Time of feeding orchestrates circadian post-feeding intake patterns in dairy cows

摘要

The objective was to determine effects of feed presentation time and dietary forage to concentrate ratio on circadian and postprandial patterns of feed intake in lactating cows. Four multiparous [body weight (BW) = 652 +/- 14kg, body condition score (BCS) = 2.87 +/- 0.14, days in milk = 83 +/- 22] and four primiparous [BW = 667 +/- 110kg, BCS = 3.19 +/- 0.66, 81 +/- 23 days in milk; mean +/- SD] Holstein cows were used in a 4x4 Latin square design with a 2x2 factorial arrangement of treatments. A higher (HC, forage to concentrate ratio = 38.5:61.5) or a lower (LC, forage to concentrate ratio = 50.6:49.4) concentrate total mixed ration (TMR) was delivered at either 2100h or 0900h. The study consisted of four 21d periods, each with 14d of adaptation. A metabolic acquisition system was used to monitor continuous feed intake electronically. Feed presentation at 2100h vs. 0900h increased the amount of feed consumed within 3h post-feeding, from 26 to 37% of total daily intake. Dry matter intake (DMI) over the 24h remained similar. Provision of TMR at 2100h vs. 0900h increased DMI in primiparous cows but not in multiparous cows. Results establish that evening compared to morning feed presentation increased eating rate and feed intake shortly post-feeding. Time of feeding, thus, is a determinant of postprandial circadian intake patterns in lactating dairy cows