Seasonal changes of DNA fragmentation and quality of raw and cold-stored stallion spermatozoa.

In this study annual fluctuations of DNA fragmentation and quality of cold-stored equine sperm were evaluated. Ejaculates were collected weekly during one year from 15 stallions. Ejaculate volume, sperm concentration and total sperm count were determined and semen was then extended and cold-stored for 48 h. Sperm motility was evaluated by CASA before and after 24 as well as 48 h of cold storage. In addition, the percentages of sperm with intact plasma membrane and acrosome (PMAI %) and with low intracellular Ca2+ level were determined in cold-stored semen (24 h, 48 h). SCSA™ was performed to assess mean DFI, SD of DFI and % DFI in raw frozen-thawed as well as in extended sperm after 24 and 48 h of storage. The month of semen collection affected (P < 0.05) all parameters evaluated in raw semen and all criteria except progressive motility as well as rapid cells in semen stored for 24 and 48 h, respectively. Ejaculate volume was higher and sperm concentration lower in summer compared to winter and motility lower in July than in any other month of the year (P < 0.05). In semen processed in April and stored for 24 h the percentage of rapid cells was improved compared to January and after 48 h of storage progressive motility (%) was higher in January and October than in July (P < 0.05). After 24 h of cold storage PMAI % was higher in October than in January and after 48 h values were higher in September compared to January and February as well as from April to July (P < 0.05). Regarding sperm with low intracellular Ca+2 level (%) after storage for 24 and 48 h, higher values were measured in winter and in October compared to April, June and July (P < 0.01). Seasonal changes in DNA fragmentation were most evident with respect to mean DFI. In raw frozen-thawed semen mean DFI was lower from August to November than in June and July (P < 0.001). Values were lower during winter compared to spring and early summer (P < 0.05) and lower in December than from April to September (P < 0.001). After 24 h of cold storage mean DFI was lower in September and October when compared to January, February, May, July and November (P < 0.05) and after 48 h storage mean DFI was reduced in spring and autumn compared to February, June and July (P < 0.05). In conclusion, a seasonal effect was evident on semen characteristics of raw and cold-stored sperm. Semen quality was impaired in midsummer when low sperm motility and viability were combined with an elevated DNA fragmentation and Ca2+ level of sperm.

Wach-Gygax L ，Burger D ，Malama E ，Bollwein H ，Fleisch A ，Jeannerat E ，Thomas S ，Schuler G ，Janett F ... -  《-》

Seasonal changes in semen quality and freezability in the Warmblood stallion.

Janett F ，Thun R ，Niederer K ，Burger D ，Hässig M ... -  《THERIOGENOLOGY》

Seasonal changes of semen quality and freezability in Franches-Montagnes stallions.

Janett F ，Thun R ，Bettschen S ，Burger D ，Hassig M ... -  《ANIMAL REPRODUCTION SCIENCE》

The effect of season on spermatozoa motility, plasma membrane and acrosome integrity in fresh and frozen-thawed semen from Xinong Saanen bucks.

The aim of this study was to evaluate whether the season of ejaculate collection influences seminal quality parameters of pre- and post-freeze-thawing in Xinong Saanen bucks. Ejaculates were collected from eight bucks throughout the four seasons (spring, summer, autumn and winter) in a 12 months' time period, identified in the Northern Hemisphere. Semen samples were evaluated by the combinations of conventional and Computer-Assisted Sperm Analysis (CASA) when fresh and after frozen-thawed, respectively. The results clearly demonstrated that season of ejaculate collection influenced (p < 0.05) fresh semen quality. Highest semen quality was observed during autumn. On the contrary, undesirable indices (significantly lower, p < 0.05) were observed in winter as compared with the other remaining seasons. CASA has clearly shown the influences of seasonal variations on semen motility parameters. Furthermore, season of ejaculate collection was also found to influence sperm freezability. Semen characteristics after frozen-thawed followed a similar pattern with that of fresh ejaculate except in spring. The results revealed that sperm quality was higher (p < 0.01) in summer and autumn than in spring and winter. In conclusion, seasonal variation influences semen quality in Xinong Saanen bucks. In addition to summer and autumn, fresh ejaculates in spring can also be successfully used for AI. Sperm from ejaculates collected during summer and autumn are more suitable for cryopreservation. Hence, it is possible to increase the efficiency of goat breeding by manipulating the seasonal variations of semen quality for immediate AI and/or cryopreservation.

Wang W ，Luo J ，Sun S ，Xi L ，Gao Q ，Haile AB ，Shi H ，Zhang W ，Shi H ... -  《-》

Influences of a diet supplemented with linseed oil and antioxidants on quality of equine semen after cooling and cryopreservation during winter.

Seasonal changes in the reproductive physiology of stallions contribute to a decrease in the quality of frozen-thawed semen during late winter. Changes in the lipid composition of the sperm plasma membrane may contribute to this phenomenon. In the present study, we have, therefore, investigated the effects of adding linseed oil (LO) in combination with antioxidants to the diet of breeding stallions on the motility and membrane integrity of cooled-stored and cryopreserved semen. Starting in November, the diet of LO stallions (n = 6) but not control (C) stallions (n = 5) was supplemented with LO (100 mL once daily) plus an antioxidant (Myostem Protect; Audevard, Clichy, France) for a total of 84 days. Before (November) and at the end of this period (February), ejaculates were processed for cryopreservation (n = 3 ejaculates per stallion) and cooled shipping at 5 °C. Frozen-thawed and cooled-shipped semen was sent to the laboratory for computer-assisted semen analysis of total motility, progressive motility, and velocity parameters (average path velocity [VAP], curved line velocity [VCL], and straight-line velocity [VSL]) and evaluation of membrane integrity. The quality of frozen-thawed semen decreased (P < 0.05) from November (e.g., total motility LO 69 ± 3% and C 67 ± 3%) to February (total motility: LO 55 ± 4% and C 59 ± 3%) independent of treatment (P > 0.05). A decrease in the velocity parameters VAP, VCL, and VSL was more pronounced in LO stallions than in C stallions (e.g., VSL: November LO 67 ± 1 μm/s, C 64 ± 2 μm/s; February LO 59 ± 2 μm/s, C 63 ± 2 μm/s; interaction month by treatment, P < 0.05). In cooled-stored semen, total motility, progressive motility, and membrane integrity were lower in February than in November (P < 0.001 for all parameters). Supplementation of the diet with LO and antioxidants attenuated this decrease (e.g., Day 1 of cooled storage = 24 hours after semen collection: total motility in November LO 88 ± 1% and C 87 ± 3%; in February LO 83 ± 2% and C 73 ± 11%; interaction month by treatment: P < 0.05). Velocity parameters VAP, VCL, and VSL were significantly lower in February than in November (P < 0.001), but this decrease was not affected by treatment. In summary, dietary supplementation of stallions with LO plus antioxidants attenuated a decline in motility and membrane integrity of cooled-stored stallion semen during winter. This may improve the fertility of cooled-shipped semen. In contrast, the treatment did not counteract the decrease in quality of frozen-thawed semen that occurs in late winter.

Schmid-Lausigk Y ，Aurich C 《-》