The Study On Measurement Of Herbage Intake Of Cashmere Goats In Pasture By N-alkanes

In natural pasture, under the condition of grazing, using control release device (CRC) of n-alkanes as maker, 4 freely grazing cashmere goats were used to estimate herbage intake in Baicheng, Jilin Province. By experiments of both in summer and autumn, of capacity of pasture for the goats, herbage yield, body weight of the experimental goats and effects of seasons on changes of intake were studied. In addition, results of nutrient ingredients and analyses of n-alkane were compared by means of frozen and warm drying of samples. Conditions of measurement of gas chromatograph of n-alkanes were optimized. The results showed that using C31 as internal maker and CRC as external maker to estimate herbage intake of cashmere goats in pasture was scientific and reliable. Recovery rate of C31 and C36 was 0.872 0.0125 and 0.95, respectively.There were different influences on herbage intake of cashmere goats in different seasons in pasture. Intake of the goats was bigger in autumn than in summer. The OM intake of the goats was 0.6449kg/d, amounting to 0.9499kg DM/d in summer; In autumn , however, the OM intake of the goats was 0.7382kg/d, amounting to 1.2328kg DM/d. The differences of intake were reflected on changes of body weight of the goats: average gain of the goats within 20 days was 0.65kg in summer, and 0.85kg in autumn. The gain of latter was obviously higher than former. These results are valuable to be reference of hybridization and fattening in cashmere goats, there were different influences on herbage intake of cashmere goats in different method .It is good method to estimate intake of cashmere goat by using alkanes C31 and C36 as markers.Measurement results of nutrient ingredients were affected by different drying methods. Average content of OM of frozen and warm drying samples was 87.0213 and 80.1925 (P<0.05), respectively; Content of EE was 5.5503 and 408522 (P<0.01), respectively; Content of NDF was 54.3772 and 51.5859 (P<0.01); Content of ADF was 29.7616 and 29.2194(P<0.05), respectively; Contents of CF, DF and energy were no significant differences between frozen and warm drying samples.Two drying methods affected measurement results of n-alkanes. By frozen drying (-50 C), content of C31, C32 and C36 in samples was 268.29, 122.49 and 148.70 mg/kg OM, respectively; By warm drying, however, content of C31, C32 and C36 in samples was 88.56, 43.94 and 35.71 mg/kg OM, respectively. The differences were significant (P<0.01). It is suggested that it is better to utilize frozen drying method than warm drying method.The study could be reverences to pasture management, furthermore it provide base data for feeding cashmere goats.