Study on Grazing and Ruminating Behaviour of Yaks over 24 Hours by Iger-recorder in Autumn and Winter Pastures

Observation and recording with IGER-recorder on grazing and ruminating behaviour of yaks that were grazed in autumn and winter pastures was conducted from September to December of 2005 in Sanjiaocheng Sheep Breeding farm.The yaks were kept in autumn pasture over 24 h except for milking.However,the yaks were kept in the pin at night in winter pasture.The results showed that no significant difference was found in grazing and ruminating time between autumn and winter pasture(P0.05).However,the non-biting grazing jaw movement and bite rates were significantly higher in winter pasture than in autumn pasture(P0.05).A higher significant difference was found on bite mass(fresh matter,dry matter,organic matter) in autumn pasture than in winter pasture(P0.05),but no significant difference in insensible weight loss was detected between the 2 pastures(P0.05).Grazing behaviour of yaks was mainly found in the daytime.However,most ruminating behaviour was processed at night.