumen volumes and digesta flows. There were no significant differences between Churra and Merino sheep either in dry-matter or fibre apparent digestibility (P > 0·05). Liquid and solid passage rates did not differ between breeds and the estimated total mean retention times were similar for both genotypes. The volume of liquid in the rumen was proportionately 0·14 greater in Churra than in Merino sheep, although the difference was not significant. Estimated saliva secretion was greater in Churra (11·6 (s.e. 0·77) I/day) than in Merino sheep (10·5 (s.e. 0·72) I/day) but the difference did not reach statistical significance. Solid contents of the rumen did not differ between breeds. Rumen particle density was lowest at 2 h after feeding and remained stable at other sampling times, with no significant differences between breeds. There were no significant differences between breeds in the urinary excretion of total purine derivatives but urinary excretion of allantoin and microbial nitrogen supply tended to be higher in Merino than in Churra sheep (P < 0·20). This was attributed to the smaller rumen pool size of Merino (8·0 (s.e. 0·62) kg) compared with Churra sheep (9·2 (s.e. 0·63) kg). The study indicated that there were no apparent breed differences between Churra and Merino sheep in digestibility and digesta passage when they were given a good-quality forage at a low level of intake.

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Hohenboken, W. D., J. N. Clarke, P. V. Rattray, J. F. Smith, and M. Wheeler. "Responsiveness of ewe genotypes to varying nutritional management, and conventional genotype × environment interactions in sheep." Animal Science 47, no. 2 (October 1988): 253–62. http://dx.doi.org/10.1017/s0003356100003330.

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ABSTRACTAn experiment was conducted during 2 years to evaluate industry Coopworth, industry Romney and Waihora Romney ewes (a strain selected for 10 years for increased ewe productivity) in a variety of nutritional and management treatment combinations. Waihora Romneys were most productive with small and inconsistent differences between industry Romneys and Coopworths. Conventional cross-classified analyses of variance did not reveal large, consistent nor economically important ewe genotype × nutritional treatment or year interactions. Additional analyses were designed to investigate whether the ewe genotypes responded to changes in the nutritional and(or) management environment with similar quantitative changes in production. A sensitive genotype would be one that responded to environmental changes with relatively large changes in productivity; a stable genotype would be one whose changes in production in response to a variable environment were smaller. By several statistical procedures designed to assess relative ‘sensitivity’ v. ‘stability’, Waihora Romney ewes appeared to be the most stable, with industry Romney and Coopworth ewes similar in their sensitivity.

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Journal articles on the topic 'Sheep stable'

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