Sperm count in male dogs; especially those that are used in breeding programs are affected by a number of different factors, including organ development, environmental factors, and the rate at which sperm is harvested, whether artificially or through breeding.
Early Male Development
In order to understand what affects the male dog’s ability to produce sperm, one must understand the male dog’s reproductive system. Each dog, while in the early stages of development is female. It is the presence of a Y chromosome that influences the development of the testes, which in turn stimulate the production of the hormones required to create the male reproductive system.
Male Reproductive System
The testes are contained in the scrotum and kept separate from each other by a wall of connective tissue. In the scrotum, a complex system of blood vessels and muscles work together to maintain a constant temperature in the scrotum, ideal for creating sperm. If this temperature exceeds the ideal or drops below, sperm production is diminished, or even halted. The sperm that are produced in these less than desirable conditions are usually abnormal and do not facilitate a successful breeding.
Pesticides have also been blamed for lowering the sperm production in dogs. Scientists have identified the following substances as having a negative impact on sperm counts in otherwise healthy dogs: alachor, atrazine, and diazinon, all of which are commonly used to treat crops for pests.
Overbreeding a dog will also reduce sperm count as the spermatozoa will not have adequate time to mature before released in the semen. The sperm count in these specimens will remain reduced as long as the dog is being breed once a day or more. This is why it is recommended to breed a dog every other day to achieve ultimate potency. It is not harmful to the dog to breed more than once a day during the breeding cycle, however, subsequent matings will be less effective as the viable sperm count will be reduced with each additional mating.
Lastly, age will affect a dog’s ability to produce sperm. As a dog ages, his pituitary gland will produce less and less testosterone, reducing the signal to the testes to produce sperm. This is a natural course of aging and cannot be reversed, though feeding the dog high quality dog food, exercising him regularly, and proper veterinary care will slow the aging process, keeping the dog in prime breeding health for many years.