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Effect of selection for size of testes in boars on semen traits and time to collect their semen
Abstract
Ten generations of selection for increased size of testes in boars were practiced in one line of pigs (TS) and random selection in another line (C). Twenty-five TS and 18 C boars were used. Semen was collected from boars beginning at approximately 8 mo at 3 times per wk for 3 wk followed by daily collection for 3 wk. Then semen was collected once per wk for 5 wk followed by the sequence of 3 collections per wk for 3 wk and daily collection for 3 wk. Time to mount the collection dummy (MTIM) and time to complete the collection (JTIM) were recorded. Total semen volume (TVOL), volume of the sperm-rich fraction (SVOL), percent motile sperm cells (MOTI), percent abnormal sperm cells (ABNO), concentration of sperm cells (SCON), total number of sperm cells per collection (TOTS), estradiol concentration in seminal plasma (E2CO), and total estradiol content per collection (TOE2) were measured in semen. Boars were slaughtered and testes were recovered and weight and daily sperm production were measured. TS boars had greater trimmed testis weight (73.0 g), epididymal weight (18.4 g), tunica weight (8.3 g), parenchymal weight (62.9 g), total testicular sperm (18.7 billion), daily sperm production (4.3 billion), and total sperm reserves (37.3 billion) than C boars (P $<$.01). Although not significant, at three collections per week, TS boars had 11.3 ml less TVOL and 5.7 ml less SVOL than C boars, but C boars took longer to complete the ejaculation (JTIM) (1.4 min, P $<$.01). The SCON was greater (35.0 million/ml, P $<$.01) for TS boars and their TOTS averaged 6.1 billion cells more (P $<$.01). The E2CO was 76.0 pg/ml greater (P $<$.05) and the TOE2 was 12.5 ng greater (P $<$.05) for TS boars. The MOTI was greater and the ABNO was less for TS boars, but differences were not significant. At the daily collection period, TS boars had 6.2 ml less TVOL and 0.3 ml less SVOL than C boars, differences were not significant, but C boars took longer to complete the ejaculation (JTIM) (1.2 min, P $<$.01). The SCON was again greater (29.6 million/ml, P $<$.01) for TS boars so their TOTS averaged 4.3 billion cells more (P $<$.01). The E2CO was greater (92.4 pg/ml, P $<$.05) and the TOE2 was greater (14.0 ng, P $<$.01) for TS boars. The MOTI was greater and the ABNO was less for TS boars, but differences were not significant. Boars with larger testes produced greater total numbers of spermatozoa and would have greater reproductive capacity for pig producers using artificial insemination.
Subject Area
Livestock
Recommended Citation
Huang, Ying-Tsorn, "Effect of selection for size of testes in boars on semen traits and time to collect their semen" (1994). ETD collection for University of Nebraska-Lincoln. AAI9513716.
https://digitalcommons.unl.edu/dissertations/AAI9513716