title: Plasma cortisol and prolactin secretion rhythms in cattle under varying external environments and management techniques.
abstract: The secretion rhythms of plasma cortisol (CORT) and prolactin (PRL), hormones related to stress responsiveness and biological rhythm and controlled by light and temperature, were investigated under varying external environments and different management techniques. Serial blood samples were collected from female cattle reared in free-stall and freely fed (FF) conditions (n = 4) or in tie-stall and restricted feeding (RF) conditions (hay and concentrate twice daily, n = 4). Plasma CORT and PRL concentrations, eating behavior, and environmental parameters were analyzed. Cyclic patterns for each parameter were examined using spectral analysis, and correlations between CORT, PRL and other parameters were investigated using cross-spectral analysis. Under FF conditions, CORT secretion was not related to the lighting intensity and eating behavior. However, under RF conditions, the CORT secretion rhythm showed a distinct correlation with lighting intensity and eating behavior. Under FF conditions, the PRL secretion rhythm was similar in all seasons. However, under RF conditions, the PRL rhythm oscillated with high frequency in summer and low frequency in winter, indicating a seasonal change in rhythm. The present study demonstrates that hormone secretion rhythms change under different environments and management techniques.
authors.affiliation: School of Veterinary Medicine, Kitasato University, Towada, Aomori, Japan.
authors.forename: Mizuna
authors.initials: M
authors.lastname: Ogino
authors.forename: Akihiro
authors.initials: A
authors.lastname: Matsuura
authors.forename: Atusi
authors.initials: A
authors.lastname: Yamazaki
authors.forename: Mami
authors.initials: M
authors.lastname: Irimajiri
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Shiro
authors.initials: S
authors.lastname: Kushibiki
authors.forename: Hroyuki
authors.initials: H
authors.lastname: Singu
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kasuya
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Koichi
authors.initials: K
authors.lastname: Hodate
mesh_terms: D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D002417:Cattle / Q000502:physiology* / Q000523:psychology*; D002940:Circadian Rhythm / Q000502:physiology*; D004777:Environment; D005247:Feeding Behavior / Q000502:physiology / Q000523:psychology; D005260:Female; D006854:Hydrocortisone / Q000097:blood* / Q000378:metabolism*; D008027:Light; D011388:Prolactin / Q000097:blood* / Q000378:metabolism*; D012621:Seasons; D013315:Stress, Psychological / Q000097:blood* / Q000503:physiopathology*; D013696:Temperature
chemical_list: D011388:Prolactin; D006854:Hydrocortisone
keywords: biological rhythms; cattle; cortisol; prolactin; spectral analysis