The timing of feed intake can alter circadian rhythms of peripheral tissues. Milk synthesis displays a daily rhythm across several species, but the effect of feeding time on these rhythms is poorly characterised. The objective of this experiment was to determine if the time of feed intake modifies the daily patterns of milk synthesis, plasma metabolites and body temperature in dairy cows. Sixteen lactating Holstein dairy cows were randomly assigned to one of the two treatment sequences in a cross-over design with 17 d periods. Treatments included day-restricted feeding (DRF; feed available from 07.00 to 23.00 hours) and night-restricted feeding (NRF; feed available from 19.00 to 11.00 hours). Cows were milked every 6 h on the last 7 d of each period, and blood samples were collected to represent every 4 h over the day. Peak milk yield was shifted from morning in DRF to evening in NRF, while milk fat, protein and lactose concentration peaked in the evening in DRF and the morning in NRF. Plasma glucose, insulin, NEFA and urea nitrogen concentration fit daily rhythms in all treatments. Night feeding increased the amplitude of glucose, insulin and NEFA rhythms and shifted the daily rhythms by 8 to 12 h (P < 0·05). Night feeding also phase-delayed the rhythm of core body temperature and DRF increased its amplitude. Altering the time of feed availability shifts the daily rhythms of milk synthesis and plasma hormone and metabolite concentrations and body temperature, suggesting that these rhythms may be entrained by food intake.
Bibliographical noteFunding Information:
This research was supported in part by US Department of Agriculture (USDA) Agriculture and Food Research Initiative Competitive Grant no. 2015-67015-23358 from the USDA National Institute of Food and Agriculture (principal investigator K. J. H.), National Institutes of Health Training Grant no. GM108563 (I. J. S.), and Penn State University including USDA National Institute of Food and Agriculture Federal Appropriations under Project number PEN04539 and accession number 1000803.
© 2020 The Authors.
- Circadian rhythms
- Daily rhythm
- Food entrainment
- Milk synthesis
PubMed: MeSH publication types
- Journal Article
- Randomized Controlled Trial, Veterinary
- Research Support, N.I.H., Extramural
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.