Rapid evolution of horse satellite DNA Wijers, E.R; Zijlstra, C; Lenstra, J.A
Genomics (San Diego, Calif.),
10/1993, Letnik:
18, Številka:
1
Journal Article
Recenzirano
The major satellite of the horse genome consists of about 1 million copies of a 221-bp tandem repeat unit. By fluorescence in situ hybridization it has been localized in the centromeres of 58 of the ...64 horse chromosomes. The donkey genome contains a similar but not identical satellite. Strikingly, the equine repeat did not hybridize to DNA of the Grevy zebra, despite the divergence of the horse and zebra only 3 to 5 million years ago and the ability of these species to crossbreed. The evolution of satellite DNA in the Equidae is more rapid than that in other mammalian families, which may be explained by their rapid karyotypic evolution.
The pathophysiology and lesions associated with vitamin E deficiency are similar between domestic and exotic species, and circulating plasma concentrations are also similar between comparable groups. ...However, many ecological variables must be considered for the most relevant comparisons. Tissue values of vitamin E, apart from plasma, are unknown for most exotics. Dietary vitamin E requirements of exotic species and domestics appear to differ; based on natural foodstuff analyses and clinical observations, between 50 and 200 mg vitamin E/kg DM are necessary to prevent vitamin E deficiency, 5- to 10-fold higher than current livestock recommendations.
A manual technique was used to collect representative ejaculates from an unrestrained Grevy's zebra stallion beginning at 13 mo of age to determine the onset of sperm production, to calculate the ...number of spermatozoa produced per ejaculate, and to determine any seasonality associated with sperm production. Spermatozoa first appeared in the ejaculate at 31 mo of age. By 48 mo of age the zebra was producing up to 40 billion spermatozoa per ejaculate. Progressive sperm motility ranged from 75 to 95%. Gel-free semen volume averaged 75 to 120 ml/ejaculate. Gel volume ranged from 0 to 1100 ml/ejaculate. Semen was frozen in 2 different extenders in 0.5-ml PVC straws. The post-thaw motility of cryopreserved spermatozoa ranged from 30 to 70%. A domestic horse mare became pregnant on the first cycle after insemination with frozen-thawed spermatozoa from this zebra. Sperm production data obtained from semen collections made on a Grant's Zebra stallion from 3 to 8 yr of age is presented for comparison of the 2 species
Department of pathobiology, Ontario Veterinary College, University of Guelph, Canada.
Ninety-two equine herpesvirus type 1 isolates were recovered from aborted, stillborn, or neonatal foals from ...Ontario, Canada, from 1986 to 1992. From this total, 32 strains were randomly chosen for further study. Four or 5 isolates from each winter were selected, each from a different premises, and characterized by restriction enzyme analysis using BamHI, KpnI, BglII, HindIII, and EcoRI. Additional isolates from 2 premises and from a zebra foal were also assessed. For the strains isolated in 1986 and 1989-1992, the DNA pattern of 18 strains was similar to that of type 1P (Kentucky D) for BamHI and KpnI. None of the 32 strains studied could be differentiated by HindIII or EcoRI. Using BglII, an inconsistent fragment pattern and distribution were observed. Of the 8 strains isolated in 1987 and 1988, 7 were assigned into the 1B prototype group. The geographic distribution of 17 type 1P and 12 1B isolates was random across southern Ontario. These findings suggest that both electropherotypes can be recovered from horses in Ontario. The patterns of the additional equine isolates from the same premises were identical. The zebra isolate was different from the prototype equine herpesvirus type 1 and type 4 patterns and from all other equine isolates.
Ivermectin toxicosis in a zebra Hautekeete, L.A; Khan, S.A.A; Hales, W.S
Veterinary and human toxicology,
02/1998, Letnik:
40, Številka:
1
Journal Article
Recenzirano
A 3-mo-old zebra was accidentally given 2.08 mg ivermectin/kg bw orally. Ataxia, blindness and depression developed within a few hours and resolved with symptomatic and supportive treatment by the ...fifth day post-exposure. These effects were similar to those reported in horses, including the temporary blindness.
The viraemic period of African horsesickness is significantly longer in experimentally infected zebra than in horses. The virus could be isolated 40 d post-infection from blood and 48 d ...post-infection from spleen. The introduction of zebra into African horsesickness-free countries should therefore be considered carefully, and preferably be restricted to serologically negative zebra.
A survey was carried out in horse, zebra, elephant, camel, sheep and goat and wild carnivore sera for virus-serum neutralising antibody to the nine type strains of African horse sickness virus. ...Antibody was found amongst the horse, zebra and elephant sera to all nine different strains. No antibody was detected in any sera from camels, sheep and goats. None was found in sera from hyaena and jackals in this series but had been detected earlier.
This study describes the presence of immunoactive and bioactive eCG-like material in full-term placentas of both domestic horses and zebras. Term placental extracts were immunoreactive in an LH ...monoclonal antibody RIA, and methods successfully used previously for the purification of eCG and eLH were employed to further concentrate the immunoreactive materials to the point where additional characterization studies could be performed. Sufficient equine material was obtained to perform a final fractionation on a concanavalin A Sepharose column yielding an unadsorbed fraction, e17A, and an adsorbed fraction, e17B. There was insufficient zebra material, z5D, for this step. HPLC gel filtration coupled with LH immunoassays of the column eluates showed all the final placental fractions to be highly heterogeneous, but a discrete peak of immunoactivity was found in one of the two equine fractions (el7B) and in the zebra fraction (z5D). The HPLC gel filtration elution volumes for el7B and z5D suggest that they have a smaller molecular size than either eCG or eLH but almost the same size as ovine LH. Both el7B and z5D were bioactive in the rat Leydig cell assay for LH but low in potency compared to eCG or eLH; el7A was inactive at very high doses (5 microgram). This latter fraction, however, cross-reacted in an eCG alpha RIA to a much greater extent (6 times) than el7B, suggesting that it may be an incompletely formed or degraded alpha subunit. RIAs for LH, eCG, and eCG beta suggest that epitopes distinctive for these molecules are also present or similar to those in the term placental materials. Insofar as the endometrial cups, the placental source of chorionic gonadotropin in equids, disappear long before the end of pregnancy, the results suggest that other cell types may be responsible for the presence of the eCG-like material in the term placentas of the horse and the zebra
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