Table 3.

Semen handling factors affecting boar semen quality

Factor	Details	Effect of semen quality	Reference
Collection	Latex gloves.	Toxic for the sperm	[76]
	Preputial liquid into the collection container	Increases bacteriospermia	[68]
	Collection longer than 7 min,	Increases bacteriospermia	[68]
Dilution
Temperature	Final dilution at 22 °C vs 30 °C (2-step dilution)	No differences in sperm motility, morphology or acrosome integrity after 3 days storage	[14]
	Final dilution at 20 °C vs 32 °C (2-step dilution)	No differences on membrane integrity or responsiveness to capacitating conditions	[82]
	Final dilution at 21 °C vs 32 °C (2-step dilution)	Lower motility, increased membrane damage after 6 days storage	[80]
Dilution rate	0.5 × 109 sperm/80 ml vs 2.5 × 109/80 ml	Lower motility	[83]
Storage media	Short vs long	Lower motility after 4 days storage	[15]a
	Magnetized extender	Improve membrane integrity	[88]
	Antibiotics	Prevent bacterial overgrowth	[92]
Packaging	Bags vs tubes.	Need less time to reach 17 °C	[96]
	Some plastic compounds	Toxic for sperm	[97]
Storage
Temperature	< 12 °C	Reduced sperm motility and vitality	[78]
Duration	> 4 days	Reduced motility and fertility	[15, 86]
Air contact	Air contact during storage	Increase in pH, reduced sperm motility	[101]
Turning doses	180° rotation/12 h or five 360° rotations/h vs. non-rotated tubes, using	Increase in pH, reduced sperm motility	[102]

^aEffect only seen in 1 of the 3 investigated long term extenders compared to 2 short term extenders