Semen evaluation in stud dogs

Stud dog fertility is also important. Semen evaluation may need to be carried out if the stud dog has "missed" to more than one bitch in succession.  In certain breeding centres (including The Guide Dogs for the Blind Association) semen evaluation is carried out routinely as part of the stud dog management programme.  Semen evaluation is usual when being used for artificial insemination.

Semen is most frequently obtained by massaging the penis using a gloved hand.  Each semen fraction is collected into a warmed plastic test tube via a glass funnel or plastic bag. (see mating the bitch part two for explanations of each fraction).  Artificial vaginas, commonly used in other species, are not recommended in the dog as the rubber liner is toxic to canine spermatozoa.  The second, or sperm rich fraction, is examined for colour:

White sample indicates normal sperm.

Watery or clear may mean few sperm.

Yellow may indicate contamination.

Red or pink sample may indicate prostatic disease.  

A drop of the sperm rich fraction of semen is placed on a warmed glass slide for microscopic examination by the veterinary surgeon.  There is a correlation between the size of the dog and the number of ejaculated spermatozoa and fig. v. shows the range of seminal characteristics for fertile dogs.  

Fig. v.

Motility is determined by the number of sperm which have normal forward progressive motion.  Sperm generally swim rapidly (faster than 200um per second) in straight lines propelled by rapid movements of the tail.  Spermatozoa which swim in circles or backwards frequently have bent tails.  These and other anatomical differences would constitute abnormal morphology.  Fertile dogs usually have approximately 80% or more morphologically normal live spermatozoa present.