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Flyinge, Sweden

Morrell J.M.,Swedish University of Agricultural Sciences | Mari G.,University of Bologna | Kutvolgyi G.,Aleback Stud Farm | Meurling S.,Flyinge AB | And 3 more authors.
Reproduction in Domestic Animals

Contents: Some stallions produce ejaculates of low quality and/or low fertility when used for artificial insemination (AI). The purpose of these five case studies was to use Single Layer Centrifugation (SLC) to select the best spermatozoa from 'problem' ejaculates for subsequent use in AI. Sperm quality, in terms of motility, morphology and chromatin integrity, was improved in the SLC-selected samples compared to the corresponding uncentrifuged samples, with the exception of one stallion thought to have ampullary stasis. In this stallion, neither the incidence of spermatozoa with detached heads nor the proportion of damaged chromatin was decreased by SLC, in contrast to previous results. Pregnancies were obtained after using SLC-selected spermatozoa from the five stallions for AI, indicating that the spermatozoa were functional after SLC. Overall, the results suggest that SLC may be useful when preparing AI doses from some 'problem' ejaculates. © 2010 Blackwell Verlag GmbH. Source

Morrell J.M.,Swedish University of Agricultural Sciences | Richter J.,National Stud Lower Saxony | Martinsson G.,National Stud Lower Saxony | Stuhtmann G.,Flyinge AB | And 3 more authors.

A successful outcome after artificial insemination with cooled semen is dependent on many factors, the sperm quality of the ejaculate being one. Previous studies have shown that spermatozoa with good motility, normal morphology, and good chromatin integrity can be selected by means of colloid centrifugation, particularly single layer centrifugation (SLC) using species-specific colloids. The purpose of the present study was to conduct an insemination trial with spermatozoa from "normal" ejaculates, i.e., from stallions with no known fertility problem, to determine whether the improvements in sperm quality seen in SLC-selected sperm samples compared with uncentrifuged controls in laboratory tests are reflected in an increased pregnancy rate after artificial insemination. In a multicentre study, SLC-selected sperm samples and uncentrifuged controls from eight stallions were inseminated into approximately 10 mares per treatment per stallion. Ultrasound examination was carried out approximately 16days after insemination to detect an embryonic vesicle. The pregnancy rates per cycle were 45% for controls and 69% for SLC-selected sperm samples, which is statistically significant (P<0.0018). Thus, the improvement in sperm quality reported previously for SLC-selected sperm samples is associated with an increase in pregnancy rate, even for ejaculates from stallions with no known fertility problem. © 2014 Elsevier Inc. Source

Morrell J.M.,Swedish University of Agricultural Sciences | Stuhtmann G.,Flyinge AB | Meurling S.,Flyinge AB | Lundgren A.,Swedish University of Agricultural Sciences | And 3 more authors.

Many attempts have been made to identify laboratory tests that are predictive of sperm fertility, both to improve the quality of stallion semen doses for artificial insemination (AI) and to identify potential breeding sires if no fertility data are available. Sperm quality at the stud is mostly evaluated by assessing subjective motility, although this parameter can be poorly indicative of fertility. Sperm morphology and chromatin integrity in Swedish stallions are correlated to pregnancy rate after AI. Because single layer centrifugation (SLC) selects for spermatozoa with normal morphology and good chromatin, retrospective analysis was carried out to investigate whether sperm yield after SLC is linked to potential fertility. Commercial semen doses for AI from 24 stallions (five stallions with four ejaculates each, 19 stallions with three ejaculates each; n = 77) obtained during the breeding season were cooled, and sent overnight to the Swedish University of Agricultural Sciences in an insulated box for evaluation, with other doses being sent to studs for commercial AI. On arrival at Swedish University of Agricultural Sciences, the semen was used for SLC and also for evaluation of sperm motility, membrane integrity, chromatin integrity, and morphology. The seasonal pregnancy rates for each stallion were available. The yield of progressively motile spermatozoa after SLC (calculated as a proportion of the initial load) was found to be highly correlated with pregnancy rate (r = 0.75; P < 0.001). Chromatin damage was highly negatively correlated with pregnancy rate (r = -0.69; P < 0.001). Pregnancy rate was also correlated with membrane integrity (r = 0.58; P < 0.01), progressive motility (r=0.63; P < 0.01), and normal morphology (r = 0.45; P < 0.05). In conclusion, these preliminary results show that sperm yield after SLC is related to the potential fertility of the original ejaculate, and could be an alternative indicator of stallion fertility if breeding data are not available. Single layer centrifugation is fast (30minutes) and does not require expensive equipment, whereas other assays require a flow cytometer and/or specialist skills. An additional option could be to transport semen doses to a laboratory for SLC if the stud personnel do not want to perform the procedure themselves. © 2014 Elsevier Inc. Source

Morrell J.M.,Swedish University of Agricultural Sciences | Winblad C.,Swedish University of Agricultural Sciences | Georgakas A.,Swedish University of Agricultural Sciences | Stuhtmann G.,Flyinge AB | And 2 more authors.
Animal Reproduction Science

There are anecdotal reports that equine fertility may decline towards the end of the breeding season. Previous studies have examined differences in sperm quality between the breeding season and non-breeding season but few studies have investigated the proportions of superoxide or peroxide containing spermatozoa at different times during the breeding season. The purpose of this study was to measure the content of these reactive oxygen species (ROS) at the beginning and end of the Swedish breeding season, using flow cytometric analysis of the fluorescence produced after staining with hydroethidium and dichlorodihydrofluorescein diacetate. In addition, the effects of a new method of selecting good quality spermatozoa by colloid centrifugation, known as Single Layer Centrifugation (SLC), on ROS-content were investigated. Superoxide production by stallion spermatozoa was found to be higher at the start than at the end of the breeding season in Sweden (22 ± 16% versus 9 ± 6%, P < 0.05), whereas sperm motility was lower (total motility 80 ± 9% versus 90 ± 6%, P < 0.01; progressive motility 55 ± 12% versus 60 ± 8%, P < 0.05, at the beginning and end of the breeding season respectively). The mean values of the other parameters of sperm quality measured did not differ with time within the breeding season although differences did occur for individual stallions. SLC was found to select motile spermatozoa that contained less superoxide (16 ± 14% versus 23 ± 18%, P < 0.01) and less peroxide (0.3 ± 0.8 versus 1 ± 2%, P < 0.01) than uncentrifuged controls, although they were capable of producing ROS when stimulated with menadione. This reduced peroxide production may contribute to the enhanced sperm survival (retention of motility) seen in the SLC samples during storage. © 2013 Elsevier B.V. Source

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