Publications by authors named "Sabine Meinecke-Tillmann"

6 Publications

  • Page 1 of 1

Viability assessment of spermatozoa in large falcons (Falco spp.) using various staining protocols.

Reprod Domest Anim 2020 Oct 17;55(10):1383-1392. Epub 2020 Aug 17.

Clinic for Birds, Reptiles, Amphibians and Fish, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.

Viability assessment is an important part of semen analysis, and various live/dead staining protocols have been used in semen of avian species. Results of live/dead count differed between dyes, staining protocols and bird species, impeding comparability between studies and requiring species-specific comparisons of viability stains. In raptor semen, similar comparisons are absent. Thus, the aim of the present study was to compare eight conventional viability stains. Eosin blue 2% [EB], eosin blue 2% with the addition of 3% sodium citrate [EB2], eosin blue-nigrosin 5% [EBN5], eosin yellow-nigrosin 5% [EYN5], eosin yellow-nigrosin 10% [EYN10], eosin blue-aniline blue [EBA], eosin yellow-aniline blue [EYA] and bromophenol blue-nigrosin [BBN] were evaluated in comparison with the fluorescence stain SYBR Green-propidium iodide [SYBR-PI] in spermatozoa of falcons. The comparison was performed using conventional light microscopy which is applicable in breeding centres, veterinary practices and field studies. Additionally, live/dead stains were correlated to motility values of the same samples to validate sperm viability. Light microscopy using EB and using SYBR-PI enabled an effective and clear differentiation between alive and dead spermatozoa of falcons. Motility values correlated significantly and strongly with EB only (r = .629; p < .001), but not with any other stain used in the study. Therefore, our results suggest EB as the most suitable stain for viability assessment in the semen of large falcons.
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http://dx.doi.org/10.1111/rda.13785DOI Listing
October 2020

Simultaneous umbilical blood flow during normal pregnancy in sheep and goat foetuses using non-invasive colour Doppler ultrasound.

Anim Reprod 2018 Aug 16;15(2):148-155. Epub 2018 Aug 16.

Institute of Reproductive Biology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany.

The characteristics of umbilical blood flow (UM) was investigated using 18 (25 foetuses) pregnant ewes and 20 (41 foetus) pregnant goats transrectal non-invasive color Doppler ultrasonographic examinations were done frequently between 2 and 8 week after breeding and then transabdominally until parturition. Colour Doppler velocimetery includes blood flow volume (BFV), time averaged maximum velocity (TAMV), resistance index (RI), pulsatility index (PI), time average of mean (TAMEAN) and impedance of blood flow (PS/ED or AB ratio). Also a qualitative evaluation of UM blood flow indicating increases (P < 0.001) in BFV, TAMV and TAMEAN were observed until 19 week of pregnancy in foetuses of sheep and goats and then those values decreased (P < 0.001) from 19 week until parturition. Conversely, UM-PI, RI and PS/ED decreased (P < 0.002-0.01) until 19 week and then increased (P < 0.01-0.0001). The umbilical artery BFV increased (P < 0.0001) during pregnancy from 7.27 ± 0.82 ml/min in sheep vs. 4.96 ± 0.54 ml/min in goats at 6 week of gestation to 700.51 ± 31.05 ml/min (~100 fold) in sheep . 665.56 ± 48.22 ml/min (~133 fold) in goats at 19 week and then decreased (P < 0.0001) to 350.561 ± 72.15 ml/min in sheep vs. 215.17 ± 35.06 ml/min in goats at 20 week. The absence of end diastolic velocity (EDV) of umbilical artery blood flow was detected in both species between 4 and 12 week of pregnancy. Results of this study clearly show that the non-invasive colour Doppler sonography can be used successfully to assess umbilical blood flow in foetuses of pregnant sheep and goats. These may provide guidelines for assessing the state of intrauterine fetal growth retardation in pregnancies of sheep and goats.
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http://dx.doi.org/10.21451/1984-3143-AR2017-976DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8186881PMC
August 2018

Cycle-specific female preferences for visual and non-visual cues in the horse (Equus caballus).

PLoS One 2018 21;13(2):e0191845. Epub 2018 Feb 21.

Institute for Reproductive Biology, University of Veterinary Medicine Hannover, Hanover, Germany.

Although female preferences are well studied in many mammals, the possible effects of the oestrous cycle are not yet sufficiently understood. Here we investigate female preferences for visual and non-visual male traits relative to the periodically cycling of sexual proceptivity (oestrus) and inactivity (dioestrus), respectively, in the polygynous horse (Equus caballus). We individually exposed mares to stallions in four experimental situations: (i) mares in oestrus and visual contact to stallions allowed, (ii) mares in oestrus, with blinds (wooden partitions preventing visual contact but allowing for acoustic and olfactory communication), (iii) mares in dioestrus, no blinds, and (iv) mares in dioestrus, with blinds. Contact times of the mares with each stallion, defined as the cumulative amount of time a mare was in the vicinity of an individual stallion and actively searching contact, were used to rank stallions according to each mare's preferences. We found that preferences based on visual traits differed significantly from preferences based on non-visual traits in dioestrous mares. The mares then showed a preference for older and larger males, but only if visual cues were available. In contrast, oestrous mares showed consistent preferences with or without blinds, i.e. their preferences were mainly based on non-visual traits and could not be predicted by male age or size. Stallions who were generally preferred displayed a high libido that may have positively influenced female interest or may have been a consequence of it. We conclude that the oestrous cycle has a significant influence on female preferences for visual and non-visual male traits in the horse.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0191845PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5842875PMC
March 2018

Exfoliative Endometrial Cytology in Embryo Donor Cows-Comparison of Sampling Localizations for the Diagnosis of Subclinical Endometritis.

Vet Sci 2016 Nov 28;3(4). Epub 2016 Nov 28.

Institute for Reproductive Biology, University of Veterinary Medicine Hannover, Bünteweg 2, Hannover 30559, Germany.

Subclinical endometritis has a major effect on the reproductive performance of dairy cows and also on the success of embryo collection. Thus it is important to minimize the number of false-negative diagnoses. In order to evaluate the question of whether or not a single cytobrush sample is representative of the whole endometrium, 53 German Holstein embryo donor cows in the northwest of Germany were examined via the cytobrush method at three different localizations of the uterus: the uterine body about 0.5 cm cranial of the cervical canal and both uterine horns about 1.5 cm cranial of the bifurcation. Although the mean percentage of polymorphonuclear neutrophils at the three locations is not significantly different ( = 0.64), the individual variations lead to the conclusion that more than one sample of the endometrium should be taken into account when diagnosing subclinical endometritis in embryo donor cows.
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http://dx.doi.org/10.3390/vetsci3040035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5606587PMC
November 2016

The use of semen evaluation and assisted reproduction in Spix's macaws in terms of species conservation.

Zoo Biol 2014 May-Jun;33(3):234-44. Epub 2014 Apr 19.

Clinic for Birds, Reptiles, Amphibians and Fish, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.

The Spix's macaw (Cyanopsitta spixii) is the rarest parrot on earth. The remaining captive population consists of 79 individuals. Captive propagation is ongoing to increase the number of individuals for future reintroduction back into the wild. Unfortunately, from 2004 to 2012, only 33 chicks hatched from 331 eggs. Semen evaluation and assisted reproduction might help to overcome this problem. Therefore, a recently developed electro-stimulated semen collection technique was used in Spix's macaws. Semen collection was successful in 39 of 78 attempts in 10 out of 17 males. Examination of the semen included evaluation of volume, color, consistency, contaminations and pH, as well as determination of motility, viability, morphology, concentration, and total count of spermatozoa. The median volume of semen samples was 5.6 µl. On average, 34.7 ± 21.9% (median 30%) of the sperm were motile and 23.1 ± 22.1% (median 16.5%) were progressively motile. In addition to spermatozoa, round cells were detected in the samples. Median sperm concentration was 15,500/µl (range 500-97,500/µl) and median viability was 50% (range 5-87%). Morphological examination revealed in 26.5% normal spermatozoa, high numbers of malformations of the head (50.2%) and tail region (20.5%), with 29% of all sperm showing multiple abnormalities. Artificial insemination was performed in three females; two eggs laid after artificial insemination had spermatozoa present on the perivitelline layer, suggesting the possible success of the insemination technique. Although no fertilization could be demonstrated, these preliminary results are promising, as they indicate that assisted reproduction might be a tool for species conservation in the Spix's macaw.
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http://dx.doi.org/10.1002/zoo.21129DOI Listing
August 2014

Preparation and ultrastructure of spermatozoa from green poison frogs, Dendrobates auratus, following hormonal induced spermiation (Amphibia, Anura, Dendrobatidae).

Anim Reprod Sci 2009 Jul 20;113(1-4):177-86. Epub 2008 Jun 20.

Department of Reproductive Biology, University of Veterinary Medicine Hannover Foundation, Buenteweg 2, Hannover 30559, Germany.

Few ultrastructural studies have been performed on members of the Dendrobatidae, although such investigations can be useful for the understanding of reproductive patterns, as a diagnostic method for males in breeding programs for endangered amphibians and for phylogenetic analysis. The sperm ultrastructure of the Green Poison Frog, Dendrobates auratus, from Panama is described following induced spermiation in living animals. To date only testicular spermatozoa in other dendrobatid frogs have been analysed. Moreover, an electron microscopic preparation method (transmission and scanning electron microscopy) for dendrobatid sperm cells in low concentration is presented. Sperm cells from stimulated frogs (100 IU human chorionic gonadotropin, hCG, twice at an interval of 1h) were recovered via cloaca lavage using 600 microl isotonic phosphate-free amphibian saline (IPS). Centrifuged flushings (5 min, 173 x g) were deposited on microscopic slides. Adherent spermatozoa were treated with Karnovsky fixative (overnight, 4 degrees C). After postfixation (2h, 1% osmium tetroxide), samples were dehydrated in series of ascending acetones (30-100%). For transmission electron microscopy sperm cells were encapsulated using Epon and 1.5% 2,4,6-tris(dimethylaminomethyl)phenol (DMP 30). Ultrathin sections (70 nm) were cut and stained with uranyl acetate (30 min) and lead citrate (5 min). Sperm cells are filiform with a 21.1+/-2.7 microm long and arcuated head and a single tail (35.0+/-4.2 microm length). Their acrosomal complex is located at the anterior portion of the head and consists of the acrosomal vesicle which has low electron density, and the subjacent electron-dense subacrosomal cone. In transverse section, the nucleus is circular (1.9+/-0.2 microm diameter) and conical in longitudinal section. It is surrounded by several groups of mitochondria. The chromatin is highly condensed and electron-dense but shows numerous electron-lucent inclusions. A short midpiece has a mitochondrial collar with a proximal and a distal centriole. The latter gives rise to the axoneme which alone forms the flagellum. The sperm ultrastructure of D. auratus differs from that of other Dendrobatidae because of the absence of a nuclear space and the absence of the undulating membrane associated with an axial fibre. This tail conformation is found in the Ranoidea but not in the Bufonoidea. These results show that the spermatozoa of D. auratus are the first within the Dendrobatidae without accessory tail structures. Methods of using sperm samples from hormonal treated frogs for ultrastructural studies is not only reasonable to examine e.g. amphibian phylogeny without killing frogs threatened with extinction but allows investigations in the field of assisted reproduction and male fertility for example in conservation programs for endangered amphibians.
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http://dx.doi.org/10.1016/j.anireprosci.2008.06.005DOI Listing
July 2009