title: Effects of a long-day light programme on the motility and membrane integrity of cooled-stored and cyropreserved semen in Shetland pony stallions.
abstract: Increasing day length in spring stimulates reproductive functions in horses. In this study, we have analysed the effect of artificial long days on the quality of cooled-stored and cryopreserved semen in Shetland stallions. Stallions of the treatment group (AL, n = 8) were exposed to 16 h light and 8h darkness from 15th December to 20th March while control stallions (CON, n = 7) were kept under natural photoperiod. Semen was collected once weekly and processed for cooled-storage and cryopreservation once per month. Total and progressive motility and percentage of membrane intact spermatozoa were analysed at 24, 48 and 72 h of cooled-storage and after freezing-thawing, respectively. Total and progressive motility and membrane integrity decreased during cooled-storage for 72 h in each month and both groups (p < 0.001). All these parameters were lower in CON versus AL stallions (p < 0.05) and the decrease was more pronounced in group CON (storage time x group p < 0.05). Differences between groups decreased throughout the observation period from January (p < 0.05 between groups) to July (e.g. total motility after 72 h of cooled-storage in January for group AL 80 ± 3 and group CON 49 ± 12%, respective values in July, 83 ± 2 and 72 ± 6%). Neither total and progressive motility nor percentage of membrane-intact and morphologically defect spermatozoa in frozen-thawed semen differed between groups and months. In conclusion, motility of cooled-stored semen was reduced in January and increased in stallions kept under a long day light programme for at least 30 days.
authors.affiliation: Division for Obstetrics and Gynaecology, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria. Electronic address: katharina.deichsel@vetmeduni.ac.at.
authors.forename: Katharina
authors.initials: K
authors.lastname: Deichsel
authors.affiliation: Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, 1210 Vienna, Austria.
authors.forename: Nadine
authors.initials: N
authors.lastname: Schrammel
authors.affiliation: Division for Obstetrics and Gynaecology, Department for Small Animals and Horses, Vetmeduni Vienna, Vienna, Austria. Electronic address: joerg.aurich@vetmeduni.ac.at.
authors.forename: Jörg
authors.initials: J
authors.lastname: Aurich
authors.affiliation: Centre for Artificial Insemination and Embryo Transfer, Department for Small Animals and Horses, Vetmeduni Vienna, 1210 Vienna, Austria. Electronic address: christine.aurich@vetmeduni.ac.at.
authors.forename: Christine
authors.initials: C
authors.lastname: Aurich
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000502:physiology*; D003080:Cold Temperature; D015925:Cryopreservation / Q000662:veterinary*; D006736:Horses / Q000502:physiology*; D008297:Male; D017440:Photoperiod; D012661:Semen / Q000502:physiology*; D055101:Semen Analysis / Q000662:veterinary*; D012662:Semen Preservation / Q000662:veterinary; D013081:Sperm Motility
keywords: Cooled storage; Cryopreservation; Photoperiod; Semen; Stallion