title: Assessment of development of the testes and accessory glands by ultrasonography in bull calves and associated endocrine changes.
abstract: The testes, prostate and vesicular glands of 10 bull calves were examined by ultrasonography every 2 wk from 2 to 46 wk of age, at which time the scrotal circumference (SC) of all the calves had reached pubertal size (28 cms). Computer-assisted image intensity analysis (numerical pixel values) was conducted. Blood samples were collected every other week from 2 to 46 wk of age. Testicular diameter increased in a linear manner from 2 to 46 wk of age, but the diameter measured in a transverse plane (caudal) was greater between 10 and 34 wk of age than when measured in a longitudinal (lateral) plane (P<0.05). Growth of the prostate and vesicular glands, based on dimensions, was linear, but vesicular gland length increased more rapidly after 32 wk of age (P<0.05). Image intensity of the vesicular glands and prostate declined from birth or 8 wk of age, respectively, to 14 wk of age, increased to 18 wk and then declined to a nadir at 30 wk, followed by a rapid increase to 34 wk of age for the vesicular glands and to 46 wk of age for the prostate (P<0.05). Image intensity of the testes showed an early increase to 6 to 8 wk of age and a subsequent increase from about 20 wk of age to 46 wk of age, with an inflection at 30 wk of age (P<0.05). There was a transient increase in mean serum concentrations of LH between 6 and 20 wk of age (P<0.05), and LH concentrations appeared to increase again after 36 wk of age (P>0.05). Mean serum concentrations of FSH declined with age (P<0.05). Mean serum concentrations of testosterone increased after 32 wk of age (P<0.05) In summary, numerical pixel values comprising the ultrasound images of the developing testes, prostate and vesicular glands revealed a complex development pattern that may reflect important details of developmental stages.
authors.affiliation: Department of Veterinary Physiological Sciences, University of Saskatchewan, Saskatoon, SK, Canada.
authors.forename: R K
authors.initials: RK
authors.lastname: Chandolia
authors.forename: A
authors.initials: A
authors.lastname: Honaramooz
authors.forename: B C
authors.initials: BC
authors.lastname: Omeke
authors.forename: R
authors.initials: R
authors.lastname: Pierson
authors.forename: A P
authors.initials: AP
authors.lastname: Beard
authors.forename: N C
authors.initials: NC
authors.lastname: Rawlings