Preliminary report: a pregnancy from frozen centrifuged dog semen.

: Semen obtained from a pure-bred Beagle was diluted 1:3 with a Tris (hydroxymethyl) - aminomethane buffered egg yolk diluent, centrifuged at 450 g for 10 minutes and the spermatozoa thus concentrated stored in 8 Cassou mini straws (0,25 ml) in liquid nitrogen. One month after collection, a single semen straw was thawed, rediluted with 4 ml of diluent containing no glycerol and inseminated into a Beagle in oestrus. This was repeated daily for 4 days. The vagina of the bitch was flushed with 4 ml of the diluent immediately prior to insemination on each occasion. The bitch whelped 7 pups 60 days after the first insemination.