From: Boar management and semen handling factors affect the quality of boar extended semen
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] |
Organic vs inorganic | Increase concentration, increase oxidative stress, increase PGHX | ||
 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] |