True navigation in migrating gulls requires intact olfactory nerves.

During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated.

Morphometry of normal and teratozoospermic canine sperm heads using an image analyzer: work in progress.

Combining the traditional morphologic evaluation of spermatozoa with computer assisted image analysis adds randomness, objectivity, repeatability and accuracy to morphometric measurements. We collected semen from 10 fertile, normospermic dogs aged 1 to 7 yr and from 3 teratozoospermic breed-matched dogs. Sperm head morphology was examined in Giemsa-stained smears by light microscopy, using a computer-assisted image analyzer and by transmission electron microscopy.

Fertility parameters in male Irish wolfhounds: a two-year follow-up study.

The reproductive performance of 25 male Irish wolfhounds was examined in a two-year follow-up study. Results of a previous study showed that 37 Irish wolfhounds had lower libidos, smaller testicles and poorer semen quality than 67 control dogs examined. This study was undertaken to determine whether fertility parameters had changed after a further two years.

Probable spermatozoal diploidy in the semen of a golden retriever.

The semen of a 3-year-old golden retriever was examined for breeding purposes. When the morphology of the spermatozoa was analysed for the first time, 37% were observed to have giant heads. In most of the giant heads, a diadem defect was also found.