Seasonal Changes Of Grazing Grassland Nutrition And Feeding Preferences Of Tibetan Cashmere Goats In Nagqu Region

This article selects Nima County in Nagqu Prefecture,Tibet.Studying the seasonal changes in forage nutrition,the feeding preferences of Tibetan cashmere goats,and the estimation of grassland yield and livestock carrying capacity based on the vegetation index from the returning green period,the green-grass period and the grass-withering period in 2017 respectively.In order to control the seasonal dynamic changes of forage grass,formulate a reasonable feeding plan,understand the feeding preferences of Tibetan cashmere goats,and rationally use the grassland resources,so as to accelerate the development of animal husbandry in the county,prevent grassland degradation,and protect the grassland ecological environment.The specific conclusions are as follows:(1)The nutrient content of herbage changes regularly with the seasons.The crude protein content(CP)in pasture and the weight of dry matter(DM)per unit area of pasture have presented a trend of inverted “V” as the season increases.The trend of the pattern has reached the peak in August,and they were 11.25% DM and 29.63 g respectively.The content of crude fat(EE)in pasture was higher in summer and autumn than in winter and spring.The content of crude ash(ASH)in pasture is high from April to August.The content of neutral detergent fiber(NDF)in herbage showed a “V” change,which was the lowest in July(50.92% DM)and relatively high in February and November.The content of acidic detergent fiber(ADF)was higher in winter and spring than in summer and autumn.(2)Tibetan cashmere goats also experienced significant changes with the season when they grazing pasture.In summer to autumn,(Carex moorcroftii Falc.Ex Boott),(Kobresia pygmaea(CB Clarke)CB Clarke),(Kobresia humilis(CA Mey.ex Trautv.)Sergiev)all show as like and love eating;(Stipa purpurea)Change from like eating to eating less,(Potentilla bifurca Linn)and(Anaphalis xylorrhiza Sch.-BiP)from edible and eating less to love eating;(Cirsium souliei),(Leontopodium pusillum)changing from edible to not eating.(3)In the summer and autumn,although Tibetan goats ate more than 40% of their forage species,they accounted for 85% and 39% of the frequency of feeding,and the sum of their coverage was also It reached 62% and 16%,accounting for most of the pasture.Therefore,the cover of pasture greatly affects the feeding of Tibetan cashmere goats,especially in summer.In addition,feeding areas also affect goat feeding.(4)There was a linear relationship and logarithmic linear relationship between the NDVI extracted from the TM remote sensing image of the alpine meadow grassland in Nima County and the fresh grass biomass and biomass respectively.The correlation coefficients were 0.9004 and 0.8927,respectively.The NDVI has no significant difference in estimating fresh grass quantity and estimating biomass.(5)The yield of edible pasture produced in the alpine meadow grassland in Nima County is respectively returning green period(13.70 kg/hm2),the green-grass period(29.11 kg/hm2),and the grass-withering period(10.20 kg/hm2);There are over grazing phenomenon in all seasons,and the over rates are returning green period(75%),the green-grass period(108%),and the grass-withering period(240%).