Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SHEEP”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed1983

Studies of the large intestine of sheep. 3. Nitrogen kinetics in sheep given chopped lucerne (medicago sativa) hay.

A study was made of nitrogen kinetics in the large intestine of sheep given 800 g chopped lucerne (Medicago sativa) hay/d. Four sheep were continuously infused with (15NH4)2SO4 into the caecum and three other sheep were infused intravenously with [15N]urea. A digesta marker, 51Cr complexed with EDTA (51Cr-EDTA), was infused into the rumen of each sheep to allow estimation of the rates of digesta constituents. Infusions were continued until tracer concentrations reached plateaux in digesta and blood pools, after which the sheep were anaesthetized and slaughtered. Pre-infusion samples and samples on plateau were obtained before slaughter for subsequent analysis to give plasma urea and rumen ammonia-N concentration and enrichment. At slaughter, digesta were obtained from the ileum and segments of the large intestine. These were analysed for 51Cr-EDTA content and concentration and enrichment of ammonia-N, microbial N and non-urea non-ammonia-N (NU-NAN). N flows in segments of the large intestine were calculated and represented in a quantitative eight-pool model. Transfer of plasma urea across the wall of the caecum and proximal colon was negligible but there was an input of 0.8 g endogenous NU-NAN/d. Flow of urea plus ammonia-N in digesta from the ileum into the caecum contributed 1.0 g N/d to the caecal ammonia pool. Proteolysis and deamination produced a further 3.0 g ammonia-N/d in the caecum and proximal colon. The net absorption of N between the ileum and the rectum was 2.8 g N/d but 3.0 g ammonia-N/d was absorbed from the caecum and proximal colon and, in addition, at least 0.9 g ammonia-N/d from the distal colon and rectum. Ammonia-N was incorporated into caecal microbes (0.6 g N/d) and approximately 57% of the NU-NAN in caecal digesta was microbial N. The majority of the microbial N flowing from the caecum was excreted in faeces. The rate of irreversible loss of urea-N from plasma, measured by intravenous infusion of [15N]urea, was 13.6 g/d. On average 83 (SE 6.8)% of the 15NH3 apparently absorbed from the caecum was incorporated into plasma urea; caecal ammonia contributed 9-19% of the N in plasma urea and 0.2-3.1% of the N in rumen ammonia.

Ammonia↗
PubMed1976

Metabolism of O,O-dimethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate in sheep and rats and of 3,5,6-trichloro-2-pyridinol in sheep.

Sheep and rats metabolized single oral doses of O-O-dimethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate (I) to three major metabolites that were excreted in the urine (approximately 70% of the 14C). These were the glucuronide of 3,5,6-trichloro-2-pyridinol, O-methyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate, and 3,5,6-trichloro-2-pyridinol. The latter two metabolites and the parent compound were isolated from sheep feces. Sheep plasma contained the same metabolites that were found in sheep urine, and no parent compound was detected in the plasma. Tissue residues from I were determined. Visceral fat contained the highest concentration of I-equivalents (11.8 ppm). Sheep excreted a single oral dose of 3,5,6-trichoropyridinol (II) unchanged in the feces and as II-glucuronide in the urine.

Animals↗
PubMed1989

[Consumption and ruminating behavior of sheep. 4. Experiments on young female sheep in different rearing intensities].

In the framework of two rearing experiments with female merino meat sheep, measurings of the consumption and ruminating behaviour were carried out. Animals raised with a lot of roughage ruminated longer both in their lamb and young sheep periods. An increased quota of roughage in the ration increased both the ruminating time and the number of chewing moves and cycles significantly for young sheep. The dry matter intake capacity of animals raised with high quotas of roughage was by 14 and 8% resp. higher in the lamb period and by 26 and 18% resp. higher in the young sheep period. Rations with 24% chopped and dried green fodder and 11 ... 14% resp. crude fibre brought about a period of more than 6 hours ruminating and a minimum of 22,000 ruminating movements per day for lambs. Young sheep raised with high quotas of roughage showed an increased ruminating activity in subsequent periods of sole feeding with roughage.

Animal Feed↗
PubMedDate not supplied

Blood group comparisons between European mouflon sheep and north American desert bighorn sheep.

Blood group systems in true sheep (Ovis) provide an additional method by which phylogenetic relationships can be measured. Of the eight genetic systems of blood groups identified in domestic sheep, all appeared to have their homologue in European mouflons and at least six might have their equivalent in North American desert bighorns. The red cells of the European mouflon, which is believed to be ancestral to domestic sheep, cross-reacted with domestic sheep blood-group typing reagents much more strongly and extensively than did the red cells of desert bighorn sheep. It also was noted that all the Mexican desert bighorns tested were Da positive, but their blood factor was not observed in the Nelson desert bighorns sampled. This observation indicated that the two subspecies might differ from each other with respect to the D blood group system. Transferrin type D was observed in the mouflons, while Tfs D and E were in the desert bighorns. Hemoglobins B and AB were observed in the mouflons but only Hb B occurred in the desert bighorns. The systematic implications of blood group polymorphisms are discussed.

Animals↗
PubMed1992

Polyclonal B-lymphocyte activation of sheep by Mycobacterium phlei against sheep pox virus.

A trypsinized preparation of Mycobacterium phlei, non specific stimulator of immunity (NSI), and Sheep Pox Virus (SPV) were inoculated in different groups of sheep to activate B-lymphocytes and induce SPV neutralizing substance(s). NSI sensitized sheep B-lymphocytes in the presence of NSI or lymphokine elaborated SPV neutralizing substance(s). The SPV sensitized B-lymphocytes also mediated such neutralizing substance(s). Healthy control sheep B-lymphocytes failed to show any appreciable amount of viral neutralizing substance. However, a significant virus neutralizing substance(s) was detected when healthy sheep B-lymphocytes were cultured in presence of NSI antigen along with lymphokines.

Animals↗
PubMed2026

Integrative ATAC-seq and RNA-seq analysis reveals lactation performance between Sewa sheep and East Friesian sheep.

Lactation performance is a pivotal economic trait in sheep production, yet its underlying epigenetic regulatory mechanisms remain poorly understood. In the present study, we integrated ATAC-seq and RNA-seq to compare chromatin accessibility landscapes and transcriptomic in mammary gland tissues from Sewa sheep (SWS) and East Friesian sheep (EFS). Histological characterization revealed that SWS exhibited significantly smaller mammary acini area, smaller lipid droplet area, and reduced lipid droplet diameter compared to EFS. ATAC-seq analysis identified 15,902 differentially accessible regions (DARs) between the two breeds, with motif enrichment analysis uncovering key transcription factors potentially governing lactation traits. RNA-seq analysis revealed 1,163 differentially expressed genes (DEGs), which were involved in lactation regulation. Integrated analysis identified 441 overlapping genes, and enriched in glycolysis/gluconeogenesis (e.g., PGAM1, ENO1) and pyruvate metabolism (e.g., ACACA, ACSS1, ACYP1). Collectively, our study provides new insights into the epigenetic regulatory mechanisms underlying lactation performance differences in sheep.

Animals↗
PubMed1995

Interspecific transfer of IVM IVF-derived red sheep (Ovis orientalis gmelini ) embryos to domestic sheep (Ovis aries ).

Two embryo production methodologies were investigated to generate Red sheep embryos for use in an interspecific embryo transfer program. In Experiment 1, 4 multiparous female Red sheep (Ovis orientalis gmelini ) were implanted with CIDR type G devices for 11 d. Forty-eight hours prior to CIDR removal, a total of 22.5 mg bid of FSH-P was administered over a 3-d period. Laparoscopic embryo collection was performed 5 d post breeding, and embryos were transferred to domestic recipient ewes (Ovis aries and Ovis orientalis musimon ). In Experiment 2, 7 nulliparous female Red sheep were implanted with CIDR devices and injected with 200 IU of PMSG and 25 mg of FSH-P on the 8th day of implant insertion. At 60 to 70 h post PMSG/FSH-P treatment, follicular oocytes were aspirated laparoscopically. The recovered oocytes were matured in M199 (with fetal calf serum, FSH, LH, penicillin and streptomycin) at 39 degrees C in a humidified atmosphere containing 5% CO(2). At 24 h oocytes were fertilized with frozen-thawed semen at a concentration of 1.6 x 10(6) sperm/ml. The ova/embryos were placed in CR2 or BOEC culture medium at 20-22 h post IVF. Following 3 to 4 d in culture, embryos were transferred laparoscopically to the uterine horn of synchronized recipients. In Experiment 1, 4 embryos and 6 UFO were collected from 2 embryo donors, respectively. Two embryos were transferred with the aid of a laparoscope to each of 2 Rambouillet recipients, one of which gave birth to a healthy Red sheep lamb at 158 d of gestation. In Experiment2, a total of 62 oocytes was collected from 7 oocyte donors; 16 developed to the 16- to 32-cell stage and were transferred to 8 recipients. Three of these IVM-IVF embryos were transferred laparoscopically to 2 Mouflon recipients, resulting in no pregnancies. Thirteen IVM-IVF embryos were transferred to 6 Rambouillet recipients. Each of these gave birth to a single healthy Red sheep lamb. Gestation lengths of the 3 IVM-IVF lambs ranged from 152 to 162 d. This research demonstrates that when using compatible species IVM-IVF technology in conjunction with interspecific ET can lead to the production of live offspring and can be used to propagate exotic ovine species.

Journal Article↗
PubMed1984

Measurement of vitamin B12 in the livers and sera of sheep and cattle and an investigation of factors influencing serum vitamin B12 levels in sheep.

Modifications of a radioassay method for the analysis of vitamin B12 using chicken serum as the binder are described. This obviates the need to use individual serum blanks to correct for non-specific binding in vitamin B12 assays of the sera and livers of sheep and cattle. Samples with high vitamin B12 levels can be diluted prior to assay without loss of linearity. Recoveries of added cyanocobalamin or hydroxocobalamin were better than 95% and results correlated significantly with those obtained using a microbiological assay (Poteriochromonas malhamensis). Sera and liver samples stored for four weeks at temperatures ranging from -20 degrees to 22 degrees showed no change in vitamin B12 levels. Withholding food from sheep for 44 hours led to a marked increase in serum vitamin B12. This effect was also evident in sheep eating a limited amount of cut grass. In sheep at pasture there was no evidence of a diurnal variation in serum vitamin B12 levels. Serum vitamin B12 levels in sheep at pasture were shown to be an unreliable indicator of liver vitamin B12.

Journal Article↗
PubMedDate not supplied

Cytogenetical anchoring of sheep linkage map and syntenic groups using a sheep BAC library.

In order to simultaneously integrate linkage and syntenic groups to the ovine chromosomal map, a sheep bacterial artificial chromosome (BAC) library was screened with previously assigned microsatellites using a sheep-hamster hybrid panel and genetic linkage. Thirty-three BACs were obtained, fluorescently labelled and hybridised on sheep-goat hybrid metaphases (2n = 57). This study allowed us, (i), to anchor all linkage groups on sheep chromosomes, (ii), to give information on the probable position of the centromere on the linkage map for the centromeric chromosomes, (iii), to contradict the previous orientation of the ovine X linkage group by the mapping of BMS1008 on OARXq38. Concerning our somatic cell hybrid panel, this study resulted in the assignment of all the previously unassigned groups to ovine chromosomes and a complete characterisation of the hybrid panel. In addition, since hybridisations were performed on a sheep-goat hybrid, new marker/anchoring points were added to the caprine cytogenetic map.

Journal Article↗
PubMed1996

Comparison of ovarian follicles (stage, number and estradiol concentration) in high fecundity Olkuska sheep, low fecundity Polish mountain sheep and their crossbreeds.

The objective of this study was to identify whether high ovulation rate in high fecundity Polish Olkuska Sheep results from within ovary differences by comparing the number, size and estradiol concentration in ovarian follicles obtained from high fecundity ewes of Olkuska breed, non prolific Polish Mountain Sheep and the crossbreed between them. The ovaries were obtained after laparotomy from the anesthetized animals on the 17th day after the onset of estrus. The diameter of individual follicles was estimated with the use of operating microscope with a calibrated scale in the ocular. Dissected follicles were stored at -20 °C for the estradiol estimations in the homogenates. The mean number of highly estrogenic and medium follicles in crossbreed was significantly lower than that in Olkuska and significantly higher than that in Polish Mountain. However, mean estradiol level in high estrogenic and medium follicles in three investigated groups was not significantly different. Mean ovulation rates were 3.1 for Olkuska, 1.5 for Polish Mountain and 2.2 for crossbreed. It is concluded that, like in Booroola sheep, the increased number of follicles that mature and ovulate results from the differences within the ovary. The recruitment of ovulatory follicles in high fecundity Olkuska sheep, lasts longer than in non prolific Polish Mountain sheep and similar tendency has been observed in crossbreed.

Journal Article↗
PubMed2006

A missense mutation (c.184C>T) in ovine CLN6 causes neuronal ceroid lipofuscinosis in Merino sheep whereas affected South Hampshire sheep have reduced levels of CLN6 mRNA.

The neuronal ceroid lipofuscinoses (NCLs, Batten disease) are a group of fatal recessively inherited neurodegenerative diseases of humans and animals characterised by common clinical signs and pathology. These include blindness, ataxia, dementia, behavioural changes, seizures, brain and retinal atrophy and accumulation of fluorescent lysosome derived organelles in most cells. A number of different variants have been suggested and seven different causative genes identified in humans (CLN1, CLN2, CLN3, CLN5, CLN6, CLN8 and CTSD). Animal models have played a central role in the investigation of this group of diseases and are extremely valuable for developing a better understanding of the disease mechanisms and possible therapeutic approaches. Ovine models include flocks of affected New Zealand South Hampshires and Borderdales and Australian Merinos. The ovine CLN6 gene has been sequenced in a representative selection of these sheep. These investigations unveiled the mutation responsible for the disease in Merino sheep (c.184C>T; p.Arg62Cys) and three common ovine allelic variants (c.56A>G, c.822G>A and c.933_934insCT). Linkage analysis established that CLN6 is the gene most likely to cause NCL in affected South Hampshire sheep, which do not have the c.184C>T mutation but show reduced expression of CLN6 mRNA in a range of tissues as determined by real-time PCR. Lack of linkage precludes CLN6 as a candidate for NCL in Borderdale sheep.

Amino Acid Sequence↗
PubMed2003

Demonstration of sheep-associated malignant catarrhal fever virions in sheep nasal secretions.

Ovine herpesvirus-2 (OvHV-2) is the causative agent for sheep-associated malignant catarrhal fever, which has never been propagated in vitro. Previous studies from this laboratory demonstrated significantly high levels of OvHV-2 DNA in sheep nasal secretions, suggesting a likely avenue of transmission. In the present study, real-time PCR was used to identify sheep experiencing an episode of intense OvHV-2 DNA shedding in their nasal secretions. A nuclease-resistance assay was used to examine the secretions for the presence of intact cell-free enveloped OvHV-2 virions. The results revealed that all nasal secretion samples from five selected individuals experiencing intensive shedding events contained cell-free OvHV-2 virions. Virions could not be identified in secretion samples from 11 OvHV-2 infected sheep that were not experiencing a shedding event. This is the first unequivocal demonstration of cell-free OvHV-2 virions. These results suggest that OvHV-2 lytic infection occurs in the epithelium of certain tissues in the upper respiratory tract of the natural host.

Animals↗
PubMed2003

Comparison of the resistance to sympatric and allopatric isolates of Haemonchus contortus of Black Belly sheep in Guadeloupe (FWI) and of INRA 401 sheep in France.

The resistance of a tropical breed of sheep towards the nematode parasite Haemonchus contortus (Hc) was compared to that of a European breed after artificial infection with the parasite following a 2 x 2 x 2 experimental design: two isolates (Hc Gua from Guadeloupe versus Hc Fra from France), two breeds each reared in their native habitats (Black Belly (BB) in Guadeloupe, FWI, INRA 401 reared in France), and two groups of lambs with differing infection status (one naive, i.e. infected for the first time during the experiment, and one primed, i.e. which had previously received doses of 5000 L3 on Days -35 and -32 before the infection during this experiment). Both groups were composed of 10 male lambs, which were 20 weeks of age when they were given a dose of 10,000 L3 of the relevant isolate on Day 0. Resistance was assessed by regular fecal egg counts (FECs) and blood samples, and worm counts were processed on Day 35 p.i. The FEC was lower in the BB than in INRA 401 lambs, lower in the primed than naive groups, and lower in Hc Fra than in Hc Gua. The eosinophil count remained unchanged in the naive INRA 401 groups, but increased in all the other groups. The hematocrit fell after infection, but the live weight was not affected by the infection. Worm burdens were 1868 and 5237 in the naive BB and INRA 401 groups, respectively, and 596 and 4835 in the primed BB and INRA 401 groups. The daily production of eggs per Hc Gua female worm was 1.5-fold that of Hc Fra. The number of worms had no effect on worm length or Hc in utero egg count in the BB sheep, but a positive and significant correlation between these two traits was seen in the INRA 401 lambs. These findings are indicative of innate resistance, and confirmed the high acquired resistance of the BB sheep to both sympatric and allopatric isolates of Hc. The regulation of worm population and fecundity differed in the BB and INRA 401 sheep.

Animals↗
PubMed1999

The behaviour of sheep with sheep scab, Psoroptes ovis infestation.

Methods of behavioural data collection as applied to the study of sheep scab are described. The behaviour of a number of marked animals within an affected flock was recorded using an event recorder. Focal sampled data were analysed for duration and frequency of the observed behaviours. In addition, the flock was observed at intervals and the instantaneous behaviour of each animal recorded. These data were compared with similar observational data from the same flock recorded at intervals during post-treatment recovery. Sheep scab resulted in pathological behaviours of rubbing, scratching and biting at the lesion, and these resulted in interruption of the normal behaviours, grazing, cudding and idling, but did not result in reduced levels of these behaviours. Infested sheep showed stereotypic mouthing behaviour, initiated by rubbing or scratching, or in some cases without any external stimulus. No stereotypic behaviour was seen in animals after treatment. The implications of the behavioural data for the welfare of the sheep is discussed.

Analysis of Variance↗
PubMed1998

Serum and skin surface antibodies and their associations with sheep biting lice, Bovicola ovis, on experimentally infested sheep.

The sheep biting louse (Bovicola ovis) feeds superficially on the skin of sheep but appears to stimulate an immune response. In this study we examined the association between louse infestation and serum and skin surface antibodies. Louse numbers were monitored on experimentally infested Polypay and Columbia ewes for two years and on their lambs in the second year. Serum and skin wash samples were tested for antibodies to soluble extracts of B. ovis, Stomoxys calcitrans and Musca autumnalis by enzyme linked immunosorbent assay (ELISA). In addition, the effects of skin wash extracts on B. ovis were examined in vitro. The titre of anti-B. ovis antibodies in the serum did not differ significantly between infested and naive ewes. However, there was an increase in serum antibody titre which coincided with periods of high louse density in ewes with high louse counts. Infested lambs had higher serum antibody levels than naive lambs. Substantial cross reactivity was evident among extracts of the different insects. Densities of lice on the ewes during population decline were negatively related to the titre of skin surface antibodies. Skin washings collected from sheep during B. ovis population decline reduced the number of louse progeny when incorporated into louse diet. These results indicate that B. ovis stimulates an immune response in sheep and suggest that compounds on the skin surface may play a role in the regulation of louse populations.

Animals↗
PubMed1984

Inclusion keratoconjunctivitis ('pink eye') in sheep. A proposal for a new name for chlamydial keratoconjunctivitis in sheep and comment on recent clinical trials.

The cytoplasmatic inclusion bodies, which, in 1931, Coles discovered in the corneal cells of sheep suffering from contagious keratoconjunctivitis are now considered to be the reticulate bodies of a chlamydia, Colesiota conjunctivae (synonym: Chlamydia psittaci ovis). According to the postulates of Koch Colesiota conjunctivae is a primary cause of contagious keratoconjunctivitis in sheep, but the clinical picture is complex and is a result of the interaction between the infecting chlamydiae, host resistance factors, and secondary infections caused by opportunistic bacterial ocular pathogens. The clinical syndrome might also be caused by other micro-organisms, such as Mycoplasma conjunctivae or environmental factors, such as dust. However, in these cases, cytoplasmatic inclusion bodies cannot be found in the corneal cells of diseased eyes. To differentiate chlamydial keratoconjunctivitis from keratoconjunctivitis due to other causes, it is proposed to include in the name the laboratory findings typical for this disease: Sheep Inclusion Keratoconjunctivitis. Chlamydia are Gram-negative bacteria, which are obligate intracellular parasites. Prolonged treatment seems to be required to eradicate chlamydiae from a host and antibiotics must reach intracellular levels that are higher than their minimum inhibitory concentration for chlamydiae. Tetracyclines are the drugs of choice. This means that for a microbiological cure, diseased sheep must be injected several times a day for a week or more. Because the disease is usually self-limiting and economic losses are considered low, this seems unnecessary and control of the disease by local treatment of secondary infections seems sufficient. However, this will not prevent spreading of the disease in a herd and relapses may occur.

Animals↗
PubMed1996

Production and characterisation of monoclonal antibodies to Brucella melitensis cytosoluble proteins that are able to differentiate antibody responses of infected sheep from Rev. 1 vaccinated sheep.

Monoclonal antibodies (MAbs) were produced to Brucella melitensis cytosoluble proteins (CP) with apparent molecular masses of 12, 24 and 28 kDa (CP12, CP24 and CP28) which were previously shown by immunoblotting to differentiate antibody responses of infected sheep from those of B. melitensis strain Rev. 1 vaccinated sheep. These MAbs were derived from mice infected with virulent smooth (S) B. melitensis strain H38. Most MAbs obtained were directed to CP28, which indicated (as was shown in infected sheep) that this protein was also highly immunogenic in mice. A large number of MAbs that showed reactivity to CP in ELISA but did not show reactivity in immunoblotting of CP were also obtained and might recognise conformational epitopes of these proteins. MAbs were used to localise CP12, CP24 and CP28. None of the MAbs reacted with whole B. melitensis cells in ELISA but showed reactivity with sonicated bacteria in ELISA, which indicated an internal localisation of these proteins. Among several B. melitensis B115 subcellular fractions tested, the anti-CP12 and anti-CP28 MAbs reacted essentially with the CP extract (CPE) in both ELISA and immunoblotting, whereas the anti-CP24 MAbs reacted with both CPE and cell envelope fraction (CEF)-although with lower intensity to the latter fraction. The internal localisation of these proteins was confirmed by immuno-electron microscopy of thin-sectioned B. melitensis B115 or B. melitensis 16M cells. Immunogold labelling was mainly observed in the cytoplasm and, consequently, CP12, CP24 and CP28 are probably cytoplasmic proteins. Immunoblotting of whole cell lysates with the MAbs also showed the presence of these proteins in all Brucella species and biovars, including the vaccine strains B. melitensis Rev. 1 and B. abortus B19. The use of these MAbs should help further study of antibody responses in sheep and other hosts and may be of considerable value for developing new diagnostic tests for ovine brucellosis.

Animals↗
PubMed1995

Observations on the indirect transmission of virulent ovine footrot in sheep yards and its spread in sheep on unimproved pasture.

Virulent ovine footrot was transmitted accidentally to a group of 23 adult Merino sheep (flock B) after holding for 1 hour in sheep yards, which earlier the same day had contained another flock (flock A) with < 1% prevalence of sheep with footrot lesions. Sheep in flock B were rendered susceptible to virulent footrot by grazing 600 mm high unimproved pasture dominated by paspalum (Paspalum dilatatum) and kangaroo grass (Themeda australis) during warm, humid and wet weather. In addition to moisture, interdigital abrasions caused by the pasture might have predisposed the interdigital skin to infection with Dichelobacter nodosus.

Animal Husbandry↗