Characterization of Northern pintail (Anas acuta) ejaculate and the effectof sperm preservation on fertility

Northern pintail duck semen and sperm traits were characterized, and the fe rtility of cold-stored spermatozoa was investigated using artificial insemi nation. Excellent quality ejaculates containing high proportions of motile spermatozoa were collected from drakes within 20 s by a massage technique. Semen was collected in Beltsville poultry semen extender, pooled and cold-s tored (4 degreesC) for 0, 24, 48 or 72 h. Hens were inseminated with 100 mu l twice a week, and eggs were assessed for fertilization and hatch success. fertilization success was similar (P >0.05) for semen cold-stored for 0 (5 1.6%), 24 (51.5%), 48 (41.1%) and 72 h (22.3%; P >0.05). Similar (P >0.05) percentages of fertilized eggs hatched to live offspring (73.1, 71.4, 87.0 and 80.0%, respectively). Fresh semen was also equilibrated with 1 or 4% di methylsulphoxide or glycerol, and cryopreserved at the following rates: (1) approximately 60 degreesC min(-1) (in liquid nitrogen [LN2] vapour) for 10 min; (2) 1 degreesC min(-1) to -20 degreesC, LN2 vapour for 10 min; and (3 ) 1 degreesC min(-1) to -35 degreesC, all followed by immersion in LN2. Aft er thawing for 30 s at 37 degreesC or 20 min at 4 degreesC, sperm motility and viability were assessed. The highest numbers of motile spermatozoa were recovered after slow-fast freezing (2) and thawing at 0 degreesC (P <0.05) , but survival was inadequate to allow artificial insemination. Nonetheless , cold storage provides an effective means of short-term storage with no lo ss of fertility in this waterfowl species.