Boar management and semen handling factors affect the quality of boar extended semen

Table 1 Factors related to boar management affecting boar semen quality

Factor	Details	Effect of semen quality	Reference
Boar selection
Breed	Pietrain and Duroc vs. GL, LW, YS	Reduced sperm counts	[5]
Back fat	Back fat thickness in highly selected Piétrain	Positive association with motility	[8]
Housing
Group housing	Groups of prepupebertal boars vs individual	Higher sperm counts	[45]
Photoperiod	24 h of complete light or darkness for 3 months	Reduced volume and concentration	[11]
Heat stress	34.5 °C (8 h) or 31 °C (16 h) for 90 days vs. 23 °C	Reduced motility, reduced morphology	[48]
Nutrition
Feed restriction	1.4 times below maintenance	Reduced sperm counts	[51]
Protein restriction	12.0% crude protein (CP) in growers	Reduced sperm counts	[51]
Selenium	0.06 ppm vs 0.5 ppm continuously	Reduced motility, reduced morphology	[56]
Selenium	Organic vs inorganic	Increase concentration, increase oxidative stress, increase PGHX	[57, 60]
L carnitine	625 mg/boar/day supplementation	Improved morphology in Piétrain	[61]
Collection
Collection frequency	Twice a day during 4 days compared to once every 2 days	Reduced motility and morphology	[9]
Collection pen	Pen allowing sexual stimulus	higher sperm counts	[63]

ISSN: 2055-5660