Which factor does NOT affect the shelf life of semen in swine?

The correct answer is that the type of breed does not affect the shelf life of semen in swine. The shelf life of semen primarily depends on how the semen is processed, handled, and stored, rather than the specific breed of the animal from which the semen originates.

Factors like shipment, storage temperature, and fluctuations in temperature directly influence the viability of sperm cells. For instance, optimal storage conditions and stable temperatures are crucial for maintaining sperm viability during transportation and storage. Variability in temperature can lead to detrimental effects on sperm quality, while poor shipment practices can cause additional stress or damage to the semen. Hence, these aspects are significant in determining how long semen remains effective for breeding purposes, making the breed type an irrelevant factor in this context.