Morphological and structural characteristics of &lt;i&gt;Urochloa decumbens&lt;/i&gt; Stapf. deferred pasture grazed by heifers under two periods of protein-energy supplementation

Pedro Henrique Ferreira Da Silva,Carlos Augusto Brandão De Carvalho,Pedro Malafaia,Robson Leandro Ferreira,Rondineli Pavezzi Barbero,Felipe Zumkeller Garcia

doi:10.4025/actascianimsci.v41i1.44425

Morphological and structural characteristics of <i>Urochloa decumbens</i> Stapf. deferred pasture grazed by heifers under two periods of protein-energy supplementation

Pedro Henrique Ferreira Da Silva, Carlos Augusto Brandão De Carvalho + Show 4 more

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https://doi.org/10.4025/actascianimsci.v41i1.44425

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Abstract

The aim of this study was to evaluate the morphological and structural characteristics of deferred Urochloa decumbens Stapf. ‘Basilisk’ grazed by Nellore heifers under two periods of protein and energy supplementation (PES). The experiment was carried out from Jun 21 to Nov 15, 2016, under a completely randomized design and two PES periods (55 [P55] and 147 [P147] days). Forage mass (FM), leaf blade dry mass (LBDM), stem dry mass (SDM), dead material dry mass (DMDM), canopy height (CH), and forage bulk density (FBD) were evaluated. Data were analyzed by the SAS® PROC MIXED procedure and treatment means were compared with the Student's t test (p < 0.05). LBDM was higher for P147 heifers after 21, 84, and 126 days of grazing, similar to those observed after 63 days, and was higher for P55 heifers at 42, 105, and 147 days of grazing. SDM was lower for P147 heifers after 21, 42, 105, and 126 days, and similar in the other grazing periods. Protein and energy supplementation for heifers over 147 days resulted in a lower stem mass of U. decumbens Stapf. ‘Basilisk’ deferred pastures.

Highlights

Deferment pasture strategies are an efficient method of attenuating the effect of seasonality on forage production in Brazil, and are technically feasible when the regrowth period and grazing intensity of each forage species is considered
Forage plants must have the capacity for high accumulation, and experience a limited reduction in forage quality during the stockpiling period; for this purpose, grazing is not allowed at the end of the rainy season and is used at the beginning or middle of the dry period (Hoffmann et al, 2014)
When seeking greater efficiency in the utilization of the forage from deferred pastures, knowledge on variation in the structure of these pastures and the morphological composition of the forage is essential. This is because changes in canopy height, forage mass, proportions of leaf, stems, and dead material modify the quality of the forage, mainly as a function of the physiological maturity of the plants (Santos et al, 2008)

Summary

Introduction

Deferment pasture strategies are an efficient method of attenuating the effect of seasonality on forage production in Brazil, and are technically feasible when the regrowth period and grazing intensity of each forage species is considered. Urochloa decumbens is one of the most commonly used forage species in Brazil because it presents desirable characteristics, such as adaptation to most Brazilian regions, an herbaceous canopy, and a higher proportion of leaf than stem It presents less of a seasonality effect than grasses of the genus Panicum spp. and Pennisetum spp., which potentiate forage accumulation during the dry period (Santos, Fonseca, Gomes, Balbino, & Magalhães, 2010). When seeking greater efficiency in the utilization of the forage from deferred pastures, knowledge on variation in the structure of these pastures and the morphological composition of the forage is essential This is because changes in canopy height, forage mass, proportions of leaf, stems, and dead material modify the quality of the forage, mainly as a function of the physiological maturity of the plants (Santos et al, 2008)

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