The effect of physiological state (lactating or dry) and sward surface height on grazing behaviour and intake by dairy cows

摘要: Abstract The effect of physiological state lactating vs. non-lactating (dry) on grazing behaviour and herbage intake by Holstein-Friesian cows was examined grass pastures maintained at 5, 7 or 9 cm sward surface height (SSH), typical those provided under continuous variable stocking management. Intake rates were estimated over periods 1 h weighing the animals before after grazing, retaining faeces urine excreted, applying a correction for insensible weight loss. Grazing during these 24 recorded automatically using sensors to measure jaw movements. Bite mass (BM) did not differ significantly between dry but decreased ( P −1 as overall mean SSH from 5 cm. An increase =0.040) in movement (GJM) rate, 75.3 80.3 GJM min , decreased, compensate reductions bite mass, rate declined linearly =0.006) 24.6 18.9 g OM . Lactating compensated reduction increasing total time number bites per day. As cm, increased eating (528 607 419 510 min), (40 400 49 300 31 300 40 600 GJM) (31 100 37 900 24 600 31 200 bites, respectively). result, there no significant daily OM, although had greater intakes than cows; 12.9 9.3 kg day =0.060), allowing them 120 160 more idling (i.e., non-grazing, non-ruminating) =0.001).