THE EFFECTS OF SEMEN COLLECTION ON FERTILITY IN CAPTIVE,
NATURALLY FERTILE, SANDHILL CRANES
GUOJUN CHEN, USGS Patuxent Wildlife Research Center, 12011 Beech Forest Road, Laurel, MD 20708-4041, USA and Heilongjiang Research Institute of Wildlife, Haping Road, Harbin, 150040, People's Republic of China
GEORGE F. GEE, USGS Patuxent Wildlife Research Center, 12011 Beech Forest Road, Laurel, MD 20708-4041, USA
JANE M. NICOLICH, USGS Patuxent Wildlife Research Center, 12302 Beech Forest Road, Laurel, MD 20708-4022, USA
JOANNA A. TAYLOR, USGS Patuxent Wildlife Research Center, 109 Merriam, 11510 American Holly Drive, Laurel, MD 20708-4019, USA
We tested to see if semen collection interferes with fertility in naturally fertile pairs of cranes. We used 12 naturally fertile, Florida sandhill crane (Grus canadensis pratensis) pairs for this study, 6 control and 6 experimental. All pairs had previously produced fertile eggs. Semen was collected on Tuesday mornings and Friday afternoons from 26 February 1993 to 4 June 1993. We used standard artificial insemination methods to collect and to evaluate the semen and spermatozoa. Semen collection had minimal effect on semen quality and semen quantity. Semen volume, sperm density, sperm motility, sperm morphology, sperm viability, sperm number per collection, and male response to semen collection exhibited significant daily variation. Although semen collection began 13 days before the first egg in the experimental group, we did not observe differences in the date of first egg laid or in fertility between experimental and control groups. Also, we observed no statistically significant differences in the interval between clutches or in the percentage of broken eggs between experimental and control groups. However, 4 eggs were broken by adults during the disturbance associated with capturing birds for semen collection. We found that females with mates from which we consistently gathered better semen samples produced fewer fertile eggs than females with sires producing poorer semen samples (r = 0.60). We interpret these results to mean that males that were successfully breeding with their mates had little left at the time of our collection.
PROCEEDINGS NORTH AMERICAN CRANE WORKSHOP 8:185-194
Key words: artificial insemination, egg production, fertility, Florida sandhill crane, Grus canadensis pratensis, semen, semen collection, spermatozoa quality.
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