Abstract #M36
Section: ADSA-SAD Original Research POSTER Competition
Session: ADSA-SAD Original Research POSTER Competition
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall A
Session: ADSA-SAD Original Research POSTER Competition
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall A
# M36
Disrupting circadian rhythms during the dry period decreases blood glucose but significantly increases milk production.
G. Wernert*1, A. Suarez-Trujillo1, M. Grott1, J. Johnson2, T. Steckler1, J. Townsend3, K. Plaut1, J. Boerman1, T. Casey1, 1Department of Animal Sciences, Purdue University, West Lafayette, IN, 2USDA-ARS, West Lafayette, IN, 3Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN.
Disrupting circadian rhythms during the dry period decreases blood glucose but significantly increases milk production.
G. Wernert*1, A. Suarez-Trujillo1, M. Grott1, J. Johnson2, T. Steckler1, J. Townsend3, K. Plaut1, J. Boerman1, T. Casey1, 1Department of Animal Sciences, Purdue University, West Lafayette, IN, 2USDA-ARS, West Lafayette, IN, 3Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN.
The circadian timing system (CTS) functions to maintain homeostasis and we hypothesized that disrupting the CTS during the prepartum dry period would affect metabolic homeostasis and decrease milk yield in the subsequent lactation. Our objectives were to determine the effect of disrupting the CTS on: 1) Blood glucose, β-hydroxy butyrate (BHBA) and nonesterified fatty acids (NEFA) in the pre and postpartum, and 2) milk production to 60 d in milk (DIM). Five weeks before expected calving (BEC) multiparous cows (n = 32) were moved to a tie-stall barn and divided into 2 treatments: control (n = 16; 16 h light: 8 h dark) or phase-shifted (PS, n = 16), a chronic jet lag paradigm which shifted the light-dark phase 6 h every 3 d until parturition. All cows were exposed to control lighting after calving. Blood samples were taken at least bi-weekly at 0600 in the pre- and postpartum to measure glucose, BHBA and NEFA, and every 4 h over 48 h at 3 time points: d 23 BEC, d 9 BEC, and 5 d postpartum (PP). NEFA was measured using colorimetric assay; blood glucose and BHBA were measured with Centrivet monitor. Core body temperature was recorded every 30 min vaginally using ibutton data loggers at 23 BEC, 9 BEC, and 5 PP. PS (P < 0.05) shifted phase and attenuated circadian rhythms of core body temperature. Daily feed intake was not different between control (30.5 ± 0.6 kg) and PS (29.8 ± 0.6 kg) cows. Blood glucose was (P < 0.05) decreased in PS cows pre and postpartum, however there was no effect of treatment on BHBA or NEFA concentration. Cosine fit analysis found control cows exhibited circadian rhythms of plasma NEFA only at 5PP (R2 = 0.69; P = 0.002); whereas PS cows lacked circadian rhythms throughout study. Milk yield and fat corrected milk yield were significantly increased (P < 0.05) through 60 DIM in PS (42 ± 0.92 and 43.5 ± 1.04 kg/d) versus control (39.3 ± 0.92 and 40.3 ± 1.04 kg/d) cows. Thus, lack of difference in BHBA, NEFA and feed intake along with decreased blood glucose, supports that disrupting circadian rhythms in late parturition increases milk production efficiency.
