放牧家畜采食量和采食成分测定技术评述

A comprehensive review of the estimation technology of feed intake and diet composition in grazing livestock

放牧家畜的采食量是人们了解放牧系统动力学的关键之一。研究已查明,了解了放牧家畜的采食量和采食成分就能明晰家畜的营养状况,预测其生产性能,从而为草地管理决策提供目标,为优化资源利用提供基础数据。然而,估测放牧家畜的采食量及其组分是困难的,也是昂贵的。虽然那些改进的技术和方法有效地增强了人们获取家畜牧食行为数据的能力,但是测定放牧动物的采食量、采食成分和养分消化率一直以来都是营养学研究的挑战,方法众多,却各有利弊。因此,本研究针对目前估测放牧家畜采食量和采食成分的常用方法,如模拟采食法、牧前牧后差额法、酸不溶灰分法、三结合法、植物蜡层指示剂法和近红外光谱技术法,对它们的利弊和准确性进行讨论,并探析未来发展趋向,为今后的研究提供资料。

Forage intake by grazing livestock is one of the keys to understanding forage grazing system dy namics. It is confirmed that understanding the types of plant species selected by the animal and the contri bution of each species to the total intake could give an insight into the nutritional status of the animal and predict their performance, thus providing an objective basis for various management decisions and offering a feasible range management strategy to optimize resource utilization. However, estimating intake and diet composition of free-ranging livestock is difficult and expensive. The advanced technology and the improved methods have significantly improved our ability to collect grazing behavior data, but measurement of feed intake, diet composition and nutrient digestibility in free-ranging animals remains a challenge in nutritional study because of the inherent errors associated with the methods that are used at present. In this review, we discussed the advantages and disadvantages, and more or less accuracy of those main methods （including imitation, pre-and post-grazing teehnique, acid-insoluble ash method, in vitro digestibility in combi nation of intraruminal chromic oxide method, n-alkanes plant cuticular wax markers and near infrared reflectance spectroscopy） and also expounded a growing tendency to evaluate the feed intake and diet composition, consequently to supply information for further studies.