Grazing Seasons and Stocking Rates Affects the Relationship between Herbage Traits of Alpine Meadow and Grazing Behaviors of Tibetan Sheep in the Qinghai–Tibetan Plateau

SIMPLE SUMMARY: The relationship between vegetation and grazing behavior of Tibetan sheep on the Qinghai–Tibetan Plateau (QTP) remains a major concern for pursuing the sustainable grazing management of grassland. Grazing behavior is the daily activity of grazing livestock, which can reflect the growth status of the pasture and the level of grassland health in the local pasture, as well as the nutritional needs of Tibetan sheep. We studied the relationship between the grazing behaviors of Tibetan sheep and the quantity and quality of forage in different seasons and different stocking rates. Our results showed that the grazing behavior of Tibetan sheep was greatly affected by the quantity and nutritional quality of the forage. These results may be helpful for local herders to evaluate the nutritional status of forage and condition of grassland degradation, so that appropriate measures can be taken to protect local pastures in advance. ABSTRACT: Under the combined effect of stocking rate and grazing season, it is very significant to ascertain whether there is a quantitative relationship between plant community characteristics, chemical composition of forage, and grazing behaviors of Tibetan sheep to better utilize native pasture in the northeast region of the Qinghai–Tibetan Plateau (QTP). The two consecutive year observation experiments on Tibetan sheep’s grazing behavior were conducted to evaluate the above-stated relationships between stocking rates of 8 sheep/ha and 16 sheep/ha stocking rates in the both the warm and cold seasons. The results demonstrated that at 8 sheep/ha or in the warm season, due to better forage quality, Tibetan sheep had higher herbage mass, forage crude protein (CP) concentration, CP intake, dry matter intake (DMI), and interval between feed boluses and total number of steps, as well as lower fiber concentration than that at 16 sheep/ha or in the cold season. Diurnal intake rate and walking velocity while intaking increased as both average daylight ambient temperature and relative humidity rose. Using the CP concentration, acid detergent fiber (ADF) concentration, neutral detergent fiber (NDF) concentration, and forage metabolic energy (ME) to predict grazing behavior yielded the best fit equation for Tibetan sheep. For local herdsmen to sustainably use the alpine meadow, 8 sheep/ha in the warm season should be considered as the better grazing condition for preventing grassland degradation.