Effects of forages and total mixed rations particle size on physical effectiveness and chewing activity of lactating cows

B Stojanovic,A Bozickovic,G Grubic,N Djordjevic,A Ivetic

doi:10.2298/bah1103935s

Abstract

In study are determined effects of four different mean lengths of corn silage, alfalfa haylage and total mixed ration (TMR) for lactating cows on physical effectiveness (pef), physically effective fiber content (peNDF) and total chewing activity. High correlations were found between mean particle length of forages and TMR and their physical effectiveness in lactating cows nutrition as also with physically effective fiber content. Significant effect of ration particle size on stimulating total chewing activity of lactating cows was determined.

Highlights

Using of NDF as chemical indicator of dietary fiber content, does not indicate on more subtle fibers’ characteristics such as their importance for the kinetic of digestion and digesta passage, regarding to fibers’ physical characteristics
High correlations were found between mean particle length of forages and total mixed ration (TMR) and their physical effectiveness in lactating cows nutrition as with physically effective fiber content
Physical characteristics of rations for lactating cows are influenced by dietary forage to concentrate ratio, type of forages and concentrates, and mean particle size of feeds (Stojanović et al 2009)

Summary

Introduction

Using of NDF as chemical indicator of dietary fiber content, does not indicate on more subtle fibers’ characteristics such as their importance for the kinetic of digestion and digesta passage, regarding to fibers’ physical characteristics. Physical characteristics of fibers affect on animal health, ruminal fermentation and feed conversion efficiency, animal metabolism, milk fat content. Balch (1971) proposed the chewing time per kg of dry matter (DM) as indicator of physical characteristics of forages, which was called index of roughage value. Sudweeks et al (1981) measured required chewing time for forages and concentrate feeds, and developed indexing system where each feed were given appropriate value regarding to ability for stimulating chewing activity. Using of this index for anticipation of milk fat content, indicated on total chewing time required per kg of consumed DM as 21.4, 32.4 and 44.8 min. Mertens (1997) developed a system for physically effectiveness factor (pef) determination used for calculating of feeds’ physically effective fiber –peNDF content

Methods

Results

Conclusion