放牧家畜采食量估测方法研究进展

Study progress on the estimation of intake ingrazing livestock

摘要:

放牧家畜采食量是评价草地生态系统转化效率和动物生产力的主要参数，受草地植被生长情况、环境条件、放牧方式、家畜生理特征及其瘤胃内环境等因素影响。放牧家畜采食量的准确测定一直以来都是食性研究的难点和热点问题，关系到动物营养状态的评估、补饲策略的制定以及食性理论的探索。传统采食量估测方法大多基于观察法或放牧前后牧草生物量差值法，这些方法对动物的干扰较小，但是受技术本身和适用范围的限制，如未能估测单个动物的采食量，很难适用于大范围的采食量估测。链烷烃技术和近红外技术的出现为准确测定采食量提供了前所未有的机遇，不仅能克服传统测定方法的缺点，还在准确率、适用范围（圈养动物和放牧动物）等方面优势较为明显，但由于粪便回收率和数据库完整性等因素的影响，目前应用于生物多样性较高草地的放牧动物采食量估测尚有难度。在简要总结不同方法的原理和影响因素基础上，综述了差值法、内标法、链烷烃法和近红外法在放牧家畜采食量测定方面取得的最新进展及存在的问题，并建议多种方法结合可以准确测定放牧家畜采食量，以期为制定合理的草地生态系统管理策略和实现草地可持续生态服务功能提供新思路和启发。

Abstract:

The intake of grazing livestock is the vital parameter to evaluate the conversion efficiency and produc-tivity of grassland ecosystem， and is affected by plant growth， environmental condition， grazing management， physi-ological characteristics of livestock and its rumen environment. Accurate determination of intake is always difficult forresearchers， which is related to the assessment of animal nutrition status， formulation of supplementary feeding strat-egy and the exploration of diet theory. Traditional quantification method for intake is based on direct observation orthe biomass difference between pre - and post - grazing of grazing animals. These methods have well - known limita-tions. It could not estimate the intake of individual animal and is not suited for widely intake estimation. n -Alkaneand near infrared spectrum（NIRS） methods outperforms these traditional methods in many respects （e. g. ， accuracyor application condition）. However， to date few studies have attempted to analysis intake of grazing animals by n-Al-kane and near infrared spectrum （NIRS） methods because of incomplete feces recovery and inaccurate database. Thereview illustrates and compares the principle of various methods， including different value， internal marker，n-alkane，near infrared spectroscopy and their recent process. It is also suggested that the combination of several methods couldbe used for the estimation of intake in grazing livestock. The review could provide new information and novel meth-ods to formulate reasonable management strategies of grassland ecosystem and realize the sustainable grassland eco-system function.