Previous nutrition and entry time to pasture affect weight gain and grazing behaviour in steers

摘要

Sixteen Holstein steers (139 +- 12 kg body weight (BW)) were used in a randomized block, 2 X 2 factorial, 64-d experiment, to assess the effect of previous nutrition (PN) and entry time (ET) to a winter Avena saliva pasture on daily weight gain (DWG)and grazing (G) and ruminating (R) time. Steers were initially fed Lolium perenne and Medicago saliva hay, for 21 d, to gain 8 +- 43 (L; N = 8) or 345 +- 92 (H; N = 8) g BW d~(-1), and then allowed to graze individual paddocks of winter Avena saliva pasture (one-day strip grazing) for 29 d. Entry time to the paddocks was at 8:30 (M; N = 8) or 14:30 (A; N = 8) h. Steers were weighed on days 28 and 64 to estimate DWG. Grazing time and R were estimated over 24 h using IGER behaviour recorders from days 51to 60. Daily weight gain was affected by PN (564 (L) vs. 675 (H) g d~(-1); P = 0.074) and ET (573 (M) vs. 668 (A) g d~(-1); P = 0.077). Entry time altered G (425 (M) vs. 514 (A) min d~(-1); P = 0.012) and PN affected R (438 (H) vs. 520 (L) min d~(-1); P= 0.02).