Studies On The Feed Balance Of Typical Farmers In Alpine Meadow At Eastern Margin Of Qinghai Tibet Plateau

In this study, pasture and the Oula Tibetan sheep of two typical farmers were used as the experimental materials. Following studies, including the dynamic of aboveground biomass and nutrition of mixture forage and dominant species on alpine pasture and swamp meadow, development rule and production performance of Oula tibetan sheep, and the relationship between pasture supply and livestock demand at typical households on eastern margin of the Tibetan Plateau for two typical farmers, were carried out in 2013 and 2014 Main results were as follows,(1) The aboveground biomass of alpine meadow and swamp meadow increased from March to August, and decreased from September to the following March. The main growth period for pasture was from June to August, the lowest biomass was in March, and the highest biomass was in August. The dry matter content(DM), acid detergent fiber(ADF), and neutral detergent fiber(NDF) of mixed forages decreased from March to July or August and increased from that time to October. But the results were opposite for Crude protein(CP), ether extract(EE), and dry matter digestibility(DMD). The biomass and the quality of pasture could completely meet the demand of domestic animals from June to August.(2) The contents of CP, ADF, and DMD in Kobresia were the highest, the lowest, and the medium, respectively compared with other species on alpine meadow, and the contents of CP, ADF, and DMD in Carex were relatively higher, lower and higher, respectively, which could be regarded as obvious advantages. On the whole, the content of DM, ADF and NDF of the dominant forages during the experimental period decreased from May to June or July, and then increased from that time to October. The content of crude ash showed no obvious change during the whole experimental period.(3) The early growth and development rate of Oula Tibetan sheep was changed with the change of the age and the seasons. From birth to 6 months, it was the main stage to gain weight, and the fastest rate of gaining weight was 2 to 4 months of age, and the body weight decreased significantly from 8 to 12 months, which showed that Oula Tibetan sheep was suitable for production of lamb meat. The period from birth to 6 months of age was also the main stage for body development, and the body development has been completed when they were 6 months age. They have reached the requirements of slaughtering. There were no significant differences between the male and the female in the early stage of growth and development, and there was no obvious regularity between the changes of various body condition indexes in the later stage of growth and development. Because of the rapid growth and development of Oula Tibetan sheep at early stage, lambs in this year should be harvested or use supplementary feeding, before the coming withering period on the basis of maintaining the quantity and quality of replacement ewes.(4) There were significant differences for the body weight and body size among different months, ages and gender on two types of pastures from 2 tooth-old to 8 tooth-old. Live weight and body size indexes increased from March to September 2013, and from September 2013 to March 2014, Liveweight and chest circumference decreased, the growth of other indicators slowed down, or even stoped. Main period of growth was from July to September. The liveweight and other body size of the ram were higher than that of the ewe on two types of pasture. Liveweight and body size among different ages of sheep were significantly different, in late September the weight peaked, and the mean value was 73.20-75.80 kg, after then the weight began to decline. According to these, it could be more accurate to determine the time of sale or slaughter at this period.(5) The metabolizable energy(ME) carrying capacity was higher than population carrying capacity on summer pastures. The nutrients were adequate on summer-autumn pastures and the biomass became the limiting factor, so the estimation of carrying capacity in warm season should be based on the quantity of edible forages. The temporal and spatial variations between energy supply and demand could lead to grassland degradation, which could resulted in a vicious cycle of livestock production, and the current imbalance between forage and livestock may be improved by postponing the lambing time.