Semen quality in dogs and the influence of a short-interval second ejaculation

Semen quality was examined in each of 65 known fertile dogs. Values were fo und to be similar to those previously published, although an apparent breed influence was demonstrated, with German shepherd dogs producing ejaculates of larger volume and greater total spermatozoal output than other breeds. A second ejaculate was collected from each dog with a mean interval of 63 m in. The second samples had significantly lower values for the volume of the second fraction, the spermatozoal concentration and the total spermatozoal output. There were no differences for the percentage motility or the perce ntage of morphologically normal live spermatozoa. While there was no increa se in semen quality of the second ejaculate, the technique may be useful si nce it results in the collection of approximately 70% more spermatozoa than a single ejaculate. These spermatozoa also had normal motility and morphol ogy and could, therefore, be used for insemination or cryopreservation. (C) 1999 by Elsevier Science inc.