תפריט נגישות
ניגודיות עדינהניגודיות גבוהה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם תפריט נגישותניגודיות עדינהניגודיות גבוההמונוכרוםהדגשת קישוריםחסימת אנימציהפונט קריאסגוראיפוס הגדרות נגישותלהורדת מודול נגישות חינםMugagga Kalyesubula
Theresa M. Casey
Naama Reicher
Chris Sabastian
Yossi Wein
Enav Bar Shira
Nguyen Hoang
Uduak Z. George
Avi Shamay
Karen Plaut
Sameer J. Mabjeesh
Short-day photoperiod (SDPP; 8 h light:16 h dark) during the dry period increases milk production compared with long-day photoperiod (LDPP; 16 h light:8 h dark). We hypothesized that the impact of photoperiod on lactation is mediated by alterations in the circadian system. Twelve Saanen goats were blocked at dry off into SDPP (n = 6) and LDPP (n = 6) treatments and mammary biopsies were taken in the middle of light and dark phases at 3 wk prepartum and 5 wk postpartum. Total RNA was isolated, and the expression of clock genes was analyzed by qPCR. SDPP goats produced more milk than LDPP goats (3.15 ± 0.04 vs. 2.7 ± 0.05 kg/d). In the 24 h period, LDPP goats had a greater body temperature than SDPP goats at 3 wk prepartum (39.6 ± 0.06 vs. 39.3 ± 0.1 °C) and 5 wk postpartum (40.1 ± 0.15 vs. 39.7 ± 0.1 °C). Cosinor analysis revealed that physiological state affected body temperature mesor (P< 0.001), peak (P< 0.01), amplitude (P< 0.05), and phase (P< 0.001). Plasma prolactin was 20, 10, and 17-fold higher in LDPP than in SDPP goats at 3 wk prepartum, 3 wk postpartum and 5 wk postpartum, respectively. Cosinor analysis revealed that photoperiod affected prolactin mesor (P< 0.0001), peak (P< 0.0001), trough (P< 0.001), amplitude (P< 0.01), and the peak to trough ratio (P< 0.01). Mammary expression of a core clock gene, PER1, was affected by the light-dark phase and the photoperiod treatment (P< 0.05). It also exhibited a photoperiod-physiological state interaction. Changes in the circadian rhythms with the onset of lactation and photoperiod manipulation support further studies of their role in the regulation of milk yield.
Mugagga Kalyesubula
Theresa M. Casey
Naama Reicher
Chris Sabastian
Yossi Wein
Enav Bar Shira
Nguyen Hoang
Uduak Z. George
Avi Shamay
Karen Plaut
Sameer J. Mabjeesh
Short-day photoperiod (SDPP; 8 h light:16 h dark) during the dry period increases milk production compared with long-day photoperiod (LDPP; 16 h light:8 h dark). We hypothesized that the impact of photoperiod on lactation is mediated by alterations in the circadian system. Twelve Saanen goats were blocked at dry off into SDPP (n = 6) and LDPP (n = 6) treatments and mammary biopsies were taken in the middle of light and dark phases at 3 wk prepartum and 5 wk postpartum. Total RNA was isolated, and the expression of clock genes was analyzed by qPCR. SDPP goats produced more milk than LDPP goats (3.15 ± 0.04 vs. 2.7 ± 0.05 kg/d). In the 24 h period, LDPP goats had a greater body temperature than SDPP goats at 3 wk prepartum (39.6 ± 0.06 vs. 39.3 ± 0.1 °C) and 5 wk postpartum (40.1 ± 0.15 vs. 39.7 ± 0.1 °C). Cosinor analysis revealed that physiological state affected body temperature mesor (P< 0.001), peak (P< 0.01), amplitude (P< 0.05), and phase (P< 0.001). Plasma prolactin was 20, 10, and 17-fold higher in LDPP than in SDPP goats at 3 wk prepartum, 3 wk postpartum and 5 wk postpartum, respectively. Cosinor analysis revealed that photoperiod affected prolactin mesor (P< 0.0001), peak (P< 0.0001), trough (P< 0.001), amplitude (P< 0.01), and the peak to trough ratio (P< 0.01). Mammary expression of a core clock gene, PER1, was affected by the light-dark phase and the photoperiod treatment (P< 0.05). It also exhibited a photoperiod-physiological state interaction. Changes in the circadian rhythms with the onset of lactation and photoperiod manipulation support further studies of their role in the regulation of milk yield.
