Blood metabolites and fecal starch as indicators of feed efficiency of beef cattle in the feedlot

A Fornazari Neto,C.E.N Martins,E Schwegler,J.O.J Barcellos,A.L Barth

doi:10.1590/1678-4162-12360

Abstract

ABSTRACT The use of blood metabolites (BM), fecal starch (FS), and apparent digestion of starch, (ATTSD) as indicators of feed efficiency (FE) in beef cattle in the feedlot was studied. Fourteen bulls were used, originating in an industrial cross, without a defined racial group, with mean body weight of 284.86kg, individually fed, being evaluated in a 42-day confinement system. After the evaluation, the animals were divided into two groups according to the individual FE: high feed efficiency (HE) and low feed efficiency (LE). There was a difference between the groups in the variables FE, feed conversion (FC), final weight (FW), and daily weight gain (DWG). The FE had a positive correlation with DWG, FC, and FW. There was no difference between the groups for the variables BM, FS, and ATTSD, nor was there any correlation between these variables and FE. Considering the feed cost, the HE animals proved more profitable. BM, FS, and ATTSD did not statistically show potential to be used as indicators of FE, despite the evidence of numerical differences of these variables between the different groups, tendency of correlations with FE, and discriminating function with potential assertiveness.

Highlights

The termination of beef cattle in a confinement system is a reality implanted in the world's major players of meat production
This study aimed to verify the possibility of using blood metabolites levels (BM), the rate of digestion of starch in the total digestive tract (ATTSD) and starch excreted in feces - fecal starch (FS) as indicators of Feed efficiency (FE) in beef cattle in the feedlot
The sorting diagram (Figure 1) presents the result of the analysis of the main components, where we observe the distribution of the high feed efficiency (HE) and low feed efficiency (LE) animals on the chart, showing that there is a tendency to separate animals from different FE (HE, left side and LE, right side)

Summary

Introduction

The termination of beef cattle in a confinement system is a reality implanted in the world's major players of meat production. These farms work with the objectives of producing quality meat and maximizing profitability. The higher costs are related to energy sources, such as cereals in the form of silages and. Concentrates, the main sources of this nutrient, basically in the form of starch. The difference in the metabolization of nutrients in biologically different animals concerning FE may have modifications in blood metabolites levels (BM) (Richardson et al, 2000; Montanholi, 2006; Santana et al, 2014)

Objectives

Methods

Results