title: Time within reproductive season, but not age or inbreeding coefficient, affects seminal and sperm quality in the whooping crane (Grus americana).
abstract: All living whooping cranes (Grus americana) are descended from 16 or fewer birds that remained alive in the early 1940s, a bottleneck that puts the species at potential risk for inbreeding depression. Although AI is commonly used in the management of the captive population of this species, little is known about seminal traits or factors affecting sperm quality in the whooping crane. In the present study, semen samples were collected from 29 adult males (age 3-27 years) during the early (March), mid (April) and late (May) breeding season over 2 consecutive years. The effects of donor age, time within reproductive season and level of inbreeding on seminal characteristics were analysed using regression and information-theoretic model selection. Only time within reproductive season significantly affected seminal traits, with total numbers of spermatozoa and proportions of pleiomorphisms increasing across the season. We conclude that, even with a highly restricted number of founders, there is no discernible influence of inbreeding (at the levels described) on sperm output or quality. Furthermore, although there is variance in seminal quality, the whooping crane produces significant numbers of motile spermatozoa throughout the breeding season, similar to values reported for the greater sandhill crane (Grus canadensis tabida).
authors.affiliation: Department of Animal and Avian Sciences, 1413 Animal Sciences Center, University of Maryland, College Park, MD 20742, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Brown
authors.affiliation: United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, MD 2078, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Converse
authors.affiliation: United States Geological Survey, Patuxent Wildlife Research Center, 12100 Beech Forest Road, Laurel, MD 2078, USA.
authors.forename: J N
authors.initials: JN
authors.lastname: Chandler
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA 22630, USA.
authors.forename: A L
authors.initials: AL
authors.lastname: Crosier
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA 22630, USA.
authors.forename: W
authors.initials: W
authors.lastname: Lynch
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA 22630, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Wildt
authors.affiliation: Department of Animal and Avian Sciences, 1413 Animal Sciences Center, University of Maryland, College Park, MD 20742, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Keefer
authors.affiliation: Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Road, Front Royal, VA 22630, USA.
authors.forename: N
authors.initials: N
authors.lastname: Songsasen
mesh_terms: D000367:Age Factors; D000818:Animals; D001717:Birds / Q000502:physiology*; D048430:Cell Shape / Q000502:physiology; D007178:Inbreeding; D008297:Male; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D055101:Semen Analysis; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology*