title: Relationships among scrotal and testicular characteristics, sperm production, and seminal quality in 129 beef bulls.
abstract: Standard breeding soundness examinations plus measurement of scrotal surface temperature (SST), internal/scrotal testicular temperatures, testicular ultrasonographic echotexture, daily sperm production, and epididymal sperm reserves were conducted on 129, 16-month-old crossbred beef bulls. There were significant positive linear correlations between SST and internal scrotal/testicular temperatures, a positive linear regression (P < 0.06) of bottom SST with the incidence of secondary sperm defects, but a negative linear regression (P < 0.01) with the incidence of primary sperm defects. Testicular echotexture had a positive linear regression with daily sperm production (P < 0.002) and testicular tone had a negative linear regression (P < 0.008) with epididymal sperm reserves. Scrotal circumference had a positive linear regression (P < 0.04) with the percentage of progressively motile sperm, a negative linear regression (P < 0.1) with the incidence of primary sperm defects, and a positive linear regression (P < 0.0001) with epididymal sperm reserves. In addition to seminal quality and scrotal circumference, testicular ultrasonographic echotexture has considerable promise for augmenting breeding soundness examinations of bulls.
authors.affiliation: Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta. kastelic@em.agr.ca
authors.forename: J P
authors.initials: JP
authors.lastname: Kastelic
authors.forename: R B
authors.initials: RB
authors.lastname: Cook
authors.forename: R A
authors.initials: RA
authors.lastname: Pierson
authors.forename: G H
authors.initials: GH
authors.lastname: Coulter
mesh_terms: D000818:Animals; D001831:Body Temperature / Q000502:physiology; D001947:Breeding; D002417:Cattle / Q000502:physiology*; D008297:Male; D012044:Regression Analysis; D012611:Scrotum / Q000033:anatomy & histology* / Q000502:physiology; D012661:Semen / Q000502:physiology; D013081:Sperm Motility; D013091:Spermatogenesis; D013094:Spermatozoa; D013737:Testis / Q000000981:diagnostic imaging* / Q000502:physiology; D014463:Ultrasonography