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[Studies of BMPR-IB and BMP15 as candidate genes for fecundity in little tailed han sheep].

BMPR-IB gene which controls the fecundity of Booroola Merino and BMP15 gene which affects the ovulation of Invedale and Hanna were studied as candidate genes on the fecundity of Little Tailed Han Sheep, and their mutations and genetic effects were analyzed. The results showed that there was a same mutation in BMPR-IB gene (A746G) of Little Tailed Han Sheep as that of Booroola Merino. The BB mutation genotype was superior in prolific Little Tailed Han Sheep, and the ewes with genotype BB had 0.97(P < 0.05) and 1.5(P < 0.01) lambs more than those with genotype + + in the first parity and later parities, respectively. It could be inferred that BMPR-IB gene was related with the major gene that controls the high prolificacy of Little Tailed Han Sheep. While there was not mutation of V31D or Q23Ter in BMP15 gene of Little Tailed Han Sheep, it showed that the fecundity mechanism of Little Tailed Han Sheep was different from that of Romney sheep. Then it was ruled out the possibility that the ovulation of Little Tailed Han Sheep was affected by the mutation of BMP15 gene.

Alleles↗

Diverse biological parameters in clinically healthy sheep from a flock with scrapie: variations, and correlations with OLA antigens.

A comparison was made in the blood levels of various cell types and biochemical substances and in lymphocyte antigens between 107 healthy sheep from a flock contaminated with scrapie (HC sheep) and 93 sheep from a noncontaminated flock (NC sheep), which served as a control population. Significant differences between the two groups of sheep were found in some of the levels, as had previously been found with lymphocyte antigens. The HC sheep, which included genetically resistant animals, could be distinguished from the NC sheep by their lower levels of various white cells, a noticeable decrease in urea, a moderate decrease in Mg2+ and Mn2+ ions, beta- and gamma-globulins, serotonin and vitamin B12, a strong increase in uric acid and a moderate increase in K+, Cl-, HCO3-, Zn2+, and Al3+ ions, as well as in total lipids and in the albumin to globulin ratio. In this HC population, the only enzyme with an increased level was aldolase; the levels of the other 7 enzymes measured were lowered. The observed modifications were considered to be signs of latent disturbances in the leukocyte system and in hepatic and renal functions, in spite of apparent resistance. Eleven lymphocyte antigens were studied. These antigens are not independent of the blood levels of the various substances measured, but are often correlated in a statistically significant manner with some of them. In the HC sheep, the lymphocyte antigens correlated with the modified levels in the blood were different from those in the control population.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Study on SNP of melanocyte stimulating hormone receptor gene in several Chinese indigenous sheep breeds using DHPLC.

Single nucleotide polymorphism (SNP) of melanocyte stimulating hormone receptor (MSHR) gene was studied by sequencing and denaturing high performance liquid chromatography (DHPLC) in Mongolian sheep, Kazakstan sheep, Tan sheep and Tibetan sheep. The results showed that there is a mutation at position 317 (T317C) within the length of 415bp and the DHPLC is a high-throughput and simple method for screening this mutation. The heterozygote (TC) with shoulder peak could be detected quickly at the first time of DHPLC, and two homozygotes (TT or CC) could be discriminated easily through two times of DHPLC when each homozygous DNA was mixed with a known homozygous reference sample at the second time of DHPLC. All of the populations for this site are in Hardy-Weinberg equilibrium. The results also indicated that Mongolian sheep and Kazakstan sheep had close relationship, Tibetan sheep and Tan sheep had close relationship. The relationship among breeds was consistent with that of microsatellite DNA.

Animals↗

The effect of anesthesia and surgery on diaphragmatic lymph vessel flow after endotoxin in sheep.

Increases in diaphragmatic lymph vessel flow (Qdi) may be important in preventing ascites because diaphragmatic lymph vessels drain the peritoneal space. However, lymphatic vessel function may be depressed in anesthetized, open chested animals. To test this hypothesis, we cannulated diaphragmatic lymph vessels in five sheep which were anesthetized with 1-2% halothane. We performed a thoracotomy and cannulated a diaphragmatic lymph vessel in each sheep. Then we infused 0.75-1.0 micrograms/kg of E. coli endotoxin intravenously and we measured Qdi and the lymph protein concentration for 2-4 hrs. The data were compared to previously reported data for five unanesthetized sheep (J. Appl. Physiol. 62:706-710, 1987). At baseline Qdi = 0.8 +/- 0.7 (SD) in the anesthetized sheep and 1.0 +/- 0.8 ml/hr in the unanesthetized sheep. After endotoxin, Qdi increased to 4.5 +/- 3.1 ml/hr in the unanesthetized sheep (p less than 0.05) but Qdi did not change in the anesthetized sheep. However, the lymph protein concentration increased similarly in each group, indicating that endotoxin caused the same degree of injury in each group. Our results indicate that diaphragmatic lymph vessel function is depressed in anesthetized, open chested sheep.

Analysis of Variance↗

Response of plasma and tissue D-alpha-tocopherol in sheep to graded dietary levels of dl-alpha-tocopheryl acetate.

The objective of this experiment was to establish the validity of using plasma alpha-tocopherol values as an index of alpha-tocopherol status in sheep. alpha-tocopherol values were obtained for tissues and blood of 40 sheep given four different dietary intakes of dl-alpha-tocopheryl acetate. Group 1 sheep were given a basal diet containing 25 to 32 mg dl-alpha-tocopheryl acetate kg-1 while groups 2, 3 and 4, comprising 10 sheep each, received the basal diet plus 200, 400 and 600 mg dl-alpha-tocopheryl acetate per sheep, respectively. Blood samples were obtained at zero time and then twice weekly for eight weeks, at which time sheep were killed and organs retrieved for tissue alpha-tocopherol analysis. Tocopherol concentrations were higher in all tissues (P less than 0.001) of sheep fed the vitamin E supplemented diets than the basal diet. Vitamin E stored in the liver of sheep at the end of the experiment (eight weeks) showed a linear response to the level of vitamin E in the diet. Blood plasma vitamin E concentrations increased following vitamin E supplementation, but no direct relationship was found between vitamin E intake and plasma vitamin E content.

Animals↗

Sheep MHC class II molecules. I. Immunochemical characterization.

The physicochemical features, biosynthesis and glycosylation of sheep class II molecules were investigated using a panel of seven monoclonal antibodies. The class II molecules recognized by different monoclonal antibodies could be differentiated using SDS-PAGE. Two monoclonal antibodies, SBU.II 42-20 and 49-1, reacted with dissociated sheep class II molecules and recognized epitopes on class II alpha and beta polypeptides, respectively. The structure of the sheep class II heterodimer differed from that of mouse and man in that it was unstable in the presence of 1% SDS at 20 degrees and, following reduction, sheep beta polypeptides displayed a marked increase in MW, resulting in the apparent co-migration of reduced alpha and beta polypeptides on SDS-PAGE. This phenomenon was not seen using sheep class II molecules synthesized in the presence of tunicamycin. Pulse-chase analyses of biosynthetically labelled sheep class II molecules suggested the rapid association and glycosylation of sheep class II alpha and beta polypeptides during synthesis. Both alpha and beta polypeptides of sheep class II molecules carried N-linked oligosaccharides of MW 6,000 and 3,000, respectively. However, unlike human class II oligosaccharides, these were exclusively of the complex or sialylated type.

Acetylglucosaminidase↗

Experimental bluetongue virus infection of sheep; effect of previous vaccination: clinical and immunologic studies.

Clinical and immunologic responses of sheep to vaccination and subsequent bluetongue virus (BTV) challenge exposure were studied and compared with those of non-vaccinated sheep. Sheep were vaccinated with inactivated BTV administered with aluminum hydroxide and cimetidine or levamisole. After sheep were vaccinated, precipitating group-specific antibodies to BTV were detected, but serotype-specific neutralizing antibodies were not detected. Cellular immune responses (lymphocyte blastogenesis) to BTV were not detected. After virulent BTV challenge exposure, vaccinated and nonvaccinated sheep developed acute clinical disease of similar severity. Clinical signs included hyperemia and petechiae of oral mucosa and coronary bands of the feet, excess salivation, nasal discharge with crusting, ulceration of the muzzle, and edema of lips and intermandibular space. Marked increases in serum creatine kinase activity were associated with stiff gait, reluctance to move, and vomiting. Fever and leukopenia were detected in most of the challenge-exposed sheep. Viremia and neutralizing antibodies were detected in vaccinated and nonvaccinated sheep after challenge exposure. Bluetongue virus-specific reaginic antibodies were not detected in sera from any of the sheep when the passive cutaneous anaphylaxis test was used.

Animals↗

[Serological study of the occurrence of L. hardjo in sheep in The Netherlands].

Sheep (3918) from 137 farms in the regions of North-, West- and Mid-Netherlands and Gelderland were serologically investigated for the presence of antibodies against Leptospira hardjo. Antibodies were detected in 3.3% of the sheep. There were large regional differences with respect to both the percentage of positive sheep and the percentage of positive flocks. All sera from sheep in Gelderland were negative. In West- en Mid-Netherlands there were 0.9 and 6.5% positive sera, respectively, and 19.4 and 32.7% positive flocks. The percentage of positive sheep per positive flocks varied from 1 tot 51.6. Serological positive sheep were from farms with and without cattle. On farms with cattle, there was no clear relationship between serologically sheep and the presence of hardjo antibodies in cattle. It thus seems plausible that sheep can be infected with hardjo independently of cattle.

Animals↗

[Efficacy of the administration of serum amd vaccine for the antirabies treatment of experimentally-infected sheep].

The objectives of this study were to examine the humoral immune response of sheep to experimental infection with an isolate of rabies virus from a fox, to analyse the efficacy of vaccination as a method of post-infection treatment, and to find a suitable animal model to evaluate new procedures for human vaccination following infection. A total of 47 sheep were used. Initially, 26 sheep received an intramuscular injection of a suspension of virus (titre: 10(6.8) 50% lethal dose for mice by the intracerebral route). Half of the sheep were subsequently treated using a vaccine on the day of infection and at 3, 7, 14 and 30 days post-infection. The remaining half comprised the unvaccinated controls. This vaccination protected seven of thirteen sheep, while nine of the thirteen controls died. Subsequently, 21 sheep were inoculated under the same conditions as in the previous trial. The animals were divided into three groups of seven animals each. The first group was vaccinated in the same way as described above. The second group received an injection of anti-rabies immunoglobulin of human origin (26.3 IU/kg of body weight), followed by the course of vaccine treatment 24 hours later. The remaining group acted as unvaccinated controls. Of the seven sheep given vaccine alone, four were protected, while all seven animals given immunoglobulin and vaccine were protected. Six of the seven untreated controls died. In this study, no apparently-healthy carriers of rabies virus were created by any of the treatments used, nor was there any shortening of the incubation periods. Additional observations were made concerning incubation periods and the course of the disease, as well as symptoms, lesions and the presence of rabies virus in various nerve centres and salivary glands of the experimental sheep.

Animals↗

Evidence for the presence of AH 13205-sensitive EP2-prostanoid receptors in the pregnant baboon but not in the pregnant sheep myometrium near term.

OBJECTIVE: Our purposes were to assess the effects of prostaglandin (PG) E2 and PGF2 alpha on myometrial contractility in pregnant sheep and baboons in an in vitro superfusion study, and to characterize further the PGE-sensitive (EP) receptor subtype involved in the myometrial response to PGE2 by using the selective prostanoid EP2 agonist AH 13205. METHODS: Strip preparations of uterine muscle from 15 sheep (107-145 days' gestational age) and ten baboons (158-185 days' gestation) were studied. Cumulative concentration-response curves (CRC) were constructed to oxytocin (4.2 pmol/L to 0.42 mumol/L, PGE2 (0.1 nmol/L to 1 mumol/L), and PGF2 alpha (1 nmol/L to 100 mumol/L), and 50% effective concentration (EC50) values (mean and 95% confidence interval) were calculated. We also tested the hypothesis that PGE2-induced myometrial relaxation in pregnant baboons could be mediated by EP2-prostanoid receptors. Myometrial strips were stimulated by oxytocin (0.42 nmol/L), and CRCs to the EP2-agonist AH 13205 (0.1 nmol/L to 10 mumol/L) were constructed. RESULTS: Prostaglandin F2 alpha stimulated myometrial activity in a concentration-related fashion in all preparations from both sheep and baboons. The EC50 in the sheep myometrium for PGF2 alpha (52 nmol/L, 95% confidence interval [CI] 25-110) was significantly (P < .05) lower than that in baboon myometrium (183 nmol/L, 95% CI 93-355). Oxytocin stimulated myometrial activity in preparations of both sheep (EC50 = 0.29 nmol/L, 95% CI 0.11-0.71) and baboon (EC50 = 0.31 nmol/L, 95% CI 0.18-0.52). In contrast, responses to PGE2 were species-related: PGE2 caused concentration-related stimulation of myometrial activity in sheep tissue (EC50 = 3.2 nmol/L, 95% CI 2.0-5.0), but induced concentration-related inhibition of activity in baboon myometrium (50% inhibitory concentration [IC50] = 21 nmol/L, 95% CI 2.2-203). A concentration-related inhibitory response to AH 13205 (IC50 = 3.56 nmol/L, 95% CI 1.28-5.99) was obtained in the baboon. In contrast, AH 13205 failed to inhibit comparable myometrial strip preparations from pregnant sheep. CONCLUSIONS: The present studies suggest that both sheep and baboon myometrium contain prostanoid receptors that mediate stimulation. In addition, baboon myometrium, like that from the human, contains AH 13205-sensitive EP receptors (EP2 receptors), which mediate inhibition. The pregnant baboon may therefore represent a suitable animal model for investigations into the use of EP2 agonists for the prevention of premature labor in humans.

Animals↗

[Continuation of the observation and serological investigation of a Maedi-Visna virus infected sheep flock from January 1990 to June 1996].

This paper describes the second part of a longtime-study, started in 1987. Serologic investigations for detecting antibodies against Maedi Visna-virus (MVV) were performed, involving an institute own sheep flock. The method used was the immunodiffusiontest. The flock consisted of different breeds and their offsprings. So far, the virus seems to persist in the herd. This work also shows the importance of the central role of the does for spreading the virus. Seroconversion was detected in a sheep at the age of 32 months. The mother of this sheep was a thoroughbred and MVV-negative mountain sheep. After removal of the animals with high antibody (ab)-titers, until the end of 1991, the percentage of seronegative sheep increased. Then seropositive sheep didn't show high ab-titers anymore. Since 1990 only offsprings increased the size of the herd. The health status of the flock was clinically inconspicuous. It can be concluded that in spite of good food quality, good hygiene, without culling positive animals and just giving away accidentally some sheep, no elimination of MVV was registered in the flock over a period of more than six years. There was only seen a reduction of seropositive animals. Single results of serological tests, without knowing the sheep and the serological status of the herd, could pretend a false negative status.

Animals↗

Detection of foot-and-mouth disease by reverse transcription polymerase chain reaction and virus isolation in contact sheep without clinical signs of foot-and-mouth disease.

Two non-vaccinated sheep were experimentally infected with FMDV and one day later 4 other sheep were brought in contact. Although the contact sheep showed no clinical signs, serology indicated that all sheep became infected. Various secretion samples, taken over a period of at least one month, and various tissue samples were examined for the presence of FMDV by RT-PCR and by virus isolation. FMDV was most often found in saliva (mouth swabs), followed by nasal secretion and sera. Faecal material, wool and milk were less suitable. The period of detection with the highest frequency of positive isolations was between 2 to 4 days pi for the infected sheep and between 5 to 10 days pc for the contact animals. It was established that in subclinically infected sheep, with a very low amount of virus present, FMD viral RNA could be detected by a sensitive RT-PCR-ELISA although virus isolation and standard RT-PCR remained negative. Moreover there was some evidence of active spreading of FMDV from the contact sheep to two sentinel pigs. This indicates that serologically positive contact sheep without clinical signs may be considered as a danger for the transmission of FMDV.

Animals↗

L-antigen and active potassium transport in HK and LK red cells of Barbary sheep (Ammotragus lervia).

1. The potassium concentration in red cells of 21 Barbary sheep showed a bimodal distribution, with five animals of LK type (K+ conc. 30-45 mM) and 16 of HK type (K+ conc. 80-95 mM). 2. Evidence is presented that both Lp and Ll antigens are present on LK Barbary sheep red cells. 3. Active K+ transport in LK Barbary sheep red cells was stimulated 3-5 fold by sheep and goat anti-L. 4. Active K+ transport in HK Barbary sheep red cells was higher than in LK red cells. Five out of six HK animals tested showed no stimulation of active K+ transport with anti-L. One HK animal (2BA2) showed some stimulation of active K+ transport, and also absorbed some anti-L from antisera, suggesting that Lp antigen is present on these red cells. 5. Ouabain-sensitive ATPase in membranes from HK and LK Barbary sheep red cells showed kinetics characteristic of HK and LK membranes of domestic goats and sheep; the ATPase of LK Barbary sheep membranes sensitized with anti-L was stimulated 2-fold due to an alteration in the internal sodium and potassium affinities in favour of sodium.

Adenosine Triphosphatases↗

Human face recognition in sheep: lack of configurational coding and right hemisphere advantage.

Face recognition in sheep is qualitatively similar to that in humans in terms of its left visual field bias, and the effects of expertise and configural coding. The current study was designed to determine whether such effects are species specific by investigating the case of sheep recognising humans. It was found that the sheep could identify human faces and while they showed a small inversion-induced decline in discriminatory performance, this was significantly less than seen with sheep faces. In other aspects, there were qualitative differences with human face recognition compared with conspecific recognition. In contrast with sheep faces there was no left visual field advantage in the recognition of human faces and the internal features were not used at all as visual cues. The data suggest that these sheep, whilst being extensively exposed to interactions with humans, were unable to identify them with all the same 'expert' methods as were used to discriminate other sheep. This suggests that different neural systems may, to some extent, be used for recognition of sheep as opposed to human faces. The relative contribution to differential neural processing of the faces of the different species and the role of expertise are discussed.

Journal Article↗

Grazing behaviour and diet selection by Dorper sheep.

The grazing behaviour and diet selection by Dorper sheep, as well as other related aspects (pasture intake, walking habits and trampling) is reviewed. It was clear that Dorper sheep are less-selective grazers, compared to Merino-type breeds. Dorpers utilised shrubs and bushes to a greater extent, but grass to a lesser extent in relation to Merino sheep. The Dorper also utilised a larger number of different plant species than Merinos. Dorpers walked less to select food, or a suitable spot to graze, which consequently led to a shorter grazing time and less separate grazing periods. Dorpers consumed less herbage per metabolic size compared to Merino-type sheep. No uniform pattern in the walking distance of Dorpers was observed when compared to other sheep breeds. The relative trampling factor for Dorper sheep was less than that of evaluated Merino-type sheep. The review revealed a lack on information on the grazing behaviour and diet selection of Dorper sheep under more intensive grazing conditions. There is also a total lack of scientific information on other behaviour aspects of this unique breed.

Journal Article↗

Status of Dorper sheep as hosts of ectoparasites.

Seventeen ixodid tick species or subspecies have been collected from Dorper sheep in South Africa. The diseases transmitted or the conditions caused by these ticks in sheep are discussed. Although Dorper sheep may be infested with the scab mite, Psoroptes ovis, this does not seem to cause production losses. These sheep may, however, serve as a source of mite infestation for woolled sheep. The majority of Dorper sheep are infested with the larvae of the nasal bot fly, Oestrus ovis, they may also be subject to myiasis caused by the larvae of two calliphorid flies. In certain regions of the country Dorper sheep are prone to serious fly worry by female Simulium chutteri. Although Dorper sheep may be infested by various louse species these do not seem to reach large numbers or cause production losses.

Journal Article↗

Analysis of a type D retroviral capsid gene expressed in ovine pulmonary carcinoma and present in both affected and unaffected sheep genomes.

Ovine pulmonary carcinoma is a contagious neoplastic disease of sheep which can be transmitted experimentally with cell-free filtrate. Products homologous to structural proteins of type D and type B retroviruses are expressed in the tumors, but an infectious retrovirus has yet to be isolated. Retroviral RNA was isolated from an affected Peruvian sheep and used as a substrate for reverse transcription. The DNA obtained was subjected to polymerase chain reaction amplification using degenerate primers designed to amino acid sequences shared by the capsid peptides of the viruses that cross-react with the proteins found in the tumor tissues. A retroviral capsid region of type D lineage was isolated that proved to be highly homologous to the jaagsiekte sheep retrovirus isolated from affected sheep in South Africa. This capsid sequence was used to detect the virus in the genomes of sheep with and without ovine pulmonary carcinoma. More than 20 endogenous sequences that hybridized with the probe were found in the sheep examined, and assortment of these could be followed in sheep families. Initial experiments did not show any obvious differences in viral presence in the tumors compared with the background of endogenous viral sequences in unaffected lungs.

Amino Acid Sequence↗

A specific RFLP type associated with the occurrence of sheep scrapie in Japan.

We have investigated restriction fragment length polymorphism (RFLP) on the PrP gene and the frequencies of RFLP patterns in 35 healthy Suffolk sheep randomly collected. According to the combinations of PrP encoding DNA fragments generated by restriction enzymes Eco RI and Hind III, the RFLP patterns were classified into six types and designated as types I to VI. The frequencies of these types were as follows: I, 8.6%; II, 11.4%; III, 17.6%; IV, 11.4%; V, 28.6%; and VI, 22.9%. In 10 sheep diagnosed as having natural scrapie, RFLP types, I, III, IV, and V were determined. To examine the correlation between the RFLP type and the occurrence of scrapie, the frequencies of RFLP types in sheep infected with natural scrapie were compared with those in healthy sheep. It was found that the frequency of type I in the sheep with natural scrapie was 70%, about eight times higher than that in randomly collected healthy sheep. In the 13 experimentally infected sheep that had been used for other purposes, however, no relationship between the RFLP type and onset of scrapie was found.

Animals↗