Grazing Management Effects On Intaking Behaviour And Body Weight Of Tibetan Sheep

The Alpine Meadow-Tibetan sheep grazing system is one of the most advantage agricultural systems in Qinghai-Tibetan Plateau, the grazing behaviour is one of the most important indicator which can reflect grazing management. Thus, we investigated the effects of grazing system(rotational grazing and continuous grazing), grazing season(summer and winter) and stocking rate(24 and 48 sheep month/ha) on intaking behaviour and body weight gain of Tibetan sheep in Alpine Meadow of Maqu, Gansu province, at the convergence of Qinghai, Xizang and Sichuan. To study the adjusting mechanism of grazing management on grazing of Tibetan sheep’s intaking behaviour can provide theoretical basis for improving productivity of Tibetan sheep and achieving sustainable grazing of Alpine Meadow.Our results show as following:(1) In the summer rotation grazing system, The sheep with 48 sheep month/ha(SM/ha)had a higher daily grazing time and number of bites/min, but a lower daily ruminating time and intervals in boluses when compared to the sheep under 24 SM/ha(P < 0.05); In the winter rotation grazing system, daily grazing time, number of bites/min and number of chewing per bolus under 48 SM/ha were significantly higher than 24 SM/ha(P < 0.05), but the daily ruminating time and walking velocity while eating under 24 SM/ha were higher than 48 SM/ha(P < 0.05). For both seasons, the number of bites/min and number of chewing per bolus in continuous grazing system were significantly higher than rotational grazing system(P < 0.05).(2) In summer rotation grazing system, the average daily gain(ADG) per head, metabolic energy(ME) intake and dry matter(DM) intake under24 SM/ha were significantly higher than 48 SM/ha, whereas ADG per ha and feed conversion efficiency were lower(P < 0.05). In winter of rotational grazing system, ADG per head in 24 SM/ha was significant higher than 48 SM/ha(P < 0.01). The sheep under 24 SM/ha had a significantly higher ME intake and DM intake, but a lower feed conversion efficiency than the sheep under 48 SM/ha. For both seasons, there was no significant difference between continuous grazing system and rotational grazing system(SC24 vs. SR24) in terms of ADG per head and ADG per ha.(3) In summer, the energy cost of eating, faeces, CH4 and maintenance were lower than winter significantly(P < 0.001), while the energy cost of walking and urine were higher than winter(P < 0.001).(4) Foraging rate and ratio of intaking time to ruminating time affect the relative growth rate of Tibetan sheep, directly(P< 0.01). Different season had an impact on the relative growth rate of Tibetan sheep by crude protein(P<0.05), neutral detergent fibre-relative(P< 0.01), acid detergent fibre-relative(P<0.01) and foraging rate, indirectly.