Feeding Strategies to Increase Nitrogen Retention and Improve Rumen Fermentation and Rumen Microbial Population in Beef Steers Fed with Tropical Forages

Sandra Guisela Durango,Diana Bolívar,Ngonidzashe Chirinda,Rolando Barahona,Jacobo Arango

doi:10.3390/su131810312

Abstract

The effect of the inclusion of Leucaena leucocephala and Tithonia diversifolia in Zebu steers receiving a diet based on improved pastures such as Brachiaria decumbens and Brachiaria hybrid cv Cayman on nitrogen (N) excretion, urinary volume and rumen microbial population was evaluated. To determine the dry matter intake and nutrient excretion, eight steers were used in a 4 × 4 Latin square design consisting of four periods and four diets. Four of them were cannulated for ruminal fluid extraction and quantification of ruminal microorganisms in three times of grazing (T0, T7 and T15). Forage intake was calculated through the external marker titanium dioxide. Diet including forages with superior protein content generated an increase in the gene copy numbers of Prevotella ruminicola and total bacteria on 15 sampling day (p < 0.001). Animals receiving diets with the dietary inclusion of Leucaena and Tithonia had daily N intakes of 228 and 113.5g N intake d−1, of which they excreted 42% and 61%, respectively. Inclusion of both protein forages increased daily urinary volume (9% and 7% d−1), with respect to the pasture-based diet. This study revealed that the inclusion of 18% Leucaena in a pasture-based diet improves the dry matter intake and N retention in Zebu steers under tropical conditions.

Highlights

Published: 15 September 2021Improving productivity is a challenge for the entire agricultural sector, including livestock production, since the growth of the world’s population requires meeting the growing demand for more food with fewer resources
The inclusion of L. leucocephala and T. diversifolia in pasture-based diets increased the total dry matter intake (p < 0.0001), and the silvopastoral system resulted in being the diet with the highest dry matter intake from the evaluated treatments
Nitrogen intake by steers on diet B. decumbens based increased when T. diversifolia was included in the diet, but there was no difference when steers were fed with Cayman in monoculture

Summary

Introduction

Improving productivity is a challenge for the entire agricultural sector, including livestock production, since the growth of the world’s population requires meeting the growing demand for more food with fewer resources. It has all the potential to constitute a sustainable productive system, since its inception cattle production has developed as a productive activity based on grass monocultures, commonly offering diets characterized by high-fiber and low crude protein (CP) contents, in the tropical region [2]. A low-protein diet reduces the efficiency of the productive system, since it can be unfavorable for microbial growth, ruminal digestion, availability of nitrogen (N) and carbohydrates by the animals [3]. A deficit of metabolizable energy and the low CP content of the diets usually consumed by livestock generate losses of N and excretion of nutrients that lead to great economic and environmental costs.

Objectives

Methods

Results

Discussion

Conclusion