Restricting time at pasture: effects on dairy cow herbage intake, foraging behavior, hunger-related hormones, and metabolite concentration during the first grazing session.

摘要: This study investigated the effect of restricting grazing time on circulating concentrations ghrelin, nonesterified fatty acids (NEFA), and glucose before, foraging behavior dairy cows during, first session day (GS, 0800-1200 h). Forty-eight Holstein-Friesian (470 ± 47 kg BW; 35 9 d in milk) were strip-grazed a perennial ryegrass pasture for either 4 h after each milking (2 x 4), 8 between milkings (1 8), or 24-h period excluding times (CTL). Cows bled before GS; plasma was analyzed ghrelin serum NEFA. Herbage mass measured pregrazing (0730 h), during at end GS (1200 postgrazing (24 measurement). data fitted to model estimate herbage disappearance rates. intake bite calculated using behavioral measurements. Bite rate, eating, searching, ruminating, idling determined cow. No difference concentration found treatments. Concentrations NEFA greatest 1 treatment. Daily did not differ treatments; however, had greater than 2 CTL. differed treatments throughout GS. smallest CTL 60 min last 90 min, when treatment mass. spent longest eating least searching ruminating. Eating Searching only second it lowest 8. from all ruminate 120 min. rumination The represent dynamics presented differences fractional rate. There an interaction depletion results this present fuller picture its potential relationship with physiological markers hunger as affected by management.