Tag Archives: Leonberger

Anatomy and Normal Reproductive Physiology

1) When should I expect my male dog to be fertile? That depends on his breed. Animals of most species go through puberty and become sexually mature when they reach about 80% of their adult body weight. For a Maltese, that may occur when he is 4 months old. For a Leonberger, that may not occur until he is almost 2 years old. The only ways to know for sure that a male is fertile are either to breed him or to collect semen for evaluation. 2) My dog has poor libido. Does he have a testosterone deficiency? No. I have never documented lack of testosterone as a cause of poor libido in dogs nor has anyone else, to my knowledge. Embryology and anatomy of the male reproductive tract Determination of gender is dependent on the type of sex chromosomes present in the embryo. All dogs have 78 chromosomes, two of which are sex chromosomes; in females both are X chromosomes, and in males there is one X and one Y chromosome. Two tubular tracts are present in the developing embryo: the mullerian (paramesonephric) duct system, which goes on to form the female reproductive tract, and the wolffian (mesonephric) duct system, which goes on to form the tubular portions of the male reproductive tract. In the presence of a Y chromosome, Read more […]