Effects of the timing of protein infusion on the daily rhythms of milk synthesis and plasma hormones and metabolites in dairy cows

• DOI: 10.3168/jds.2022-22633
• Publication Date: 2023-06-01T10:30:26Z
• Authors: Isaac J. Salfer; Cesar I. Matamoros; P.A. Bartell; Kevin J. Harvatine
• Keywords: Latin square; Entrainment (biomusicology)

Milk synthesis exhibits a daily rhythm that is modified by the timing of feed intake. However, it unknown how specific nutrients entrain this rhythm. Amino acids have an important role in milk synthesis, and may entrainment mammary circadian rhythms. The objective study was to determine effects intestinally absorbed protein on rhythms component key plasma hormones metabolites. Nine lactating Holstein cows were assigned 1 3 treatment sequences × Latin square. Treatments included abomasal infusions 500 g/d sodium caseinate either continuously throughout day (CON), for 8 h/d from 0900 1700 h (DAY), or 2100 0500 (NGT). Cows milked every 6 during final d each period. A 24-h fit data using cosine analysis amplitude acrophase determined. Night infusion decreased yield 8.2% 9.2%, respectively. fat increased 5.5% DAY concentration 8.8% NGT. exhibited all treatments, with NGT increasing 33% compared CON. CON NGT, but not DAY, whereas Moreover, abolished glucose concentration, induced insulin nonesterified fatty acid concentrations. Results suggest feeding levels early part increase modify energy metabolism through variation insulin-stimulated lipid release, additional research focused multiple diets across required.