Aleutian Canada geese (Branta canadensis leucopareia) were inseminated with frozen-thawed semen containing 6% or 7% dimethylsulfoxide (DMSO) resulting in 32 fertile eggs and 17 goslings; with 7% DMSO, 19 of 31 eggs were fertile. Beltsville Poultry Semen Extender (BPSE), adjusted to 270 ? 30 mOs and 7.5 ? 0.4 pH, was used to dilute semen samples and the DMSO before cryopreservation. About half of the live spermatozoa in the fresh semen (92.9 ? 2.5% live cells, laboratory studies; 87.3 ? 7.3%, insemination trials) survived the freeze-thaw process (46.7 ? 7.8%, laboratory; 33.3 ? 17.8%, insemination trials). Samples of frozen-thawed semen contained a greater percentage of bent spermatozoa (27.1 ? 8.4% of live cells) than fresh semen (14.4 ? 3.0% of live cells). Fecal- and urate-contaminated semen (a common problem when collecting goose semen) reduced the sperm motility score from 3.2 ? 0.6 to 2.7? 0.7 and number of live spermatozoa in frozen-thawed semen from 49 ? 9% to 24 ?18%. Other variables examined that had less of an effect on semen quality included semen extenders, semen holding temperature, dilution and equilibration, relationship between hour of semen collection and level of semen contamination, and the relationship between season and sperm concentration.
