不同类型藏羊消化率与采食量的比较研究

采食量是放牧家畜生产性能的重要影响因素,在草地生态系统中起重要作用。夏季在甘南夏河分别选取不同生理类群(羔羊、1岁母羊、2岁母羊、3岁母羊、4岁母羊、羯羊和种公羊)的欧拉型、甘加型和乔科型藏羊各4只进行试验。采用二氧化钛指示剂法与粪氮指数法分别测定藏羊排粪量和牧草有机物质消化率,从而计算放牧采食量,并对特征间的相关性进行研究。结果表明:欧拉型、乔科型和甘加型藏羊的平均放牧采食量分别为1031.93、834.59和956.15 g·d^-1,乔科型藏羊放牧采食量显著(P<0.05)小于欧拉型和甘加型藏羊。3个类型藏羊的每kg代谢体重采食量和干物质采食量占体重比差异均不显著(P>0.05)。欧拉型、乔科型和甘加型藏羊对夏河天然草地牧草的平均有机物质消化率分别为50.79%、47.22%和55.58%。欧拉型、乔科型和甘加型藏羊的平均排粪量分别为561.26、484.06和466.74 g·d^-1,其中欧拉型藏羊的排粪量显著高于其他两个类型。试验在高寒地区天然草地研究不同类型藏羊的排粪量、有机物质消化率和放牧采食量,旨在为该地区放牧藏羊的科学饲养与管理提供理论依据。

A comparative study on digestibility and feed intake of Tibetan sheep of different types

Feed intake is an important factor affecting the production performance of grazing livestock and plays an important role in determining outcomes in grassland ecosystems. This research compared groups of 4 sheep of differing age and sex (lamb, 1-, 2-, 3-, and 4-year-old ewes, wethers and stud stock, of Oula, Ganjia and Qiaoke types of Tibetan sheep). For these 21 groups of sheep, the feces output and organic matter digestibility were measured using the TiO₂ inert marker method and fecal nitrogen index method respectively in order to calculate grazing intake. The correlations between the various feed nutritive value, intake and digestibility data were also evaluated. The results showed that the average grazing intake of Oula, Qiaoke and Ganjia Tibetan sheep was 1032, 835 and 956 g·d^-1, respectively. Although the grazing intake of Qiaoke Tibetan sheep was significantly lower than that of Oula and Ganjia types (P<0.05), there was no significant difference among the three Tibetan sheep types in grazing intake per kg metabolic body weight or in the ratio of dry matter intake to body weight (P>0.05). The average organic matter digestibility of the Xiahe pasture when consumed by Oula, Qiaoke and Ganjia types of Tibetan sheep was 51%, 47% and 56%, respectively, and their average feces output was 561, 484 and 467 g·d^-1, respectively, with the difference in excretion of Oula Tibetan sheep being significantly higher than the values for the other two types of Tibetan sheep. The defecation, organic matter digestibility and grazing intake of the different types of Tibetan sheep were studied while grazing natural pasture in an alpine region in order to provide a sound scientific basis for the husbandry and management of Tibetan sheep.